Navigation Points Research Articles

Turning Point and Free Segments Strategies for Navigation of Wheeled Mobile Robot

The basic idea of the developed work is to solve the problem of mobile robot navigation with obstacle avoidance and the trajectory tracking problem in simple and complex environments. The research contribution aims to develop a strategy of navigation based on the turning point and the free segments algorithms. Indeed, a turning point method is developed in order to solve the problem of navigation in a simple environment. Then, the free segments approach is applied in order to solve the problem of obstacle avoidance in a complex environment. The second part of this paper aims to solve the problem of trajectory tracking. For this reason, a sliding mode controller is proposed as a solution to control the stability of the mobile robot. Finally, some simulation results which are developed using Matlab software are given to prove the validity of the developed work.

Fast and Reliable Vision-Based Navigation for Real Time Kinematic Applications

Abstract: Automatic Image Matching (AIM) is the term used to identify the automatic detection of corresponding points located on the overlapping areas of multiple images. AIM is extensively used with Mobile Mapping System (MMS) for different engineering applications, such as highway infrastructure mapping, monitoring of road surface quality and markings, telecommunication, emergency response, and collecting data for Geographical Information Systems (GIS). Robotics community and Simultaneous Localization And Mapping (SLAM) based applications are other important areas that require fact and welldistributed AIM for robust vision navigation solutions. Different robust feature detection methods are commonly used for AIM, such as Scale Invariant Feature Transform (SIFT), Principal Component Analysis (PCA)–SIFT and Speeded Up Robust Features (SURF). The performance of such techniques have been widely investigated and compared, showing high capability to provide reliable and precise results. However, these techniques are still limited to be used for real and nearly real time SLAM based applications, such as intelligent Robots and low-cost Unmanned Aircraft Vehicles (UAV) based on vision navigation. The main limitations of these AIM techniques are represented in the relatively long processing time and the random distribution of matched points over the common area between images. This paper works on overcoming these two limitations, providing extremely fast AIM with well- distributed common points for robust real time vision navigation. Digital image pyramid, Epipolar line and 2D transformation have been utilized for limiting the size of search windows significantly and determining the rotating angle and scale level of features, reducing the overall processing time considerably. Using limited number of well-distributed common points has also helped to speed up the automatic matching besides providing robust vision navigation solution. The idea has been tested with terrestrial MMS images, and surveying UAV aerial images. The results reflect the high capability of the followed technique in providing fast and robust AIM for real-time SLAM based applications. Keywords: Automatic Image Matching, Epipolar Line, Image Pyramid, SLAM, Vision Navigation, Real Time, Vision Navigation.

"They tell us little and we end up being confused": Parent-child communication on familial experiences of genocide and its aftermath in Rwanda.

In the current study we explore how Rwandan youth negotiate, within the family setting, a myriad of social and interpersonal dilemmas around silence and disclosure of genocide-related experiences of their parents. The study draws primarily on individual interviews and focus group discussions with 20 children of genocide survivor and perpetrator parents in the western and eastern provinces of Rwanda. Using the conceptual framework of social navigation which theorizes agency in a fluid, often unpredictable, and constantly moving social environment, we focus specifically on the difficult and often contradictory complex of factors that drive the communication strategies and tactics of the children as they seek information to understand the past of their parents. This includes the children's urge to get to know the specific stories of their family but fearing the emotional disruption it may cause in the parent-child relationship; the push-pull dynamics of the parents wanting to disclose some experiences but admonishing silence on others; and the often ambiguous divergences between the public and private discourses. Our findings show that the steadiest navigational point guiding communication choices, made by both parents and their offspring, was a desire to contribute to a peaceful social environment, and to reduce the risk of future violence. We present emerging evidence suggesting that community-based sociotherapy, a program that includes healing the social space and not only intrapsychic wounds, may contribute to a steadier navigation of the tricky communication issues, enhancing psychosocial wellbeing.

‘It absolutely needs to move out of that structure’: Māori with bipolar disorder identify structural barriers and propose solutions to reform the New Zealand mental health system

ABSTRACT Objectives This paper synthesises critique from Māori patients with Bipolar Disorder (BD) and their whānau to identify barriers and propose changes to improve the structure and function of the New Zealand mental health system. Design A qualitative Kaupapa Māori Research methodology was used. Twenty-four semi-structured interviews were completed with Māori patients with BD and members of their whānau. Structural, descriptive and pattern coding was completed using an adapted cultural competence framework to organise and analyse the data. Results Three key themes identified the impact of structural features of the New Zealand mental health system on health equity for Māori with BD. Themes involved the accessibility, delivery and scope of the current health system, and described how structural features influenced the quality, utility and availability of BD services for Māori patients and whānau. Structural barriers in the existing design, and potential changes to improve the accessibility, delivery and scope of BD services for Māori, were proposed including a redesign of operational, environmental, staffing, and navigation points (information, transition, fatigue) to better meet the needs of Māori with BD. Conclusion A commitment to equity when implementing structural change is needed, including ongoing evaluation and refinement. This paper provides specific recommendations that should be considered in health service redesign to ensure the New Zealand mental health system meets the needs of Māori patients with BD and their whānau.

A New Multirobot Path Planning With Priority Order Based on the Generalized Voronoi Diagram

This paper proposes a new path planning method called the priority order navigation algorithm (PONA) for multi-robot navigation in a large flat space. The PONA can guarantee collision-free and efficient travel in the space with fixed or/and dynamic obstacles. The priority order of robots is assigned by the user based on the importance degree of the robots’ tasks and the objective is to make the higher priority robot reach its target faster than the lower priority robot. This study uses the generalized Voronoi diagram (GVD) to establish the initial map for PONA and links the navigation points in GVD to plan the path for each robot. Further, we modify the navigation point links to shorten feasible paths for the lower priority robot and its shortest two feasible paths can be switched to each other based on a certain condition to avoid hitting the higher priority robot. The proposed PONA is compared to several benchmark path planning methods, which are the shortest distance algorithm (SDA) and reciprocal orientation algorithm (ROA), in the simulation section and it is found that the PONA can reduce the average length of the trajectory by more than 10% compared with ROA and SDA.

Robust Pose Estimation via Hybrid Point and Twin Line Reprojection for RGB-D Vision Navigation

Pose estimation is a crucial technique to achieve robot localization using natural features for an RGB-D vision navigation system. However, it still suffers from the impoverishment of robustness and accuracy in complex workspaces. A robust real-time pose estimation approach using hybrid point and twin line reprojection is proposed to allow accurate localization for a vision-based robot under various challenging scenarios including low-texture, low-structure, occlusion, and viewpoint and illumination changes. Firstly, an improved adaptive threshold (IAT)-based oriented fast and rotated Brief (ORB) feature detection method is developed to extract sufficient IAT-ORB point features, which are matched by a multi-stage KNN-RTC-CS-RANSAC (KRCR) refinement feature matching strategy to generate reliable point matches. Then a robust EDLines line feature matching method is developed by integrating dynamic matching (DM) and median absolute deviation (MAD) to obtain fine line matches. Furthermore, the hybrid point reprojection errors are built from the fusion of 3D-2D and 3D-3D point pairs, and the twin line reprojection errors are constructed by integrating virtual right-eye lines generated by depth measurement, which both are incorporated into a novel unified errors optimization model to achieve optimal motion estimation by minimizing the reprojection errors of points and lines concurrently. Finally, the extensive experiments verify the robustness, accuracy, and real-time performance of the proposed approach on the public datasets and our real indoor scenarios. The quantitative results demonstrate that our proposed approach gains more accurate and stable localization than other state-of-the-art methods under challenging environments.

IoT based Speed Control for Semi-Autonomous Electric On-Road Cargo Vehicle

The paper develops an investigative GSM enabled IoT based speed control scheme suitable for electric On-Road cargo vehicles. The design involves the bounding of the parameters that include the vehicle speed, motor speed, Truck payload, battery SoC (State of Charge), battery SoH (State of Health), real time navigation points using GPS, tire pressure, motor temperature and current consumption, driver fatigue detection and vehicle proximity detection which enters the system using GSM enabled wireless sensors and IoT based maps for arriving at the recommended speed. It engages a state-of-the-art Microcontroller based embedded system to govern the operation of the three-phase induction motor in accordance with the changes that the vehicle either experiences or becomes necessary for it to negotiate. It incorporates a close monitoring methodology for evolving a sequence of steps that enable the system to remain in operation over scheduled time frames. The results obtained from a simulation process carried out using embedded-c firmware code on ARM Core STM32 micro-controller exemplify the merits and illustrate the performance of the chosen vehicle in terms of its ability to be used in real world systems.

Pacific People Navigating the Sacred Vā to Frame Relational Care: A Conversation between Friends across Space and Time

In many cultures of the Pacific region, the self is relational, inevitably and permanently connected to other people and entities as a fact of existence. Among the articulations of Pacific relationality is the sacred relational space of connection and separation: vā. Differences in relational thinking around vā in the region should be celebrated, but in an increasingly mobile world, Pacific wisdom can also be honored by paying attention to commonalities. In his essay, we offer a dialogue between friends who seek mutual learning across our various fields in relation to the concept of vā: Samoan village life, Tongan leadership in the New Zealand Public Service, and Pacific education. Through an informed and critical conversation across established and emerging social spaces, we hope to provide navigation points for others who value the vā in research and other pursuits.

Utility of deformable image registration for adaptive prostate cancer treatment. Analysis and comparison of two commercially available algorithms

IntroductionThis study aimed to assess and compare the capabilities of two commercially available deformable image registration algorithms implemented in Raystation 9A (A1) and Velocity AI (A2) for possible usage in adaptive prostate radiotherapy based on the propagation of anatomical contours from computed tomography (CT) images to cone-beam CT (CBCT) images. Material and methodsTen patients were retrospectively selected from a group treated for localized prostate cancer. The propagation of rectum contours was analyzed in a set of CT-CBCT pairs. Two independent observers carried out qualitative analysis using the two-level descriptive scale (meet/fail). Quantitative analysis was done using landmark points distances based on implanted markers as navigation points and differently obtained contours (manually and automatically using DIR algorithms). Quantitative analysis was taken on sets preselected by qualitative analysis. ResultsQualitative analysis shows that 83.7% of the rectum contours were scored identically (meet or fail) for both algorithms, from which 53.5% and 55.8% are failed results for A1 and A2, respectively. For the rectum size (RWD parameter), differences between referenced and deformation-based values were 5.5 and 5.8mm, and for the rectum wall, the prostate marker distance (WMD parameter) was 4.5 and 5.5mm for A1 and A2, respectively. The differences between the WMD parameters were statistically significant (p=0.007). ConclusionsIn both tested algorithms, neither effectiveness nor measured uncertainties in the propagation of rectum contour process in prostate patient cases were satisfactory. Careful selection of input images followed by case/set-based verification of every deformable registration is a substantial step to avoid inappropriate results.

Sensitivity of back‐projection algorithm (BPA) synthetic aperture radar (SAR) image formation to initial position, velocity, and attitude navigation errors

The Back-Projection Algorithm (BPA) is a time-domain-matched filtering technique to form synthetic aperture radar (SAR) images. To produce high-quality BPA images, precise navigation data for the radar platform must be known. Errors in position, velocity, or attitude result in improperly formed images that are corrupted by shifting and blurring. The contribution of this paper is the development of analytical expressions that characterise the relationship between navigation errors and image formation errors from an inertial navigation point of view, where trajectory estimation errors in position, velocity, and attitude propagate through time and cause compounding errors in the vehicle state vector. These analytical expressions are verified via simulated image formation and real-data image formation.

The Economic Implications of the Israel-UAE Normalization Agreement in the Red Sea and the Gulf of Aden and the Potential Impacts on the GCC

The new relationship that has emerged between UAE and Israel, after the conclusion of the Abraham agreement, includes common economic orientations between both sides. There is potential cooperation within the navigational routes and strategic points in the Red Sea and the Gulf of Aden and this initial cooperation could open the way for a bilateral economic partnership. This research paper has two main goals: Firstly, to uncover the economic cooperation between Israel and UAE in the Red Sea and the Gulf of Aden by applying a methodology of qualitative case study. Secondly, exposing the repercussions of Israel-UAE economic cooperation on the future role of the Gulf Cooperation Council, specifically in the economic domain and addressing the factors accompanying this cooperation that may raise the level of competition among member states, especially between the UAE, Saudi Arabia and Qatar. By analysing these goals, the paper attempts to examine the possibilities that such economic cooperation between Israel and the UAE may pave the way towards future bilateral or multilateral alliances among different countries within the region.

Internal and external frontier‐based algorithm for autonomous mobile robot exploration in unknown environment

Navigation in the absence of initial environmental information is a situation in which a robot is faced with the difficulty of traversing an unknown area for exploration with obtaining the environmental information simultaneously. Therefore, to complete and optimize the exploration efficiently, the robot needs an autonomous path-planning algorithm. This work proposes a new autonomous path-planning algorithm for exploration in an unknown environment based on paired frontiers, which we call internal and external frontiers algorithm (IEFA), that defines extended area for navigation of the mobile robot. For each exploration round, the robot defines external frontiers using the maximum range of sensors. Then, the robot generates internal frontiers, that is, pairs of external frontiers by varying the range of sensors. According to the size of each pair of frontiers, the algorithm generates the target point for robot navigation. The frontiers of internal layer are utilized as a main parameter for generation of next exploration point. We evaluated the proposed algorithm in simulation environments using the ROS toolbox of MATLAB and compared it with two previous exploration algorithms. From the experimental results, the proposed algorithm showed from 31% to 85% better performance in the path distance than previous algorithms.

The response of common minnows, Phoxinus phoxinus, to visual cues under flowing and static water conditions

While fixed visual cues provide reliable reference points for navigation in static water, it remains unclear whether fish energetically benefit from their presence in flowing water. Furthermore, benefits of visual feedback from fixed sources may be less for group members that can gain additional information from others. Using an open-channel flume, this study investigated how the response of fish to stationary visual stimuli is influenced by flow and group membership under two treatments: vertical black and white stripes placed on (1) both side walls of the channel or (2) one side wall only compared to a control where both walls were uniform white. The responses were compared in flowing and static water, and between individuals and groups of five. Fish exhibited a positive affiliation for the visual cues, travelling more slowly and spending more time closer to the striped walls. Fish were more edge oriented under flowing conditions, presumably utilizing the lower velocities at the wall boundary to reduce energy expenditure. When only one wall presented visual cues, individual fish spent more time associated with it in flowing water, suggesting some energetic benefit in lotic conditions. This may result from a greater ability to maintain station or control position relative to a reference point and/or the use of visual stimuli as a proxy indicator of physical structure which may provide drag-reducing refuge. A lesser association with the striped wall in static water suggests that visual cues provide other nonhydrodynamic benefits, such as physical refuge from predators or opportunities for crypsis. Conversely, less association of shoals with the striped walls may reflect a greater dependence on information provided by conspecifics or increased security associated with being part of a group. This study indicates that fixed visual cues likely provide several benefits that vary depending on flow and group membership.

Emotional labor dynamics as precursors to mundane violence in a Philippine city jail

This paper analyzes narratives on emotional labor among officers working in an overpopulated and undermanned city jail in the Philippines. Taking off from Hochschild (1983) and Crawley (2004) as theoretical departure points and using Sikolohiyang Pilipino as an approach in deploying institutional ethnography, I forward three arguments that enrich the understanding of emotion management dynamics in the carceral setting. First, emotional labor in the city jail is largely based on rank. Rank is a fixed navigation point where officers need to be in their “rightful place” (lugar) in interacting with and expressing emotions to others. Second, leadership regimes in forms of sistema (substandard yet acceptable ways of doing things) or kalakaran (corrupted sistema) also dictate emotion regimes among officers in the facility. And third, narratives of professionalism dominate accounts that normalize, reify, moralize, and even prize emotional laboring. In contrast to existing literature, data suggest that emotion management can be endowing, as it clarifies expectations and harmonizes relationships. Officers, in addition, claim that they are willing to endure emotional labor as it helps them to be more dutiful as a public servant. In fact, officers value emotional labor with a nationalist tone. With strong appreciation for emotional management in the narratives, I end with critical reflections and forwarded interrogations on the danger of moralizing emotional labor and recommend further investigation of its aspects that could lead to mundane violence.

Association of Health Insurance Literacy with Health Care Utilization: a Systematic Review.

BackgroundGiven increasing numbers of people experiencing transitions in health insurance due to declines in employer-sponsored insurance and changes in health policy, the understanding and application of health insurance terms and concepts (health insurance literacy) may be important for navigating use of health care. The study objective was to systematically review evidence on the relationship between health insurance literacy and health care utilization.MethodsMedline, SCOPUS, Web of Science, CINAHL, PsychInfo, Cochrane Library, and reference lists of published literature were searched in August 2019. Quantitative, qualitative, and intervention studies that assessed the association of health insurance literacy as the exposure and health care utilization as the outcome were identified, without language or date restrictions. Outcomes were independently assessed by 2–3 reviewers.ResultsTwenty-one studies including a total of 62,416 subjects met inclusion criteria: three interventional trials, two mixed-methods studies, and sixteen cross-sectional studies. Ten of thirteen preventive care studies suggested that higher health insurance literacy was associated with greater utilization of primary care and other preventive services. Eight of nine studies of care avoidance demonstrated that individuals with lower health insurance literacy were more likely to delay or avoid care. A few studies had mixed results regarding the utilization of emergency department, inpatient, and surgical care.DiscussionThe emerging literature in this area suggests that health insurance literacy is an important factor that can enable effective utilization of health care, including primary care and preventive services. However, the literature is limited by a paucity of studies using validated tools that broadly measure health insurance literacy (rather than testing knowledge of specific covered services). Improving health insurance literacy of the general public and increasing plain language communication of health insurance plan features at the point of health care navigation may encourage more effective and cost-conscious utilization.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11606-021-06819-0.

Prototyp zaawansowanego autopilota okrętowego zaimplementowany w środowisku CPDev

Ship autopilots can be divided into conventional, only capable of maintaining a given course, and advanced, which can additionally follow a “track” connecting the given navigation points along the ship’s route. The article presents the structure of the prototype autopilot of the ship implemented in the CPDev environment and the formulas allowing to determine the settings of the course controller (PID) and track controller (PI) in the cascade control. For each of them, individual design parameters were adopted to define the dynamics of the closed control loop. These rules were applied in the software of the autopilot prototype, created in cooperation with a Dutch company designing control and visualization systems for ships.

Comparison of the accuracies of computed tomography-based navigation and image-free navigation for acetabular cup insertion in total hip arthroplasty in the lateral decubitus position

Image-free navigation has been proven as reliable as that using computed tomography (CT) in positioning the acetabular cup in total hip arthroplasty (THA), but previous studies rarely included hip dysplasia cases. The purpose of the present study was to determine the accuracies of CT-based navigation and image-free navigation for acetabular cup insertion, including hip dysplasia cases. Sixty-three hips were studied, including 57 with hip dysplasia. The hips were divided into two groups based on the registration point of image-free navigation. In Group I, the ipsilateral anterior superior iliac spine (ASIS) and the L5 spinous process were registered in 31 hips. In Group II, bilateral ASIS points were registered in 32 hips. Final component orientation was measured from postoperative CT scans. The accuracy of cup orientation was compared between CT-based and image-free navigation. In Group I, the cup inclination was more accurate with CT-based navigation (1.9°) than with image-free navigation (4.4°, p=.009). Cup anteversion was also more accurate with CT-based navigation (2.9°) than with image-free navigation (7.1°, p<.001). In Group II, the accuracies of cup inclination and anteversion showed no differences between CT-based and image-free navigation. The accuracy of cup positioning was better with CT-based navigation than with image-free navigation when the ipsilateral ASIS and L5 spinous process were digitized. However, accuracy was similar when bilateral ASIS points were digitized.

Social and Robust Navigation for Indoor Robots Based on Object Semantic Grid and Topological Map

For the indoor navigation of service robots, human–robot interaction and adapting to the environment still need to be strengthened, including determining the navigation goal socially, improving the success rate of passing doors, and optimizing the path planning efficiency. This paper proposes an indoor navigation system based on object semantic grid and topological map, to optimize the above problems. First, natural language is used as a human–robot interaction form, from which the target room, object, and spatial relationship can be extracted by using speech recognition and word segmentation. Then, the robot selects the goal point from the target space by object affordance theory. To improve the navigation success rate and safety, we generate auxiliary navigation points on both sides of the door to correct the robot trajectory. Furthermore, based on the topological map and auxiliary navigation points, the global path is segmented into each topological area. The path planning algorithm is carried on respectively in every room, which significantly improves the navigation efficiency. This system has demonstrated to support autonomous navigation based on language interaction and significantly improve the safety, efficiency, and robustness of indoor robot navigation. Our system has been successfully tested in real domestic environments.

On the Norms and Habits of the European Union as a Meta-organisation

With the aim of methodological reflection, this article analyses the three approaches (realist, constructivist and relational) in international relations theory most commonly employed to study foreign policy and the global influence of the European Union. Pivotal notions such as 'agency', 'identity', 'norms', 'system' and 'practice' provide us with navigation points between these approaches, enabling us to achieve a clearer impression of the many different meanings these terms can contain. These meanings, in their turn, fix the direction, limitations and scope of any concrete theoretic analysis. This article is meant to draw particular attention to Bourdieuvian practice theory and Alexander Bogdanov's tektology as two differing variants of relationism, with a view to overcoming certain deficiencies in application to the studies of the EU of methodological individualism, as employed in more 'traditional' theories. To illustrate the relationalist way of theorising when dealing with the paradoxes of the EU external policies and global role, a follow-up interpretation, based on tektology, is given in conclusion to the resilience turn in the EU global strategy.

Navigation path extraction for greenhouse cucumber-picking robots using the prediction-point Hough transform

Accurate extraction of navigation path is very important for automated navigation of agricultural robots. Based on the machine vision system, this paper proposes a new algorithm for the fitting of navigation path of greenhouse cucumber-picking robots. Aiming at the problems that the traditional Hough transform has a large amount of calculation and the least square method has a low precision, the prediction point Hough transform algorithm is proposed to extract the navigation path. The prediction-point Hough transform contains 4 parts: intercept area of interest, image segmentation, navigation point extraction, navigation path fitting. In this paper, only the final 160-pixel rows of image captured by the camera are taken as the region of interest. In the image segmentation stage, this paper proposes a new graying factor. For navigation path extraction, a regression equation is used to determine the prediction point, and finally the proposed prediction point Hough transform is used to fit the navigation path. The experimental results show that the proposed grayscale factor can well segment cucumber plants and soil, and the segmentation effect is better than 2G-B-R and G-B grayscale factors. The proposed prediction point Hough transform fits the navigation paths with an average error less than 0.5°, which is 10.25° lower than the average error of the least-square method. Also, the computation time of the proposed Hough transform is 17.92 ms. Compared with the traditional Hough transform, it saves 35.20 ms.