We show a simple proof of the existence of a path on the "border of water and rocks" based on combinatorial induction procedure and we present an algorithm for computing L, shortest path in "Fjord Scene...
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We show a simple proof of the existence of a path on the "border of water and rocks" based on combinatorial induction procedure and we present an algorithm for computing L, shortest path in "Fjord Scenery". The proposed algorithm is a version of the dijkstra technique adapted to a rectangle map with a square network. A few pre-processing modifications of the algorithm following from the combinatorial procedure are included. The validity of this approach is shown by numerical calculations for an example. (C) 2003 Elsevier B.V. All rights reserved.
This paper proposes a new algorithm for automatic crack detection from 2D pavement images. It strongly relies on the localization of minimal paths within each image, a path being a series of neighboring pixels and its...
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This paper proposes a new algorithm for automatic crack detection from 2D pavement images. It strongly relies on the localization of minimal paths within each image, a path being a series of neighboring pixels and its score being the sum of their intensities. The originality of the approach stems from the proposed way to select a set of minimal paths and the two post-processing steps introduced to improve the quality of the detection. Such an approach is a natural way to take account of both the photometric and geometric characteristics of pavement images. An intensive validation is performed on both synthetic and real images (from five different acquisition systems), with comparisons to five existing methods. The proposed algorithm provides very robust and precise results in a wide range of situations, in a fully unsupervised manner, which is beyond the current state of the art.
Safe lane changing of the dynamic industrial park and port scenarios with autonomous trucks involves the problem of planning an effective and smooth trajectory. To solve this problem, we propose a new trajectory plann...
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Safe lane changing of the dynamic industrial park and port scenarios with autonomous trucks involves the problem of planning an effective and smooth trajectory. To solve this problem, we propose a new trajectory planning method based on the dijkstra algorithm, which combines the dijkstra algorithm with a cost function model and the Bezier curve. The cost function model is established to filter target trajectories to obtain the optimal target trajectory. The third-order Bezier curve is employed to smooth the optimal target trajectory. Road experiments are carried out with an autonomous truck to illustrate the effectiveness and smoothness of the proposed method. Compared with other conventional methods, the improved method can generate a more effective and smoother trajectory in the truck lane change.
Because most link-state routing protocols, such as OSPF and IS-IS, calculate routes using the dijkstra algorithm, which poses scalability problems, implementors often introduce an artificial delay to reduce the number...
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Because most link-state routing protocols, such as OSPF and IS-IS, calculate routes using the dijkstra algorithm, which poses scalability problems, implementors often introduce an artificial delay to reduce the number of route calculations. Although this delay directly affects IP packet forwarding, it can be acceptable when the network topology does not change often. However, when the topology of a network changes frequently, this delay can lead to a complete loss of IP reachability for the affected network prefixes during the unstable period. In this paper, we propose the Cached Shortest-path Tree (CST) approach, which speeds up intra-domain routing convergence without extra execution of the dijkstra algorithm, even if the routing for a network is quite unstable. The basic idea of CST is to cache shortest-path trees (SPTs) of network topologies that appear frequently, and use these SPTs to instantly generate a routing table when the topology after a change matches one in the caches. CST depends on a characteristic that we found from an investigation of routing instability conducted on the WIDE Internet in Japan. That is, under unstable routing conditions, both frequently changing Link State Advertisements (LSAs) and their instances tend to be limited. At the end of this paper, we show CST's effectiveness by a trace-driven simulation.
Real-valued data are quantized according to the magnitude of their fluctuations around regional mean values or around a given, real-valued signal. Quantization does not require any parameter or threshold value except ...
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Real-valued data are quantized according to the magnitude of their fluctuations around regional mean values or around a given, real-valued signal. Quantization does not require any parameter or threshold value except the desired number of regions. By the introduction of suitable fluctuation measures and a so-called change point graph, the determination of a minimum quantization is transformed to the computation of the shortest path with a prescribed number of intermediate nodes. Such shortest paths are shown to be computable by dynamic programming and by a variation of the dijkstra algorithm. Evaluations and extensions of the approach are included. Copyright (C) 2011 John Wiley & Sons, Ltd.
The research presented in this paper focuses on the use of different computing and wireless techniques and technological systems for real-time navigation support and location based information delivery for a pedestria...
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The research presented in this paper focuses on the use of different computing and wireless techniques and technological systems for real-time navigation support and location based information delivery for a pedestrian user interacting with city architectural information system on a digital handheld device while on the move. In this research case, the use of basic GPS receiver, dijkstra algorithm, Radio Frequency Identification (RFID)/Near Field Communication (NFC) systems and 2 Dimensional (2D) barcode technologies was examined and the potential for the use of WiFi and mobile cells is noted. This paper explores the virtue and shortcomings of each in order to determine the best possible integrated solution. The suggested integration will locate the pedestrian user in the virtual city representation on location, informs the user about buildings and other artefacts relating to the site where s/he is currently located and guide the user to a next point of interest efficiently. (C) 2009 Elsevier B.V. All rights reserved.
The multiobjective route selection problem (m-RSP) is a key research topic in the car navigation system (CNS) for ITS (Intelligent Transportation System). In this paper, we propose an interactive multistage weight-bas...
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The multiobjective route selection problem (m-RSP) is a key research topic in the car navigation system (CNS) for ITS (Intelligent Transportation System). In this paper, we propose an interactive multistage weight-based dijkstra genetic algorithm (mwD-GA) to solve it. The purpose of the proposed approach is to create enough Pareto-optimal route's with good distribution for the car driver depending on his/her preference. At the same time, the routes can be recalculated according to the driver's preferences by the multistage framework proposed. In the solution approach proposed, the accurate route searching ability of the dijkstra algorithm and the exploration ability of the Genetic algorithm (GA) are effectively combined together for solving the m-RSP problems. Solutions provided by the proposed approach are compared with the current research to show the effectiveness and practicability of the solution approach proposed.
A properly arranged subsea production system reduces costs and contributes to production performance due to favorable hydraulic characteristics and flow assurance. Therefore, the layout design of subsea production sys...
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A properly arranged subsea production system reduces costs and contributes to production performance due to favorable hydraulic characteristics and flow assurance. Therefore, the layout design of subsea production systems is very important in offshore field development. The design of these systems mainly includes locating the subsea facilities, determining the subsea topology and identifying the pipe route. Each of these three aspects have been studied, for instance, optimization of the pipe network or identification of the optimal single pipe route. However, the combination of these three aspects has not yet been discussed in detail. This paper presents an integrated optimization model for the layout design of a wellhead-manifold-FPSO system, with the aim of obtaining a minimum total pipe length. There are two key details of this model that distinguish it from other models. The first detail is that the seabed topography and obstacles are taken into consideration. The second detail is that all three above-mentioned aspects are considered together in the model to determine the optimal number of manifolds, manifold and riser base positions, pipe network topology and pipe routes. The simulated annealing and dijkstra algorithms are coupled to solve the model by using a newly proposed process. The application of this method is demonstrated by designing the layout of an oil field with 22 wellheads and one FPSO. The results are compared with the situation that neglects the seabed topography, showing a difference in suggested pipe length. In addition, the pipe route effect on both hydraulic and flow assurance is briefly discussed. The model provides a method to link related issues of interest to the layout design, resulting in a practical subsea layout that can be used to more reliably estimate costs, more accurately describe multiphase flow and help in decision-making for flow assurance.
Wearable systems can provide accurate cardiovascular evaluations by estimating hemodynamic indices in real-time. Key hemodynamic parameters can be non-invasively estimated using the seismocardiogram (SCG), a cardiomec...
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Wearable systems can provide accurate cardiovascular evaluations by estimating hemodynamic indices in real-time. Key hemodynamic parameters can be non-invasively estimated using the seismocardiogram (SCG), a cardiomechanical signal whose features link to cardiac events like aortic valve opening (AO) and closing (AC). However, tracking a single SCG feature is unreliable due to physiological changes, motion artifacts, and external vibrations. This work proposes an adaptable Gaussian Mixture Model (GMM) to track multiple AO/AC correlated features in quasi-real-time from the SCG. The GMM calculates the likelihood of an extremum being an AO/AC feature for each SCG beat. The dijkstra algorithm selects heartbeat-related extrema, and a Kalman filter updates the GMM parameters while filtering features. Tracking accuracy is tested on a porcine hypovolemia dataset with varying noise levels. Blood volume loss estimation accuracy is also evaluated using the tracked features on a previously developed model. Experimental results show a 4.5 ms tracking latency and average root mean square errors (RMSE) of 1.47 ms for AO and 7.67 ms for AC at 10 dB noise, and 6.18 ms for AO and 15.3 ms for AC at -10 dB noise. When considering all AO/AC correlated features, the combined RMSE remains in similar ranges, specifically 2.70 ms for AO and 11.91 ms for AC at 10 dB noise, and 7.50 ms for AO and 16.35 ms for AC at -10 dB noise. The proposed algorithm offers low latency and RMSE for all tracked features, making it suitable for real-time processing. These systems enable accurate, timely extraction of hemodynamic indices for many cardiovascular monitoring applications, including trauma care in field settings.
Historic aircraft trajectory data are valuable resources for various research in the field of air traffic management. With the widespread use of Automatic Dependent Surveillance-Broadcast (ADS-B), these data are relat...
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Historic aircraft trajectory data are valuable resources for various research in the field of air traffic management. With the widespread use of Automatic Dependent Surveillance-Broadcast (ADS-B), these data are relatively easier to obtain. However, there are instances, where the original flight plans that do not contain controller interventions are necessary, such as developing scenarios for Human-in-The-Loop (HiTL) simulations. Even though the air traffic control system keeps records of the flight plan data, they are more difficult to obtain and often are not in the correct format to be applied to simulations. In this study, an algorithm is developed, which can extract the flight plan from recorded ADS-B trajectory and the Aeronautical Information Publication (AIP) that contains all the route and procedure information. The algorithm was validated against HiTL simulation results, where both the resulting trajectories with controller interventions and the original flight plans are available and showed a 98 percent success rate. The algorithms are applied to find the flight plans of about one million flights in the year 2019 that contain trajectory points inside the Incheon Flight Information Region (FIR). This flight plan extraction algorithm will be useful not only for the fast-time or real-time simulations of the air traffic but also for aviation safety-related research areas, where the controller-pilot interactions are important.
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