WorldWideScience

Sample records for navigation methods applicable

  1. Self Localization Method Using Parallel Projection Model for Mobile Sensor in Navigation Applications

    Institute of Scientific and Technical Information of China (English)

    Shung Han Cho; Yuntai Kyong; Sangjin Hong; We-Duke Cho

    2009-01-01

    This paper presents a novel self localization method using parallel projection model for mobile sensor in navigation applications. The algorithm estimates the coordinate and the orientation of mobile sensor using projected on visual image. The proposed method considers the lens non-linearity of the camera and compensates the distortion by using a calibration table. The method determines the coordinates and orientations with iterative process, which is very accurate with low computational demand. We identify various sources of error on the coordinate and orientation estimations, and present both static sensitivity analysis of the algorithm and dynamic behavior of the mobile sensor. The algorithm can be utilized in mobile robot navigation as well as positioning application where accurate self localization is necessary.

  2. New Method of Reconstruction from Nonparallel Stereo and Application to Surgical Navigator

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new method to reconstruct 3D scene points from nonparallel stereo is proposed. From a pair of conjugate images in an arbitrarily configured stereo system that has been calibrated, coordinates of 3D scene points can be computed directly using the method, bypassing the process of rectifying images or iterative solution involved in existing methods. Experiment results from both simulated data and real images validate the method. Practical application to surgical navigator shows that the method has advantages to improve efficiency and accuracy of 3D reconstruction from nonparallel stereo system in comparison with the conventional method that employs algorithm for standard parallel axes stereo geometry.

  3. Alternative applications of the method of moments: from electromagnetic waves to source synthesis, deconvolution, and data processing in navigation systems

    Science.gov (United States)

    Tamas, Razvan; Dumitrascu, Ana; Caruntu, George

    2015-02-01

    The method of moments is mostly used in electromagnetism to solve linear operator equations. In this paper, we present three different, alternative applications of this numerical technique: resolution of the integral equation of convolution i.e., deconvolution, synthesis of electromagnetic radiators optimized to yield a given time-domain or frequency-domain response, and processing of data provided by an inertial navigation system, with the aim to decompose a complex displacement into elementary movements.

  4. Integrated navigation method based on inertial navigation system and Lidar

    Science.gov (United States)

    Zhang, Xiaoyue; Shi, Haitao; Pan, Jianye; Zhang, Chunxi

    2016-04-01

    An integrated navigation method based on the inertial navigational system (INS) and Lidar was proposed for land navigation. Compared with the traditional integrated navigational method and dead reckoning (DR) method, the influence of the inertial measurement unit (IMU) scale factor and misalignment was considered in the new method. First, the influence of the IMU scale factor and misalignment on navigation accuracy was analyzed. Based on the analysis, the integrated system error model of INS and Lidar was established, in which the IMU scale factor and misalignment error states were included. Then the observability of IMU error states was analyzed. According to the results of the observability analysis, the integrated system was optimized. Finally, numerical simulation and a vehicle test were carried out to validate the availability and utility of the proposed INS/Lidar integrated navigational method. Compared with the test result of a traditional integrated navigation method and DR method, the proposed integrated navigational method could result in a higher navigation precision. Consequently, the IMU scale factor and misalignment error were effectively compensated by the proposed method and the new integrated navigational method is valid.

  5. Bering Mission Navigation Method

    OpenAIRE

    2003-01-01

    "Bering", after the name of the famous Danish explorer, is a near Earth object (NEO) and main belt asteroids mapping mission envisaged by a consortium of Danish universities and research institutes. To achieve the ambitious goals set forth by this mission, while containing the costs and risks, "Bering" sports several new technological enhancements and advanced instruments under development at the Technical University of Denmark (DTU). The autonomous on-board orbit determination method is part...

  6. Fault-tolerant and Diagnostic Methods for Navigation

    DEFF Research Database (Denmark)

    Blanke, Mogens

    2003-01-01

    Precise and reliable navigation is crucial, and for reasons of safety, essential navigation instruments are often duplicated. Hardware redundancy is mostly used to manually switch between instruments should faults occur. In contrast, diagnostic methods are available that can use analytic redundancy...... to diagnose faults and autonomously provide valid navigation data, disregarding any faulty sensor data and use sensor fusion to obtain a best estimate for users. This paper discusses how diagnostic and fault-tolerant methods are applicable in marine systems. An example chosen is sensor fusion for navigation...

  7. Research on integrated navigation method for AUV

    Institute of Scientific and Technical Information of China (English)

    GUO Zhen; SUN Feng

    2005-01-01

    The principles of the SINS/DVL integrated navigation system are introduced, and the compass status accuracy is compared. When the heading is changed, the dead reckoning algorithm using the heading information of the SINS (Strapdown inertial navigation systems) and DVL (doppler velocity log) is adopted to substitute the SINS/DVL integrated system. The simulation results show that the method can improve the accuracy of integrated navigation system when AUV (autonomous underwater vehicle) is in motion.

  8. Global navigation satellite systems and their applications

    CERN Document Server

    Madry, Scott

    2015-01-01

    Dr. Madry, one of the world's leading experts in the field, provides in a condensed form a quick yet comprehensive overview of satellite navigation. This book concisely addresses the latest technology, the applications, the regulatory issues, and the strategic implications of satellite navigation systems. This assesses the strengths and weaknesses of satellite navigation networks and review of all the various national systems now being deployed and the motivation behind the proliferation of these systems.

  9. Automated Functional Testing based on the Navigation of Web Applications

    CERN Document Server

    García, Boni; 10.4204/EPTCS.61.4

    2011-01-01

    Web applications are becoming more and more complex. Testing such applications is an intricate hard and time-consuming activity. Therefore, testing is often poorly performed or skipped by practitioners. Test automation can help to avoid this situation. Hence, this paper presents a novel approach to perform automated software testing for web applications based on its navigation. On the one hand, web navigation is the process of traversing a web application using a browser. On the other hand, functional requirements are actions that an application must do. Therefore, the evaluation of the correct navigation of web applications results in the assessment of the specified functional requirements. The proposed method to perform the automation is done in four levels: test case generation, test data derivation, test case execution, and test case reporting. This method is driven by three kinds of inputs: i) UML models; ii) Selenium scripts; iii) XML files. We have implemented our approach in an open-source testing fra...

  10. Current state in tracking and robotic navigation systems for application in endovascular aortic aneurysm repair

    NARCIS (Netherlands)

    De Ruiter, Quirina M B; Moll, Frans L.; Van Herwaarden, Joost A.

    2015-01-01

    Objective This study reviewed the current developments in manual tracking and robotic navigation technologies for application in endovascular aortic aneurysm repair (EVAR). Methods EMBASE and MEDLINE databases were searched for studies reporting manual tracking or robotic navigation systems that are

  11. Current state in tracking and robotic navigation systems for application in endovascular aortic aneurysm repair

    NARCIS (Netherlands)

    De Ruiter, Quirina M B; Moll, Frans L.|info:eu-repo/dai/nl/070246882; Van Herwaarden, Joost A.|info:eu-repo/dai/nl/304814733

    2015-01-01

    Objective This study reviewed the current developments in manual tracking and robotic navigation technologies for application in endovascular aortic aneurysm repair (EVAR). Methods EMBASE and MEDLINE databases were searched for studies reporting manual tracking or robotic navigation systems that are

  12. Autonomous navigation system and method

    Science.gov (United States)

    Bruemmer, David J [Idaho Falls, ID; Few, Douglas A [Idaho Falls, ID

    2009-09-08

    A robot platform includes perceptors, locomotors, and a system controller, which executes instructions for autonomously navigating a robot. The instructions repeat, on each iteration through an event timing loop, the acts of defining an event horizon based on the robot's current velocity, detecting a range to obstacles around the robot, testing for an event horizon intrusion by determining if any range to the obstacles is within the event horizon, and adjusting rotational and translational velocity of the robot accordingly. If the event horizon intrusion occurs, rotational velocity is modified by a proportion of the current rotational velocity reduced by a proportion of the range to the nearest obstacle and translational velocity is modified by a proportion of the range to the nearest obstacle. If no event horizon intrusion occurs, translational velocity is set as a ratio of a speed factor relative to a maximum speed.

  13. Autonomous navigation system and method

    Energy Technology Data Exchange (ETDEWEB)

    Bruemmer, David J [Idaho Falls, ID; Few, Douglas A [Idaho Falls, ID

    2009-09-08

    A robot platform includes perceptors, locomotors, and a system controller, which executes instructions for autonomously navigating a robot. The instructions repeat, on each iteration through an event timing loop, the acts of defining an event horizon based on the robot's current velocity, detecting a range to obstacles around the robot, testing for an event horizon intrusion by determining if any range to the obstacles is within the event horizon, and adjusting rotational and translational velocity of the robot accordingly. If the event horizon intrusion occurs, rotational velocity is modified by a proportion of the current rotational velocity reduced by a proportion of the range to the nearest obstacle and translational velocity is modified by a proportion of the range to the nearest obstacle. If no event horizon intrusion occurs, translational velocity is set as a ratio of a speed factor relative to a maximum speed.

  14. Advanced Navigation System for Aircraft Applications

    Directory of Open Access Journals (Sweden)

    G. Satheesh Reddy

    2013-03-01

    Full Text Available Various forms of navigation are present in today’s world, leading from satellite based navigation to several archaic forms of navigation like star gazing. Now, lots of technologies are available to achieve this but with certain limitations. For example, FOG based navigation provides accuracy with in 0.10-100 range which is not sufficient for various military applications. Therefore, there is a need to design a system which will have better accuracy and thus requires development of ring laser gyro-based inertial systems. This paper concentrates on the aided navigation system based on ring laser gyro of 0.01 deg/hr class and GPS - GLONASS to further enhance the capability of system in terms of accuracy. The usage of such systems not only provides accurate results momentarily but it also persists for longer duration with the aid of GPS - GLONASS for applications like aircraft, ship and long range missiles. The system provides accuracy of the level of 1 Nm/hr in pure navigation and 30 m with the aid of GPS - GLONASS. Apart from this, the availability of gyro-compass and baro-inertial algorithms further enhances the system capabilities and made them self dependent to the major extent.Defence Science Journal, 2013, 63(2, pp.131-137, DOI:http://dx.doi.org/10.14429/dsj.63.4254

  15. Multi-Flight-Phase GPS Navigation Filter Applications to Terrestrial Vehicle Navigation and Positioning

    Science.gov (United States)

    Park, Young W.; Montez, Moises N.

    1994-01-01

    A candidate onboard space navigation filter demonstrated excellent performance (less than 8 meter level RMS semi-major axis accuracy) in performing orbit determination of a low-Earth orbit Explorer satellite using single-frequency real GPS data. This performance is significantly better than predicted by other simulation studies using dual-frequency GPS data. The study results revealed the significance of two new modeling approaches evaluated in the work. One approach introduces a single-frequency ionospheric correction through pseudo-range and phase range averaging implementation. The other approach demonstrates a precise axis-dependent characterization of dynamic sample space uncertainty to compute a more accurate Kalman filter gain. Additionally, this navigation filter demonstrates a flexibility to accommodate both perturbational dynamic and observational biases required for multi-flight phase and inhomogeneous application environments. This paper reviews the potential application of these methods and the filter structure to terrestrial vehicle and positioning applications. Both the single-frequency ionospheric correction method and the axis-dependent state noise modeling approach offer valuable contributions in cost and accuracy improvements for terrestrial GPS receivers. With a modular design approach to either 'plug-in' or 'unplug' various force models, this multi-flight phase navigation filter design structure also provides a versatile GPS navigation software engine for both atmospheric and exo-atmospheric navigation or positioning use, thereby streamlining the flight phase or application-dependent software requirements. Thus, a standardized GPS navigation software engine that can reduce the development and maintenance cost of commercial GPS receivers is now possible.

  16. A New Feature Points Reconstruction Method in Spacecraft Vision Navigation

    Directory of Open Access Journals (Sweden)

    Bing Hua

    2015-01-01

    Full Text Available The important applications of monocular vision navigation in aerospace are spacecraft ground calibration tests and spacecraft relative navigation. Regardless of the attitude calibration for ground turntable or the relative navigation between two spacecraft, it usually requires four noncollinear feature points to achieve attitude estimation. In this paper, a vision navigation system based on the least feature points is designed to deal with fault or unidentifiable feature points. An iterative algorithm based on the feature point reconstruction is proposed for the system. Simulation results show that the attitude calculation of the designed vision navigation system could converge quickly, which improves the robustness of the vision navigation of spacecraft.

  17. Dynamic Navigation Method with Multisubstations Based on Doppler Shift

    Directory of Open Access Journals (Sweden)

    Jianyang Zhao

    2015-01-01

    Full Text Available The mobile terminals must be compensated for the Doppler effect in their moving communication. This special characteristic of mobile communication can be developed in some new applications. This paper proposes methods to realize mobile navigation calculation via Doppler shifts. It gives the theory of relationship between the motion parameters, like directions and speed, and frequency shifts caused by multibase stations. The simulation illustrates how to compute the movement parameters of numerical calculation and what should be care for the problem near angle 90 degree. It also gives an application with Google map and dynamical locating position and direction on a mobile phone by public wireless network. Given the simulation analysis and navigation test, the results show that this method has a good effect.

  18. Automated Functional Testing based on the Navigation of Web Applications

    Directory of Open Access Journals (Sweden)

    Boni García

    2011-08-01

    Full Text Available Web applications are becoming more and more complex. Testing such applications is an intricate hard and time-consuming activity. Therefore, testing is often poorly performed or skipped by practitioners. Test automation can help to avoid this situation. Hence, this paper presents a novel approach to perform automated software testing for web applications based on its navigation. On the one hand, web navigation is the process of traversing a web application using a browser. On the other hand, functional requirements are actions that an application must do. Therefore, the evaluation of the correct navigation of web applications results in the assessment of the specified functional requirements. The proposed method to perform the automation is done in four levels: test case generation, test data derivation, test case execution, and test case reporting. This method is driven by three kinds of inputs: i UML models; ii Selenium scripts; iii XML files. We have implemented our approach in an open-source testing framework named Automatic Testing Platform. The validation of this work has been carried out by means of a case study, in which the target is a real invoice management system developed using a model-driven approach.

  19. Applications of navigation for orthognathic surgery.

    Science.gov (United States)

    Bobek, Samuel L

    2014-11-01

    Stereotactic surgical navigation has been used in oral and maxillofacial surgery for orbital reconstruction, reduction of facial fractures, localization of foreign bodies, placement of implants, skull base surgery, tumor removal, temporomandibular joint surgery, and orthognathic surgery. The primary goals in adopting intraoperative navigation into these different surgeries were to define and localize operative anatomy, to localize implant position, and to orient the surgical wound. Navigation can optimize the functional and esthetic outcomes in patients with dentofacial deformities by identifying pertinent anatomic structures, transferring the surgical plan to the patient, and verifying the surgical result. This article discusses the principles of navigation-guided orthognathic surgery.

  20. Navigation Method for Autonomous Robots in a Dynamic Indoor Environment

    Directory of Open Access Journals (Sweden)

    Stanislav Věchet

    2013-11-01

    Full Text Available The present paper considers issues related to navigation by autonomous mobile robots in overcrowded dynamic indoor environments (e.g., shopping malls, exhibition halls or convention centers. For robots moving among potentially unaware bystanders, safety is a key issue. A navigation method based on mixed potential field path planning is proposed, in cooperation with active artificial landmarks-based localization, in particular the bearing of infrared beacons placed in known coordinates processed via particle filters. Simulation experiments and tests in unmodified real-world environments with the actual robot show the proposed navigation system allows the robot to successfully navigate safely among bystanders.

  1. The Global Positioning System and its application in spacecraft navigation

    Science.gov (United States)

    Van Leeuwen, A.; Rosen, E.; Carrier, L. M.

    1979-01-01

    The paper presents an overview of the Global Positioning System (GPS) as well as a discussion of the user system parameters govering the design of a low-earth-orbit spacecraft GPS navigation system. A specific application, the Space Shuttle orbiter GPS navigation system, is discussed with particular attention given to its receiver/processor.

  2. Application Method of Department of Orthopedics, Robot Navigation and Positioning System%骨科机器人导航定位系统的应用方法

    Institute of Scientific and Technical Information of China (English)

    曾田勇

    2015-01-01

    目的:介绍骨科机器人导航定位系统(Galen GD-2000型)的工作原理;探讨骨科机器人在股骨颈骨折闭合复位空心钉内固定手术中的应用及配合模式。方法:对我院2013年7月至2014年10月施行的骨科机器人微创手术进行临床应用总结。结果:骨科机器人辅助手术定位精确,固定复位可靠,操作安全,明显减少C臂照射次数及时间;但系统操作复杂、精度要求高,且设备价格昂贵,医务人员使用、维护及保养难度大。结论:该系统显著提高了股骨颈闭合复位内固定的治疗效果,并有利于维护医患双方健康;加强医务人员培训,掌握仪器设备性能,规范手术操作,提高配合质量,实施细节管理及优化服务意识。%Objective: To Introduction the Department of orthopedics robot navigation positioning system (Galen GD-2000) principle of work;to explore the Department of orthopedics robot fractures treated by close reduction and cannulated screw ifxation in operation and cooperation mode in femoral neck.Method: Minimaly invasive operation in Department of orthopedics in our hospital in 2013 July to 2014 robot October implementation of the clinical application of summary.Result: Department of orthopedics, robot assisted operation of accurate positioning, reposition, reliable, safe operation, signiifcantly reduce the C arm irradiation times and time; but the system operation is complex, high precision, and expensive equipment, medical personnel to use, maintenance and maintenance diffcult.Conclusion: The system signiifcantly improves the femoral neck closed reduction and internal ifxation treatment effect, and is beneifcial to the maintenance of both doctors and patients health; strengthen the medical personnel training, to master the instrument and equipment performance, standardized operation, improve the quality of ift, the implementation details of management and optimization of service

  3. Apparatus and method of navigating an instrument

    NARCIS (Netherlands)

    Bakker, N.H.; Den Heeten, G.J.

    2004-01-01

    An apparatus to be used with navigating an instrument in a vascular tree of a patient, comprises a patient's examination table, a C-arm, mounted to which is an X-ray source and an image recorder for registering first X-ray images of the patient, obtained by the use of the X-ray source, and a process

  4. A new visualization method for navigated bronchoscopy.

    Science.gov (United States)

    Reynisson, Pall Jens; Hofstad, Erlend Fagertun; Leira, Håkon Olav; Askeland, Christian; Langø, Thomas; Sorger, Hanne; Lindseth, Frank; Amundsen, Tore; Hernes, Toril Anita Nagelhus

    2017-05-30

    In flexible endoscopy techniques, such as bronchoscopy, there is often a challenge visualizing the path from start to target based on preoperative data and accessing these during the procedure. An example of this is visualizing only the inside of central airways in bronchoscopy. Virtual bronchoscopy (VB) does not meet the pulmonologist's need to detect, define and sample the frequent targets outside the bronchial wall. Our aim was to develop and study a new visualization technique for navigated bronchoscopy. We extracted the shortest possible path from the top of the trachea to the target along the airway centerline and a corresponding auxiliary route in the opposite lung. A surface structure between the centerlines was developed and displayed. The new technique was tested on non-selective CT data from eight patients using artificial lung targets. The new display technique anchored to centerline curved surface (ACCuSurf) made it easy to detect and interpret anatomical features, targets and neighboring anatomy outside the airways, in all eight patients. ACCuSurf can simplify planning and performing navigated bronchoscopy, meets the challenge of improving orientation and register the direction of the moving endoscope, thus creating an optimal visualization for navigated bronchoscopy.

  5. Gamifying Navigation in Location-Based Applications

    DEFF Research Database (Denmark)

    Nadarajah, Stephanie Githa; Overgaard, Benjamin Nicholas; Pedersen, Peder Walz

    2017-01-01

    Location-based games entertain players usually by interactions at points of interest (POIs). Navigation between POIs often involve the use of either a physical or digital map, not taking advantage of the opportunity available to engage users in activities between POIs. The paper presents riddle s...

  6. Educational and Scientific Applications of the \\itTime Navigator}

    Science.gov (United States)

    Cole, M.; Snow, J. T.; Slatt, R. M.

    2001-05-01

    electronic version of \\itOrigins} can be a demonstration project for delivering multimedia content to a variety of audiences. In the first half of this presentation, we give a brief overview of \\itTime Navigator}, including a demonstration of the content and sophistication of the database, We will focus on layered, multimedia features, ease of use, and interactivity. The second half of the presentation will feature undergraduate and 9-12 applications which are built around a series of "research projects" emphasizing application of the Scientific Method, analyzing scientific data, and how scientists achieve consensus on theories.

  7. Image processing and applications based on visualizing navigation service

    Science.gov (United States)

    Hwang, Chyi-Wen

    2015-07-01

    When facing the "overabundant" of semantic web information, in this paper, the researcher proposes the hierarchical classification and visualizing RIA (Rich Internet Application) navigation system: Concept Map (CM) + Semantic Structure (SS) + the Knowledge on Demand (KOD) service. The aim of the Multimedia processing and empirical applications testing, was to investigating the utility and usability of this visualizing navigation strategy in web communication design, into whether it enables the user to retrieve and construct their personal knowledge or not. Furthermore, based on the segment markets theory in the Marketing model, to propose a User Interface (UI) classification strategy and formulate a set of hypermedia design principles for further UI strategy and e-learning resources in semantic web communication. These research findings: (1) Irrespective of whether the simple declarative knowledge or the complex declarative knowledge model is used, the "CM + SS + KOD navigation system" has a better cognition effect than the "Non CM + SS + KOD navigation system". However, for the" No web design experience user", the navigation system does not have an obvious cognition effect. (2) The essential of classification in semantic web communication design: Different groups of user have a diversity of preference needs and different cognitive styles in the CM + SS + KOD navigation system.

  8. Application of inertial navigation to wellbore positional surveying

    Energy Technology Data Exchange (ETDEWEB)

    Watts, A.C.

    1982-06-01

    There is an increasing need for higher accuracy in wellbore directional and positional surveying than is currently available using conventional techniques. Among the factors contributing to this need are closed interspacing of wells particularly from offshore platforms, deeper and more highly deviated wells, smaller target formations and the requirement for rapid drilling of relief wells in the case of blowouts. The application of inertial navigation system (INS) of suitable size and cost for this type of application is not inherently accurate enough to offer significant improvements in well-surveying accuracy. Techniques to improve accuracy are, in general, based on the fact that the dynamics associated with the propagation of the navigator errors are very well known. Inertial systems are routinely aided using external data from a number of sources. Such aiding may take the form of an external position or velocity measurement which is compared to the position or velocity indicated by the navigator. Kalman filter theory provides a convenient formulation for generation of a minimum variance estimate of the state vector of a linear system. The theory may be extended to the nonlinear case through the use of linearization about a state trajectory. This approach is currently seeing wide use in aiding of inertial navigation systems. The approach proposed here would use the Kalman filter formulation for estimation of the INS errors and updating of the navigator. This formulation also provides a structure for estimation of various instrument parameters which should improve system performance.

  9. MULTI-GNSS RECEIVER FOR AEROSPACE NAVIGATION AND POSITIONING APPLICATIONS

    Directory of Open Access Journals (Sweden)

    T. R. Peres

    2014-03-01

    Full Text Available The upcoming Galileo system opens a wide range of new opportunities in the Global Navigation Satellite System (GNSS market. However, the characteristics of the future GNSS signals require the development of new GNSS receivers. In the frame of the REAGE project, DEIMOS and ISEL have developed a GNSS receiver targeted for aerospace applications, supporting current and future GPS L1 and Galileo E1 signals, based on commercial (or, in the furthest extent, industrial grade components. Although the REAGE project aimed at space applications, the REAGE receiver is also applicable to many terrestrial applications (ground or airborne, such as Georeferencing and Unmanned Aerial Vehicle (UAV navigation. This paper presents the architecture and features of the REAGE receiver, as well as some results of the validation campaign with GPS L1 and Galileo E1 signals.

  10. Monocular vision based navigation method of mobile robot

    Institute of Scientific and Technical Information of China (English)

    DONG Ji-wen; YANG Sen; LU Shou-yin

    2009-01-01

    A trajectory tracking method is presented for the visual navigation of the monocular mobile robot. The robot move along line trajectory drawn beforehand, recognized and stop on the stop-sign to finish special task. The robot uses a forward looking colorful digital camera to capture information in front of the robot, and by the use of HSI model partition the trajectory and the stop-sign out. Then the "sampling estimate" method was used to calculate the navigation parameters. The stop-sign is easily recognized and can identify 256 different signs. Tests indicate that the method can fit large-scale intensity of brightness and has more robustness and better real-time character.

  11. A Bionic Polarization Navigation Sensor and Its Calibration Method.

    Science.gov (United States)

    Zhao, Huijie; Xu, Wujian

    2016-01-01

    The polarization patterns of skylight which arise due to the scattering of sunlight in the atmosphere can be used by many insects for deriving compass information. Inspired by insects' polarized light compass, scientists have developed a new kind of navigation method. One of the key techniques in this method is the polarimetric sensor which is used to acquire direction information from skylight. In this paper, a polarization navigation sensor is proposed which imitates the working principles of the polarization vision systems of insects. We introduce the optical design and mathematical model of the sensor. In addition, a calibration method based on variable substitution and non-linear curve fitting is proposed. The results obtained from the outdoor experiments provide support for the feasibility and precision of the sensor. The sensor's signal processing can be well described using our mathematical model. A relatively high degree of accuracy in polarization measurement can be obtained without any error compensation.

  12. A Bionic Polarization Navigation Sensor and Its Calibration Method

    Science.gov (United States)

    Zhao, Huijie; Xu, Wujian

    2016-01-01

    The polarization patterns of skylight which arise due to the scattering of sunlight in the atmosphere can be used by many insects for deriving compass information. Inspired by insects’ polarized light compass, scientists have developed a new kind of navigation method. One of the key techniques in this method is the polarimetric sensor which is used to acquire direction information from skylight. In this paper, a polarization navigation sensor is proposed which imitates the working principles of the polarization vision systems of insects. We introduce the optical design and mathematical model of the sensor. In addition, a calibration method based on variable substitution and non-linear curve fitting is proposed. The results obtained from the outdoor experiments provide support for the feasibility and precision of the sensor. The sensor’s signal processing can be well described using our mathematical model. A relatively high degree of accuracy in polarization measurement can be obtained without any error compensation. PMID:27527171

  13. The Satellite Systems Applications to Automate Navigation in the Coastal Zone

    Directory of Open Access Journals (Sweden)

    Katenin Vladimir

    2015-12-01

    Full Text Available The methods of automatic pilotage along a guided path are well known in the practice of navigation. However these methods have a number of drawbacks, which reduce the effectiveness of their application. It is especially important for river-sea vessel in poor visibility. Because of the large inertia of the vessel and its hydrodynamic properties that are changed by external influences, the process has unstable oscillatory nature. Therefore the vessel moves not in a straight line, but on a winding curve having the general direction that corresponds to the specified value. In this paper new method of coastal navigation with invented new devices supported with satellite navigation receiver is presented.

  14. Navigation Algorithm Using Fuzzy Control Method in Mobile Robotics

    Directory of Open Access Journals (Sweden)

    Cviklovič Vladimír

    2016-03-01

    Full Text Available The issue of navigation methods is being continuously developed globally. The aim of this article is to test the fuzzy control algorithm for track finding in mobile robotics. The concept of an autonomous mobile robot EN20 has been designed to test its behaviour. The odometry navigation method was used. The benefits of fuzzy control are in the evidence of mobile robot’s behaviour. These benefits are obtained when more physical variables on the base of more input variables are controlled at the same time. In our case, there are two input variables - heading angle and distance, and two output variables - the angular velocity of the left and right wheel. The autonomous mobile robot is moving with human logic.

  15. An improved potential field method for mobile robot navigation

    Institute of Scientific and Technical Information of China (English)

    李广胜

    2016-01-01

    In order to overcome the inherent oscillation problem of potential field methods ( PFMs) for au-tonomous mobile robots in the presence of obstacles and in narrow passages, an enhanced potential field method that integrates Levenberg-Marquardt ( L-M ) algorithm and k-trajectory algorithm into the basic PFMs is proposed and simulated.At first, the mobile robot navigation function based on the basic PFMs is established by choosing Gaussian model.Then, the oscillation problem of the nav-igation function is investigated when a mobile robot nears obstacles and passes through a long and narrow passage, which can cause large computation cost and system instability.At last, the L-M al-gorithm is adopted to modify the search direction of the navigation function for alleviating the oscilla-tion, while the k-trajectory algorithm is applied to further smooth trajectories.By a series of compar-ative experiments, the use of the L-M algorithm and k-trajectory algorithm can greatly improve the system performance with the advantages of reducing task completion time and achieving smooth traj-ectories.

  16. Navigational Tools for Interventional Radiology and Interventional Oncology Applications

    Science.gov (United States)

    Chehab, Monzer A.; Brinjikji, Waleed; Copelan, Alexander; Venkatesan, Aradhana M.

    2015-01-01

    The interventional radiologist is increasingly called upon to successfully access challenging biopsy and ablation targets, which may be difficult based on poor visualization, small size, or the proximity of vulnerable regional anatomy. Complex therapeutic procedures, including tumor ablation and transarterial oncologic therapies, can be associated with procedural risk, significant procedure time, and measurable radiation time. Navigation tools, including electromagnetic, optical, laser, and robotic guidance systems, as well as image fusion platforms, have the potential to facilitate these complex interventions with the potential to improve lesion targeting, reduce procedure time, and radiation dose, and thus potentially improve patient outcomes. This review will provide an overview of currently available navigational tools and their application to interventional radiology and oncology. A summary of the pertinent literature on the use of these tools to improve safety and efficacy of interventional procedures compared with conventional techniques will be presented. PMID:26622105

  17. Efficient ranging-sensor navigation methods for indoor aircraft

    Science.gov (United States)

    Sobers, David Michael, Jr.

    Unmanned Aerial Vehicles (UAVs) are often used for reconnaissance, search and rescue, damage assessment, exploration, and other tasks that are dangerous or prohibitively difficult for humans to perform. Often, these tasks include traversing indoor environments where radio links are unreliable, hindering the use of remote pilot links or ground-based control, and effectively eliminating Global Positioning System (GPS) signals as a potential localization method. As a result, any vehicle capable of indoor flight must be able to stabilize itself and perform all guidance, navigation, and control (GNC) tasks without dependence on a radio link, which may be available only intermittently. Stability and control of rotorcraft UAVs is usually achieved by either a passive stability system, such as a Bell stabilizer bar, or by actively measuring body accelerations and angular rates with an onboard Inertial Measurement Unit (IMU) and using that data for feedback control. However, neither active nor passive attitude stabilization methods provide position control by themselves. Therefore, GNC methods must either be tolerant to position drift or have some means of estimating and controlling position, which requires an external reference in order to measure and correct errors in the position estimate. GPS signals are often the most convenient method for providing this external position reference. As a result, most UAVs utilize GPS for localization and to bound error on position drift. Unfortunately, the availability of GPS signals in unknown environments is not assured, especially during indoor operation. As a result, other sensors must be used to provide position information relative to the environment. This research covers a description of different ranging sensors and methods for incorporating them into the overall guidance, navigation, and control system. Various sensors are analyzed to determine their performance characteristics and suitability for indoor navigation, including

  18. SpaceNav - A high accuracy navigation system for space applications

    Science.gov (United States)

    Evers, H.-H.

    The technology of the SpaceNav-system is based on research performed by the Institute of Flight Guidance and Control at the Technical University of Braunschweig, Germany. In 1989 this institute gave the worlds first public demonstration of a fully automatic landing of an aircraft, using inertial and satellite informations exclusively. The SpaceNav device components are: Acceleration-/Gyro Sensor Package; Global Positioning System (GPS) Receiver/optional more than one; Time Reference Unit; CPU; Telemetry (optional); and Differential GPS (DGPS) Receiver (optional). The coupling of GPS receivers with inertial sensors provides an extremely accurate navigation data set in real time applications even in phases with high dynamic conditions. The update rate of this navigation information is up to 100 Hz with the same accuracy in 3D-position, velocity, acceleration, attitude and time. SpaceNav is an integrated navigation system, which operates according to the principle of combining the longterm stability and accuracy of GPS, and the high level of dynamic precision of conventional inertial navigation system (INS) strapdown systems. The system's design allows other aiding sensors e.g. GLONASS satellite navigation system, distance measuring equipment (DME), altimeter (radar and/or barometric), flux valve etc. to be connected, in order to increase the redundancy of the system. The advantage of such an upgraded system is the availability of more sensor information than necessary for a navigation solution. The resulting redundancy in range measurement allows real-time detection and identification of sensor signals that are incompatible with the other information. As a result you get Receiver Autonomous Integrity Monitoring (RAIM) as described in 'A Multi-Sensor Approach to Assuring GPS Integrity', presented by Alison Brown in the March/April 1990 issue of 'GPS World'. In this paper the author presents information about the principles of the Satellite Navigation System GPS, and

  19. METHOD FOR DETECTING AND REPAIRING CYCLE SLIPS IN GPS NAVIGATION

    Institute of Scientific and Technical Information of China (English)

    CHAIYan-ju; OUJi-kun; RENChao

    2005-01-01

    A new method is proposed for detecting and repairing cycle slips in GPS navigation based on the dual frequency observations. It can be implemented through the following three steps: (1) The integer ambiguities of the current epoch are substituted by that of the previous epoch, so the ambiguity parameters are removed from the observation equations. (2) The abnormal observations are detected using the quasi accurate detection (QUAD) method and the satellite pairs of these abnormal observations are determined. Then the coefficient matrix of these satellite pairs is recovered. (3) The cycle slips of these satellite pairs are calculated using the LAMBDA method and integer ambiguities of the current epoch can be determined by adding the cycle slips into the integer ambiguities of the previous epoch. The key of this method is that the abnormal observations must accurately he detected, i.e. , the satellites having cycle slips must correctly be judged. Finally, compared with other methods the feasibility of the method is verified.

  20. An Optimal Moving Horizon Estimation for Aerial Vehicular Navigation Application

    Science.gov (United States)

    Ubaid Gul, Haris; Kai, Yang Dong

    2017-03-01

    In this article, an optimal state is estimated using the moving horizon estimation technique (MHE), based on the minimizing the deterministic cost function defined for moving window with a finite number of samples at specific time interval. The optimal moving horizon observer was designed and implemented for the non-linear dynamic problem of aerial vehicle integrated navigation. The low grade commercial inertial measuring instrument (IMU) equipped with accelerometers and gyros sensors instrumented on-board in the strapdown configuration, is employed for collection of the real time experimental data. The data fusion algorithm of moving horizon estimation is realized and the results are collected from the offline algorithm testing on the Matlab software platform. Essential data processing and cleaning of data processing was conducted before algorithm application i.e. solving the multi rate sensors data synching and removing high frequency unwanted contents. Finally, the aerial vehicle dead reckoning integrated navigation was performed with recursive observer using IMU/GPS avionics. Contrary to the widely practiced extended Kalman filter results, recursive observer of MHE exhibited performance enhancement in the response and precision aspect, regardless of environmental noise and failure scenarios.

  1. Indoor inertial navigation application for smartphones with Android

    Science.gov (United States)

    Kamiński, Ł.; Tarapata, G.

    2015-09-01

    Inertial navigation is widely used by the military, in logistics and sailing. In mobile devices, inertial sensors are mostly used as a support for GPS and Wi-Fi-based navigation systems. Inertial-based navigation might prove useful on mobile devices running Android OS. At present, in spite of the accelerometer sensor's precision having been greatly improved, as well as the devices' computing power continuously rising, inertial navigation's precision still suffers. For smartphones, the key solution seems to be the usage of sensor fusion and signal smart filtering, both discussed in this paper. The paper also describes implementation of inertial navigation in Android devices, their analysis as well as test results.

  2. SDF technology in location and navigation procedures: a survey of applications

    Science.gov (United States)

    Kelner, Jan M.; Ziółkowski, Cezary

    2017-04-01

    The basis for development the Doppler location method, also called the signal Doppler frequency (SDF) method or technology is the analytical solution of the wave equation for a mobile source. This paper presents an overview of the simulations, numerical analysis and empirical studies of the possibilities and the range of SDF method applications. In the paper, the various applications from numerous publications are collected and described. They mainly focus on the use of SDF method in: emitter positioning, electronic warfare, crisis management, search and rescue, navigation. The developed method is characterized by an innovative, unique property among other location methods, because it allows the simultaneous location of the many radio emitters. Moreover, this is the first method based on the Doppler effect, which allows positioning of transmitters, using a single mobile platform. In the paper, the results of the using SDF method by the other teams are also presented.

  3. Anticipated prospects and civilian applications of Indian satellite navigation services in Sri Lanka

    Directory of Open Access Journals (Sweden)

    I.P. Senanayake

    2013-06-01

    In this paper, positive impacts of 3 Indian Navigational Satellite programmes (GAGAN, IRNSS and INSAT-MSS reporting system for the civilian applications over Sri Lanka are discussed. Other neighbouring countries covered under the footprint of Indian navigational satellite programmes can also employ these services for the location based applications productively.

  4. Performance analysis of device-level SINS/ACFSS deeply integrated navigation method

    Science.gov (United States)

    Zhang, Hao; Qin, Shiqiao; Wang, Xingshu; Jiang, Guangwen; Tan, Wenfeng

    2016-10-01

    The Strap-Down Inertial Navigation System (SINS) is a widely used navigation system. The combination of SINS and the Celestial Navigation System (CNS) is one of the popular measures to constitute the integrated navigation system. A Star Sensor (SS) is used as a precise attitude determination device in CNS. To solve the problem that the star image obtained by SS under dynamic conditions is motion-blurred, the Attitude Correlated Frames (ACF) is presented and the star sensor which works based on ACF approach is named ACFSS. Depending on the ACF approach, a novel device-level SINS/ACFSS deeply integrated navigation method is proposed in this paper. Feedback to the ACF process from the error of the gyro is one of the typical characters of the SINS/CNS deeply integrated navigation method. Herein, simulation results have verified its validity and efficiency in improving the accuracy of gyro and it can be proved that this method is feasible in theory.

  5. 视觉方向导航新方法%Novel method of vision heading navigation

    Institute of Scientific and Technical Information of China (English)

    于俊伟; 翁璐斌; 田原; 杨一平

    2009-01-01

    针对运行方向上导航目标本身不具有明显视觉特征的情况,提出了一种新的视觉导航方法.该方法利用环境中与目标位置关系已知的显著特征点作为参考点,根据参考点的成像位置确定系统运动的姿态调整量,实现机器人运行方向的导航.为了提高算法对环境的适应能力,该算法只利用一个参考点,具有结构简单和计算复杂度小等特点.实验结果表明,该文方法能够有效地消除导航过程的方向误差,能够配合位置导航装置实现机器人的方向导航,具有较高的实用性和稳定性.%According to the target with no significant visual features,a novel vision navigation method is proposed.In the vision heading navigation,the salient feature point with known relative position to the target is chosen as the reference point.And the pose adjustment quantities of the robot are determined according to the image of the reference point.To improve the environmental adaptability,this algorithm uses only one reference point and has the advantages of simple structure and low computation complexity.Experimental results show that the vision navigation method combined with the location navigation device can eliminatethe pose errors effectively,and the applicability and stability of the method are verified.

  6. Npl Ionospheric Model for Radio Communication and Navigational Applications

    Science.gov (United States)

    Singh Dabas, Raj

    In the areas of Radio Communication and Navigation, present day need of the users are to achieve higher performance communication, better navigation, positioning which can only be possible through improved Ionospheric Modeling, its now casting and forecast-ing. Therefore, National Physical Laboratory (NPL), New Delhi has develop a user friendly, Empirical Ionospheric Model (NPL Model) for the Indian zone which gives all the F-region Parameters like foF2, NmF2, hmF2, Ne Profiles and the Ionospheric Electron Content (IEC) for different Radio Communication/Navigational applications. Basically, two HF prediction models for short and long term predictions are developed for equatorial and low latitude iono-sphere. Short term HF prediction model is based on Multiple Regression Analysis (MRA) for the dependence of F-region parameters namely foF2 and M(3000)F2, on solar 2800 MHz flux (F10), and geomagnetic index Ap whereas for long term prediction, Second Degree (SD) coefficients are generated by fitting monthly median foF2 and M(3000)F2 with corresponding 12 monthly mean sunspot numbers (R12) using data over three solar cycles. For generating MRA coefficients, daily foF2, M(3000)F2 values for each hour, obtained from Delhi (28.6N, 77.1E) digital ionosonde for about half a solar cycle are used. MRA coefficients, separately for quiet (Ap25) periods, for foF2 and M(3000)F2, are obtained for every month over 24 UT times using daily F10 and Ap values. Whereas SD coefficients are obtained each month at all local times for all the 14 stations covering a geographic latitude range from about 0 to 45 N. IEC model is developed in two ways. Firstly, IEC model is also developed using monthly median foF2 and hmF2 values for each hours for all the 14 stations which are feed into IRI 2000 model to calculate respective IEC values for two altitudes namely 1000km and 2000km. Then, second degree coefficients are generated by fitting monthly median IEC with corresponding 12 monthly mean

  7. A Parallel Hypothesis Method of Autonomous Underwater Vehicle Navigation

    Science.gov (United States)

    2009-06-01

    matching ( TERCOM ), as presented in Golden’s seminal article [30]. Since then, the idea of terrain relative navigation has been adapted for underwater...SMG Speed Made Good SMM Static Multiple Model SR Slant Range STRONG Single Transponder Range Only Navigation SVP Sound Velocity Profile 261 TERCOM ...Geological Survey, 1998. [29] A. Gelb, editor. Applied Optimal Estimation. MIT Press, Cambridge, MA, 1974. [30] J.P. Golden. Terrain contour matching ( TERCOM

  8. GNSS applications and methods

    CERN Document Server

    Gleason, Scott

    2009-01-01

    Placing emphasis on applications development, this unique resource offers a highly practical overview of GNSS (global navigation satellite systems), including GPS. The applications presented in the book range from the traditional location applications to combining GNSS with other sensors and systems and into more exotic areas, such as remote sensing and space weather monitoring. Written by leading experts in the field, this book presents the fundamental underpinnings of GNSS and provides you with detailed examples of various GNSS applications. Moreover, the software included with the book cont

  9. Advanced Bayesian Methods for Lunar Surface Navigation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The key innovation of this project is the application of advanced Bayesian methods to integrate real-time dense stereo vision and high-speed optical flow with an...

  10. Advanced Bayesian Methods for Lunar Surface Navigation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The key innovation of this project will be the application of advanced Bayesian methods to integrate real-time dense stereo vision and high-speed optical flow with...

  11. On-the-fly Locata/inertial navigation system integration for precise maritime application

    Science.gov (United States)

    Jiang, Wei; Li, Yong; Rizos, Chris

    2013-10-01

    The application of Global Navigation Satellite System (GNSS) technology has meant that marine navigators have greater access to a more consistent and accurate positioning capability than ever before. However, GNSS may not be able to meet all emerging navigation performance requirements for maritime applications with respect to service robustness, accuracy, integrity and availability. In particular, applications in port areas (for example automated docking) and in constricted waterways, have very stringent performance requirements. Even when an integrated inertial navigation system (INS)/GNSS device is used there may still be performance gaps. GNSS signals are easily blocked or interfered with, and sometimes the satellite geometry may not be good enough for high accuracy and high reliability applications. Furthermore, the INS accuracy degrades rapidly during GNSS outages. This paper investigates the use of a portable ground-based positioning system, known as ‘Locata’, which was integrated with an INS, to provide accurate navigation in a marine environment without reliance on GNSS signals. An ‘on-the-fly’ Locata resolution algorithm that takes advantage of geometry change via an extended Kalman filter is proposed in this paper. Single-differenced Locata carrier phase measurements are utilized to achieve accurate and reliable solutions. A ‘loosely coupled’ decentralized Locata/INS integration architecture based on the Kalman filter is used for data processing. In order to evaluate the system performance, a field trial was conducted on Sydney Harbour. A Locata network consisting of eight Locata transmitters was set up near the Sydney Harbour Bridge. The experiment demonstrated that the Locata on-the-fly (OTF) algorithm is effective and can improve the system accuracy in comparison with the conventional ‘known point initialization’ (KPI) method. After the OTF and KPI comparison, the OTF Locata/INS integration is then assessed further and its performance

  12. Analysis of a novel device-level SINS/ACFSS deeply integrated navigation method

    Science.gov (United States)

    Zhang, Hao; Qin, Shiqiao; Wang, Xingshu; Jiang, Guangwen; Tan, Wenfeng; Wu, Wei

    2017-02-01

    The combination of the strap-down inertial navigation system(SINS) and the celestial navigation system(CNS) is one of the popular measures to constitute the integrated navigation system. A star sensor(SS) is used as a precise attitude determination device in CNS. To solve the problem that the star image obtained by SS is motion-blurred under dynamic conditions, the attitude-correlated frames(ACF) approach is presented and the star sensor which works based on ACF approach is named ACFSS. Depending on the ACF approach, a novel device-level SINS/ACFSS deeply integrated navigation method is proposed in this paper. Feedback to the ACF process from the error of the gyro is one of the typical characters of the SINS/CNS deeply integrated navigation method. Herein, simulation results have verified its validity and efficiency in improving the accuracy of gyro and it can be proved that this method is feasible.

  13. Systems and Methods for Determining Inertial Navigation System Faults

    Science.gov (United States)

    Bharadwaj, Raj Mohan (Inventor); Bageshwar, Vibhor L. (Inventor); Kim, Kyusung (Inventor)

    2017-01-01

    An inertial navigation system (INS) includes a primary inertial navigation system (INS) unit configured to receive accelerometer measurements from an accelerometer and angular velocity measurements from a gyroscope. The primary INS unit is further configured to receive global navigation satellite system (GNSS) signals from a GNSS sensor and to determine a first set of kinematic state vectors based on the accelerometer measurements, the angular velocity measurements, and the GNSS signals. The INS further includes a secondary INS unit configured to receive the accelerometer measurements and the angular velocity measurements and to determine a second set of kinematic state vectors of the vehicle based on the accelerometer measurements and the angular velocity measurements. A health management system is configured to compare the first set of kinematic state vectors and the second set of kinematic state vectors to determine faults associated with the accelerometer or the gyroscope based on the comparison.

  14. Method of Improving the Navigation Accuracy of SINS by Continuous Rotation

    Institute of Scientific and Technical Information of China (English)

    YANG Yong; MIAO Ling-juan; SHEN Jun

    2005-01-01

    A method of improving the navigation accuracy of strapdown inertial navigation system (SINS) is studied. The particular technique discussed involves the continuous rotation of gyros and accelerometers cluster about the vertical axis of the vehicle. Then the errors of these sensors will have periodic variation corresponding to components along the body frame. Under this condition, the modulated sensor errors produce reduced system errors. Theoretical analysis based on a new coordinate system defined as sensing frame and test results are presented, and they indicate the method attenuates the navigation errors brought by the gyros' random constant drift and the accelerometer's bias and their white noise compared to the conventional method.

  15. A New Robust Method for Mobile Robot Multifloor Navigation in Distributed Life Science Laboratories

    Directory of Open Access Journals (Sweden)

    Ali A. Abdulla

    2016-01-01

    Full Text Available A new robust method is proposed for multifloor navigation in distributed Life Science Laboratories. This method proposes a solution for many technical issues including (a mapping and localization with ceiling landmarks and a StarGazer module for achieving an accurate and low cost multifloor navigation system, (b a new method for path planning to navigate across multiple floor environments called backbone method and embedded transportation management system, (c elevator environment handler with the necessary procedures to interact with the elevator presenting a new approach for elevator entry button and internal buttons detection, and (d communication system to get an expandable network; this method utilizes a TCP/IP network for the communication. Many experiments in real Life Science Laboratories proved the efficient performance of the developed multifloor navigation system in life science environment.

  16. Super-resolution image reconstruction methods applied to GFE-referenced navigation system

    Science.gov (United States)

    Yan, Lei; Lin, Yi; Tong, Qingxi

    2007-11-01

    The problem about reference grid data's overlarge spacing, which makes deviated estimation of un-surveyed points and poor accuracy of correlation positioning, has been embarrassing Geophysical Fields of the Earth (GFE) referenced navigation research. The super-resolution images reconstruction methods in remote sensing field give some inspiration, and its brief method, Maximum A-Posterior (MAP) based on Bayesian theory, is transplanted on grid data. The proposed algorithm named MAP-G can implement interpolation of reference data field by reflecting whole distribution trend. Comparison with traditional interpolation algorithms and simulation experiments on underwater terrain/gravity-aided navigation platform, indicate that MAP-G algorithm can effectively improve navigation's performance.

  17. A novel monocular visual navigation method for cotton-picking robot based on horizontal spline segmentation

    Science.gov (United States)

    Xu, ShengYong; Wu, JuanJuan; Zhu, Li; Li, WeiHao; Wang, YiTian; Wang, Na

    2015-12-01

    Visual navigation is a fundamental technique of intelligent cotton-picking robot. There are many components and cover in the cotton field, which make difficulties of furrow recognition and trajectory extraction. In this paper, a new field navigation path extraction method is presented. Firstly, the color image in RGB color space is pre-processed by the OTSU threshold algorithm and noise filtering. Secondly, the binary image is divided into numerous horizontally spline areas. In each area connected regions of neighboring images' vertical center line are calculated by the Two-Pass algorithm. The center points of the connected regions are candidate points for navigation path. Thirdly, a series of navigation points are determined iteratively on the principle of the nearest distance between two candidate points in neighboring splines. Finally, the navigation path equation is fitted by the navigation points using the least squares method. Experiments prove that this method is accurate and effective. It is suitable for visual navigation in the complex environment of cotton field in different phases.

  18. Empirical evaluation of a practical indoor mobile robot navigation method using hybrid maps

    DEFF Research Database (Denmark)

    Özkil, Ali Gürcan; Fan, Zhun; Xiao, Jizhong

    2010-01-01

    This video presents a practical navigation scheme for indoor mobile robots using hybrid maps. The method makes use of metric maps for local navigation and a topological map for global path planning. Metric maps are generated as occupancy grids by a laser range finder to represent local information...... that the method is implemented successfully on physical robot in a hospital environment, which provides a practical solution for indoor navigation........ The navigation scheme based on the hybrid metric-topologica maps saves memory space and is also scalable and adaptable since new local maps can be easily added to the global topology, and the method can be deployed with minimum amount of modification if new areas are to be explored. The video demonstrated...

  19. Learning anticipation via spiking networks: application to navigation control.

    Science.gov (United States)

    Arena, Paolo; Fortuna, Luigi; Frasca, Mattia; Patané, Luca

    2009-02-01

    In this paper, we introduce a network of spiking neurons devoted to navigation control. Three different examples, dealing with stimuli of increasing complexity, are investigated. In the first one, obstacle avoidance in a simulated robot is achieved through a network of spiking neurons. In the second example, a second layer is designed aiming to provide the robot with a target approaching system, making it able to move towards visual targets. Finally, a network of spiking neurons for navigation based on visual cues is introduced. In all cases, the robot was assumed to rely on some a priori known responses to low-level sensors (i.e., to contact sensors in the case of obstacles, to proximity target sensors in the case of visual targets, or to the visual target for navigation with visual cues). Based on their knowledge, the robot has to learn the response to high-level stimuli (i.e., range finder sensors or visual input). The biologically plausible paradigm of spike-timing-dependent plasticity (STDP) is included in the network to make the system able to learn high-level responses that guide navigation through a simple unstructured environment. The learning procedure is based on classical conditioning.

  20. Estimation with applications to tracking and navigation theory, algorthims and software

    CERN Document Server

    Bar-Shalom, Yaakov; Kirubarajan, Thiagalingam

    2001-01-01

    Expert coverage of the design and implementation of state estimation algorithms for tracking and navigation Estimation with Applications to Tracking and Navigation treats the estimation of various quantities from inherently inaccurate remote observations. It explains state estimator design using a balanced combination of linear systems, probability, and statistics. The authors provide a review of the necessary background mathematical techniques and offer an overview of the basic concepts in estimation. They then provide detailed treatments of all the major issues in estimatio

  1. Real-time total system error estimation:Modeling and application in required navigation performance

    Institute of Scientific and Technical Information of China (English)

    Fu Li; Zhang Jun; Li Rui

    2014-01-01

    In required navigation performance (RNP), total system error (TSE) is estimated to pro-vide a timely warning in the presence of an excessive error. In this paper, by analyzing the under-lying formation mechanism, the TSE estimation is modeled as the estimation fusion of a fixed bias and a Gaussian random variable. To address the challenge of high computational load induced by the accurate numerical method, two efficient methods are proposed for real-time application, which are called the circle tangent ellipse method (CTEM) and the line tangent ellipse method (LTEM), respectively. Compared with the accurate numerical method and the traditional scalar quantity summation method (SQSM), the computational load and accuracy of these four methods are exten-sively analyzed. The theoretical and experimental results both show that the computing time of the LTEM is approximately equal to that of the SQSM, while it is only about 1/30 and 1/6 of that of the numerical method and the CTEM. Moreover, the estimation result of the LTEM is parallel with that of the numerical method, but is more accurate than those of the SQSM and the CTEM. It is illustrated that the LTEM is quite appropriate for real-time TSE estimation in RNP application.

  2. Construction Method of the Topographical Features Model for Underwater Terrain Navigation

    Directory of Open Access Journals (Sweden)

    Wang Lihui

    2015-09-01

    Full Text Available Terrain database is the reference basic for autonomous underwater vehicle (AUV to implement underwater terrain navigation (UTN functions, and is the important part of building topographical features model for UTN. To investigate the feasibility and correlation of a variety of terrain parameters as terrain navigation information metrics, this paper described and analyzed the underwater terrain features and topography parameters calculation method. Proposing a comprehensive evaluation method for terrain navigation information, and constructing an underwater navigation information analysis model, which is associated with topographic features. Simulation results show that the underwater terrain features, are associated with UTN information directly or indirectly, also affect the terrain matching capture probability and the positioning accuracy directly.

  3. A self-calibration method for tri-axis rotational inertial navigation system

    Science.gov (United States)

    Gao, Pengyu; Li, Kui; Wang, Lei; Liu, Zengjun

    2016-11-01

    The navigation accuracy of the rotational inertial navigation system (RINS) could be greatly improved by periodically rotating the inertial measurement unit (IMU) with gimbals. However, error parameters in RINS should be effectively calibrated and compensated. In this paper, a self-calibration method is proposed for tri-axis RINS using attitude errors and velocity errors as measurements. The proposed calibration scheme is designed as three separate steps, and a certain gimbal rotates continuously in each step. All the error parameters in the RINS are calibrated when the whole scheme finishes. The separate calibration steps reduce the correlations between error parameters, and the observability of errors in this method is clear to demonstrate according to the relations between navigation errors and error parameters when gimbals rotate. Each calibration step only lasts 12 min, thus gyro drifts and accelerometers biases could be regarded as constant. The proposed calibration scheme is tested in both simulation and actual tri-axis RINS, and simulation and experimental results show that all 23 error parameters could be well estimated in tri-axis RINS. A long-term vehicle navigation experiment results show that after calibration and compensation, the navigation performance has doubled approximately, and the velocity accuracy is less than 2 m s-1 while the position accuracy is less than 1500 m, fully illustrating the significance of the proposed self-calibration method in improving the navigation performance of RINS.

  4. Application of surgical navigation in styloidectomy for treating Eagle's syndrome.

    Science.gov (United States)

    Dou, Geng; Zhang, Yu; Zong, Chunlin; Chen, Yuanli; Guo, Yuxuan; Tian, Lei

    2016-01-01

    The present study aimed to evaluate the feasibility, accuracy, and clinical effect of intraoperative navigation for resection of elongated styloid process (ESP) in Eagle's syndrome. Twelve patients with Eagle's syndrome with clinically and radiologically established diagnoses of ESP were included in this study. Preoperatively, all patients accepted three-dimensional computed tomography scan, and their skulls' digital imaging and communications in medicine data were inputed into the navigation system workstation to make a virtual surgical plan in advance. During surgery, the intraoperative navigation was performed to excise the ESP accurately for both intraoral (without tonsillectomy) and extraoral approaches following the virtual plan. Postoperatively, the amount of bleeding, duration of operation and hospitalization, and the length of resected styloid process (SP) were measured and compared with those cases that had traditional styloidectomy without the help of surgical navigation (SN). A simple visual analog scale questionnaire was also used to assess patients' satisfaction and the surgery effect after 3 months. In total, 17 SPs from 12 patients were precisely resected by intraoral parapharyngeal approach and small cervical approach with the aid of SN. No severe complications occurred in any patients. The length of resected SPs was 21.93±14.26 mm. The average amount of bleeding and duration of operation were 22.50±8.54 mL and 40.35±11.81 minutes, respectively, which were all less than with traditional styloidectomy. The visual analog scale analysis showed that the discomfort in all patients was relieved, while ten patients' symptoms were improved greatly, and two patients had some improvement. The higher accuracy of surgery, lesser amount of bleeding, decreased duration of surgery and hospitalization, absence of complications, and improved subjective symptoms indicated that SN is an effective and minimally invasive surgical procedure suitable for resection of

  5. Comparison of Global Navigation Satellite System Devices on Speed Tracking in Road (TranSPORT Applications

    Directory of Open Access Journals (Sweden)

    Matej Supej

    2014-12-01

    Full Text Available Global Navigation Satellite Systems (GNSS are, in addition to being most widely used vehicle navigation method, becoming popular in sport-related tests. There is a lack of knowledge regarding tracking speed using GNSS, therefore the aims of this study were to examine under dynamic conditions: (1 how accurate technologically different GNSS measure speed and (2 how large is latency in speed measurements in real time applications. Five GNSSs were tested. They were fixed to a car’s roof-rack: a  smart phone, a wrist watch, a handheld device, a professional system for testing vehicles and a high-end Real Time Kinematics (RTK GNSS. The speed data were recorded and analyzed during rapid acceleration and deceleration as well as at steady speed. The study produced four main findings. Higher frequency and high quality GNSS receivers track speed at least at comparable accuracy to a vehicle speedometer. All GNSS systems measured maximum speed and movement at a constant speed well. Acceleration and deceleration have different level of error at different speeds. Low cost GNSS receivers operating at 1 Hz sampling rate had high latency (up to 2.16 s and are not appropriate for tracking speed in real time, especially during dynamic movements.

  6. Indoor integrated navigation and synchronous data acquisition method for Android smartphone

    Science.gov (United States)

    Hu, Chunsheng; Wei, Wenjian; Qin, Shiqiao; Wang, Xingshu; Habib, Ayman; Wang, Ruisheng

    2015-08-01

    Smartphones are widely used at present. Most smartphones have cameras and kinds of sensors, such as gyroscope, accelerometer and magnet meter. Indoor navigation based on smartphone is very important and valuable. According to the features of the smartphone and indoor navigation, a new indoor integrated navigation method is proposed, which uses MEMS (Micro-Electro-Mechanical Systems) IMU (Inertial Measurement Unit), camera and magnet meter of smartphone. The proposed navigation method mainly involves data acquisition, camera calibration, image measurement, IMU calibration, initial alignment, strapdown integral, zero velocity update and integrated navigation. Synchronous data acquisition of the sensors (gyroscope, accelerometer and magnet meter) and the camera is the base of the indoor navigation on the smartphone. A camera data acquisition method is introduced, which uses the camera class of Android to record images and time of smartphone camera. Two kinds of sensor data acquisition methods are introduced and compared. The first method records sensor data and time with the SensorManager of Android. The second method realizes open, close, data receiving and saving functions in C language, and calls the sensor functions in Java language with JNI interface. A data acquisition software is developed with JDK (Java Development Kit), Android ADT (Android Development Tools) and NDK (Native Development Kit). The software can record camera data, sensor data and time at the same time. Data acquisition experiments have been done with the developed software and Sumsang Note 2 smartphone. The experimental results show that the first method of sensor data acquisition is convenient but lost the sensor data sometimes, the second method is much better in real-time performance and much less in data losing. A checkerboard image is recorded, and the corner points of the checkerboard are detected with the Harris method. The sensor data of gyroscope, accelerometer and magnet meter have

  7. Error Modeling, Calibration, and Nonlinear Interpolation Compensation Method of Ring Laser Gyroscope Inertial Navigation System

    Directory of Open Access Journals (Sweden)

    Jianli Li

    2013-01-01

    Full Text Available In order to improve the precision of Strapdown Inertial Navigation System (SINS and reduce the complexity of the traditional calibration method, a novel calibration and compensation scheme is proposed. An optimization calibration method with four-direction rotations is designed to calculate all error coefficients of Ring Laser Gyroscope (RLG SINS in a series of constant temperatures. According to the actual working environment, the temperature errors of RLG SINS are compensated by a nonlinear interpolation compensation algorithm. The experimental results show that the inertial navigation errors of the proposed method are reduced.

  8. An online visual loop closure detection method for indoor robotic navigation

    Science.gov (United States)

    Erhan, Can; Sariyanidi, Evangelos; Sencan, Onur; Temeltas, Hakan

    2015-01-01

    In this paper, we present an enhanced loop closure method* based on image-to-image matching relies on quantized local Zernike moments. In contradistinction to the previous methods, our approach uses additional depth information to extract Zernike moments in local manner. These moments are used to represent holistic shape information inside the image. The moments in complex space that are extracted from both grayscale and depth images are coarsely quantized. In order to find out the similarity between two locations, nearest neighbour (NN) classification algorithm is performed. Exemplary results and the practical implementation case of the method are also given with the data gathered on the testbed using a Kinect. The method is evaluated in three different datasets of different lighting conditions. Additional depth information with the actual image increases the detection rate especially in dark environments. The results are referred as a successful, high-fidelity online method for visual place recognition as well as to close navigation loops, which is a crucial information for the well known simultaneously localization and mapping (SLAM) problem. This technique is also practically applicable because of its low computational complexity, and performing capability in real-time with high loop closing accuracy.

  9. A Visual Navigation Method of Mobile Robot Using a Sketched Semantic Map

    Directory of Open Access Journals (Sweden)

    Xinde Li

    2012-10-01

    Full Text Available A new visual navigation method for a mobile robot is proposed in this paper. Its originality lies in integrating a sketched map with a semantic map together for the robot’s navigation and in using unified tags to help recognize landmarks. In this sketched semantic map, the outline and semantic information of key referenced objects are used to represent themselves and a rough route for the robot’s navigation is also sketched. Over the course of robot navigation along the route, and in order to easily recognize the referenced objects from the complex background, a kind of unified label is designed and pasted on the potential referenced objects in advance. A recognition method based on the Pseudo-Zernike Moment and the Normalized Moment of Inertia is used to compute the matching degree between the real‐time image of the referenced object and its similar outline in a database. In addition, the odometer information is also fused so as to roughly localize the robot. Finally, through a series of experiments, the advantage and efficiency of the new navigation method with real‐time dynamic obstacle avoidance are testified with the help of the imprecise real map and route.

  10. A Quick Method of Phase Ambiguity Resolution with X-Ray Pulsar Navigation

    Directory of Open Access Journals (Sweden)

    Xuerui Li

    2012-09-01

    Full Text Available In this study, we proposes a quick resolution method based on space search method which is based on least square method, space search method and ambiguity covariance method. The results of simulation indicate that this method can effectively improve the speed and efficiency of phase ambiguity resolution and has some certain reference value to the researches which is related to X-ray pulsar navigation.

  11. Flight Mechanics/Estimation Theory Symposium. [with application to autonomous navigation and attitude/orbit determination

    Science.gov (United States)

    Fuchs, A. J. (Editor)

    1979-01-01

    Onboard and real time image processing to enhance geometric correction of the data is discussed with application to autonomous navigation and attitude and orbit determination. Specific topics covered include: (1) LANDSAT landmark data; (2) star sensing and pattern recognition; (3) filtering algorithms for Global Positioning System; and (4) determining orbital elements for geostationary satellites.

  12. Hybrid Map-Based Navigation Method for Unmanned Ground Vehicle in Urban Scenario

    Directory of Open Access Journals (Sweden)

    Huiyan Chen

    2013-07-01

    Full Text Available To reduce the data size of metric map and map matching computational cost in unmanned ground vehicle self-driving navigation in urban scenarios, a metric-topological hybrid map navigation system is proposed in this paper. According to the different positioning accuracy requirements, urban areas are divided into strong constraint (SC areas, such as roads with lanes, and loose constraint (LC areas, such as intersections and open areas. As direction of the self-driving vehicle is provided by traffic lanes and global waypoints in the road network, a simple topological map is fit for the navigation in the SC areas. While in the LC areas, the navigation of the self-driving vehicle mainly relies on the positioning information. Simultaneous localization and mapping technology is used to provide a detailed metric map in the LC areas, and a window constraint Markov localization algorithm is introduced to achieve accurate position using laser scanner. Furthermore, the real-time performance of the Markov algorithm is enhanced by using a constraint window to restrict the size of the state space. By registering the metric maps into the road network, a hybrid map of the urban scenario can be constructed. Real unmanned vehicle mapping and navigation tests demonstrated the capabilities of the proposed method.

  13. Inertial Navigation Sensors

    Science.gov (United States)

    2010-03-01

    Capteurs de navigation a faible cout et technologie d’integration) RTO-EN-SET-116(2010) 14. ABSTRACT For many navigation applications , improved...ABSTRACT For many navigation applications , improved accuracy/performance is not necessarily the most important issue, but meeting performance at...reduced cost and size is. In particular, small navigation sensor size allows the introduction of guidance, navigation, and control into applications

  14. A navigation flow map method of representing students' searching behaviors and strategies on the web, with relation to searching outcomes.

    Science.gov (United States)

    Lin, Chia-Ching; Tsai, Chin-Chung

    2007-10-01

    To acquire a better understanding of the online search strategies that students employ to use the Internet, this study investigated six university students' approaches to Web-based information searches. A new method, called navigation flow map (NFM), is presented that graphically displays the fluid and multilayered relationships between Web navigation and information retrieval that students use while navigating the Web. To document the application of NFM, the Web search strategies of six university students were analyzed as they used the Internet to perform two different tasks: scientific-based and social studies-based information searches. Through protocol analyses using the NFM method, the students' searching strategies were categorized into two types: Match or Exploration. The findings revealed that participants with an Exploration approach had more complicated and richer task-specific ways of searching information than those with a Match approach; and further, through between-task comparisons, we found that participants appeared to use different searching strategies to process natural science information compared to social studies information. Finally, the participants in the Exploration group also exhibited better task performance on the criterion measures than those in the Match group.

  15. Preface: BeiDou Navigation Satellite System (BDS)/GNSS+: Recent progress and new applications

    Science.gov (United States)

    Jin, Shuanggen

    2017-02-01

    Nowadays, the new China's BeiDou Navigation Satellite System (BDS) has been developed well. At the end of 2016, over 23 BDS satellites were launched, including five geostationary Earth orbit (GEO) satellites, five inclined geosynchronous orbit (IGSO) satellites and nine medium Earth orbit (MEO) satellites. The current BDS service covers China and most Asia-Pacific regions with accuracy of better than 10 m in positioning, 0.2 m/s in velocity and 50 ns in timing. The BDS with global coverage will be completely established by 2020 with five GEO satellites and 30 MEO satellites. The main function of BDS is the positioning, navigation and timing (PNT) as well as short message communications. Together with the United States' GPS, Russia's GLONASS and the European Union's Galileo system as well as other regional augmentation systems, more new applications of multi-Global Navigation Satellite Systems (GNSS) will be exploited and realized in the next decades.

  16. Navigation Facility for High Accuracy Offline Trajectory and Attitude Estimation in Airborne Applications

    Directory of Open Access Journals (Sweden)

    A. Renga

    2013-01-01

    Full Text Available The paper focuses on a navigation facility, relying on commercial-off-the-shelf (COTS technology, developed to generate high-accuracy attitude and trajectory measurements in postprocessing. Target performance is cm-level positioning with tenth of degree attitude accuracy. The facility is based on the concept of GPS-aided inertial navigation but comprises carrier-phase differential GPS (CDGPS processing and attitude estimation based on multiantenna GPS configurations. Expected applications of the system include: (a performance assessment of integrated navigation systems, developed for general aviation aircraft and medium size unmanned aircraft systems (UAS; (b generation of reference measurements to evaluate the flight performance of airborne sensors (e.g., radar or laser; and (c generation of reference trajectory and attitude for improving imaging quality of airborne remote sensing data. The paper describes system architecture, selected algorithms for data processing and integration, and theoretical performance evaluation. Experimental results are also presented confirming the effectiveness of the implemented approach.

  17. Positioning Errors Predicting Method of Strapdown Inertial Navigation Systems Based on PSO-SVM

    Directory of Open Access Journals (Sweden)

    Xunyuan Yin

    2013-01-01

    Full Text Available The strapdown inertial navigation systems (SINS have been widely used for many vehicles, such as commercial airplanes, Unmanned Aerial Vehicles (UAVs, and other types of aircrafts. In order to evaluate the navigation errors precisely and efficiently, a prediction method based on support vector machine (SVM is proposed for positioning error assessment. Firstly, SINS error models that are used for error calculation are established considering several error resources with respect to inertial units. Secondly, flight paths for simulation are designed. Thirdly, the -SVR based prediction method is proposed to predict the positioning errors of navigation systems, and particle swarm optimization (PSO is used for the SVM parameters optimization. Finally, 600 sets of error parameters of SINS are utilized to train the SVM model, which is used for the performance prediction of new navigation systems. By comparing the predicting results with the real errors, the latitudinal predicting accuracy is 92.73%, while the longitudinal predicting accuracy is 91.64%, and PSO is effective to increase the prediction accuracy compared with traditional SVM with fixed parameters. This method is also demonstrated to be effective for error prediction for an entire flight process. Moreover, the prediction method can save 75% of calculation time compared with analyses based on error models.

  18. Real-time fault detection method based on belief rule base for aircraft navigation system

    Institute of Scientific and Technical Information of China (English)

    Zhao Xin; Wang Shicheng; Zhang Jinsheng; Fan Zhiliang; Min Haibo

    2013-01-01

    Real-time and accurate fault detection is essential to enhance the aircraft navigation system's reliability and safety.The existent detection methods based on analytical model draws back at simultaneously detecting gradual and sudden faults.On account of this reason,we propose an online detection solution based on non-analytical model.In this article,the navigation system fault detection model is established based on belief rule base (BRB),where the system measuring residual and its changing rate are used as the inputs of BRB model and the fault detection function as the output.To overcome the drawbacks of current parameter optimization algorithms for BRB and achieve online update,a parameter recursive estimation algorithm is presented for online BRB detection model based on expectation maximization (EM) algorithm.Furthermore,the proposed method is verified by navigation experiment.Experimental results show that the proposed method is able to effectively realize online parameter evaluation in navigation system fault detection model.The output of the detection model can track the fault state very well,and the faults can be diagnosed in real time and accurately.In addition,the detection ability,especially in the probability of false detection,is superior to offline optimization method,and thus the system reliability has great improvement.

  19. Adaptive Iterated Extended Kalman Filter and Its Application to Autonomous Integrated Navigation for Indoor Robot

    Directory of Open Access Journals (Sweden)

    Yuan Xu

    2014-01-01

    Full Text Available As the core of the integrated navigation system, the data fusion algorithm should be designed seriously. In order to improve the accuracy of data fusion, this work proposed an adaptive iterated extended Kalman (AIEKF which used the noise statistics estimator in the iterated extended Kalman (IEKF, and then AIEKF is used to deal with the nonlinear problem in the inertial navigation systems (INS/wireless sensors networks (WSNs-integrated navigation system. Practical test has been done to evaluate the performance of the proposed method. The results show that the proposed method is effective to reduce the mean root-mean-square error (RMSE of position by about 92.53%, 67.93%, 55.97%, and 30.09% compared with the INS only, WSN, EKF, and IEKF.

  20. Adaptive iterated extended Kalman filter and its application to autonomous integrated navigation for indoor robot.

    Science.gov (United States)

    Xu, Yuan; Chen, Xiyuan; Li, Qinghua

    2014-01-01

    As the core of the integrated navigation system, the data fusion algorithm should be designed seriously. In order to improve the accuracy of data fusion, this work proposed an adaptive iterated extended Kalman (AIEKF) which used the noise statistics estimator in the iterated extended Kalman (IEKF), and then AIEKF is used to deal with the nonlinear problem in the inertial navigation systems (INS)/wireless sensors networks (WSNs)-integrated navigation system. Practical test has been done to evaluate the performance of the proposed method. The results show that the proposed method is effective to reduce the mean root-mean-square error (RMSE) of position by about 92.53%, 67.93%, 55.97%, and 30.09% compared with the INS only, WSN, EKF, and IEKF.

  1. Autonomous navigation method of high elliptical orbit satellite based on celestial navigation and GPS%基于天文/GPS的HEO卫星自主导航方法

    Institute of Scientific and Technical Information of China (English)

    王鹏; 张迎春

    2015-01-01

    为了实现大椭圆轨道(HEO)卫星高精度自主导航,提出一种将直接敏感地平天文导航与全球定位系统(GPS)相结合的组合导航方法.首先,分析卫星轨道��2运动模型及其所受空间摄动,建立卫星轨道动力学模型;然后,分析单一使用天文导航和GPS的优缺点,根据HEO卫星对GPS的可见性,提出在远地点只采用天文导航,而在近地点采用以天文导航为主、适时引入GPS信号进行位速测量辅助修正的方法.通过计算机仿真和结果分析表明了所提出的设计方法导航精度比单一天文导航提高72.4%∼85.6%.%In order to realize autonomous and continuous navigation information outputs for high elliptical orbit(HEO) satellite, new integrated navigation system is proposed based on celestial navigation of directly sensing stellar and global positioning system(GPS) navigation. Firstly, satellite orbit motion model is established on the satellite orbit dynamics��2 model and suffered space perturbation. Moreover, performances of single-use celestial navigation or GPS are analyzed. When the satellite is near the apogee, observation system is established by using only celestial navigation. When the satellite is near the perigee, the estimate covariance is revised through incoming GPS signal to improve the celestial navigation estimate. The autonomous navigation system is designed and simulating. The results of computer simulation show that the navigation accuracy is improved by 72.4%∼85.6%compared with the celestial navigation method.

  2. Study of the navigation methods applicable to monitoring in sites with high level of radiation; Estudio de los metodos de navegacion aplicables al monitoreo en sitios con alto nivel de radiacion

    Energy Technology Data Exchange (ETDEWEB)

    Segovia de los Rios, J.A.; Rivero G, T. [ININ, Km. 36.5 Carretera Mexico-Toluca, 52045 Salazar, Estado de Mexico (Mexico)]. E-mail: asegovia@nuclear.inin.mx; Garduno G, M.; Zapata, R. [ITT, Av. Tecnologico s/n, Metepec, Estado de Mexico (Mexico)

    2004-07-01

    In places in which high radiation levels exist is desirable to have a system that allows the realization of mensurations without the necessity of the exhibition of human resources. It is in fact in these types of situations where a robot system, or automated, in a sense but wide, it is directly applicable. So that a monitoring system, based on a mobile robot, for example, be autonomous, it is necessary to develop and to implement functional and efficient sailing algorithms that allow its use with the minimum of human intervention. Several methods exist to achieve this objective, some of them already proven and others in roads of experimentation. The present work presents some in the sailing ways but used, and specifically, the one that intends for a system of detection of flights in a place with high temperatures and high radiation levels. (Author)

  3. A reformulation of the Linear-Quadratic-Gaussian stochastic control problem for application to low thrust navigation analysis

    Science.gov (United States)

    Jacobson, R. A.

    1978-01-01

    The formulation of the classical Linear-Quadratic-Gaussian stochastic control problem as employed in low thrust navigation analysis is reviewed. A reformulation is then presented which eliminates a potentially unreliable matrix subtraction in the control calculations, improves the computational efficiency, and provides for a cleaner computational interface between the estimation and control processes. Lastly, the application of the U-D factorization method to the reformulated equations is examined with the objective of achieving a complete set of factored equations for the joint estimation and control problem.

  4. Illumination Tolerance for Visual Navigation with the Holistic Min-Warping Method

    Directory of Open Access Journals (Sweden)

    Ralf Möller

    2014-02-01

    Full Text Available Holistic visual navigation methods are an emerging alternative to the ubiquitous feature-based methods. Holistic methods match entire images pixel-wise instead of extracting and comparing local feature descriptors. In this paper we investigate which pixel-wise distance measures are most suitable for the holistic min-warping method with respect to illumination invariance. Two novel approaches are presented: tunable distance measures—weighted combinations of illumination-invariant and illumination-sensitive terms—and two novel forms of “sequential” correlation which are only invariant against intensity shifts but not against multiplicative changes. Navigation experiments on indoor image databases collected at the same locations but under different conditions of illumination demonstrate that tunable distance measures perform optimally by mixing their two portions instead of using the illumination-invariant term alone. Sequential correlation performs best among all tested methods, and as well but much faster in an approximated form. Mixing with an additional illumination-sensitive term is not necessary for sequential correlation. We show that min-warping with approximated sequential correlation can successfully be applied to visual navigation of cleaning robots.

  5. A hybrid data fusion method for GNSS/INS integration navigation system

    Science.gov (United States)

    Yang, Ling; Li, Bofeng; Shen, Yunzhong; Li, Haojun

    2017-04-01

    Although DGNSS is widely used and PPP-GNSS is nowadays a viable precise positioning technology option, the major disadvantage of GNSS still remains: signal blockage due to obstructions in urban and built up environments, and extreme power attenuation of the signals when operated indoors. The combination of GNSS with other sensors, such as a self-contained inertial navigation system (INS), provides an ideal position and attitude determination solution which can not only mitigate the weakness of GNSS, but also bound the INS error that otherwise would grow with time when the INS operates alone. However, the navigation accuracy provided by GNSS/INS strongly depends on the quality and geometry of the GNSS observations, the quality of the INS technology used, and the integration model applied. There are two main types of coupled schemes for integration systems: loosely coupled integration and tightly coupled integration. In loosely coupled integration, position measurements are taken from both systems and combined optimally, usually in a Kalman filter. Tightly coupled integration directly combines the raw pseudorange or carrier phase measurements of GNSS with inertial measurements in an extended Kalman filter. The latter technique improves the ability to resolve ambiguities, i.e. allows a quicker recovery from outage events such as a loss of signal under vegetation. In recent years, tightly coupled differential carrier phase GNSS/INS integration has become popular, because it has the advantage of providing accurate position information even when GPS measurements are rank-deficient in stand-alone processing and is theoretically optimal in a filtering sense, especially in urban navigation applications. However, the heavier computational burden and sensor communication usually complicate the tightly coupled integration and reduce the system efficiency, compared with the loosely coupled integration. In this paper, it has been proved that the loosely coupled and tightly

  6. Design and Application of a Novel Virtual Reality Navigational Technology (VRNChair

    Directory of Open Access Journals (Sweden)

    Ahmad Byagowi

    2014-01-01

    Full Text Available This paper presents a novel virtual reality navigation (VRN input device, called the VRNChair, offering an intuitive and natural way to interact with virtual reality (VR environments. Traditionally, VR navigation tests are performed using stationary input devices such as keyboards or joysticks. However, in case of immersive VR environment experiments, such as our recent VRN assessment, the user may feel kinetosis (motion sickness as a result of the disagreement between vestibular response and the optical flow. In addition, experience in using a joystick or any of the existing computer input devices may cause a bias in the accuracy of participant performance in VR environment experiments. Therefore, we have designed a VR navigational environment that is operated using a wheelchair (VRNChair. The VRNChair translates the movement of a manual wheelchair to feed any VR environment. We evaluated the VRNChair by testing on 34 young individuals in two groups performing the same navigational task with either the VRNChair or a joystick; also one older individual (55 years performed the same experiment with both a joystick and the VRNChair. The results indicate that the VRNChair does not change the accuracy of the performance; thus removing the plausible bias of having experience using a joystick. More importantly, it significantly reduces the effect of kinetosis. While we developed VRNChair for our spatial cognition study, its application can be in many other studies involving neuroscience, neurorehabilitation, physiotherapy, and/or simply the gaming industry.

  7. [Spectral navigation technology and its application in positioning the fruits of fruit trees].

    Science.gov (United States)

    Yu, Xiao-Lei; Zhao, Zhi-Min

    2010-03-01

    An innovative technology of spectral navigation is presented in the present paper. This new method adopts reflectance spectra of fruits, leaves and branches as one of the key navigation parameters and positions the fruits of fruit trees relying on the diversity of spectral characteristics. The research results show that the distinct smoothness as effect is available in the spectrum of leaves of fruit trees. On the other hand, gradual increasing as the trend is an important feature in the spectrum of branches of fruit trees while the spectrum of fruit fluctuates. In addition, the peak diversity of reflectance rate between fruits and leaves of fruit trees is reached at 850 nm of wavelength. So the limit value can be designed at this wavelength in order to distinguish fruits and leaves. The method introduced here can not only quickly distinguish fruits, leaves and branches, but also avoid the effects of surroundings. Compared with the traditional navigation systems based on machine vision, there are still some special and unique features in the field of positioning the fruits of fruit trees using spectral navigation technology.

  8. Evolutionary programming-based univector field navigation method for past mobile robots.

    Science.gov (United States)

    Kim, Y J; Kim, J H; Kwon, D S

    2001-01-01

    Most of navigation techniques with obstacle avoidance do not consider the robot orientation at the target position. These techniques deal with the robot position only and are independent of its orientation and velocity. To solve these problems this paper proposes a novel univector field method for fast mobile robot navigation which introduces a normalized two dimensional vector field. The method provides fast moving robots with the desired posture at the target position and obstacle avoidance. To obtain the sub-optimal vector field, a function approximator is used and trained by evolutionary programming. Two kinds of vector fields are trained, one for the final posture acquisition and the other for obstacle avoidance. Computer simulations and real experiments are carried out for a fast moving mobile robot to demonstrate the effectiveness of the proposed scheme.

  9. Fuzzy Neural Network based RFID Positioning and Navigation Method for Mobile Robots

    Directory of Open Access Journals (Sweden)

    Bo-Wen Hong

    2013-07-01

    Full Text Available This study proposes the Radio Frequency Identification (RFID indoor positioning and navigation method based on fuzzy neural network. The proposed method is applied to a wheelchair home health care robot with wireless communication. One reader and four tags are used. Based on the Received Signal Strength Indication (RSSI data, the position of the robot can be determined. Further, to overcome the measurement error problem due to environmental parameter variation, a Fuzzy Neural Network (FNN is proposed to compensate the measurement data. The FNN automatically adjust the weight, the variance and the mean value to overcome effectively the environmental parameter variation. A back-propagation algorithm is developed to achieve self-learning. The successful experiment results show that the proposed system architecture and positioning system provide satisfactory accuracy and make home health care wheelchair robot positioning system available for navigation and guidance.

  10. Performance Verification Mechanism for Adaptive Assessment e-Platform and e-Navigation Application

    Directory of Open Access Journals (Sweden)

    Chang-Shing Lee

    2015-06-01

    Full Text Available Adaptive assessment e-platform is being promoted in the world to make teachers understand students’ e-learning performance on the Internet. However, system's load testing for an adaptive assessment is a very important issue during development of such an e-platform. In this paper, we have adopted the genetic fuzzy markup language (GFML to infer the performance of an adaptive assessment e-platform. Firstly, we collected the data and information of the e-platform loading in two different mechanisms. With the collected data, the proposed CPU usage calculation mechanism is first implemented to acquire the CPU usage information from the screenshot of Ganglia. Next, we used the fuzzy c-means (FCM clustering mechanism to construct the knowledge base according to the collected data. Then, number of threads, constant timer, MySQL parameter, CPU usage, and testing time of the e-platform were utilized to infer the e-platform load performance. Finally, the genetic learning algorithm was utilized to learn the knowledge and rule base to optimize the proposed approach. From these experimental results, the proposed method is feasible for verifying the performance of an adaptive assessment e-platform. In the future, the adaptive assessment e-platform can be utilized to e-Navigation systems and applications.

  11. A Novel INS and Doppler Sensors Calibration Method for Long Range Underwater Vehicle Navigation

    Directory of Open Access Journals (Sweden)

    Wenqi Wu

    2013-10-01

    Full Text Available Since the drifts of Inertial Navigation System (INS solutions are inevitable and also grow over time, a Doppler Velocity Log (DVL is used to aid the INS to restrain its error growth. Therefore, INS/DVL integration is a common approach for Autonomous Underwater Vehicle (AUV navigation. The parameters including the scale factor of DVL and misalignments between INS and DVL are key factors which limit the accuracy of the INS/DVL integration. In this paper, a novel parameter calibration method is proposed. An iterative implementation of the method is designed to reduce the error caused by INS initial alignment. Furthermore, a simplified INS/DVL integration scheme is employed. The proposed method is evaluated with both river trial and sea trial data sets. Using 0.03°/h(1σ ring laser gyroscopes, 5 × 10−5 g(1σ quartz accelerometers and DVL with accuracy 0.5% V ± 0.5 cm/s, INS/DVL integrated navigation can reach an accuracy of about 1‰ of distance travelled (CEP in a river trial and 2‰ of distance travelled (CEP in a sea trial.

  12. A novel INS and Doppler sensors calibration method for long range underwater vehicle navigation.

    Science.gov (United States)

    Tang, Kanghua; Wang, Jinling; Li, Wanli; Wu, Wenqi

    2013-10-28

    Since the drifts of Inertial Navigation System (INS) solutions are inevitable and also grow over time, a Doppler Velocity Log (DVL) is used to aid the INS to restrain its error growth. Therefore, INS/DVL integration is a common approach for Autonomous Underwater Vehicle (AUV) navigation. The parameters including the scale factor of DVL and misalignments between INS and DVL are key factors which limit the accuracy of the INS/DVL integration. In this paper, a novel parameter calibration method is proposed. An iterative implementation of the method is designed to reduce the error caused by INS initial alignment. Furthermore, a simplified INS/DVL integration scheme is employed. The proposed method is evaluated with both river trial and sea trial data sets. Using 0.03°/h(1σ) ring laser gyroscopes, 5 × 10-5 g(1σ) quartz accelerometers and DVL with accuracy 0.5% V ± 0.5 cm/s, INS/DVL integrated navigation can reach an accuracy of about 1‰ of distance travelled (CEP) in a river trial and 2‰ of distance travelled (CEP) in a sea trial.

  13. A Novel Relative Navigation Control Strategy Based on Relation Space Method for Autonomous Underground Articulated Vehicles

    Directory of Open Access Journals (Sweden)

    Fengqian Dou

    2016-01-01

    Full Text Available This paper proposes a novel relative navigation control strategy based on the relation space method (RSM for articulated underground trackless vehicles. In the RSM, a self-organizing, competitive neural network is used to identify the space around the vehicle, and the spatial geometric relationships of the identified space are used to determine the vehicle’s optimal driving direction. For driving control, the trajectories of the articulated vehicles are analyzed, and data-based steering and speed control modules are developed to reduce modeling complexity. Simulation shows that the proposed RSM can choose the correct directions for articulated vehicles in different tunnels. The effectiveness and feasibility of the resulting novel relative navigation control strategy are validated through experiments.

  14. A new adaptive state space construction method for the mobile robot navigation

    Institute of Scientific and Technical Information of China (English)

    Huang Bingqiang; Cao Guangyi; Fei Yanqiong; Li Jianhua

    2008-01-01

    In order to solve the combinative explosion problems in a continuous and high dimensional state space, a function approximation approach is usually used to represent the state space. The normalized radial basis function (NRBF) was adopted as the local function approximator and a kind of adaptive state space construction strategy based on the NRBF (ASC-NRBF) was proposed, which enables the system to allocate appropriate number and size of the basis functions automatically. Combined with the reinforcement learning method, the proposed ASC-NRBF method was applied to the robot navigation problem. Simulation results illustrate the performance of the proposed method.

  15. Remote Sensing of Tropical Cyclones: Applications from Microwave Radiometry and Global Navigation Satellite System Reflectometry

    Science.gov (United States)

    Morris, Mary

    Tropical cyclones (TCs) are important to observe, especially over the course of their lifetimes, most of which is spent over the ocean. Very few in situ observations are available. Remote sensing has afforded researchers and forecasters the ability to observe and understand TCs better. Every remote sensing platform used to observe TCs has benefits and disadvantages. Some remote sensing instruments are more sensitive to clouds, precipitation, and other atmospheric constituents. Some remote sensing instruments are insensitive to the atmosphere, which allows for unobstructed observations of the ocean surface. Observations of the ocean surface, either of surface roughness or emission can be used to estimate ocean surface wind speed. Estimates of surface wind speed can help determine the intensity, structure, and destructive potential of TCs. While there are many methods by which TCs are observed, this thesis focuses on two main types of remote sensing techniques: passive microwave radiometry and Global Navigation Satellite System reflectometry (GNSS-R). First, we develop and apply a rain rate and ocean surface wind speed retrieval algorithm for the Hurricane Imaging Radiometer (HIRAD). HIRAD, an airborne passive microwave radiometer, operates at C-band frequencies, and is sensitive to rain absorption and emission, as well as ocean surface emission. Motivated by the unique observing geometry and high gradient rain scenes that HIRAD typically observes, a more robust rain rate and wind speed retrieval algorithm is developed. HIRAD's observing geometry must be accounted for in the forward model and retrieval algorithm, if high rain gradients are to be estimated from HIRAD's observations, with the ultimate goal of improving surface wind speed estimation. Lastly, TC science data products are developed for the Cyclone Global Navigation Satellite System (CYGNSS). The CYGNSS constellation employs GNSS-R techniques to estimate ocean surface wind speed in all precipitating

  16. Adaptive Covariance Estimation Method for LiDAR-Aided Multi-Sensor Integrated Navigation Systems

    Directory of Open Access Journals (Sweden)

    Shifei Liu

    2015-01-01

    Full Text Available The accurate estimation of measurements covariance is a fundamental problem in sensors fusion algorithms and is crucial for the proper operation of filtering algorithms. This paper provides an innovative solution for this problem and realizes the proposed solution on a 2D indoor navigation system for unmanned ground vehicles (UGVs that fuses measurements from a MEMS-grade gyroscope, speed measurements and a light detection and ranging (LiDAR sensor. A computationally efficient weighted line extraction method is introduced, where the LiDAR intensity measurements are used, such that the random range errors and systematic errors due to surface reflectivity in LiDAR measurements are considered. The vehicle pose change is obtained from LiDAR line feature matching, and the corresponding pose change covariance is also estimated by a weighted least squares-based technique. The estimated LiDAR-based pose changes are applied as periodic updates to the Inertial Navigation System (INS in an innovative extended Kalman filter (EKF design. Besides, the influences of the environment geometry layout and line estimation error are discussed. Real experiments in indoor environment are performed to evaluate the proposed algorithm. The results showed the great consistency between the LiDAR-estimated pose change covariance and the true accuracy. Therefore, this leads to a significant improvement in the vehicle’s integrated navigation accuracy.

  17. A Target-Orientated Marker Image Binarization Method for Orthopaedic Surgical Navigation System

    Institute of Scientific and Technical Information of China (English)

    YAN Shi-ju; CHEN Xiao-jun; WANG Cheng-tao; SU Ying-ying; XIA Qing

    2007-01-01

    Camera calibration is the key technique in a C-arm based orthopaedic surgical navigation system. The extraction of marker location information is a necessary step in the calibration process. Ideal marker images should possess uniform background and contain marker shadow only, but in fact marker images always possess nonuniform background and are contaminated by noise and unwanted anatomic information, making the extraction very difficult. A target-orientated marker shadow extraction method was proposed. With this method a proper threshold for marker image binarization can be determined.

  18. Applications of two-way satellite time and frequency transfer in the BeiDou navigation satellite system

    Science.gov (United States)

    Zhou, ShanShi; Hu, XiaoGong; Liu, Li; Guo, Rui; Zhu, LingFeng; Chang, ZhiQiao; Tang, ChengPan; Gong, XiuQiang; Li, Ran; Yu, Yang

    2016-10-01

    A two-way satellite time and frequency transfer (TWSTFT) device equipped in the BeiDou navigation satellite system (BDS) can calculate clock error between satellite and ground master clock. TWSTFT is a real-time method with high accuracy because most system errors such as orbital error, station position error, and tropospheric and ionospheric delay error can be eliminated by calculating the two-way pseudorange difference. Another method, the multi-satellite precision orbit determination (MPOD) method, can be applied to estimate satellite clock errors. By comparison with MPOD clock estimations, this paper discusses the applications of the BDS TWSTFT clock observations in satellite clock measurement, satellite clock prediction, navigation system time monitor, and satellite clock performance assessment in orbit. The results show that with TWSTFT clock observations, the accuracy of satellite clock prediction is higher than MPOD. Five continuous weeks of comparisons with three international GNSS Service (IGS) analysis centers (ACs) show that the reference time difference between BeiDou time (BDT) and golbal positoning system (GPS) time (GPST) realized IGS ACs is in the tens of nanoseconds. Applying the TWSTFT clock error observations may obtain more accurate satellite clock performance evaluation in the 104 s interval because the accuracy of the MPOD clock estimation is not sufficiently high. By comparing the BDS and GPS satellite clock performance, we found that the BDS clock stability at the 103 s interval is approximately 10-12, which is similar to the GPS IIR.

  19. The application of surgical navigation system using optical molecular imaging technology in orthotopic breast cancer and metastasis studies

    Science.gov (United States)

    Chi, Chongwei; Zhang, Qian; Kou, Deqiang; Ye, Jinzuo; Mao, Yamin; Qiu, Jingdan; Wang, Jiandong; Yang, Xin; Du, Yang; Tian, Jie

    2014-02-01

    Currently, it has been an international focus on intraoperative precise positioning and accurate resection of tumor and metastases. The methods such as X-rays, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) have played an important role in preoperative accurate diagnosis. However, most of them are inapplicable for intraoperative surgery. We have proposed a surgical navigation system based on optical molecular imaging technology for intraoperative detection of tumors and metastasis. This system collects images from two CCD cameras for real-time fluorescent and color imaging. For image processing, the template matching algorithm is used for multispectral image fusion. For the application of tumor detection, the mouse breast cancer cell line 4T1-luc, which shows highly metastasis, was used for tumor model establishment and a model of matrix metalloproteinase (MMP) expressing breast cancer. The tumor-bearing nude mice were given tail vein injection of MMP 750FAST (PerkinElmer, Inc. USA) probe and imaged with both bioluminescence and fluorescence to assess in vivo binding of the probe to the tumor and metastases sites. Hematoxylin and eosin (H&E) staining was performed to confirm the presence of tumor and metastasis. As a result, one tumor can be observed visually in vivo. However liver metastasis has been detected under surgical navigation system and all were confirmed by histology. This approach helps surgeons to find orthotopic tumors and metastasis during intraoperative resection and visualize tumor borders for precise positioning. Further investigation is needed for future application in clinics.

  20. Multi-antenna synchronized global navigation satellite system receiver and its advantages in high-precision positioning applications

    Science.gov (United States)

    Dong, Danan; Chen, Wen; Cai, Miaomiao; Zhou, Feng; Wang, Minghua; Yu, Chao; Zheng, Zhengqi; Wang, Yuanfei

    2016-12-01

    The multi-antenna synchronized global navigation satellite system receiver is a high precision, low cost, and widely used emerging receiver. Using this type of receiver, the satellite and receiver clock errors can be eliminated simultaneously by forming between antenna single-differences, which is equivalent to the conventional double-difference model. However, current multi-antenna synchronized global navigation satellite system receiver products have not fully realized their potential to achieve better accuracy, efficiency, and broader applications. This paper introduces the conceptual design and derivable products of multi-antenna synchronized global navigation satellite system receivers involving the aspects of attitude determination, multipath effect mitigation, phase center variation correction, and ground-based carrier phase windup calibration. Through case studies, the advantages of multi-antenna synchronized global navigation satellite system receivers in high-precision positioning applications are demonstrated.

  1. Statistical methods for launch vehicle guidance, navigation, and control (GN&C) system design and analysis

    Science.gov (United States)

    Rose, Michael Benjamin

    A novel trajectory and attitude control and navigation analysis tool for powered ascent is developed. The tool is capable of rapid trade-space analysis and is designed to ultimately reduce turnaround time for launch vehicle design, mission planning, and redesign work. It is streamlined to quickly determine trajectory and attitude control dispersions, propellant dispersions, orbit insertion dispersions, and navigation errors and their sensitivities to sensor errors, actuator execution uncertainties, and random disturbances. The tool is developed by applying both Monte Carlo and linear covariance analysis techniques to a closed-loop, launch vehicle guidance, navigation, and control (GN&C) system. The nonlinear dynamics and flight GN&C software models of a closed-loop, six-degree-of-freedom (6-DOF), Monte Carlo simulation are formulated and developed. The nominal reference trajectory (NRT) for the proposed lunar ascent trajectory is defined and generated. The Monte Carlo truth models and GN&C algorithms are linearized about the NRT, the linear covariance equations are formulated, and the linear covariance simulation is developed. The performance of the launch vehicle GN&C system is evaluated using both Monte Carlo and linear covariance techniques and their trajectory and attitude control dispersion, propellant dispersion, orbit insertion dispersion, and navigation error results are validated and compared. Statistical results from linear covariance analysis are generally within 10% of Monte Carlo results, and in most cases the differences are less than 5%. This is an excellent result given the many complex nonlinearities that are embedded in the ascent GN&C problem. Moreover, the real value of this tool lies in its speed, where the linear covariance simulation is 1036.62 times faster than the Monte Carlo simulation. Although the application and results presented are for a lunar, single-stage-to-orbit (SSTO), ascent vehicle, the tools, techniques, and mathematical

  2. An Improved Otsu Threshold Segmentation Method for Underwater Simultaneous Localization and Mapping-Based Navigation

    Directory of Open Access Journals (Sweden)

    Xin Yuan

    2016-07-01

    Full Text Available The main focus of this paper is on extracting features with SOund Navigation And Ranging (SONAR sensing for further underwater landmark-based Simultaneous Localization and Mapping (SLAM. According to the characteristics of sonar images, in this paper, an improved Otsu threshold segmentation method (TSM has been developed for feature detection. In combination with a contour detection algorithm, the foreground objects, although presenting different feature shapes, are separated much faster and more precisely than by other segmentation methods. Tests have been made with side-scan sonar (SSS and forward-looking sonar (FLS images in comparison with other four TSMs, namely the traditional Otsu method, the local TSM, the iterative TSM and the maximum entropy TSM. For all the sonar images presented in this work, the computational time of the improved Otsu TSM is much lower than that of the maximum entropy TSM, which achieves the highest segmentation precision among the four above mentioned TSMs. As a result of the segmentations, the centroids of the main extracted regions have been computed to represent point landmarks which can be used for navigation, e.g., with the help of an Augmented Extended Kalman Filter (AEKF-based SLAM algorithm. The AEKF-SLAM approach is a recursive and iterative estimation-update process, which besides a prediction and an update stage (as in classical Extended Kalman Filter (EKF, includes an augmentation stage. During navigation, the robot localizes the centroids of different segments of features in sonar images, which are detected by our improved Otsu TSM, as point landmarks. Using them with the AEKF achieves more accurate and robust estimations of the robot pose and the landmark positions, than with those detected by the maximum entropy TSM. Together with the landmarks identified by the proposed segmentation algorithm, the AEKF-SLAM has achieved reliable detection of cycles in the map and consistent map update on loop

  3. An Improved Otsu Threshold Segmentation Method for Underwater Simultaneous Localization and Mapping-Based Navigation.

    Science.gov (United States)

    Yuan, Xin; Martínez, José-Fernán; Eckert, Martina; López-Santidrián, Lourdes

    2016-07-22

    The main focus of this paper is on extracting features with SOund Navigation And Ranging (SONAR) sensing for further underwater landmark-based Simultaneous Localization and Mapping (SLAM). According to the characteristics of sonar images, in this paper, an improved Otsu threshold segmentation method (TSM) has been developed for feature detection. In combination with a contour detection algorithm, the foreground objects, although presenting different feature shapes, are separated much faster and more precisely than by other segmentation methods. Tests have been made with side-scan sonar (SSS) and forward-looking sonar (FLS) images in comparison with other four TSMs, namely the traditional Otsu method, the local TSM, the iterative TSM and the maximum entropy TSM. For all the sonar images presented in this work, the computational time of the improved Otsu TSM is much lower than that of the maximum entropy TSM, which achieves the highest segmentation precision among the four above mentioned TSMs. As a result of the segmentations, the centroids of the main extracted regions have been computed to represent point landmarks which can be used for navigation, e.g., with the help of an Augmented Extended Kalman Filter (AEKF)-based SLAM algorithm. The AEKF-SLAM approach is a recursive and iterative estimation-update process, which besides a prediction and an update stage (as in classical Extended Kalman Filter (EKF)), includes an augmentation stage. During navigation, the robot localizes the centroids of different segments of features in sonar images, which are detected by our improved Otsu TSM, as point landmarks. Using them with the AEKF achieves more accurate and robust estimations of the robot pose and the landmark positions, than with those detected by the maximum entropy TSM. Together with the landmarks identified by the proposed segmentation algorithm, the AEKF-SLAM has achieved reliable detection of cycles in the map and consistent map update on loop closure, which is

  4. Kalman滤波在导航中的应用研究%Applications of Kalman Filter in the Navigation

    Institute of Scientific and Technical Information of China (English)

    洪腾腾; 胡绍林

    2016-01-01

    随着导航技术日新月异的发展,Kalman滤波技术在导航领域中的应用也随处可见。本文围绕Kalman滤波技术在导航过程中的应用问题,从技术途径的几个方面进行系统分析,简要综述Kalman滤波技术在惯性导航、卫星导航和组合导航等方面应用的发展现状,并指出在导航领域应用Kalman滤波技术存在的若干技术难点,为改进和完善Kalman滤波技术在导航领域的应用提供了潜在的研究方向。%With the rapid development of science and technology, the Kalman filtering technology is widely used in navigation. In this paper, the application of the Kalman filteringtechnology in the navigation filed were analyzed. The research achievements in recent years were introduced. The application of Kalman filter in the inertial navigation systems, satellite navigation system and integrated navigation system were mainly introduced. At the same time, point out several technical difficulties. Finally, we provide the potential research direction to improve the application of the Kalman filter in navigation.

  5. A New Underwater Acoustic Navigation Method Based on the Doppler Principle

    Directory of Open Access Journals (Sweden)

    Jinsong Tang

    2013-07-01

    Full Text Available In this paper, a new underwater acoustic navigation method is proposed, which is named from Doppler Acoustic Omnirange Beacon (DAOB. It is borrowed from the idea of Doppler VHF Omnirange (DVOR and based on the Doppler principle. The cause of Doppler effect in the received signal is the motion or position change of one or two sources. The effect of multipath is analyzed, and an improved signal form is presented to solve the rigorous multipath environment underwater. Some simulation is presented to verify the performance.    

  6. Development of Navigation Schemes for Grouped Mobile Robots Leading to Biomimetic Applications

    Directory of Open Access Journals (Sweden)

    Ming-Hsin Chen

    2012-03-01

    Full Text Available Biomimetic autonomous group manipulation of mobile robots has great potential in artificial intelligence, smart life, and automation related applications. In addition, it is also possible to use it as a tool for exploring the behavior of biological group motion in groups such as geese and fish. In order to fulfill these goals, fundamental capabilities of identification, navigation, and communication between robots must be established. In this work, key schemes are proposed for carrying out subsequent navigation tasks. By integrating omni-wheel mobile robots with X-Bee communication protocols, Arduino controls, IR range finders, and CMOS cameras, as well as with wiimote multi-zone localization, tasks such as obstacle and collision avoidance, object following, autonomous movement, and the indoor localization of group robots are implemented as the first step toward the autonomous control of group robots for subsequent biomimetic and smart life applications. With the resolution of these key issues, more realistic scenarios can be designed to achieve real group robot applications for indoor service in the future.

  7. The Application of Federated Kalman Filtering in SINS/GPS/CNS Intergrated Navigation System

    Directory of Open Access Journals (Sweden)

    DENG Chun-lin

    2012-04-01

    Full Text Available Federated filter was an important method to estimate high-precision navigation parameters based on “SINS/GPS/CNS”. A no-feedback federated filter with UD_UKF algorithm was designed in the paper, a threetime amendment scheme to correct navigation parameters was designed at the same time and the mathematical model of SINS/GPS/CNS was established in launch inertial coordinate system too. The paper discussed the simulation conditions and a lot of simulations were carried out to compare 2 aspects: (1the performance between four navigation mode, which respectively is SINS, SINS/GPS, SINS/CNS, SINS/GPS/CNS;(2the estimate precision of federated filter and that of centralized Kalman filter. The results of simulation showed that the designed federated filter and amendment scheme based on SINS/GPS/CNS had high estimate precision and led to gain high hitting precision of ballistic missile, that is to say position errors were less than 20 meter and velocity errors were less than 0.1m/s in simulation.

  8. The Performance Analysis of Smartphone-Based Pedestrian Dead Reckoning and Wireless Locating Technology for Indoor Navigation Application

    Directory of Open Access Journals (Sweden)

    Jhen-Kai Liao

    2016-12-01

    Full Text Available Recent developments in smartphone technology have increased user demand for indoors applications. The Global Navigation Satellite System (GNSS and the Inertial Navigation System (INS are the two advanced systems for navigation technology. However, it is still difficult for GNSS to provide an accurate and practical navigation solution, especially in environments with little or no signal availability. These failings should be easy to overcome; because of their portability and multiple embedded hardware sensors, smartphones seem well positioned to make pedestrian navigation easy and convenient in any environment. Pedestrian Dead Reckoning (PDR is one of the most commonly used technologies used for pedestrian navigation, but it is not always accurate because its positioning errors tend to accumulate over time. Therefore, this research introduces a new tool to overcome this failing; a Bluetooth Low-Energy (BLE beacon can maintain and improve the accuracy of PDR. Moreover, a BLE beacon can be initialized from any user position in an indoor environment. The random and unpredictable positions of pedestrians inevitably result in the degradation of navigation guidance systems’ data. To rectify this problem, we have implemented activity recognition technology to notify the proposed system so as to provide a more accurate heading estimate. This study proposes a Personal Navigation System (PNS based on this technology; it can estimate navigation solutions in real time and combines the advantages of PDR and Bluetooth positioning technology. A series of experiments were conducted to evaluate the accuracy of the system and the efficacy of our proposed algorithms. Preliminary results show the average relative precision of PDR to be about 2.5%, when using a mobile hand-held device. The error of initial position from 2-D beacon positioning is less than two meters. The proposed system works well without post-processing, and the multi-sensor activity recognition

  9. Application of surgical navigation in styloidectomy for treating Eagle’s syndrome

    Directory of Open Access Journals (Sweden)

    Dou G

    2016-04-01

    Full Text Available Geng Dou,1 Yu Zhang,1 Chunlin Zong,2 Yuanli Chen,2 Yuxuan Guo,2 Lei Tian2 1The First Brigade of Students, 2State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Oral Diseases, Department of Cranio-facial Trauma and Orthognathic Surgery, School of Stomatology, The Fourth Military Medical University, Xi’an, People’s Republic of China Purpose: The present study aimed to evaluate the feasibility, accuracy, and clinical effect of intraoperative navigation for resection of elongated styloid process (ESP in Eagle’s syndrome.Patients and methods: Twelve patients with Eagle’s syndrome with clinically and radiologically established diagnoses of ESP were included in this study. Preoperatively, all patients accepted three-dimensional computed tomography scan, and their skulls’ digital imaging and communications in medicine data were inputed into the navigation system workstation to make a virtual surgical plan in advance. During surgery, the intraoperative navigation was performed to excise the ESP accurately for both intraoral (without tonsillectomy and extraoral approaches following the virtual plan. Postoperatively, the amount of bleeding, duration of operation and hospitalization, and the length of resected styloid process (SP were measured and compared with those cases that had traditional styloidectomy without the help of surgical navigation (SN. A simple visual analog scale questionnaire was also used to assess patients’ satisfaction and the surgery effect after 3 months.Results: In total, 17 SPs from 12 patients were precisely resected by intraoral parapharyngeal approach and small cervical approach with the aid of SN. No severe complications occurred in any patients. The length of resected SPs was 21.93±14.26 mm. The average amount of bleeding and duration of operation were 22.50±8.54 mL and 40.35±11.81 minutes, respectively, which were all less than with

  10. Hybrid Method for the Navigation of Mobile Robot Using Fuzzy Logic and Spiking Neural Networks

    Directory of Open Access Journals (Sweden)

    Zineb LAOUICI

    2014-11-01

    Full Text Available the aim of this paper is to present a strategy describing a hybrid approach for the navigation of a mobile robot in a partially known environment. The main idea is to combine between fuzzy logic approach suitable for the navigation in an unknown environment and spiking neural networks approach for solving the problem of navigation in a known environment. In the literature, many approaches exist for the navigation purpose, for solving separately the problem in both situations. Our idea is based on the fact that we consider a mixed environment, and try to exploit the known environment parts for improving the path and time of navigation between the starting point and the target. The Simulation results, which are shown on two simulated scenarios, indicate that the hybridization improves the performance of robot navigation with regard to path length and the time of navigation.

  11. 3D photo mosaicing of Tagiri shallow vent field by an autonomous underwater vehicle (3rd report) - Mosaicing method based on navigation data and visual features -

    Science.gov (United States)

    Maki, Toshihiro; Ura, Tamaki; Singh, Hanumant; Sakamaki, Takashi

    Large-area seafloor imaging will bring significant benefits to various fields such as academics, resource survey, marine development, security, and search-and-rescue. The authors have proposed a navigation method of an autonomous underwater vehicle for seafloor imaging, and verified its performance through mapping tubeworm colonies with the area of 3,000 square meters using the AUV Tri-Dog 1 at Tagiri vent field, Kagoshima bay in Japan (Maki et al., 2008, 2009). This paper proposes a post-processing method to build a natural photo mosaic from a number of pictures taken by an underwater platform. The method firstly removes lens distortion, invariances of color and lighting from each image, and then ortho-rectification is performed based on camera pose and seafloor estimated by navigation data. The image alignment is based on both navigation data and visual characteristics, implemented as an expansion of the image based method (Pizarro et al., 2003). Using the two types of information realizes an image alignment that is consistent both globally and locally, as well as making the method applicable to data sets with little visual keys. The method was evaluated using a data set obtained by the AUV Tri-Dog 1 at the vent field in Sep. 2009. A seamless, uniformly illuminated photo mosaic covering the area of around 500 square meters was created from 391 pictures, which covers unique features of the field such as bacteria mats and tubeworm colonies.

  12. Development of a two-step touch method for website navigation on smartphones.

    Science.gov (United States)

    Jung, Kihyo; Jang, Jinah

    2015-05-01

    The touch method for hyperlink selection in smartphones can often create usability problems because a hyperlink is universally smaller than a finger contact area as well as visually occluded by a finger while pressing. In this study, we developed a two-step touch method (called Press and Flick method) and comprehensively examined its effectiveness using the goals, operators, methods, and selection rules (GOMS) model and user testing. The two-step touch method consisted of finger press and flick motions; a target hyperlink was selected by a finger press motion, and a finger flick method was subsequently conducted for error correction if the initial interaction (press) failed. We compared the two-step touch method with the current touch method through the GOMS model and user testing. As a result, the two-step touch method was significantly superior to the current touch method in terms of error rate and subjective satisfaction score; however, its superiority in terms of number of interactions and touch time was vulnerably affected by error rate. The two-step touch method developed in this study can improve the usability and user experience of website navigation using smartphones.

  13. Three-dimensional Modelling Technology for City Indoor Positioning and Navigation Applications

    Science.gov (United States)

    Zhang, Xin; Chen, Yongxin; Wang, Weisheng

    2016-11-01

    For city indoor positioning and navigation applications, there are two technical problems should be solved, which are the modelling efficiency and the validity and accuracy of the spatial models. In this paper, the quick modelling technology is introduced which uses the multi-angle remote sensing based on the unmanned aerial vehicle measurement. To enhance the validity and accuracy of the spatial models, we proposed an algorithm to remove the line style and planar style foreground occlusions before reconstructing backgrounds. The three-dimensional models can only provide the spatial framework for the city indoor positioning. Furthermore, the simple indoor three-dimensional modelling technology which is based on the building design drawings. In the end, the application in the public safety emergency rescue is introduced.

  14. A 3D terrain reconstruction method of stereo vision based quadruped robot navigation system

    Science.gov (United States)

    Ge, Zhuo; Zhu, Ying; Liang, Guanhao

    2017-01-01

    To provide 3D environment information for the quadruped robot autonomous navigation system during walking through rough terrain, based on the stereo vision, a novel 3D terrain reconstruction method is presented. In order to solve the problem that images collected by stereo sensors have large regions with similar grayscale and the problem that image matching is poor at real-time performance, watershed algorithm and fuzzy c-means clustering algorithm are combined for contour extraction. Aiming at the problem of error matching, duel constraint with region matching and pixel matching is established for matching optimization. Using the stereo matching edge pixel pairs, the 3D coordinate algorithm is estimated according to the binocular stereo vision imaging model. Experimental results show that the proposed method can yield high stereo matching ratio and reconstruct 3D scene quickly and efficiently.

  15. A fast and accurate initial alignment method for strapdown inertial navigation system on stationary base

    Institute of Scientific and Technical Information of China (English)

    Xinlong WANG; Gongxun SHEN

    2005-01-01

    In this work,a fast and accurate stationary alignment method for strapdown inertial navigation system (SINS) is proposed.It has been demonstrated that the stationary alignment of SINS can be improved by employing the multiposition technique,but the alignment time of the azimuth error is relatively longer.Over here,the two-position alignment principle is presented.On the basis of this SINS error model,a fast estimation algorithm of the azimuth error for the initial alignment of SINS on stationary base is derived fully from the horizontal velocity outputs and the output rates,and the novel azimuth error estimation algorithm is used for the two-position alignment.Consequently,the speed and accuracy of the SINS's initial alignment is enhanced greatly.The computer simulation results illustrate the efficiency of this alignment method.

  16. Extraction method of suitable matching regions in the gravity-aided inertial navigation

    Science.gov (United States)

    Yan, Li; Ma, Xudong; Shi, Juan; Shi, Yulong

    2009-10-01

    The data organization of gravitational field is based on a form of Grid, which is similar to the data structure of DEM in the terrain. So this paper proposes a method of gravitational field analysis for extracting features by adopting some spatial analysis means of topography. First of all, the gravity anomaly data is used to calculate the roughness features of gravitational field. after comparing and anglicizing the features, roughness features are selected as the feature factor of gravity. Then, the method of calculating contour lines is applied to calculate region segmentation of roughness features and extract the vector edge of the larger feature regions, and clustering analysis to these contour of the region. At last, the scope line for Convex Hull of the region is calculated by the Convex Hull algorithm, and so as to obtain a more prominent region (matching region) that have significant changes in gravity anomaly, which provide the necessary reference data for the gravity-aided inertial navigation.

  17. A Ka-band Celestial Reference Frame with Applications to Deep Space Navigation

    Science.gov (United States)

    Jacobs, Christopher S.; Clark, J. E.; García-Miró, C.; Horiuchi, S.; Sotuela, I.

    2011-10-01

    The Ka-band radio spectrum is now being used for a wide variety of applications. This paper highlights the use of Ka-band as a frequency for precise deep space navigation based on a set of reference beacons provided by extragalactic quasars which emit broadband noise at Ka-band. This quasar-based celestial reference frame is constructed using X/Ka-band (8.4/32 GHz) from fifty-five 24-hour sessions with the Deep Space Network antennas in California, Australia, and Spain. We report on observations which have detected 464 sources covering the full 24 hours of Right Ascension and declinations down to -45 deg. Comparison of this X/Ka-band frame to the international standard S/X-band (2.3/8.4 GHz) ICRF2 shows wRMS agreement of ~200 micro-arcsec (μas) in α cos δ and ~300 μas in δ. There is evidence for systematic errors at the 100 μas level. Known errors include limited SNR, lack of instrumental phase calibration, tropospheric refraction mis-modeling, and limited southern geometry. The motivation for extending the celestial reference frame to frequencies above 8 GHz is to access more compact source morphology for improved frame stability and to support spacecraft navigation for Ka-band based NASA missions.

  18. A Ka-Band Celestial Reference Frame with Applications to Deep Space Navigation

    Science.gov (United States)

    Jacobs, Christopher S.; Clark, J. Eric; Garcia-Miro, Cristina; Horiuchi, Shinji; Sotuela, Ioana

    2011-01-01

    The Ka-band radio spectrum is now being used for a wide variety of applications. This paper highlights the use of Ka-band as a frequency for precise deep space navigation based on a set of reference beacons provided by extragalactic quasars which emit broadband noise at Ka-band. This quasar-based celestial reference frame is constructed using X/Ka-band (8.4/32 GHz) from fifty-five 24-hour sessions with the Deep Space Network antennas in California, Australia, and Spain. We report on observations which have detected 464 sources covering the full 24 hours of Right Ascension and declinations down to -45 deg. Comparison of this X/Ka-band frame to the international standard S/X-band (2.3/8.4 GHz) ICRF2 shows wRMS agreement of approximately 200 micro-arcsec in alpha cos(delta) and approximately 300 micro-arcsec in delta. There is evidence for systematic errors at the 100 micro-arcsec level. Known errors include limited SNR, lack of instrumental phase calibration, tropospheric refraction mis-modeling, and limited southern geometry. The motivation for extending the celestial reference frame to frequencies above 8 GHz is to access more compact source morphology for improved frame stability and to support spacecraft navigation for Ka-band based NASA missions.

  19. A Navigation Method for Multiple Robots Based on a Single Mobile Node

    Institute of Scientific and Technical Information of China (English)

    JI Daxiong; LIU Jian

    2012-01-01

    To satisfy the requirements of independent navigation in low cost multiple robots,a navigation frame of masterslave robots with only one master robot is introduced briefly.A range-only navigation algorithm for slave robots of low cost is presented for the navigation in unknown current.This algorithm only needs a master robot.The master is just a single mobile node which has high navigation performance.Observability of this master-salve system is theoretically analyzed.The conditions of slave robot trajectory under which observability is guaranteed are evaluated by a slave robot in real-time.The slave takes appropriate action to control its heading to achieve observability if observability is lost on the current trajectory.The navigation algorithm is implemented by a standard extended Kalman filter,and it is able to acquire accurate estimation of robot's position.The simulation results show its effectiveness of the proposed algorithm.

  20. Method and System for Gamma-Ray Localization Induced Spacecraft Navigation Using Celestial Gamma-Ray Sources

    Science.gov (United States)

    Sheikh, Suneel I. (Inventor); Hisamoto, Chuck (Inventor); Arzoumanian, Zaven (Inventor)

    2015-01-01

    A method and system for spacecraft navigation using distant celestial gamma-ray bursts which offer detectable, bright, high-energy events that provide well-defined characteristics conducive to accurate time-alignment among spatially separated spacecraft. Utilizing assemblages of photons from distant gamma-ray bursts, relative range between two spacecraft can be accurately computed along the direction to each burst's source based upon the difference in arrival time of the burst emission at each spacecraft's location. Correlation methods used to time-align the high-energy burst profiles are provided. The spacecraft navigation may be carried out autonomously or in a central control mode of operation.

  1. A Fault-tolerance Estimating Method for Ionosphere Corrections in Satellite Navigation System

    Institute of Scientific and Technical Information of China (English)

    GAO Shuliang; LI Rui; HUANG Zhigang

    2011-01-01

    Aiming to the reliable estimates of the ionosphere differential corrections for the satellite navigation system in the presence of the ionosphere anomaly,a fault-tolerance estimating method,which is based on the distributed Kalman filtering,is proposed.The method utilizes the parallel sub-filters for estimating the ionosphere differential corrections.Meanwhile,an infinite norm (IN) method is proposed for the detection of the ionosphere irregularity in the filter processing.Once the anomaly is detected,the sub-filter contaminated by the anomaly measurements will be excluded to ensure the reliability of the estimates.The simulation is conducted to validate the method and the results indicate that the anomaly can be found timely due to the novel fault detection method based on the infinite norm.Because of the parallel sub-filter architecture,the measurements are classified by the spatial distribution so that the ionosphere anomaly can be positioned and excluded more easily.Thus,the method can provide the robust and accurate ionosphere differential corrections.

  2. An Application of UAV Attitude Estimation Using a Low-Cost Inertial Navigation System

    Science.gov (United States)

    Eure, Kenneth W.; Quach, Cuong Chi; Vazquez, Sixto L.; Hogge, Edward F.; Hill, Boyd L.

    2013-01-01

    Unmanned Aerial Vehicles (UAV) are playing an increasing role in aviation. Various methods exist for the computation of UAV attitude based on low cost microelectromechanical systems (MEMS) and Global Positioning System (GPS) receivers. There has been a recent increase in UAV autonomy as sensors are becoming more compact and onboard processing power has increased significantly. Correct UAV attitude estimation will play a critical role in navigation and separation assurance as UAVs share airspace with civil air traffic. This paper describes attitude estimation derived by post-processing data from a small low cost Inertial Navigation System (INS) recorded during the flight of a subscale commercial off the shelf (COTS) UAV. Two discrete time attitude estimation schemes are presented here in detail. The first is an adaptation of the Kalman Filter to accommodate nonlinear systems, the Extended Kalman Filter (EKF). The EKF returns quaternion estimates of the UAV attitude based on MEMS gyro, magnetometer, accelerometer, and pitot tube inputs. The second scheme is the complementary filter which is a simpler algorithm that splits the sensor frequency spectrum based on noise characteristics. The necessity to correct both filters for gravity measurement errors during turning maneuvers is demonstrated. It is shown that the proposed algorithms may be used to estimate UAV attitude. The effects of vibration on sensor measurements are discussed. Heuristic tuning comments pertaining to sensor filtering and gain selection to achieve acceptable performance during flight are given. Comparisons of attitude estimation performance are made between the EKF and the complementary filter.

  3. A novel vehicle navigation map matching algorithm based on fuzzy logic and its application

    Institute of Scientific and Technical Information of China (English)

    TONG Xiao-hua; WU Song-chun; WU Shu-qing; LIU Da-jie

    2005-01-01

    A new real-time map matching algorithm based on fuzzy logic is proposed. 3 main factors affecting the reliability of map matching, including the distance between the vehicle location and the matching road segment, the angle between the vehicle direction and the road segment direction and the road connectivity are discussed. Fuzzy rules for the distance, angle and connectivity are presented to calculate the matching reliability. 2 indicators for estimating the matching reliability are then derived, one is the lower limit of the reliability, and the other is the limit error of the difference between the maximal value and the second-maximal value of the reliability. A real-time map-matching system based on fuzzy logic is therefore developed. Using the real data of global positioning system(GIS) based navigation and geographic information system(GPS) based road map, the method is verified and the results prove the effectiveness of the proposed method.

  4. Comparative study of camera calibration algorithms with application to spacecraft navigation

    Science.gov (United States)

    Poelzleitner, Wolfgang; Ulm, Michael

    1994-10-01

    This paper deals with the problem of camera calibration based on 3D feature measurements. It occurs in industrial 3D measurement systems, as well as in autonomous navigation systems, where the estimation of motion parameters is required. We have selected the problem of extrinsic calibration (exterior orientation) of a camera that is looking at flat or almost flat surfaces (or terrain). This situation causes numerical and stability problems to many of the known calibration methods. To study the impact of flatness of the reference surface (or calibration target) on the calibration errors we have done a comparative study using sixteen available calibration procedures. The major emphasis was on robustness with respect to 3D measurement errors and sensitivity to flatness. A new calibration method is also investigated, which can be used independently of whether the calibration reference surface is flat, almost flat, or rugged.

  5. Application of navigation template to fixation of sacral fracture using three-dimensional reconstruction and re-verse engineering technique

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yuan-zhi; LU Sheng; XU Yong-qing; SHI Ji-hong; LI Yan-bing; FENG Zi-liang

    2009-01-01

    Objective: To provide a new method in the fixation of sacral fracture by means of three-dimensional reconstruc-tion and reverse engineering technique.Methods: Pelvis image data were obtained from three-dimensional CT scan in patients with sacral fracture. The data were transferred into a computer workstation. The three-dimensional models of pelvis were reconstructed using Amira 3.1 software and saved in STL format. Then the three-dimensional fracture models were imported into Imageware 9.0 software. Different situations of reduction (total reduction, half reduction and non-reduction) were simulated using Imageware 9.0 software. The best direction and loca-tion of extract iliosacral lag screws were defined using re-verse engineering according to these three situations and navigation templates were designed according to the ana-tomic features of the postero-iliac part and the channel. The exact navigational template was made by rapid prototyping.Drill guides were sterilized and used intraoperatively to as-sist in surgical navigation and the placement of iliosacral lag screws.Results: Accurate screw placement was confirmed with postoperative X-ray and CT scanning. The navigation template was found to be highly accurate. Conclusion: The navigation template may be a useful method in minimal-invasive fixation of sacroiliac joint fracture.

  6. A novel separation and calibration method for DVL and compass error in dead reckoning navigation systems

    Science.gov (United States)

    Zhang, Yanshun; Guo, Yajing; Yang, Tao; Li, Chunyu; Wang, Zhanqing

    2016-06-01

    The scale factor error δ C of the Doppler velocity log (DVL) and the heading angle error δ \\psi of a compass are so integrated in dead reckoning (DR) navigation systems that it is difficult to separate them. This paper aims to solve this problem by putting forward an online separation and calibration method for δ C and δ \\psi based on an ‘arc and linear’ trajectory. This method introduces the high-accuracy location information of a long base line (LBL) acoustic positioning system. At first, the relationship between the displacements on the ‘arc’ trajectory in directions of east and north, output by the LBL and DR systems, serves to judge the carrier direction and calibrate δ C . And then by compensating δ C , the displacement on the ‘linear’ trajectory is used to calibrate δ \\psi . Finally, a semi-physical simulation experiment is conducted to test and verify this calibration method to see how effective and accurate it is. Experimental results show that after calibration the residual error ratios of δ C and δ \\psi are 8.24% and 3.70% respectively. Therefore, online calibration of δ C and δ \\psi is realized effectively. What’s more, when the DR system is working alone in 400 s, this method reduces position error by up to 93.39%, from 18.91 m to 1.25 m.

  7. Control algorithms for autonomous robot navigation

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, C.C.

    1985-09-20

    This paper examines control algorithm requirements for autonomous robot navigation outside laboratory environments. Three aspects of navigation are considered: navigation control in explored terrain, environment interactions with robot sensors, and navigation control in unanticipated situations. Major navigation methods are presented and relevance of traditional human learning theory is discussed. A new navigation technique linking graph theory and incidental learning is introduced.

  8. A New Time Measurement Method Using a High-End Global Navigation Satellite System to Analyze Alpine Skiing

    Science.gov (United States)

    Supej, Matej; Holmberg, Hans-Christer

    2011-01-01

    Accurate time measurement is essential to temporal analysis in sport. This study aimed to (a) develop a new method for time computation from surveyed trajectories using a high-end global navigation satellite system (GNSS), (b) validate its precision by comparing GNSS with photocells, and (c) examine whether gate-to-gate times can provide more…

  9. Aids to Navigation Service Force Mix 2000 Project. Volume 1. Development and Application of an Aids to Navigation Service Force Mix Decision Support System

    Science.gov (United States)

    1992-07-01

    Hours: 0.00 LT ANT ?: DBN ANT ?: (Database: Survey.db Report#: 6) Appendix H Page H-21 12/02/91 BUOY TENDER SUMMARY Page 22 Primary Unit: ACACIA District...2-5 2.2.4 ATON Tug Barges ........................ 2-5 2.2.5 Aids to Navigation Teams ( ANTs ) ................. 2-6 2.3 ATON SERVICES...navigation boat ANT aids to navigation team AOPS abstract of operations ATON aids to navigation ATONIS aids to navigation information system BRIDGE

  10. Guidance, navigation, and control subsystem equipment selection algorithm using expert system methods

    Science.gov (United States)

    Allen, Cheryl L.

    1991-01-01

    Enhanced engineering tools can be obtained through the integration of expert system methodologies and existing design software. The application of these methodologies to the spacecraft design and cost model (SDCM) software provides an improved technique for the selection of hardware for unmanned spacecraft subsystem design. The knowledge engineering system (KES) expert system development tool was used to implement a smarter equipment section algorithm than that which is currently achievable through the use of a standard data base system. The guidance, navigation, and control subsystems of the SDCM software was chosen as the initial subsystem for implementation. The portions of the SDCM code which compute the selection criteria and constraints remain intact, and the expert system equipment selection algorithm is embedded within this existing code. The architecture of this new methodology is described and its implementation is reported. The project background and a brief overview of the expert system is described, and once the details of the design are characterized, an example of its implementation is demonstrated.

  11. Microgravity monitoring instrument development and application to vernier guidance, navigation, and vehicle control

    Science.gov (United States)

    Howell, Joseph J.

    1992-01-01

    The fact that a spacecraft traveling through the 'vacuum' of space conforms to the classical Keplerian ellipse has recently been disproven. It is now well known that such a vehicle is acted on by many external forces such as drag in the rarefied particle atmosphere, solar wind and particle impact. This paper discusses the development of sensors and sensor systems to measure these minute forces of acceleration/deceleration. Four systems will be discussed: a 10 exp -4 g system, a 10 exp -6 g system, a 10 exp -(6-8) g system and a 10 exp -9 g system. The design of each system will be explained along with the advantages/disadvantages of each. Various applications unique to each system will be discussed. Configurations, design schemes, test plans and calibration procedures, both in the ground laboratory and inflight, will be presented. The current design/development/operational status of each system will be examined and future plans discussed. Application to aerodynamic studies and vernier guidance, navigation, and vehicle control will also be examined.

  12. 33 CFR 67.35-10 - Private aids to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Private aids to navigation. 67.35-10 Section 67.35-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES Applications §...

  13. Autonomous Navigation Motion Control of Mobile Robots using Hybrid System Control Method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.M. [Samsung Electronics Co., Ltd., Seoul (Korea); Lim, M.S. [Kyonggi Institute of Technology, Shihung (Korea); Lim, J.H. [Hanyang University, Seoul (Korea)

    2002-05-01

    This paper presents a framework of hybrid dynamic control systems for the motion control of wheeled mobile robot systems with nonholonomic constraints. The hybrid control system has the 3-layered hierarchical structure: digital automata for the higher process, mobile robot system for the lower process, and the interface as the interaction process between the continuous dynamics and the discrete dynamics. In the hybrid control architecture of mobile robot, the continuous dynamics of mobile robots are modeled by the switched systems. The abstract model and digital automata for the motion control are developed. In high level, the discrete states are defined by using the sensor-based search windows and the reference motions of a mobile robot in low level are specified in the abstracted motions. The mobile robots can perform both the motion planning and autonomous maneuvering with obstacle avoidance in indoor navigation problem. Simulation and experimental results show that hybrid system approach is an effective method for the autonomous maneuvering in indoor environments. (author). 13 refs., 13 figs., 1 tab.

  14. A BD/SINS Integrated Navigation Algorithm and a Clock Error Handling Method%BD/SINS紧组合导航及时钟误差处理算法

    Institute of Scientific and Technical Information of China (English)

    王龙; 王楠; 鲁浩

    2015-01-01

    The navigation accuracy of the pure SINS system can not satisfy the high performance requirement of air-to-air missile when the cruise range of the missile is too long .The GNSS/SINS integrated navigation is an effective method to solve this problem .Because of the successful application of the Beidou satellites navigation system,the research on BD/SINS integrated navigation has become a hot engineering field .In this paper,the integrated navigation algorithm of the BD/SINS is studied .The gain-restriction Kalman filter is adopted in the fusion of the information from the SINS and the BD receiver .In order to mitigate the inverse effect of the clock error of the receiver,a special method is used to eliminate the clock error .Simulation result proved that the integrated navigation method has a high navigation accuracy .%远距空空导弹飞行时间长,纯惯性导航难以满足高精度要求,而卫星定位/捷联惯性组合导航是解决此难题的一种有效方式,因此,采用基于伪距/伪距率的北斗/捷联惯性组合导航算法,该导航算法使用限定增益Kalman滤波器,对接收机钟差做了特殊处理,使得滤波结果不受钟差影响。仿真表明,该北斗/捷联惯性组合导航算法有较高的导航精度。

  15. Application of a 3-dimensional printed navigation template in Bernese periacetabular osteotomies

    Science.gov (United States)

    Zhou, You; Kang, Xiaopeng; Li, Chuan; Xu, Xiaoshan; Li, Rong; Wang, Jun; Li, Wei; Luo, Haotian; Lu, Sheng

    2016-01-01

    Abstract The aim of the present study was to describe the application of 3D printed templates for intraoperative navigation and simulation of periacetabular osteotomies (PAOs) in a cadaveric model. Five cadaveric specimens (10 sides) underwent thin-slice computed tomographic scans of the ala of ilium downwards to the proximal end of femoral shaft. Bernese PAO was performed. Using Mimics v10.1 software (Materialise, Leuven, Belgium), 3D computed tomographic reconstructions were created and the 4 standard PAO bone cuts—ischial, pubic, anterior, and posterior aspects of the ilium—as well as rotation of the dislocated acetabular bone blocks were simulated for each specimen. Using these data, custom 3D printed bone-drilling templates of the pelvis were manufactured, to guide surgical placement of the PAO bone cuts. An angle fix wedge was designed and printed, to help accurately achieve the predetermined rotation angle of the acetabular bone block. Each specimen underwent a conventional PAO. Preoperative, postsimulation, and postoperative lateral center-edge angles, acetabular indices, extrusion indices, and femoral head coverage were measured and compared; P and t values were calculated for above-mentioned measurements while comparing preoperative and postoperative data, and also in postsimulation and postoperative data comparison. All 10 PAO osteotomies were successfully completed using the 3D printed bone-drilling template and angle fix wedge. No osteotomy entered the hip joint and a single posterior column fracture was observed. Comparison of preoperative and postoperative measurements of the 10 sides showed statistically significant changes, whereas no statistically significant differences between postsimulation and postoperative values were noted, demonstrating the accuracy and utility of the 3D printed templates. The application of patient-specific 3D printed bone-drilling and rotation templates in PAO is feasible and may facilitate improved clinical outcomes

  16. Application of a 3-dimensional printed navigation template in Bernese periacetabular osteotomies: A cadaveric study.

    Science.gov (United States)

    Zhou, You; Kang, Xiaopeng; Li, Chuan; Xu, Xiaoshan; Li, Rong; Wang, Jun; Li, Wei; Luo, Haotian; Lu, Sheng

    2016-12-01

    The aim of the present study was to describe the application of 3D printed templates for intraoperative navigation and simulation of periacetabular osteotomies (PAOs) in a cadaveric model.Five cadaveric specimens (10 sides) underwent thin-slice computed tomographic scans of the ala of ilium downwards to the proximal end of femoral shaft. Bernese PAO was performed. Using Mimics v10.1 software (Materialise, Leuven, Belgium), 3D computed tomographic reconstructions were created and the 4 standard PAO bone cuts-ischial, pubic, anterior, and posterior aspects of the ilium-as well as rotation of the dislocated acetabular bone blocks were simulated for each specimen. Using these data, custom 3D printed bone-drilling templates of the pelvis were manufactured, to guide surgical placement of the PAO bone cuts. An angle fix wedge was designed and printed, to help accurately achieve the predetermined rotation angle of the acetabular bone block. Each specimen underwent a conventional PAO. Preoperative, postsimulation, and postoperative lateral center-edge angles, acetabular indices, extrusion indices, and femoral head coverage were measured and compared; P and t values were calculated for above-mentioned measurements while comparing preoperative and postoperative data, and also in postsimulation and postoperative data comparison.All 10 PAO osteotomies were successfully completed using the 3D printed bone-drilling template and angle fix wedge. No osteotomy entered the hip joint and a single posterior column fracture was observed. Comparison of preoperative and postoperative measurements of the 10 sides showed statistically significant changes, whereas no statistically significant differences between postsimulation and postoperative values were noted, demonstrating the accuracy and utility of the 3D printed templates.The application of patient-specific 3D printed bone-drilling and rotation templates in PAO is feasible and may facilitate improved clinical outcomes, through the use

  17. QUATERNIONIC JACOBI METHOD APPLICATIONS

    OpenAIRE

    SANCREY RODRIGUES ALVES

    2008-01-01

    O método tipo-Jacobi quaterniônico foi proposto em 1993. Vários estudos provaram sua convergência e melhoram a teoria proposta desde então. O presente trabalho realiza uma síntese do método tipo- Jacobi quaterniônico, apresentando aplicações do mesmo a diferentes tipos de matrizes. The quaternionic Jacobi method was proposed on 1993. Lots of studies has proved his convergence and also has improved the theory proposed. This document makes a survey of this me...

  18. An Aircraft Navigation System Fault Diagnosis Method Based on Optimized Neural Network Algorithm

    Institute of Scientific and Technical Information of China (English)

    Jean-dedieu Weyepe

    2014-01-01

    Air data and inertial reference system (ADIRS) is one of the complex sub-system in the aircraft navigation system and it plays an important role into the flight safety of the aircraft. This paper propose an optimize neural network algorithm which is a combination of neural network and ant colony algorithm to improve efficiency of maintenance engineer job task.

  19. A Concise Guide to Feature Histograms with Applications to LIDAR-Based Spacecraft Relative Navigation

    Science.gov (United States)

    Rhodes, Andrew P.; Christian, John A.; Evans, Thomas

    2017-01-01

    With the availability and popularity of 3D sensors, it is advantageous to re-examine the use of point cloud descriptors for the purpose of pose estimation and spacecraft relative navigation. One popular descriptor is the oriented unique repeatable clustered viewpoint feature histogram (OUR-CVFH), which is most often utilized in personal and industrial robotics to simultaneously recognize and navigate relative to an object. Recent research into using the OUR-CVFH descriptor for spacecraft navigation has produced favorable results. Since OUR-CVFH is the most recent innovation in a large family of feature histogram point cloud descriptors, discussions of parameter settings and insights into its functionality are spread among various publications and online resources. This paper organizes the history of feature histogram point cloud descriptors for a straightforward explanation of their evolution. This article compiles all the requisite information needed to implement OUR-CVFH into one location, as well as providing useful suggestions on how to tune the generation parameters. This work is beneficial for anyone interested in using this histogram descriptor for object recognition or navigation - may it be personal robotics or spacecraft navigation.

  20. 民用航空中组合导航的应用研究%Application Research of integrated navigation in Civil Aviation

    Institute of Scientific and Technical Information of China (English)

    宁方清

    2016-01-01

    本文首先分别介绍惯性导航与卫星导航两者的优缺点,随后提到当前我国民航系统使用组合导航的必要性,最后介绍组合导航的特点,通过本文的研究,以期能够为我国民用航空应用组合导航提供一定的借鉴。%This paper first describes the advantages and disadvantages of inertial navigation and satellite navigation both,then referred to China's civil aviation system is currently using the necessity of integrated navigation,finally introduces the characteristics of integrated navigation,through the study of this paper,in order to provide some reference for China's civil aviation application integrated navigation.

  1. A Novel Dynamic Physical Storage Model for Vehicle Navigation Maps

    Directory of Open Access Journals (Sweden)

    Shaohua Wang

    2016-04-01

    Full Text Available The physical storage model is one of the key technologies for vehicle navigation maps used in a navigation system. However, the performance of most traditional storage models is limited in dynamic navigation due to the static storage format they use. In this paper, we proposed a new physical storage model, China Navigation Data Format (CNDF, which helped access and update the navigation data. The CNDF model used the reach-based hierarchy method to build a road hierarchal network, which enhanced the efficiency of data compression. It also adopted the Linear Link Coding method, in which the start position was combined with the end position as the identification code for multi-level links, and each link traced up-level links consistently without recording the array of identifications. The navigation map of East China (including Beijing, Tianjin, Shandong, Hebei, and Jiangsu at 1:10,000, generated using the CNDF model, and the real time traffic information in Beijing were combined to test the performance of a navigation system using an embedded navigation device. Results showed that it cost less than 1 second each time to refresh the navigation map, and the accuracy of the hierarchal shortest-path algorithm was 99.9%. Our work implied that the CNDF model is efficient in vehicle navigation applications.

  2. An improved TERCOM algorithm and its application in a submarine terrain aided navigation system

    Science.gov (United States)

    Xu, Zunyi; Yan, Lei; Liu, Guangjun; Wang, Hua

    2006-10-01

    Terrain contour matching (TERCOM) algorithm is the main one in the conventional terrain aided navigation system. When it has been directly applied to the submarine terrain aided navigation (STAN) system, the accuracy and stability are primely reduced. To solve these problems, the detail analyses about the particularities of the STAN and the disadvantages of the conventional TERCOM algorithm have been made. The improvement for the TERCOM algorithm on the measurement function, the water depth survey error and the scheme to prevent fail positioning has been done. Moreover, experiments with pedestrian simulation confirm the effectiveness of the improved TERCOM algorithm. The system achieves higher positioning precision than that of conventional one.

  3. Virtual local target method for avoiding local minimum in potential field based robot navigation.

    Science.gov (United States)

    Zou, Xi-Yong; Zhu, Jing

    2003-01-01

    A novel robot navigation algorithm with global path generation capability is presented. Local minimum is a most intractable but is an encountered frequently problem in potential field based robot navigation. Through appointing appropriately some virtual local targets on the journey, it can be solved effectively. The key concept employed in this algorithm are the rules that govern when and how to appoint these virtual local targets. When the robot finds itself in danger of local minimum, a virtual local target is appointed to replace the global goal temporarily according to the rules. After the virtual target is reached, the robot continues on its journey by heading towards the global goal. The algorithm prevents the robot from running into local minima anymore. Simulation results showed that it is very effective in complex obstacle environments.

  4. Virtual local target method for avoiding local minimum in potential field based robot navigation

    Institute of Scientific and Technical Information of China (English)

    邹细勇; 诸静

    2003-01-01

    A novel robot navigation algorithm with global path generation capability is presented. Local minimum is a most intractable but is an encountered frequently problem in potential field based robot navigation. Through appointing appropriately some virtual local targets on the journey, it can be solved effectively. The key concept employed in this algorithm are the rules that govern when and how to appoint these virtual local targets. When the robot finds itself in danger of local minimum, a virtual local target is appointed to replace the global goal temporarily according to the rules. After the virtual target is reached, the robot continues on its journey by heading towards the global goal. The algorithm prevents the robot from running into local minima anymore. Simulation results showed that it is very effective in complex obstacle environments.

  5. Virtual local target method for avoiding local minimum in potential field based robot navigation

    Institute of Scientific and Technical Information of China (English)

    邹细勇; 诸静

    2003-01-01

    A novel robot navigation algorithm with global path generation capability is presented. Local minimum is a most intractable but is an encountered frequently problem in potential field based robot navigation.Through appointing appropriately some virtual local targets on the journey, it can be solved effectively. The key concept employed in this algorithm are the rules that govern when and how to appoint these virtual local targets. When the robot finds itself in danger of local minimum, a virtual local target is appointed to replace the global goal temporarily according to the rules. After the virtual target is reached, the robot continues on its journey by heading towards the global goal. The algorithm prevents the robot from running into local minima anymore. Simulation results showed that it is very effective in complex obstacle environments.

  6. COMPARISON AND ANALYSIS OF NONLINEAR LEAST SQUARES METHODS FOR VISION BASED NAVIGATION (VBN) ALGORITHMS

    OpenAIRE

    Sheta, B.; M. Elhabiby; Sheimy, N.

    2012-01-01

    A robust scale and rotation invariant image matching algorithm is vital for the Visual Based Navigation (VBN) of aerial vehicles, where matches between an existing geo-referenced database images and the real-time captured images are used to georeference (i.e. six transformation parameters - three rotation and three translation) the real-time captured image from the UAV through the collinearity equations. The georeferencing information is then used in aiding the INS integration Kalman filter a...

  7. Statistical, Graphical, and Learning Methods for Sensing, Surveillance, and Navigation Systems

    Science.gov (United States)

    2016-06-28

    One important problem in machine learning approaches to “ big data ” problems in signal processing is the development of computationally efficient and...important part of our work is the study for efficient fusion of sensory data and environmental information for network localization and navigation in...techniques developed enable efficient and accurate context modeling and data fusion through belief condensation. The results obtained through

  8. Basic study for ultrasound-based navigation for pedicle screw insertion using transmission and backscattered methods.

    Directory of Open Access Journals (Sweden)

    Ziqiang Chen

    Full Text Available The purpose of this study was to understand the acoustic properties of human vertebral cancellous bone and to study the feasibility of ultrasound-based navigation for posterior pedicle screw fixation in spinal fusion surgery. Fourteen human vertebral specimens were disarticulated from seven un-embalmed cadavers (four males, three females, 73.14 ± 9.87 years, two specimens from each cadaver. Seven specimens were used to measure the transmission, including tests of attenuation and phase velocity, while the other seven specimens were used for backscattered measurements to inspect the depth of penetration and A-Mode signals. Five pairs of unfocused broadband ultrasonic transducers were used for the detection, with center frequencies of 0.5 MHz, 1 MHz, 1.5 MHz, 2.25 MHz, and 3.5 MHz. As a result, good and stable results were documented. With increased frequency, the attenuation increased (P0.05. At about 0.6 cm away from the cortical bone, warning signals were easily observed from the backscattered measurements. In conclusion, the ultrasonic system proved to be an effective, moveable, and real-time imaging navigation system. However, how ultrasonic navigation will benefit pedicle screw insertion in spinal surgery needs to be determined. Therefore, ultrasound-guided pedicle screw implantation is theoretically effective and promising.

  9. A Method for Measuring the Structure Complexity of Web Application

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The precise and effective measure results of Web applications not only facilitate good comprehension of them, but also benefit to the macro-management of software activities, such as testing, reverse engineering, reuse, etc. The paper exploits some researches on measuring the structure complexity of Web application. Through a deep analysis of the configuration and objects' interactions of Web system, two conclusions have been drawn:①A generic Web application consists of static web page, dynamic page, component and database object;②The main interactions have only three styles, that is static link, dynamic link and call/return relation. Based on analysis and modeling of the content of a Web page (static or dynamic), complexity measure methods of both control logic of script and nesting of HTML code are further discussed. In addition, two methods for measuring the complexity of inter-page navigation are also addressed by modeling the inter-page navigation behaviors of Web application via WNG graph.

  10. AUTOMATIC NAVIGATION.

    Science.gov (United States)

    NAVIGATION, REPORTS), (*CONTROL SYSTEMS, *INFORMATION THEORY), ABSTRACTS, OPTIMIZATION, DYNAMIC PROGRAMMING, GAME THEORY, NONLINEAR SYSTEMS, CORRELATION TECHNIQUES, FOURIER ANALYSIS, INTEGRAL TRANSFORMS, DEMODULATION, NAVIGATION CHARTS, PATTERN RECOGNITION, DISTRIBUTION THEORY , TIME SHARING, GRAPHICS, DIGITAL COMPUTERS, FEEDBACK, STABILITY

  11. How Students Experience and Navigate Transitions in Undergraduate Medical Education: An Application of Bourdieu's Theoretical Model

    Science.gov (United States)

    Balmer, Dorene F.; Richards, Boyd F.; Varpio, Lara

    2015-01-01

    Using Bourdieu's theoretical model as a lens for analysis, we sought to understand how students experience the undergraduate medical education (UME) milieu, focusing on how they navigate transitions from the preclinical phase, to the major clinical year (MCY), and to the preparation for residency phase. Twenty-two medical students participated in…

  12. Application of X-Ray Pulsar Navigation: A Characterization of the Earth Orbit Trade Space

    Science.gov (United States)

    Yu, Wayne Hong

    2016-01-01

    The potential for pulsars as a navigation source has been studied since their discovery in 1967. X-ray pulsar navigation (XNAV) is a celestial navigation system that uses the consistent timing nature of x-ray photons from millisecond pulsars (MSP) to perform space navigation. By comparing the detected arrival of x-ray photons to a reference database of expected pulsar light-curve timing models, one can infer a range and range rate measurement based on light time delay. Much of the challenge of XNAV comes from the faint signal, availability, and distant nature of pulsars. This is a study of potential pulsar XNAV measurements to measure extended Kalman filter (EKF) tracking performance with a wide trade space of bounded Earth orbits, using a simulation of existing x-ray detector space hardware. An example of an x-ray detector for XNAV is the NASA Station Explorer for X-ray Timing and Navigation (SEXTANT) mission, a technology demonstration of XNAV set to perform on the International Space Station (ISS) in late 2016early 2017. XNAV hardware implementation is driven by trajectory and environmental influences which add noise to the x-ray pulse signal. In a closed Earth orbit, the radiation environment can exponentially increase the signal noise from x-ray pulsar sources, decreasing the quality and frequency of measurements. The SEXTANT mission in particular improves on the signal to noise ratio by focusing an array of 56 x-ray silicon drift detectors at one pulsar target at a time. This reduces timing glitches and other timing noise contributions from ambient x-ray sources to within a 100 nanosecond resolution. This study also considers the SEXTANT scheduling challenges inherent in a single target observation. Finally, as the navigation sources are now relatively inertial targets, XNAV measurements are also subject to periods of occultation from various celestial bodies. This study focuses on the characterization of these drivers in closed Earth orbits and is not a

  13. Unified Desktop for Monitoring & Control Applications - The Open Navigator Framework Applied for Control Centre and EGSE Applications

    Science.gov (United States)

    Brauer, U.

    2007-08-01

    The Open Navigator Framework (ONF) was developed to provide a unified and scalable platform for user interface integration. The main objective for the framework was to raise usability of monitoring and control consoles and to provide a reuse of software components in different application areas. ONF is currently applied for the Columbus onboard crew interface, the commanding application for the Columbus Control Centre, the Columbus user facilities specialized user interfaces, the Mission Execution Crew Assistant (MECA) study and EADS Astrium internal R&D projects. ONF provides a well documented and proven middleware for GUI components (Java plugin interface, simplified concept similar to Eclipse). The overall application configuration is performed within a graphical user interface for layout and component selection. The end-user does not have to work in the underlying XML configuration files. ONF was optimized to provide harmonized user interfaces for monitoring and command consoles. It provides many convenience functions designed together with flight controllers and onboard crew: user defined workspaces, incl. support for multi screens efficient communication mechanism between the components integrated web browsing and documentation search &viewing consistent and integrated menus and shortcuts common logging and application configuration (properties) supervision interface for remote plugin GUI access (web based) A large number of operationally proven ONF components have been developed: Command Stack & History: Release of commands and follow up the command acknowledges System Message Panel: Browse, filter and search system messages/events Unified Synoptic System: Generic synoptic display system Situational Awareness : Show overall subsystem status based on monitoring of key parameters System Model Browser: Browse mission database defintions (measurements, commands, events) Flight Procedure Executor: Execute checklist and logical flow interactive procedures Web

  14. Mobile Robot Navigation

    DEFF Research Database (Denmark)

    Andersen, Jens Christian

    2007-01-01

    Abstract Robots will soon take part in everyone’s daily life. In industrial production this has been the case for many years, but up to now the use of mobile robots has been limited to a few and isolated applications like lawn mowing, surveillance, agricultural production and military applications....... The research is now progressing towards autonomous robots which will be able to assist us in our daily life. One of the enabling technologies is navigation, and navigation is the subject of this thesis. Navigation of an autonomous robot is concerned with the ability of the robot to direct itself from...

  15. Pulsar/CNS integrated navigation based on federated UKF

    Institute of Scientific and Technical Information of China (English)

    Jin Liu; Jie Ma; Jinwen Tian

    2010-01-01

    In order to improve the autonomous navigation capability of satellite,a pulsar/CNS(celestial navigation system)integrated navigation method based on federated unscented Kalman filter(UKF)is proposed.The celestial navigation is a mature and stable navigation method.However,its position determination performance is not satisfied due to the low accuracy of horizon sensor.Single pulsar navigation is a new navigation method,which can provide highly accurate range measurements.The major drawback of single pulsar navigation is that the system is completely unobservabie.As two methods are complementary to each other,the federated UKF is used here for fusing the navigation data from single pulsar navigation and CNS.Compared to the traditional celestial navigation method and single pulsar navigation,the integrated navigation method can provide better navigation performance.The simulation results demonstrate the feasibility and effectiveness of the navigation method.

  16. Research on Application of Data Fusion Technology in Boat's Integrated Navigation System%数据融合技术在船舶组合导航中的应用研究

    Institute of Scientific and Technical Information of China (English)

    孟士超; 唐正茂

    2011-01-01

    As the combined application type of boat's navigation system,it is necessary to fuse integrated navigation information in order to supply reliability navigation information.This paper discussed the main data fusion methods that used in the boat's navigation system,of which on the basis the sensor local information fusion algorithm was pointed out aiming at the structure of federated filter,and the fault-tolerance of federated filter that adopted local sensor navigation information fusion algorithm was also analyzed in the end.All this work is significative for promoting the application of data fusion technology in boat's integrated navigation system.%随着船舶导航系统的组合应用,有必要对组合导航信息进行数据融合以提供高可靠性的导航信息。在简单分析了船舶导航信息主要的数据融合方法的基础上,针对联邦滤波器的结构设计了传感器本地多次数据融合决策算法,并对融合了传感器本地决策数据融合算法的容错性进行了分析,对于推动数据融合在船舶组合导航中的应用具有一定借鉴意义。

  17. Combinatorial methods with computer applications

    CERN Document Server

    Gross, Jonathan L

    2007-01-01

    Combinatorial Methods with Computer Applications provides in-depth coverage of recurrences, generating functions, partitions, and permutations, along with some of the most interesting graph and network topics, design constructions, and finite geometries. Requiring only a foundation in discrete mathematics, it can serve as the textbook in a combinatorial methods course or in a combined graph theory and combinatorics course.After an introduction to combinatorics, the book explores six systematic approaches within a comprehensive framework: sequences, solving recurrences, evaluating summation exp

  18. MEASURING THE EFFICIENCY OF AIR NAVIGATION SERVICES SYSTEM BY USING DEA METHOD

    Directory of Open Access Journals (Sweden)

    Mara Ćujić

    2015-03-01

    Full Text Available This paper examines the possibilities for measuring performance of current Air Navigation Services Providers (ANSPs in Europe. ANSPs are in the process of operational integration into functional air blocks (FABs tracking direction towards Single European Sky goals, but there are a lot of obstacles and air traffic management is still organized in a fragmented way. This is a reason for comparing national ANSPs. A Data Envelopment Analysis (DEA is applied as a tool for performance measurement. Effectiveness of 36 units of ANS system is measured and the limitations and benefits of this kind of performance model are presented.

  19. An Effective Terrain Aided Navigation for Low-Cost Autonomous Underwater Vehicles.

    Science.gov (United States)

    Zhou, Ling; Cheng, Xianghong; Zhu, Yixian; Dai, Chenxi; Fu, Jinbo

    2017-03-25

    Terrain-aided navigation is a potentially powerful solution for obtaining submerged position fixes for autonomous underwater vehicles. The application of terrain-aided navigation with high-accuracy inertial navigation systems has demonstrated meter-level navigation accuracy in sea trials. However, available sensors may be limited depending on the type of the mission. Such limitations, especially for low-grade navigation sensors, not only degrade the accuracy of traditional navigation systems, but further impact the ability to successfully employ terrain-aided navigation. To address this problem, a tightly-coupled navigation is presented to successfully estimate the critical sensor errors by incorporating raw sensor data directly into an augmented navigation system. Furthermore, three-dimensional distance errors are calculated, providing measurement updates through the particle filter for absolute and bounded position error. The development of the terrain aided navigation system is elaborated for a vehicle equipped with a non-inertial-grade strapdown inertial navigation system, a 4-beam Doppler Velocity Log range sensor and a sonar altimeter. Using experimental data for navigation performance evaluation in areas with different terrain characteristics, the experiment results further show that the proposed method can be successfully applied to the low-cost AUVs and significantly improves navigation performance.

  20. SBIR Technology Applications to Space Communications and Navigation (SCaN)

    Science.gov (United States)

    Liebrecht, Phil; Eblen, Pat; Rush, John; Tzinis, Irene

    2010-01-01

    This slide presentation reviews the mission of the Space Communications and Navigation (SCaN) Office with particular emphasis on opportunities for technology development with SBIR companies. The SCaN office manages NASA's space communications and navigation networks: the Near Earth Network (NEN), the Space Network (SN), and the Deep Space Network (DSN). The SCaN networks nodes are shown on a world wide map and the networks are described. Two types of technologies are described: Pull technology, and Push technologies. A listing of technology themes is presented, with a discussion on Software defined Radios, Optical Communications Technology, and Lunar Lasercom Space Terminal (LLST). Other technologies that are being investigated are some Game Changing Technologies (GCT) i.e., technologies that offer the potential for improving comm. or nav. performance to the point that radical new mission objectives are possible, such as Superconducting Quantum Interference Filters, Silicon Nanowire Optical Detectors, and Auto-Configuring Cognitive Communications

  1. Application of Genetic Control with Adaptive Scaling Scheme to Signal Acquisition in Global Navigation Satellite System Receiver

    Directory of Open Access Journals (Sweden)

    Ho-Nien Shou

    2012-02-01

    Full Text Available This paper presents a genetic-based control scheme that not only utilizes evolutionary characteristics to find the signal acquisition parameters, but also employs an adaptive scheme to control the search space and avoid the genetic control converging to local optimal value so as to acquire the desired signal precisely and rapidly. Simulations and experiment results show that the proposed method can improve the precision of signal parameters and take less signal acquisition time than traditional serial search methods for global navigation satellite system (GNSS signals.

  2. Study on dynamic model of tractor system for automated navigation applications

    Institute of Scientific and Technical Information of China (English)

    FENG Lei; HE Yong

    2005-01-01

    This research aims at using a dynamic model of tractor system to support navigation system design for an automatically guided agricultural tractor. This model, consisting of a bicycle model of the tractor system, has been implemented in the MATLAB environment and was developed based on a John Deere tractor. The simulation results from this MATLAB model was validated through field navigation tests. The accuracy of the trajectory estimation is strongly affected by the determination of the cornering stiffness of the tractor. In this simulation, the tractor cornering stiffness analysis was identified during simulation analysis using the MATLAB model based on the recorded trajectory data. The obtained data was used in simulation analyses for various navigation operations in the field of interest. The analysis on field validation test results indicated that the developed tractor system could accurately estimate wheel trajectories of a tractor system while operating in agricultural fields at various speeds. The results also indicated that the developed system could accurately determine tractor velocity and steering angle while the tractor operates in curved fields.

  3. Modeling 3D Objects for Navigation Purposes Using Laser Scanning

    Directory of Open Access Journals (Sweden)

    Cezary Specht

    2016-07-01

    Full Text Available The paper discusses the creation of 3d models and their applications in navigation. It contains a review of available methods and geometric data sources, focusing mostly on terrestrial laser scanning. It presents detailed description, from field survey to numerical elaboration, how to construct accurate model of a typical few storey building as a hypothetical reference in complex building navigation. Hence, the paper presents fields where 3d models are being used and their potential new applications.

  4. IMU navigation performance evaluation method based on signal grafting technology%基于信号嫁接技术的IMU导航性能评估方法

    Institute of Scientific and Technical Information of China (English)

    高琳; 班亚龙; 牛小骥

    2015-01-01

    为了探究新型惯性测量单元( IMU)的导航定位精度以便选用,需要对其进行方便有效和低成本的测试评估。对一种新颖的基于信号嫁接技术的IMU导航性能评估方法进行了验证和分析。以三种中低精度IMU为样本,将该方法的评估结果与该IMU的现场测试结果对比,从而对该方法的评估效果进行验证。结果表明:相对于IMU的仿真评估,使用信号嫁接技术合成出的IMU数据在导航性能上与现场测试结果有更高的一致性,更为有效和可信。该方法相比于权威的现场测试评估具有成本低、效率高的独特优势,在中低精度惯性器件性能评估上具有很高的应用价值。%In order to evaluate navigation performance of inertial measurement unit( IMU),convenient,efficient and low-cost evaluation methods are needed. A new method based on signal grafting is verified and analyzed,to evaluate the navigation performance of IMU. Three kinds of medium and low precision IMUs are used as samples, to check the evaluation effectiveness of the proposed method,the evaluation results using this method are compared with their actual road test results. Experimental results show that the navigation performances of the grafted IMU data matched much better with that of the real IMU data compared with the simulation IMU data. The proposed signal grafting method is not only reliable and feasible,but also low-cost and efficient,therefore,it has high application value in IMU performance evaluation of medium and low precision.

  5. Informetrics theory, methods and applications

    CERN Document Server

    Qiu, Junping; Yang, Siluo; Dong, Ke

    2017-01-01

    This book provides an accessible introduction to the history, theory and techniques of informetrics. Divided into 14 chapters, it develops the content system of informetrics from the theory, methods and applications; systematically analyzes the six basic laws and the theory basis of informetrics and presents quantitative analysis methods such as citation analysis and computer-aided analysis. It also discusses applications in information resource management, information and library science, science of science, scientific evaluation and the forecast field. Lastly, it describes a new development in informetrics- webometrics. Providing a comprehensive overview of the complex issues in today's environment, this book is a valuable resource for all researchers, students and practitioners in library and information science.

  6. Access 3 project protocol: young people and health system navigation in the digital age: a multifaceted, mixed methods study.

    Science.gov (United States)

    Kang, Melissa; Robards, Fiona; Sanci, Lena; Steinbeck, Katharine; Jan, Stephen; Hawke, Catherine; Kong, Marlene; Usherwood, Tim

    2017-08-07

    The integration of digital technology into everyday lives of young people has become widespread. It is not known whether and how technology influences barriers and facilitators to healthcare, and whether and how young people navigate between face-to-face and virtual healthcare. To provide new knowledge essential to policy and practice, we designed a study that would explore health system access and navigation in the digital age. The study objectives are to: (1) describe experiences of young people accessing and navigating the health system in New South Wales (NSW), Australia; (2) identify barriers and facilitators to healthcare for young people and how these vary between groups; (3) describe health system inefficiencies, particularly for young people who are marginalised; (4) provide policy-relevant knowledge translation of the research data. This mixed methods study has four parts, including: (1) a cross-sectional survey of young people (12-24 years) residing in NSW, Australia; (2) a longitudinal, qualitative study of a subsample of marginalised young people (defined as young people who: identify as Aboriginal and/or Torres Strait Islander; are experiencing homelessness; identify as sexuality and/or gender diverse; are of refugee or vulnerable migrant background; and/or live in rural or remote NSW); (3) interviews with professionals; (4) a knowledge translation forum. Ethics approvals were sought and granted. Data collection commenced in March 2016 and will continue until June 2017. This study will gather practice and policy-relevant intelligence about contemporary experiences of young people and health services, with a unique focus on five different groups of marginalised young people, documenting their experiences over time. Access 3 will explore navigation around all levels of the health system, determine whether digital technology is integrated into this, and if so how, and will translate findings into policy-relevant recommendations. © Article author(s) (or

  7. [Computer-assisted navigation in orthognathic surgery. Application to Le Fort I osteotomy.

    Science.gov (United States)

    Benassarou, M; Benassarou, A; Meyer, C

    2013-08-05

    Computer-assisted navigation is a tool that allows the surgeon to reach intraoperatively a previously defined target. This technique can be applied to the positioning of bone fragments in orthognathic surgery. It is not used routinely yet because there are no specifically dedicated systems available on the market for this kind of surgery. The goal of our study was to describe the various systems that could be used in orthognathic surgery and to report our experience of computer-assisted surgery in the positioning of the maxilla during maxillomandibular osteotomies.

  8. Formal safety assessment and application of the navigation simulators for preventing human error in ship operations

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The International Maritime Organization (IMO) has encouraged its member countries to introduce Formal Safety Assessment (FSA) for ship operations since the end of the last century. FSA can be used through certain formal assessing steps to generate effective recommendations and cautions to control marine risks and improve the safety of ships. On the basis of the brief introduction of FSA, this paper describes the ideas of applying FSA to the prevention of human error in ship operations. It especially discusses the investigation and analysis of the information and data using navigation simulators and puts forward some suggestions for the introduction and development of the FSA research work for safer ship operations.

  9. Application of H∞ filtering in the initial alignment of strapdown inertial navigation system

    Institute of Scientific and Technical Information of China (English)

    YU Fei; SUN Feng

    2005-01-01

    In this paper , the principle of H∞ filtering is discussed and H∞ filter is constructed, which is used in the initial alignment of the strapdown inertial navigation systems(SINS). The error model of SINS is derived. By utilizing constructed H∞ filter, the filtering calculation to that system has been conducted. The simulation results of the misalignment angle are given under the condition of unknown noises. The results show that the process of alignment with H∞ filter is much faster and with excellent robustness.

  10. Designing eHealth Applications to Reduce Cognitive Effort for Persons With Severe Mental Illness: Page Complexity, Navigation Simplicity, and Comprehensibility

    Science.gov (United States)

    Spring, Michael R; Hanusa, Barbara H; Eack, Shaun M; Haas, Gretchen L

    2017-01-01

    Background eHealth technologies offer great potential for improving the use and effectiveness of treatments for those with severe mental illness (SMI), including schizophrenia and schizoaffective disorder. This potential can be muted by poor design. There is limited research on designing eHealth technologies for those with SMI, others with cognitive impairments, and those who are not technology savvy. We previously tested a design model, the Flat Explicit Design Model (FEDM), to create eHealth interventions for individuals with SMI. Subsequently, we developed the design concept page complexity, defined via the design variables we created of distinct topic areas, distinct navigation areas, and number of columns used to organize contents and the variables of text reading level, text reading ease (a newly added variable to the FEDM), and the number of hyperlinks and number of words on a page. Objective The objective of our study was to report the influence that the 19 variables of the FEDM have on the ability of individuals with SMI to use a website, ratings of a website’s ease of use, and performance on a novel usability task we created termed as content disclosure (a measure of the influence of a homepage’s design on the understanding user’s gain of a website). Finally, we assessed the performance of 3 groups or dimensions we developed that organize the 19 variables of the FEDM, termed as page complexity, navigational simplicity, and comprehensibility. Methods We measured 4 website usability outcomes: ability to find information, time to find information, ease of use, and a user’s ability to accurately judge a website’s contents. A total of 38 persons with SMI (chart diagnosis of schizophrenia or schizoaffective disorder) and 5 mental health websites were used to evaluate the importance of the new design concepts, as well as the other variables in the FEDM. Results We found that 11 of the FEDM’s 19 variables were significantly associated with all 4

  11. CORRECTION OF FEMUR DEFORMITIES BY ILIZAROV METHOD AND BY APPARATUS «ORTHO-SUV» BASED ON COMPUTER NAVIGATION

    Directory of Open Access Journals (Sweden)

    L. N. Solomin

    2011-01-01

    Full Text Available Results of correction of femur deformations by Ilizarov method and with apparatus Orto-SuV working on the basis of computer navigation are analyzed. For elimination of difficult deformations in order to avoid multiple external fixator remounting with stage-by-stage radiological control it is expedient to use apparatus Orto-SUV. In order to elimination of moderate and simple deformations (except torsion as hexapods and traditional techniques can be a choice method. The use «Orto-SUV» apparatus allows to reduce time necessary for deformation correction and osteosynthesis term in 1,4–2,4 times (for average and severe deformations.

  12. Case-based reactive navigation: a method for on-line selection and adaptation of reactive robotic control parameters.

    Science.gov (United States)

    Ram, A; Arkin, R C; Moorman, K; Clark, R J

    1997-01-01

    We present a new line of research investigating on-line adaptive reactive control mechanisms for autonomous intelligent agents. We discuss a case-based method for dynamic selection and modification of behavior assemblages for a navigational system. The case-based reasoning module is designed as an addition to a traditional reactive control system, and provides more flexible performance in novel environments without extensive high level reasoning that would otherwise slow the system down. The method is implemented in the ACBARR (case-based reactive robotic) system and evaluated through empirical simulation of the system on several different environments, including "box canyon" environments known to be problematic for reactive control systems in general.

  13. Introductory Course on Satellite Navigation

    Science.gov (United States)

    Giger, Kaspar; Knogl, J. Sebastian

    2012-01-01

    Satellite navigation is widely used for personal navigation and more and more in precise and safety-critical applications. Thus, the subject is suited for attracting the interest of young people in science and engineering. The practical applications allow catching the students' attention for the theoretical background. Educational material on the…

  14. Global navigation system with RFID tags

    Science.gov (United States)

    Tsukiyama, Toshifumi

    2002-02-01

    A new navigation system is described for a mobile robot moving around in man-made environments such as hallways in a building. The system is based on a commercial three-wheel mobile platform with the addition of a Linux-based laptop computer, a Radio Frequency Identification (RDID) tag sensor and a vision system. At critical junctions such as the intersection of two passages the navigation system must identify the robot's location on a given map. We propose a method using RFID tags as landmarks. Each RFID tag has a unique ID number corresponding to its location on the map. The navigation system can decide the next movement (left-turn, right-turn and so on) toward a given goal based on this number. The navigation system also can automatically follow walls using the vision system. Since the equipment setup is very simple and the navigation system is easily combined with general mobile robot systems, our proposed technique would be useful for real-world robotic applications such as intelligent navigation for motorized wheelchairs.

  15. Biometrics Theory, Methods, and Applications

    CERN Document Server

    Boulgouris, N V; Micheli-Tzanakou, Evangelia

    2009-01-01

    An in-depth examination of the cutting edge of biometrics. This book fills a gap in the literature by detailing the recent advances and emerging theories, methods, and applications of biometric systems in a variety of infrastructures. Edited by a panel of experts, it provides comprehensive coverage of:. Multilinear discriminant analysis for biometric signal recognition;. Biometric identity authentication techniques based on neural networks;. Multimodal biometrics and design of classifiers for biometric fusion;. Feature selection and facial aging modeling for face recognition;. Geometrical and

  16. Distance sampling methods and applications

    CERN Document Server

    Buckland, S T; Marques, T A; Oedekoven, C S

    2015-01-01

    In this book, the authors cover the basic methods and advances within distance sampling that are most valuable to practitioners and in ecology more broadly. This is the fourth book dedicated to distance sampling. In the decade since the last book published, there have been a number of new developments. The intervening years have also shown which advances are of most use. This self-contained book covers topics from the previous publications, while also including recent developments in method, software and application. Distance sampling refers to a suite of methods, including line and point transect sampling, in which animal density or abundance is estimated from a sample of distances to detected individuals. The book illustrates these methods through case studies; data sets and computer code are supplied to readers through the book’s accompanying website.  Some of the case studies use the software Distance, while others use R code. The book is in three parts.  The first part addresses basic methods, the ...

  17. Application of local Lyapunov exponents to maneuver design and navigation in the three-body problem

    Science.gov (United States)

    Anderson, Rodney L.; Lo, Martin W.; Born, George H.

    2003-01-01

    Dynamical systems theory has recently been employed to design trajectories within the three-body problem for several missions. This research has applied one stability technique, the calculation of local Lyapunov exponents, to such trajectories. Local Lyapunov exponents give an indication of the effects that perturbations or maneuvers will have on trajectories over a specified time. A numerical comparison of local Lyapunov exponents was first made with the distance random perturbations traveled from a nominal trajectory, and the local Lyapunov exponents were found to correspond well with the perturbations that caused the greatest deviation from the nominal. This would allow them to be used as an indicator of the points where it would be important to reduce navigation uncertainties.

  18. Application of local Lyapunov exponents to maneuver design and navigation in the three-body problem

    Science.gov (United States)

    Anderson, Rodney L.; Lo, Martin W.; Born, George H.

    2003-01-01

    Dynamical systems theory has recently been employed to design trajectories within the three-body problem for several missions. This research has applied one stability technique, the calculation of local Lyapunov exponents, to such trajectories. Local Lyapunov exponents give an indication of the effects that perturbations or maneuvers will have on trajectories over a specified time. A numerical comparison of local Lyapunov exponents was first made with the distance random perturbations traveled from a nominal trajectory, and the local Lyapunov exponents were found to correspond well with the perturbations that caused the greatest deviation from the nominal. This would allow them to be used as an indicator of the points where it would be important to reduce navigation uncertainties.

  19. How students experience and navigate transitions in undergraduate medical education: an application of Bourdieu's theoretical model.

    Science.gov (United States)

    Balmer, Dorene F; Richards, Boyd F; Varpio, Lara

    2015-10-01

    Using Bourdieu's theoretical model as a lens for analysis, we sought to understand how students experience the undergraduate medical education (UME) milieu, focusing on how they navigate transitions from the preclinical phase, to the major clinical year (MCY), and to the preparation for residency phase. Twenty-two medical students participated in this longitudinal case study. Students had similar preclinical and post-MCY experiences but different MCY experiences (rotational vs. longitudinal tracks). We interviewed students every 6 months in the preclinical phase, mid-way through MCY, and 7-8 months before graduation (101 total interviews). We inductively created codes, iteratively revised codes to best-fit the data, and thematically clustered codes into Bourdieu-informed categories: field (social structures), capital (resources) and habitus (dispositions). We found that students acclimated to shifts in the UME field as they moved through medical school: from medical school itself to the health system and back. To successfully navigate transitions, students learned to secure capital as medical knowledge and social connections in the preclinical and preparation for residency phases, and as reputable patient care and being noticed in the clinical phase. To obtain capital, and be well-positioned for the next phase of training, students consistently relied on dispositions of initiative and flexibility. In summary, students experience the complex context of medical school through a series of transitions. Efforts to improve UME would be well-served by greater awareness of the social structures (field) that students encounter, the resources to which they afford value (capital), and the dispositions which aid acquisition of these resources (habitus).

  20. Navigation domain representation for interactive multiview imaging.

    Science.gov (United States)

    Maugey, Thomas; Daribo, Ismael; Cheung, Gene; Frossard, Pascal

    2013-09-01

    Enabling users to interactively navigate through different viewpoints of a static scene is a new interesting functionality in 3D streaming systems. While it opens exciting perspectives toward rich multimedia applications, it requires the design of novel representations and coding techniques to solve the new challenges imposed by the interactive navigation. In particular, the encoder must prepare a priori a compressed media stream that is flexible enough to enable the free selection of multiview navigation paths by different streaming media clients. Interactivity clearly brings new design constraints: the encoder is unaware of the exact decoding process, while the decoder has to reconstruct information from incomplete subsets of data since the server generally cannot transmit images for all possible viewpoints due to resource constrains. In this paper, we propose a novel multiview data representation that permits us to satisfy bandwidth and storage constraints in an interactive multiview streaming system. In particular, we partition the multiview navigation domain into segments, each of which is described by a reference image (color and depth data) and some auxiliary information. The auxiliary information enables the client to recreate any viewpoint in the navigation segment via view synthesis. The decoder is then able to navigate freely in the segment without further data request to the server; it requests additional data only when it moves to a different segment. We discuss the benefits of this novel representation in interactive navigation systems and further propose a method to optimize the partitioning of the navigation domain into independent segments, under bandwidth and storage constraints. Experimental results confirm the potential of the proposed representation; namely, our system leads to similar compression performance as classical inter-view coding, while it provides the high level of flexibility that is required for interactive streaming. Because of

  1. A LiDAR and IMU Integrated Indoor Navigation System for UAVs and Its Application in Real-Time Pipeline Classification.

    Science.gov (United States)

    Kumar, G Ajay; Patil, Ashok Kumar; Patil, Rekha; Park, Seong Sill; Chai, Young Ho

    2017-06-02

    Mapping the environment of a vehicle and localizing a vehicle within that unknown environment are complex issues. Although many approaches based on various types of sensory inputs and computational concepts have been successfully utilized for ground robot localization, there is difficulty in localizing an unmanned aerial vehicle (UAV) due to variation in altitude and motion dynamics. This paper proposes a robust and efficient indoor mapping and localization solution for a UAV integrated with low-cost Light Detection and Ranging (LiDAR) and Inertial Measurement Unit (IMU) sensors. Considering the advantage of the typical geometric structure of indoor environments, the planar position of UAVs can be efficiently calculated from a point-to-point scan matching algorithm using measurements from a horizontally scanning primary LiDAR. The altitude of the UAV with respect to the floor can be estimated accurately using a vertically scanning secondary LiDAR scanner, which is mounted orthogonally to the primary LiDAR. Furthermore, a Kalman filter is used to derive the 3D position by fusing primary and secondary LiDAR data. Additionally, this work presents a novel method for its application in the real-time classification of a pipeline in an indoor map by integrating the proposed navigation approach. Classification of the pipeline is based on the pipe radius estimation considering the region of interest (ROI) and the typical angle. The ROI is selected by finding the nearest neighbors of the selected seed point in the pipeline point cloud, and the typical angle is estimated with the directional histogram. Experimental results are provided to determine the feasibility of the proposed navigation system and its integration with real-time application in industrial plant engineering.

  2. A LiDAR and IMU Integrated Indoor Navigation System for UAVs and Its Application in Real-Time Pipeline Classification

    Science.gov (United States)

    Kumar, G. Ajay; Patil, Ashok Kumar; Patil, Rekha; Park, Seong Sill; Chai, Young Ho

    2017-01-01

    Mapping the environment of a vehicle and localizing a vehicle within that unknown environment are complex issues. Although many approaches based on various types of sensory inputs and computational concepts have been successfully utilized for ground robot localization, there is difficulty in localizing an unmanned aerial vehicle (UAV) due to variation in altitude and motion dynamics. This paper proposes a robust and efficient indoor mapping and localization solution for a UAV integrated with low-cost Light Detection and Ranging (LiDAR) and Inertial Measurement Unit (IMU) sensors. Considering the advantage of the typical geometric structure of indoor environments, the planar position of UAVs can be efficiently calculated from a point-to-point scan matching algorithm using measurements from a horizontally scanning primary LiDAR. The altitude of the UAV with respect to the floor can be estimated accurately using a vertically scanning secondary LiDAR scanner, which is mounted orthogonally to the primary LiDAR. Furthermore, a Kalman filter is used to derive the 3D position by fusing primary and secondary LiDAR data. Additionally, this work presents a novel method for its application in the real-time classification of a pipeline in an indoor map by integrating the proposed navigation approach. Classification of the pipeline is based on the pipe radius estimation considering the region of interest (ROI) and the typical angle. The ROI is selected by finding the nearest neighbors of the selected seed point in the pipeline point cloud, and the typical angle is estimated with the directional histogram. Experimental results are provided to determine the feasibility of the proposed navigation system and its integration with real-time application in industrial plant engineering. PMID:28574474

  3. 昆虫视觉启发的光流复合导航方法%An Optical Flow-based Composite Navigation Method Inspired by Insect Vision

    Institute of Scientific and Technical Information of China (English)

    潘超; 刘建国; 李峻林

    2015-01-01

    Many insects can use optical flow (OF) for various navigational tasks. Inspired by the OF navigation strategies of insects, this paper develops an OF-based composite navigation method for more efficient and precise visual location. The composite navigation method is composed of an OF navigation and an OF aided navigation. The OF navigation is to measure motion at each step using an insect inspired OF method and the current position information is then obtained by path integration. As path integration can lead to increasing cumulative position errors, the OF aided navigation is thus employed to correct the position errors. This aided navigation implements an OF-based Kalman filter by studying the insect inspired OF method. It can iteratively match the actual and the predicted OF for a continuous error estimation. The OF navigation and the OF aided navigation are derived from the same OF method so that they can share input signals and some operations in navigation. Experiments using a mobile robot have demonstrated the efficiency of the proposed composite navigation method.%昆虫能够使用视觉感受的光流(Optical flow, OF)信息执行导航任务。启发于昆虫的视觉导航,本文提出了一种生物视觉启发的光流复合导航方法,它由光流导航和光流辅助导航两部分组成,以实现高效精确的视觉导航定位。该方法中,光流导航的作用是使用昆虫视觉启发的光流法,测量系统每一时刻的运动位移,然后使用路径积分累加位移得到位置信息;光流辅助导航的作用是针对路径积分会产生累积误差的缺点,使用光流匹配的方法来估计和修正导航中的位置误差。该光流辅助导航也参考了昆虫启发的光流法,通过基于光流的卡尔曼滤波器来执行实际和预测光流的迭代匹配。由于光流导航和光流辅助导航中的光流计算来源于同一昆虫启发光流法,使得光流复合导航的两部分可共享输入信号和部分

  4. Inertial Navigation Technology Introduction and Application Development Study%惯性导航技术介绍及应用发展研究

    Institute of Scientific and Technical Information of China (English)

    谭鹏辉

    2016-01-01

    本文阐述了惯性导航技术的基本原理和分类,介绍了惯性导航的核心部件陀螺仪的发展状况,并列举出代表当前最高技术水平的新型惯性器件。同时,概括了惯性技术的应用领域,并针对其优缺点介绍了一种组合导航的方式。最后指出,随着市场及实际应用的需求,未来导航系统的主要发展方向将向以惯性导航为基础的组合导航靠拢。%This paper describes the basic principles and classification of inertial navigation technology, it introduces the development of the core components of inertial navigation gyroscopes, and outlines the current representative of the highest technical level of new inertial device. It summarizes the applications of inertial technology, and introduces a combination of navigation mode for their advantages and disadvantages. Finally, with the market demand and the practical application, the main direction of the future development of the navigation system will be based on the combine navigation.

  5. [Pharmacoepidemiology: definition, methods and applications].

    Science.gov (United States)

    Montastruc, Jean-Louis; Sommet, Agnès; Montastruc, François; Moulis, Guillaume; Bagheri, Haleh; Damase-michel, Christine; Lapeyre-mestre, Maryse

    2015-01-01

    Clinical evaluation of drugs before approval is based on the experimental design of clinical trial with randomization of drug exposure. Unfortunately, conclusions of clinical trials are necessarily limited to patients enrolled in the trial. It is therefore necessary to compare these experimental data from clinical trials with the real use of drugs in clinical practice. Pharmacoepidemiology is defined as the study in real conditions and on large populations, of use, effectiveness and risk of drugs. The methods and fields of application of pharmacoepidemiology are described. They allow to characterize conditions of use, misuse, clinical effectiveness, adverse drug reactions and risks of drugs. The development of pharmacoepidemiology should allow optimization of "rational use" of drugs.

  6. A navigated mapping method for FPGA testing%应用于FPGA测试的导航映射方法

    Institute of Scientific and Technical Information of China (English)

    张倩莉; 于芳; 刘忠立; 李艳

    2012-01-01

    Because the FPGA factories presently do not offer the special testing function in their EDA tools, this paper addresses the design of a navigated mapping method used for FPGA testing. The navigated mapping tool totally controls the basic elements and exactly controls the usage of FPGA logic resource, tests Some tar- getable logic of the FPGA and increases the coverage of each test vector effectively, implements the FPGA soft- ware defect-tolerance function. The result is well proven in test converage through 128 test cases.%针对目前FPGA厂商的EDA工具不对用户提供专用芯片测试功能,提出一种可应用于FPGA测试的导航映射方法.通过导航映射对FPGA底层硬件进行完全可控操作,精确控制FPGA逻辑资源的使用,可以对FPGA逻辑资源进行有针对性的测试,有效提高FPGA的测试覆盖率,同时在用户约束文件的指导下可以绕开FPGA硬件缺陷进行编程,实现有效的FPGA软件容错功能.本文采用128个测试配置对FPGA进行了验证,结果表明,利用导航映射方法可以得到良好的测试覆盖率.

  7. Development and application of stent-based image guided navigation system for oral and maxillofacial surgery

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woo Jin; Kim, Dae Seung [Interdisciplinary Program in Radiation Applied Life Science, Dental Research Institute and BK21, College of Medicine, Seoul National University, Seoul (Korea, Republic of); Yi, Won Jin; Lee, Sam Sun; Choi, Soon Chul; Heo, Min Suk; Huh, Kyung Hoe; Kim, Myung Jin; Lee, Jee Ho [Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    2009-09-15

    The purpose of this study was to develop a stent-based image guided surgery system and to apply it to oral and maxillofacial surgeries for anatomically complex sites. We devised a patient-specific stent for patient-to-image registration and navigation. Three dimensional positions of the reference probe and the tool probe were tracked by an optical camera system and the relative position of the handpiece drill tip to the reference probe was monitored continuously on the monitor of a PC. Using 8 landmarks for measuring accuracy, the spatial discrepancy between CT image coordinate and physical coordinate was calculated for testing the normality. The accuracy over 8 anatomical landmarks showed an overall mean of 0.56 {+-} 0.16 mm. The developed system was applied to a surgery for a vertical alveolar bone augmentation in right mandibular posterior area and possible interior alveolar nerve injury case of an impacted third molar. The developed system provided continuous monitoring of invisible anatomical structures during operation and 3D information for operation sites. The clinical challenge showed sufficient accuracy and availability of anatomically complex operation sites. The developed system showed sufficient accuracy and availability in oral and maxillofacial surgeries for anatomically complex sites.

  8. Ecodesign Navigator

    DEFF Research Database (Denmark)

    Simon, M; Evans, S.; McAloone, Timothy Charles;

    The Ecodesign Navigator is the product of a three-year research project called DEEDS - DEsign for Environment Decision Support. The initial partners were Manchester Metropolitan University, Cranfield University, Engineering 6 Physical Sciences Resaech Council, Electrolux, ICL, and the Industry...

  9. DSA三维导航技术在颅内动脉瘤介入治疗中的应用%Application of DSA three-dimensional navigation technology in the interventional treatment of intracranial aneurysms

    Institute of Scientific and Technical Information of China (English)

    吴奇华; 曾勇明

    2012-01-01

    目的 探讨数字减影血管造影(DSA)三维导航技术在颅内动脉瘤介入治疗中的价值.方法 应用三维导航技术,评价86例颅内动脉瘤介入治疗患者DSA三维导航技术的应用效果.结果 86例颅内动脉瘤患者均行旋转DSA,在三维导航技术引导下,84例完成颅内动脉瘤的栓塞治疗;2例定位失败,未完成治疗,成功率为97.67%.结论 三维导航技术能提高颅内动脉瘤介入治疗成功率,缩短治疗时间,降低辐射剂量,是一种有效的介入治疗辅助技术.%Objective To explore the value of digital subtraction angiography(DSA) three-dimensional navigation technology in the interventional treatment of intracranial aneurysms. Methods Three-dimensional navigation technology was applied to 86 patients with intracranial aneurysms who accepted interventional treatment,and application effect of DSA three-dimensional navigation technology was evaluated. Results All 86 patients with intracranial aneurysms were subjected to rotational DSA. Under the guidance of three-dimensional navigation technology, 84 of them complete the embolization of intracranial aneurysms, and 2 of them failed to location and did not complete the treatment, with the success rate of 97. 6%. Conclusion Three-dimensional navigation technology is an effective assistive technology of intervention treatment, which can improve the success rate of intracranial aneurysms treatment,shorten the treatment duration,decrease the radiation dose.

  10. Navigation message designing with high accuracy for NAV

    Institute of Scientific and Technical Information of China (English)

    Wang Luxiao; Huang Zhigang; Zhao Yun

    2014-01-01

    Navigation message designing with high accuracy guarantee is the key to efficient navi-gation message distribution in the global navigation satellite system (GNSS). Developing high accu-racy-aware navigation message designing algorithms is an important topic. This paper investigates the high-accuracy navigation message designing problem with the message structure unchanged. The contributions made in this paper include a heuristic that employs the concept of the estimated range deviation (ERD) to improve the existing well-known navigation message on L1 frequency (NAV) of global positioning system (GPS) for good accuracy service; a numerical analysis approximation method (NAAM) to evaluate the range error due to truncation (RET) of different navigation messages; and a basic positioning parameters designing algorithm in the limited space allocation. Based on the predicted ultra-rapid data from the ultra-rapid data from the international GPS service for geodynamic (IGU), ERDs are generated in real time for error correction. Simulations show that the algorithms developed in this paper are general and flexible, and thus are applicable to NAV improvement and other navigation message designs.

  11. 船舶惯性导航技术应用与展望%Application and prospect of ship inertial navigation technology

    Institute of Scientific and Technical Information of China (English)

    张崇猛; 蔡智渊; 舒东亮; 侯巍

    2012-01-01

    以惯性导航技术的发展历程为基础,结合相关文献资料,简述了各类惯性导航器件的工作原理,综合阐述了国内外船舶惯性导航技术的发展水平和应用概况,并对国内外发展应用情况进行了比较分析,对未来船舶惯性导航技术及其系统技术的发展进行了展望,对船舶惯性导航技术的发展方向提出了看法.%This paper is based on development history of inertia navigation technique, according to related literature, describes all kinds of inertial navigation sensor principle of work, comprehensive elaboration the development level of general application of the ship inertial navigation technology at home and abroad, and to contrast the development situation of the domestic and foreign, look forward the future of ship inertial navigation technology, and puts forward some opinions on the developing direction to the ship inertial navigation technology.

  12. Celestial Navigation for the Novice

    Science.gov (United States)

    Sadler, Philip M.

    2011-01-01

    What kinds of astronomical lab activities can introductory astronomy students carry out easily in daytime? The most impressive is the determination of their latitude and longitude from observations of the sun. The "shooting of a noon sight” and its "reduction to a position” is a technique still practiced by navigators in this age of GPS. Indeed, the U.S. Coast Guard exams for ocean-going licenses and include celestial navigation. These techniques continue to be used by the military and by private sailors as a backup to electronic navigation systems. We present a method to establish one's latitude and longitude to better than 30 miles from measurements of the sun's altitude that is easily within the capability non-science majors. This is a practical application of astronomy in use the world over. The streamlined method used is based on an easy-to-build protractor and string quadrant. Participants will leave with all materials to conduct this activity in their own classroom.

  13. INS/CNS integrated navigation method for lunar rover%月球车的惯性/天文组合导航新方法

    Institute of Scientific and Technical Information of China (English)

    宁晓琳; 蔡洪炜; 吴伟仁; 房建成; 张学亮

    2011-01-01

    In the second phase of China's lunar exploration program, a lunar rover will be used to survey the lunar surface. Effective navigation and control of lunar rover guarantees the success of the mission. Autonomous navigation is a critical technology which compensates for the limitations of ground tracking and control. Inertial navigation system (INS) and celestial navigation system (CNS) are two kinds of important autonomous navigation systems. However, the error of INS accumulates with time and precision of CNS is low in a short period of time. In order to solve these problems, a new INS/CNS integrated navigation method for lunar rovers is presented. This method acquires a high navigation precision by periodically fusing estimates of INS and CNS. Simulation results show that a position estimation error within 25 m is obtained, which demonstrates that the method is a promising choice for long period, long distance and high precision navigation of lunar rover.%我国月球探测二期工程将进行月面巡视探测任务,而月球车的导航和控制是任务完成的重要保障.月球车实现自主导航可以弥补地面测控的局限性,是目前亟待解决的关键技术.惯性导航和天文导航都是适用于月球车的自主导航方法,但惯性导航误差随时间积累,天文导航短时精度较低.为此,提出一种月球车自主惯性/天文组合导航新方法,通过天文导航不断对惯性导航进行校正,提高了导航的精度和可靠性.仿真结果表明,该惯性/天文组合导航方法的位置精度在25 m以内,可满足月球车长时间、长距离的高精度导航要求.

  14. A local geopotential model for implementation of underwater passive navigation

    Institute of Scientific and Technical Information of China (English)

    Zhigang Wang; Shaofeng Bian

    2008-01-01

    A main aspect of underwater passive navigation is how to identify the vehicle location on an existing gravity map.and several match-ing algorithms as ICCP and SITAN are the most prevalent methods that many scholars are using.In this paper,a novel algorithm that is different from matching algorithms for passive navigation is developed.The algorithm implements underwater passive navigation by directly estimating the inertial errors through Kalman falter algorithm,and the key part of this implementation is a Fourier series.based local geopotential model.Firstly,the pfinople of local geopotential model based on Fourier series is introduced in this paper,thus the discrete gravity anomalies data can be expressed analytically with respect to geographic coordinares to establish the observation equation required in the application of Kalman filter.Whereafter,the indicated gravity anomalies can be gotten by substituting the inertial posi-tions to existing gravity anomalies map.Finally,the classical extended Kalman filter is introduced with the differences between measured gravity and indicated gravity used as observations to optimally estimate the errors of the inertial navigation system(INS).This naviga-tion algorithm is tested on simulated data with encouraging results.Although this algorithm is developed for underwater navigation using gravity data,it iS equally applicable to other domains,for example vehicle navigation on magnetic or terrain data.

  15. Autonomous Navigation Performance Evaluation Method Based on Trajectory Analysis%基于轨迹分析的自主导航性能评估方法

    Institute of Scientific and Technical Information of China (English)

    王勇鑫; 钱徽; 金卓军; 朱淼良

    2011-01-01

    在马尔可夫决策模型框架下,提出一种基于轨迹分析的计算评估方法,通过分析驾驶回报设置和车辆轨迹的特征期望衡量自主导航系统的性能.假定回报函数是回报特征的线性组合,通过逼近不同的车辆自主驾驶策略,求解应用于沙盒场景的回报设置,从而仿真导航轨迹的特征期望.实验结果表明,该方法能对自主导航系统的轨迹数据实现定性和定量评估.%This paper proposes a novel trajectory-analysis-based performance evaluation method, which assesses and compares the navigation performances by reward settings and feature expectations under Markov Decision Process(MDP) framework. Assuming that the reward function is a linear combination of known features, this method evaluates reward settings by approximating the driving styles of different land autonomous navigation systems. On this basis, reward settings are used to simulate the feature expectations of navigation trajectories in a standard land navigation environment called the sandbox. Experimental results show the validity of this method in both qualitative and quantitative performance evaluations.

  16. Application of Intraoperative CT-Guided Navigation in Simultaneous Minimally Invasive Anterior and Posterior Surgery for Infectious Spondylitis

    Directory of Open Access Journals (Sweden)

    Meng-Huang Wu

    2017-01-01

    Full Text Available This study was aimed at evaluating the safety and efficacy of using intraoperative computed tomography- (iCT- guided navigation in simultaneous minimally invasive anterior and posterior surgery for infectious spondylitis. Nine patients with infectious spondylitis were enrolled in this study. The average operative time was 327.6 min (range, 210–490 and intraoperative blood loss was 407 cc (range, 50–1,200. The average duration of hospital stay was 48.9 days (range, 11–76. Out of a total of 54 pedicle screws employed, 53 screws (98.1% were placed accurately. A reduced visual analog scale on back pain (from 8.2 to 2.2 and Oswestry disability index (from 67.1% to 25.6% were found at the 2-year follow-up. All patients had achieved resolution of spinal infection with reduced average erythrocyte sedimentation rate (from 83.9 to 14.1 mm/hr and average C-reactive protein (from 54.4 to 4.8 mg/dL. Average kyphotic angle correction was 10.5° (range, 8.4°–12.6° postoperatively and 8.5° (range, 6.9°–10.1° after 2 years. In conclusion, the current iCT-guided navigation approach has been demonstrated to be an alternative method during simultaneous minimally invasive anterior and posterior surgery for infectious spondylitis. It can provide a good intraoperative orientation and visualization of anatomic structures and also a high pedicle screw placement accuracy in patient’s lateral decubitus position.

  17. Application of Intraoperative CT-Guided Navigation in Simultaneous Minimally Invasive Anterior and Posterior Surgery for Infectious Spondylitis

    Science.gov (United States)

    Dubey, Navneet Kumar; Lee, Ching-Yu; Li, Yen-Yao; Cheng, Chin-Chang; Shi, Chung-Sheng

    2017-01-01

    This study was aimed at evaluating the safety and efficacy of using intraoperative computed tomography- (iCT-) guided navigation in simultaneous minimally invasive anterior and posterior surgery for infectious spondylitis. Nine patients with infectious spondylitis were enrolled in this study. The average operative time was 327.6 min (range, 210–490) and intraoperative blood loss was 407 cc (range, 50–1,200). The average duration of hospital stay was 48.9 days (range, 11–76). Out of a total of 54 pedicle screws employed, 53 screws (98.1%) were placed accurately. A reduced visual analog scale on back pain (from 8.2 to 2.2) and Oswestry disability index (from 67.1% to 25.6%) were found at the 2-year follow-up. All patients had achieved resolution of spinal infection with reduced average erythrocyte sedimentation rate (from 83.9 to 14.1 mm/hr) and average C-reactive protein (from 54.4 to 4.8 mg/dL). Average kyphotic angle correction was 10.5° (range, 8.4°–12.6°) postoperatively and 8.5° (range, 6.9°–10.1°) after 2 years. In conclusion, the current iCT-guided navigation approach has been demonstrated to be an alternative method during simultaneous minimally invasive anterior and posterior surgery for infectious spondylitis. It can provide a good intraoperative orientation and visualization of anatomic structures and also a high pedicle screw placement accuracy in patient's lateral decubitus position.

  18. Rapid Development of Guidance, Navigation, and Control Core Flight System Software Applications Using Simulink Models Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We will demonstrate the usefulness of SIL for GSFC missions by attempting to compile the SIL source code with an autocoded sample GNC application flight software....

  19. GLORI (GLObal navigation satellite system Reflectometry Instrument): A New Airborne GNSS-R receiver for land surface applications

    Science.gov (United States)

    Motte, Erwan; Zribi, Mehrez; Fanise, Pascal

    2015-04-01

    GLORI (GLObal navigation satellite system Reflectometry Instrument) is a new receiver dedicated to the airborne measurement of surface parameters such as soil moisture and biomass above ground and sea state (wave height and direction) above oceans. The instrument is based on the PARIS concept [Martin-Neira, 1993] using both the direct and surface-reflected L-band signals from the GPS constellation as a multistatic radar source. The receiver is based on one up-looking and one down-looking dual polarization hemispherical active antennas feeding a low-cost 4-channel SDR direct down-conversion receiver tuned to the GPS L1 frequency. The raw measurements are sampled at 16.368MHz and stored as 2-bit, IQ binary files. In post-processing, GPS acquisition and tracking are performed on the direct up-looking signal while the down-looking signal is processed blindly using tracking parameters from the direct signal. The obtained direct and reflected code-correlation waveforms are the basic observables for geophysical parameters inversion. The instrument was designed to be installed aboard the ATR42 experimental aircraft from the French SAFIRE fleet as a permanent payload. The long term goal of the project is to provide real-time continuous surface information for every flight performed. The aircraft records attitude information through its Inertial Measurement Unit and a commercial GPS receiver records additional information such as estimated doppler and code phase, receiver location, satellites azimuth and elevation. A series of test flights were performed over both the Toulouse and Gulf of Lion (Mediterranean Sea) regions during the period 17-21 Nov 2014 together with the KuROS radar [Hauser et al., 2014]. Using processing methods from the literature [Egido et al., 2014], preliminary results demonstrate the instrument sensitivity to both ground and ocean surface parameters estimation. A dedicated scientific flight campaign is planned at the end of second quarter 2015 with

  20. Verification and Validation of Numerical Models for Air/Water Flow on Coastal and Navigation Fluid-Structure Interaction Applications

    Science.gov (United States)

    Kees, C. E.; Farthing, M.; Dimakopoulos, A.; DeLataillade, T.

    2015-12-01

    Performance analysis and optimization of coastal and navigation structures is becoming feasible due to recent improvements in numerical methods for multiphase flows and the steady increase in capacity and availability of high performance computing resources. Now that the concept of fully three-dimensional air/water flow modelling for real world engineering analysis is achieving acceptance by the wider engineering community, it is critical to expand careful comparative studies on verification,validation, benchmarking, and uncertainty quantification for the variety of competing numerical methods that are continuing to evolve. Furthermore, uncertainty still remains about the relevance of secondary processes such as surface tension, air compressibility, air entrainment, and solid phase (structure) modelling so that questions about continuum mechanical theory and mathematical analysis of multiphase flow are still required. Two of the most popular and practical numerical approaches for large-scale engineering analysis are the Volume-Of-Fluid (VOF) and Level Set (LS) approaches. In this work we will present a publically available verification and validation test set for air-water-structure interaction problems as well as computational and physical model results including a hybrid VOF-LS method, traditional VOF methods, and Smoothed Particle Hydrodynamics (SPH) results. The test set repository and test problem formats will also be presented in order to facilitate future comparative studies and reproduction of scientific results.

  1. Preliminary study on magnetic tracking-based planar shape sensing and navigation for flexible surgical robots in transoral surgery: methods and phantom experiments.

    Science.gov (United States)

    Song, Shuang; Zhang, Changchun; Liu, Li; Meng, Max Q-H

    2017-10-05

    Flexible surgical robot can work in confined and complex environments, which makes it a good option for minimally invasive surgery. In order to utilize flexible manipulators in complicated and constrained surgical environments, it is of great significance to monitor the position and shape of the curvilinear manipulator in real time during the procedures. In this paper, we propose a magnetic tracking-based planar shape sensing and navigation system for flexible surgical robots in the transoral surgery. The system can provide the real-time tip position and shape information of the robot during the operation. We use wire-driven flexible robot to serve as the manipulator. It has three degrees of freedom. A permanent magnet is mounted at the distal end of the robot. Its magnetic field can be sensed with a magnetic sensor array. Therefore, position and orientation of the tip can be estimated utilizing a tracking method. A shape sensing algorithm is then carried out to estimate the real-time shape based on the tip pose. With the tip pose and shape display in the 3D reconstructed CT model, navigation can be achieved. Using the proposed system, we carried out planar navigation experiments on a skull phantom to touch three different target positions under the navigation of the skull display interface. During the experiments, the real-time shape has been well monitored and distance errors between the robot tip and the targets in the skull have been recorded. The mean navigation error is [Formula: see text] mm, while the maximum error is 3.2 mm. The proposed method provides the advantages that no sensors are needed to mount on the robot and no line-of-sight problem. Experimental results verified the feasibility of the proposed method.

  2. Three-time rapid transfer alignment method of SINS/GPS navigation system of high-speed marine missile

    Institute of Scientific and Technical Information of China (English)

    WANG Si; DENG Zheng-long; SU Ling-feng

    2008-01-01

    The transfer alignment of SINS/GPS navigation system of a high-speed marine missile was investiga-ted. With the help of the big acceleration of a high-speed missile, the transfer alignment was changed into a three-time alignment. The azimuth alignment was coarsely finished in 10s in the first time alignment, the hori-zontal alignment was accurately and rapidly finished in the second time alignment, and the azimuth alignment was accurately finished in the third time alignment. Because the second time alignment and the third time align-ment were finished by GPS after the missile was launched, the horizontal alignment and the second azimuth a-lignment got rid of the influence of the warship body flexibility deforming. The precision and rapidity of the hori-zontal alignment were prominently increased due to the vertical launch of the marine missile with the big accel-eration. Simulation verifies the effectiveness of the proposed alignment method.

  3. BDS 导航终端用户主观体验量化评价方法%The Method of Quantitative Evaluation of BDS Navigation Terminal User’s Subjective Experience

    Institute of Scientific and Technical Information of China (English)

    许培; 董晶晶

    2016-01-01

    In order to resolve the difficulty of quantitative evaluation of the user’s subjective experience quality of BDS nav-igation terminal,this paper got the users’feedback in army for the using feeling of BDS navigation terminal,through the methods such as design and implementation of the user interviews and questionnaire survey,which were based on the experi-ence accumulated in the process of BDS navigation terminal application security.In a hierarchical analysis method as the basic method,the paper puts forward a user’s subjective experience of quantitative evaluation of the BDS navigation terminal user experience evaluation index system.The system index and evaluation criteria are made in detail in the paper,and it also designs a set of test methods matched with the system,So that to achieve the quantitative evaluation of the user’s subjective feeling of BDS navigation terminal.%本文针对 BDS 导航终端的用户主观体验质量难以量化评价的问题,基于长期在 BDS 导航终端应用保障过程中积累的经验,通过针对性的设计并实施用户访谈、问卷调查等方式,获得了部队用户对 BDS 导航终端使用感受的真实反馈。以层次分析法为主要基础方法,提出了一种能够将用户的主观使用感受进行量化评价的 BDS 导航终端用户体验评价指标体系。文中对该体系的指标项目与评判标准做出了详细说明,并设计了一套与之配套的测试方法,实现了 BDS 用户终端在用户主观感受方面的量化评价。

  4. Applications of Monte Carlo Methods in Calculus.

    Science.gov (United States)

    Gordon, Sheldon P.; Gordon, Florence S.

    1990-01-01

    Discusses the application of probabilistic ideas, especially Monte Carlo simulation, to calculus. Describes some applications using the Monte Carlo method: Riemann sums; maximizing and minimizing a function; mean value theorems; and testing conjectures. (YP)

  5. Mobile Robot Navigation Support in Living Environments

    Science.gov (United States)

    Armbrust, Christopher; Koch, Jan; Stocker, Ulf; Berns, Karsten

    Navigation and application functionality of mobile robots rely on their collision-avoiding capabilities, also known as local navigation. We present the mobile robot ARTOS (Autonomous Robot for Transport and Service) that is particularly designed to operate in living environments and therefore faces the problem of fuzzy and unstructured obstacles. The local navigation architecture is motivated regarding decisions on sensor hardware setup as well as the software layers that support and influence navigation control.

  6. High accuracy GNSS based navigation in GEO

    Science.gov (United States)

    Capuano, Vincenzo; Shehaj, Endrit; Blunt, Paul; Botteron, Cyril; Farine, Pierre-André

    2017-07-01

    Although significant improvements in efficiency and performance of communication satellites have been achieved in the past decades, it is expected that the demand for new platforms in Geostationary Orbit (GEO) and for the On-Orbit Servicing (OOS) on the existing ones will continue to rise. Indeed, the GEO orbit is used for many applications including direct broadcast as well as communications. At the same time, Global Navigation Satellites System (GNSS), originally designed for land, maritime and air applications, has been successfully used as navigation system in Low Earth Orbit (LEO) and its further utilization for navigation of geosynchronous satellites becomes a viable alternative offering many advantages over present ground based methods. Following our previous studies of GNSS signal characteristics in Medium Earth Orbit (MEO), GEO and beyond, in this research we specifically investigate the processing of different GNSS signals, with the goal to determine the best navigation performance they can provide in a GEO mission. Firstly, a detailed selection among different GNSS signals and different combinations of them is discussed, taking into consideration the L1 and L5 frequency bands, and the GPS and Galileo constellations. Then, the implementation of an Orbital Filter is summarized, which adaptively fuses the GN1SS observations with an accurate orbital forces model. Finally, simulation tests of the navigation performance achievable by processing the selected combination of GNSS signals are carried out. The results obtained show an achievable positioning accuracy of less than one meter. In addition, hardware-in-the-loop tests are presented using a COTS receiver connected to our GNSS Spirent simulator, in order to collect real-time hardware-in-the-loop observations and process them by the proposed navigation module.

  7. Local Path Planning of Driverless Car Navigation Based on Jump Point Search Method Under Urban Environment

    Directory of Open Access Journals (Sweden)

    Kaijun Zhou

    2017-09-01

    Full Text Available The Jump Point Search (JPS algorithm is adopted for local path planning of the driverless car under urban environment, and it is a fast search method applied in path planning. Firstly, a vector Geographic Information System (GIS map, including Global Positioning System (GPS position, direction, and lane information, is built for global path planning. Secondly, the GIS map database is utilized in global path planning for the driverless car. Then, the JPS algorithm is adopted to avoid the front obstacle, and to find an optimal local path for the driverless car in the urban environment. Finally, 125 different simulation experiments in the urban environment demonstrate that JPS can search out the optimal and safety path successfully, and meanwhile, it has a lower time complexity compared with the Vector Field Histogram (VFH, the Rapidly Exploring Random Tree (RRT, A*, and the Probabilistic Roadmaps (PRM algorithms. Furthermore, JPS is validated usefully in the structured urban environment.

  8. The 'SAR Matrix' method and its extensions for applications in medicinal chemistry and chemogenomics.

    Science.gov (United States)

    Gupta-Ostermann, Disha; Bajorath, Jürgen

    2014-01-01

    We describe the 'Structure-Activity Relationship (SAR) Matrix' (SARM) methodology that is based upon a special two-step application of the matched molecular pair (MMP) formalism. The SARM method has originally been designed for the extraction, organization, and visualization of compound series and associated SAR information from compound data sets. It has been further developed and adapted for other applications including compound design, activity prediction, library extension, and the navigation of multi-target activity spaces. The SARM approach and its extensions are presented here in context to introduce different types of applications and provide an example for the evolution of a computational methodology in pharmaceutical research.

  9. The ‘SAR Matrix’ method and its extensions for applications in medicinal chemistry and chemogenomics

    Science.gov (United States)

    Gupta-Ostermann, Disha; Bajorath, Jürgen

    2014-01-01

    We describe the ‘Structure-Activity Relationship (SAR) Matrix’ (SARM) methodology that is based upon a special two-step application of the matched molecular pair (MMP) formalism. The SARM method has originally been designed for the extraction, organization, and visualization of compound series and associated SAR information from compound data sets. It has been further developed and adapted for other applications including compound design, activity prediction, library extension, and the navigation of multi-target activity spaces. The SARM approach and its extensions are presented here in context to introduce different types of applications and provide an example for the evolution of a computational methodology in pharmaceutical research. PMID:25383183

  10. Development of a quartz digital accelerometer for environmental sensing and navigation applications

    Energy Technology Data Exchange (ETDEWEB)

    Kass, W.J.; Vianco, P.T.

    1993-03-01

    A quartz digital accelerometer has been developed which uses double ended tuning forks as the active sensing elements. The authors have demonstrated the ability of this accelerometer to be capable of acceleration measurements between {+-}150G with {+-}0.5G accuracy. They have further refined the original design and assembly processes to produce accelerometers with < 1mG stability in inertial measurement applications. This report covers the development, design, processing, assembly, and testing of these devices.

  11. Comparing image compression methods in biomedical applications

    Directory of Open Access Journals (Sweden)

    Libor Hargas

    2004-01-01

    Full Text Available Compression methods suitable for image processing are described in this article in biomedical applications. The compression is often realized by reduction of irrelevance or redundancy. There are described lossless and lossy compression methods which can be use for compress of images in biomedical applications and comparison of these methods based on fidelity criteria.

  12. 33 CFR 209.180 - Temporary closure of waterway to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Temporary closure of waterway to navigation. 209.180 Section 209.180 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE... navigation. (a) When an application is received for the temporary closure of a waterway for the...

  13. Adiabatic bias molecular dynamics: A method to navigate the conformational space of complex molecular systems

    Science.gov (United States)

    Marchi, Massimo; Ballone, Pietro

    1999-02-01

    This study deals with a novel molecular simulation technique, named adiabatic bias molecular dynamics (MD), which provides a simple and reasonably inexpensive route to generate MD trajectories joining points in conformational space separated by activation barriers. Because of the judicious way the biasing potential is updated during the MD runs, the technique allows with some additional effort the computation of the free energy change experienced during the trajectory. The adiabatic bias method has been applied to a nontrivial problem: The unfolding of an atomistic model of lysozyme. Here, the radius of gyration (Rg) was used as a convenient reaction coordinate. For changes in Rg between 19.7 and 28 Å, we observe a net loss of the native tertiary structure of lysozyme. At the same time, secondary structure elements such as α-helices are retained although some of the original order is diminished. The calculated free energy profile for the unfolding transition shows a monotonous increase with Rg and depends crucially on the nonbonded cutoff used in the potential model.

  14. 动水域进行静水航速试验的测算方法%Estimating methods for still-water navigation speed in flowing water

    Institute of Scientific and Technical Information of China (English)

    许光祥; 陈希

    2012-01-01

    受条件限制,某些河道的静水航速实船测试不得不在动水域进行.由于动水域水面坡降的存在,船舶推力需克服坡降阻力而不能全部为航行提供动力,对水航速代替静水航速会造成一定偏差.通过在澜沧江动水域进行的静水航速实船测试试验,提出了阻力平衡法和阻力同比法以修正静水航速,两种修正方法结果差异不大,而阻力同比法更为简略.理论和实例分析表明,对水航速是否能代替静水航速取决于坡降阻力所占船舶推力比例的大小.%In order to achieve the ship still-water navigation speed, some prototype tests have to be implemented in flowing waters due to certain restrictions. The ship navigation speed in flowing waters is different from that in still water because the propulsive force can't be completely transformed to be the driving force owing to the water gradient. Based on a series of vessel prototype tests for still-water navigation speed conducted in a flowing reach of the Lancang River, this paper presents two methods for correcting still-water navigation speed, the drag balance method and the resistance comparison method. Both methods lead to close results, and the drag balance method is simpler. Theoretical analyses and case studies indicate that whether navigation speed in flowing waters is able to replace still-water navigation speed may depend on the ratio of the resistance due to hydraulic gradient to ship's propulsion.

  15. Mobile Robot Localization and Navigation in Artificial Intelligence: Survey

    Directory of Open Access Journals (Sweden)

    G. Nirmala

    2017-01-01

    Full Text Available The potential applications for mobile robots are enormous. The mobile robots must quickly and robustly perform useful tasks in a previously unknown, dynamic and challenging environment. Mobile robot navigation plays a key role in all mobile robot activities and tasks such as path planning. Mobile robots are machines which navigate around their environment getting sensory information about that environment and performing actions dependent on this sensory information. Localization is basic to navigation. Various techniques have been described for estimating the orientation and positioning of a mobile robot. Navigation may be defined as the process of guiding the movement of intelligent vehicle systems from one location to another location with the support of various types of sensors to the different environments such as indoor, outdoor and other complex environments by using various navigation methods. This paper reviews the following mobile robot systems which are used in navigation for localization (1 Odometry (2 Magnetic compass (3 Active beacons (4 Global positioning system (5 Landmark navigation (6 Pattern matching.

  16. Navigation-guided endoscopic biopsy for intraparenchymal brain tumor.

    Science.gov (United States)

    Tsuda, Kyoji; Ishikawa, Eiichi; Zaboronok, Alexander; Nakai, Kei; Yamamoto, Tetsuya; Sakamoto, Noriaki; Uemae, Yoji; Tsurubuchi, Takao; Akutsu, Hiroyoshi; Ihara, Satoshi; Ayuzawa, Satoshi; Takano, Shingo; Matsumura, Akira

    2011-01-01

    To evaluate the efficacy of intraparenchymal brain tumor biopsy using endoscopy and a navigation system (navigation-guided endoscopic biopsy) as a diagnostic tool, a case series of intraparenchymal tumor biopsies was reviewed. Navigation-guided endoscopic biopsy was applied in 9 cases, stereotactic needle biopsy in 16 cases, and open biopsy with or without navigation system in 34 cases. In all biopsy cases, 84.7% of biopsy points were sampled accurately, and 93.2% of diagnoses by biopsy were correct. Comparison of each type of biopsy showed that the resected volumes in navigation-guided endoscopic biopsy and open biopsy tended to be larger than those in stereotactic biopsy, and the mean operation time for the open biopsy procedure was the longest. To define the most applicable device or examination method to increase sampling accuracy, various factors were analyzed in 59 procedures. Navigation-guided endoscopic biopsy was the most accurate of the three types of biopsy, although the statistical difference was not significant. Older patients, histological diagnosis of high-grade glioma or malignant lymphoma, positive photodynamic diagnosis, and positive intraoperative pathology were significant factors in improving the sampling accuracy. Navigation-guided endoscopic biopsy could provide a larger sample volume within a relatively short operation time. The biopsy can be easily combined with both photodynamic diagnosis and intraoperative pathology, significantly improving the histological diagnostic yield.

  17. A Time Variant Outdoor-to-Indoor Channel Model for Mobile Radio Based Navigation Applications

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2015-01-01

    Full Text Available Time based positioning with terrestrial mobile radio signals has gained remarkable attention. To develop and validate positioning algorithms under realistic conditions, an accurate knowledge of the propagation channel is significant. However, there is still a lack of outdoor-to-indoor channel models suitable for positioning applications. To be applicable for positioning, the channel model has to fulfill three requirements that have not been accurately considered so far: the non-line-of-sight bias (affecting ranging accuracy, nondiscrete valued channel parameters (affecting algorithm performance, and the evolution of individual multipath components (MPCs with time (affecting tracking performance. In this paper, an outdoor-to-indoor channel model is proposed based on an extension of the geometry-based stochastic modeling approach to fulfill the requirements. We consider MPCs occurring due to reflection, scattering, and combinations of both. In the model, three different types of MPCs are modeled separately according to their characteristics. Each MPC is represented by a fixed scatterer, which has a fixed position while the receiver antenna is moving. The parameters of the outdoor-to-indoor channel model are extracted from two channel measurement campaigns. The proposed outdoor-to-indoor channel model is capable of accurately simulating the time variant channel. A comparison of the channel model with the channel measurement data is performed by comparing statistics.

  18. Fluorescence nanoscopy. Methods and applications

    OpenAIRE

    Requejo-Isidro, Jose

    2013-01-01

    Fluorescence nanoscopy refers to the experimental techniques and analytical methods used for fluorescence imaging at a resolution higher than conventional, diffraction-limited, microscopy. This review explains the concepts behind fluorescence nanoscopy and focuses on the latest and promising developments in acquisition techniques, labelling strategies to obtain highly detailed super-resolved images and in the quantitative methods to extract meaningful information from them.

  19. Autonomous Spacecraft Navigation With Pulsars

    CERN Document Server

    Becker, Werner; Jessner, Axel

    2013-01-01

    An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.

  20. 综合导航应用产业脆弱性分析%Vulnerability Analysis of Integrated Navigation Application Industry

    Institute of Scientific and Technical Information of China (English)

    李云志

    2014-01-01

    Navigation industry is a new industry in the world, also the strategic industry in China, application to integrated navigation technology as the dominant trend. This trend in high index, multi function of market demand, and promote economic and social development at the same time, there are also the vulnerability of integrated navigation industry itself, constraining the development of the industry. The article puts forward integrated navigation concept, mainly from the aspects of technology, mechanism and application requirements, legal regulations affecting the development of the industry to carry out a systematic analysis, this vulnerability is restricted navigation application industry development, for the industry to industry planning, identify potential risks and take measures to cope with the risks and provide theoretical basis, ensure rapid and healthy development of our the navigation industry.%导航产业是全球性的新兴产业,也是我国的战略性产业,未来以综合导航技术应用为主导趋势。这种趋势在满足高指标、多功能的市场需求,并推动经济社会发展的同时,也存在综合导航产业自身的脆弱性,制约了产业发展。文章提出综合导航概念,从技术机制和应用需求、法律法规约束等影响产业发展的主要方面进行系统性分析,提出制约综合导航应用产业发展的脆弱性所在,为业界产业规划、识别潜在风险和采取风险应对措施提供基础理论依据,保障我国导航产业快速健康发展。

  1. Fuzzy Behavior Modulation with Threshold Activation for Autonomous Vehicle Navigation

    Science.gov (United States)

    Tunstel, Edward

    2000-01-01

    This paper describes fuzzy logic techniques used in a hierarchical behavior-based architecture for robot navigation. An architectural feature for threshold activation of fuzzy-behaviors is emphasized, which is potentially useful for tuning navigation performance in real world applications. The target application is autonomous local navigation of a small planetary rover. Threshold activation of low-level navigation behaviors is the primary focus. A preliminary assessment of its impact on local navigation performance is provided based on computer simulations.

  2. Experiment Method Research on Ship Inertial Navigation System%舰船惯性导航系统试验方法研究

    Institute of Scientific and Technical Information of China (English)

    周金亮

    2014-01-01

    The Inertial navigation method experiments are introduced including its technique feature, test requirement and method. The key technical problems in this experiment are presented detailed analyzed which is meaningful to the inertial navigation experiment.%本文介绍了惯性导航方法试验的技术特点、试验需求以及试验方法,提出了试验中相关的关键技术问题,并进行了详细的分析说明与处理,对惯性导航系统试验具有重要的作用和意义。

  3. The attack navigator

    DEFF Research Database (Denmark)

    Probst, Christian W.; Willemson, Jan; Pieters, Wolter

    2016-01-01

    The need to assess security and take protection decisions is at least as old as our civilisation. However, the complexity and development speed of our interconnected technical systems have surpassed our capacity to imagine and evaluate risk scenarios. This holds in particular for risks...... that are caused by the strategic behaviour of adversaries. Therefore, technology-supported methods are needed to help us identify and manage these risks. In this paper, we describe the attack navigator: a graph-based approach to security risk assessment inspired by navigation systems. Based on maps of a socio...

  4. Bering Mission Navigation Method

    DEFF Research Database (Denmark)

    Betto, Maurizio; Jørgensen, John Leif; Jørgensen, Peter Siegbjørn

    2003-01-01

    "Bering", after the name of the famous Danish explorer, is a near Earth object (NEO) and main belt asteroids mapping mission envisaged by a consortium of Danish universities and research institutes. To achieve the ambitious goals set forth by this mission, while containing the costs and risks...

  5. Navigating through the Jungle of Allergens: Features and Applications of Allergen Databases.

    Science.gov (United States)

    Radauer, Christian

    2017-01-01

    The increasing number of available data on allergenic proteins demanded the establishment of structured, freely accessible allergen databases. In this review article, features and applications of 6 of the most widely used allergen databases are discussed. The WHO/IUIS Allergen Nomenclature Database is the official resource of allergen designations. Allergome is the most comprehensive collection of data on allergens and allergen sources. AllergenOnline is aimed at providing a peer-reviewed database of allergen sequences for prediction of allergenicity of proteins, such as those planned to be inserted into genetically modified crops. The Structural Database of Allergenic Proteins (SDAP) provides a database of allergen sequences, structures, and epitopes linked to bioinformatics tools for sequence analysis and comparison. The Immune Epitope Database (IEDB) is the largest repository of T-cell, B-cell, and major histocompatibility complex protein epitopes including epitopes of allergens. AllFam classifies allergens into families of evolutionarily related proteins using definitions from the Pfam protein family database. These databases contain mostly overlapping data, but also show differences in terms of their targeted users, the criteria for including allergens, data shown for each allergen, and the availability of bioinformatics tools. © 2017 S. Karger AG, Basel.

  6. Analysis of terrain map matching using multisensing techniques for applications to autonomous vehicle navigation

    Science.gov (United States)

    Page, Lance; Shen, C. N.

    1991-01-01

    This paper describes skyline-based terrain matching, a new method for locating the vantage point of laser range-finding measurements on a global map previously prepared by satellite or aerial mapping. Skylines can be extracted from the range-finding measurements and modelled from the global map, and are represented in parametric, cylindrical form with azimuth angle as the independent variable. The three translational parameters of the vantage point are determined with a three-dimensional matching of these two sets of skylines.

  7. Statistical methods and computer applications

    CERN Document Server

    Arora, PN

    2009-01-01

    Some of the exclusive features of the book are: Every concept has been explained with the help of solved examples. Working rules showing the various steps for the applications of formulae have also been given. The diagrams and graphs have been neatly and correctly drawn in such a way that the students have the complete understanding of the problem by simply looking at them. Efforts have been made to make the subject throughly exhaustive and nothing important has been omitted. Answer to all the problems have been throughly checked. It is a user-friendly book containing many, solved problems and

  8. a Redundant Gnss-Ins Low-Cost Uav Navigation Solution for Professional Applications

    Science.gov (United States)

    Navarro, J.; Parés, M. E.; Colomina, I.; Bianchi, G.; Pluchino, S.; Baddour, R.; Consoli, A.; Ayadi, J.; Gameiro, A.; Sekkas, O.; Tsetsos, V.; Gatsos, T.; Navoni, R.

    2015-08-01

    This paper presents the current results for the FP7 GINSEC project. Its goal is to build a pre-commercial prototype of a low-cost, accurate and reliable system for the professional UAV market. Low-cost, in this context, stands for the use of sensors in the most affordable segment of the market, especially MEMS IMUs and GNSS receivers. Reliability applies to the ability of the autopilot to cope with situations where unfavourable GNSS reception conditions or strong electromagnetic fields make the computation of the position and / or attitude of the UAV difficult. Professional and accurate mean that, at least using post-processing techniques as PPP, it will be possible to reach cm-level precisions that open the door to a range of applications demanding high levels of quality in positioning, as precision agriculture or mapping. To achieve such goal, a rigorous sensor error modelling approach, the use of redundant IMUs and a dual-GNSS receiver setup, together with close-coupling techniques and an extended Kalman filter with self-analysis capabilities have been used. Although the project is not yet complete, the results obtained up to now prove the feasibility of the aforementioned goal, especially in those aspects related to position determination. Research work is still undergoing to estimate the heading using a dual-GNNS receiver setup; preliminary results prove the validity of this approach for relatively long baselines, although positive results are expected when these are shorter than 1 m - which is a necessary requisite for small-sized UAVs.

  9. A REDUNDANT GNSS-INS LOW-COST UAV NAVIGATION SOLUTION FOR PROFESSIONAL APPLICATIONS

    Directory of Open Access Journals (Sweden)

    J. Navarro

    2015-08-01

    Full Text Available This paper presents the current results for the FP7 GINSEC project. Its goal is to build a pre-commercial prototype of a low-cost, accurate and reliable system for the professional UAV market. Low-cost, in this context, stands for the use of sensors in the most affordable segment of the market, especially MEMS IMUs and GNSS receivers. Reliability applies to the ability of the autopilot to cope with situations where unfavourable GNSS reception conditions or strong electromagnetic fields make the computation of the position and / or attitude of the UAV difficult. Professional and accurate mean that, at least using post-processing techniques as PPP, it will be possible to reach cm-level precisions that open the door to a range of applications demanding high levels of quality in positioning, as precision agriculture or mapping. To achieve such goal, a rigorous sensor error modelling approach, the use of redundant IMUs and a dual-GNSS receiver setup, together with close-coupling techniques and an extended Kalman filter with self-analysis capabilities have been used. Although the project is not yet complete, the results obtained up to now prove the feasibility of the aforementioned goal, especially in those aspects related to position determination. Research work is still undergoing to estimate the heading using a dual-GNNS receiver setup; preliminary results prove the validity of this approach for relatively long baselines, although positive results are expected when these are shorter than 1 m – which is a necessary requisite for small-sized UAVs.

  10. Data mining methods and applications

    CERN Document Server

    Lawrence, Kenneth D; Klimberg, Ronald K

    2007-01-01

    With today's information explosion, many organizations are now able to access a wealth of valuable data. Unfortunately, most of these organizations find they are ill-equipped to organize this information, let alone put it to work for them. Gain a Competitive Advantage Employ data mining in research and forecasting Build models with data management tools and methodology optimization Gain sophisticated breakdowns and complex analysis through multivariate, evolutionary, and neural net methodsLearn how to classify data and maintain qualityTransform Data into Business Acumen Data Mining Methods and

  11. Activity Recognition Using Fusion of Low-Cost Sensors on a Smartphone for Mobile Navigation Application

    Directory of Open Access Journals (Sweden)

    Sara Saeedi

    2015-08-01

    Full Text Available Low-cost inertial and motion sensors embedded on smartphones have provided a new platform for dynamic activity pattern inference. In this research, a comparison has been conducted on different sensor data, feature spaces and feature selection methods to increase the efficiency and reduce the computation cost of activity recognition on the smartphones. We evaluated a variety of feature spaces and a number of classification algorithms from the area of Machine Learning, including Naive Bayes, Decision Trees, Artificial Neural Networks and Support Vector Machine classifiers. A smartphone app that performs activity recognition is being developed to collect data and send them to a server for activity recognition. Using extensive experiments, the performance of various feature spaces has been evaluated. The results showed that the Bayesian Network classifier yields recognition accuracy of 96.21% using four features while requiring fewer computations.

  12. The Availability of Space Service for Inter-Satellite Links in Navigation Constellations

    Directory of Open Access Journals (Sweden)

    Yinyin Tang

    2016-08-01

    Full Text Available Global navigation satellite systems (GNSS are widely used in low Earth orbit (LEO satellite navigation; however, their availability is poor for users in medium Earth orbits (MEO, and high Earth orbits (HEO. With the increasing demand for navigation from MEO and HEO users, the inadequate coverage of GNSS has emerged. Inter-satellite links (ISLs are used for ranging and communication between navigation satellites and can also serve space users that are outside the navigation constellation. This paper aims to summarize their application method and analyze their service performance. The mathematical model of visibility is proposed and then the availability of time division ISLs is analyzed based on global grid points. The BeiDou navigation constellation is used as an example for numerical simulation. Simulation results show that the availability can be enhanced by scheduling more satellites and larger beams, while the presence of more users lowers the availability. The availability of navigation signals will be strengthened when combined with the signals from the ISLs. ISLs can improve the space service volume (SSV of navigation constellations, and are therefore a promising method for navigation in MEO/HEO spacecraft.

  13. The Availability of Space Service for Inter-Satellite Links in Navigation Constellations.

    Science.gov (United States)

    Tang, Yinyin; Wang, Yueke; Chen, Jianyun

    2016-08-19

    Global navigation satellite systems (GNSS) are widely used in low Earth orbit (LEO) satellite navigation; however, their availability is poor for users in medium Earth orbits (MEO), and high Earth orbits (HEO). With the increasing demand for navigation from MEO and HEO users, the inadequate coverage of GNSS has emerged. Inter-satellite links (ISLs) are used for ranging and communication between navigation satellites and can also serve space users that are outside the navigation constellation. This paper aims to summarize their application method and analyze their service performance. The mathematical model of visibility is proposed and then the availability of time division ISLs is analyzed based on global grid points. The BeiDou navigation constellation is used as an example for numerical simulation. Simulation results show that the availability can be enhanced by scheduling more satellites and larger beams, while the presence of more users lowers the availability. The availability of navigation signals will be strengthened when combined with the signals from the ISLs. ISLs can improve the space service volume (SSV) of navigation constellations, and are therefore a promising method for navigation in MEO/HEO spacecraft.

  14. GPS导航系统的应用与设计%Application and Design of GPS Navigation System

    Institute of Scientific and Technical Information of China (English)

    韩改宁; 李永锋

    2013-01-01

    Based on the embedded GPS navigation system is under linux, audio, video playback, multimedia entertainment software. Using GPS technology, electronic mapping technology, touch screen controls and LCD display technology, based on the ARM9 of S3C2410 development of platform and embedded Linux system using Qt/Embedded graphical user interface development is completed, the system has a good operation interface. Electronic map, using the A*algorithm to achieve the shortest path, reduce system development costs, to solve the GPS location and function of the shortest path. The design principle is clear, easy to implement and has certain actual application value.%基于嵌入式GPS导航系统是在linux下一个集GPS导航功能、音频,视频播放于一体的多媒体影音娱乐软件。本设计利用GPS技术、电子地图技术、触摸屏控制技术和LCD显示技术,基于ARM9的S3C2410开发平台,在嵌入式 Linux 系统中利用 Qt/Embedded 完成了嵌入式图形用户界面开发,使得系统拥有良好的操作界面。通过对电子地图的研究,采用了 A*算法实现最短路径,降低了系统开发成本,解决了 GPS 定位和最短路径等功能。该设计原理清晰,易于实现,具有一定的实际应用价值。

  15. 14 CFR 63.61 - Flight navigator courses.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Flight navigator courses. 63.61 Section 63...) AIRMEN CERTIFICATION: FLIGHT CREWMEMBERS OTHER THAN PILOTS Flight Navigators § 63.61 Flight navigator courses. An applicant for approval of a flight navigator course must submit a letter to the...

  16. APPLICATION OF RADON REDUCTION METHODS

    Science.gov (United States)

    The document is intended to aid homeowners and contractors in diagnosing and solving indoor radon problems. It will also be useful to State and Federal regulatory officials and many other persons who provide advice on the selection, design and operation of radon reduction methods...

  17. A Dynamic Navigation Model for Unmanned Aircraft Systems and an Application to Autonomous Front-On Environmental Sensing and Photography Using Low-Cost Sensor Systems

    Directory of Open Access Journals (Sweden)

    Andrew James Cooper

    2015-08-01

    Full Text Available This paper presents an unmanned aircraft system (UAS that uses a probabilistic model for autonomous front-on environmental sensing or photography of a target. The system is based on low-cost and readily-available sensor systems in dynamic environments and with the general intent of improving the capabilities of dynamic waypoint-based navigation systems for a low-cost UAS. The behavioural dynamics of target movement for the design of a Kalman filter and Markov model-based prediction algorithm are included. Geometrical concepts and the Haversine formula are applied to the maximum likelihood case in order to make a prediction regarding a future state of a target, thus delivering a new waypoint for autonomous navigation. The results of the application to aerial filming with low-cost UAS are presented, achieving the desired goal of maintained front-on perspective without significant constraint to the route or pace of target movement.

  18. Accuracy Evaluation of Stereo Vision Aided Inertial Navigation for Indoor Environments

    Science.gov (United States)

    Griessbach, D. G.; Baumbach, D. B.; Boerner, A. B.; Zuev, S. Z.

    2013-11-01

    Accurate knowledge of position and orientation is a prerequisite for many applications regarding unmanned navigation, mapping, or environmental modelling. GPS-aided inertial navigation is the preferred solution for outdoor applications. Nevertheless a similar solution for navigation tasks in difficult environments with erroneous or no GPS-data is needed. Therefore a stereo vision aided inertial navigation system is presented which is capable of providing real-time local navigation for indoor applications. A method is described to reconstruct the ego motion of a stereo camera system aided by inertial data. This, in turn, is used to constrain the inertial sensor drift. The optical information is derived from natural landmarks, extracted and tracked over consequent stereo image pairs. Using inertial data for feature tracking effectively reduces computational costs and at the same time increases the reliability due to constrained search areas. Mismatched features, e.g. at repetitive structures typical for indoor environments are avoided. An Integrated Positioning System (IPS) was deployed and tested on an indoor navigation task. IPS was evaluated for accuracy, robustness, and repeatability in a common office environment. In combination with a dense disparity map, derived from the navigation cameras, a high density point cloud is generated to show the capability of the navigation algorithm.

  19. Computer-assisted auto-frame navigation system for distal locking of tibial intramedullary nails: a preliminary report on clinical application

    Institute of Scientific and Technical Information of China (English)

    WANG Jun-qiang; GAO Yi-fei; WANG Tian-miao; ZHAO Chun-peng; WANG Man-yi; SU Yong-gong; HU Lei; SUN Lei; ZHANG Li-dan; LIU Wen-yong; ZHANG Hui

    2006-01-01

    Objective: To evaluate the clinical feasibility and effect of the computer-assisted auto-frame navigation system for distal locking of tibial intrameduilary nails.Methods: The hardware components of the system included a PC computer with a monitor, auto mechanical stereotactical locating cubic frame, foot holder and localization operative apparatus. Special navigation software can be used for registration of X-ray fluoroscopic images and real-time controlling navigation of tools.Twenty-one cases of close tibial and fibular fractures were treated with closed intramedullary nailing, 6 of which involved in middle third, 12 in middle and lower third, 3 in lower third. C-arm alignment and registration time,fluoroscopic time and drilling time involved in the locking procedure were recorded. The size of unreamed or reamed tibial nails ranged from 8/300-11/330.Results: All distal holes except 1 were locked successfully. In 9 of 41 locked holes (21.95%), the drill bit touched the canal of locking hole without damage of the nail and clinical consequences. The fluoroscopy time per pair of screws was 2.23 s ± 0.31 s.Conclusions: The computer-assisted auto-frame navigation system for distal locking is well designed, easy to operate and do not need additional instruments during the procedure. The developed system enables the physician to precisely navigate surgical instruments throughout the anatomy using just a few computer-calibrated radiographic images. The total time of x-ray exposure per procedure can be significantly reduced.

  20. Accuracy of navigation-guided socket drilling before implant installation compared to the conventional free-hand method in a synthetic edentulous lower jaw model.

    Science.gov (United States)

    Hoffmann, Jürgen; Westendorff, Carsten; Gomez-Roman, German; Reinert, Siegmar

    2005-10-01

    In this study, the three-dimensional (3D) accuracy of navigation-guided (NG) socket drilling before implant installation was compared to the conventional free-hand (CF) method in a synthetic edentulous lower jaw model. The drillings were performed by two surgeons with different years of working experience. The inter-individual outcome was assessed. NG drillings were performed using an optical computerized tomography (CT)-based navigation system. CF drillings were performed using a surgical template. The coordinates of the drilled sockets were determined on the basis of CT scans. A total of n=224 drillings was evaluated. Inter-individual differences in terms of the surgeons' years of work experience were without statistical significance. The mean deviation of the CF drilled sockets (n=112) on the vestibulo-oral and mesio-distal direction was 11.2+/-5.6 degrees (range: 4.1-25.3 degrees ). With respect to the NG drilled sockets (n=112), the mean deviation was 4.2+/-1.8 degrees (range: 2.3-11.5). The mean distance to the mandibular canal was 1.1+/-0.6 mm (range: 0.1-2.3 mm) for CF-drilled sockets and 0.7+/-0.5 mm (range: 0.1-1.8 mm) for NG drilled sockets. The differences between the two methods were highly significant (P<0.01). A potential benefit from image-data-based navigation in implant surgery is discussed against the background of cost-effectiveness.

  1. Hybrid codes: Methods and applications

    Energy Technology Data Exchange (ETDEWEB)

    Winske, D. (Los Alamos National Lab., NM (USA)); Omidi, N. (California Univ., San Diego, La Jolla, CA (USA))

    1991-01-01

    In this chapter we discuss hybrid'' algorithms used in the study of low frequency electromagnetic phenomena, where one or more ion species are treated kinetically via standard PIC methods used in particle codes and the electrons are treated as a single charge neutralizing massless fluid. Other types of hybrid models are possible, as discussed in Winske and Quest, but hybrid codes with particle ions and massless fluid electrons have become the most common for simulating space plasma physics phenomena in the last decade, as we discuss in this paper.

  2. Navigation in Augmented Reality, Navigation i Augmented Reality

    OpenAIRE

    Bernelind, Sarah

    2015-01-01

    The concept of augmented reality has existed since the 60’s. In this thesis it has been investigated if navigation using a mobile device would benefit, from a usability perspective, if the navigational data were presented using augmented reality instead of a standardized map. The usability principles from which the applications were evaluated are learnability, user satisfaction, efficiency and effectivity. An AR prototype was developed and tested against a standard map, in the form of Google ...

  3. Differential equations methods and applications

    CERN Document Server

    Said-Houari, Belkacem

    2015-01-01

    This book presents a variety of techniques for solving ordinary differential equations analytically and features a wealth of examples. Focusing on the modeling of real-world phenomena, it begins with a basic introduction to differential equations, followed by linear and nonlinear first order equations and a detailed treatment of the second order linear equations. After presenting solution methods for the Laplace transform and power series, it lastly presents systems of equations and offers an introduction to the stability theory. To help readers practice the theory covered, two types of exercises are provided: those that illustrate the general theory, and others designed to expand on the text material. Detailed solutions to all the exercises are included. The book is excellently suited for use as a textbook for an undergraduate class (of all disciplines) in ordinary differential equations. .

  4. Waves at Navigation Structures

    Science.gov (United States)

    2014-10-27

    ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER OF PAGES 2 19a. NAME...upgrades the Coastal Modeling System’s ( CMS ) wave model CMS -Wave, a phase-averaged spectral wave model, and BOUSS-2D, a Boussinesq-type nonlinear wave...provided by this work unit address these critical needs of the Corps’ navigation mission. Description Issue Addressed CMS -Wave application at Braddock

  5. Detection method of navigation route of corn harvester based on image processing%基于图像处理的玉米收割机导航路线检测方法

    Institute of Scientific and Technical Information of China (English)

    梁习卉子; 陈兵旗; 姜秋慧; 朱德利; 杨明; 乔妍

    2016-01-01

    快速精准的检测出导航路线并对田端做出准确判断是收割机视觉导航的前提。为解决玉米收割机导航作业过程中因玉米列阴影、玉米田端的杂草等因素对检测精度干扰的问题,该文通过分析视觉导航图像的颜色特征去除阴影干扰,对玉米收割机提取导航作业路径和判断田端提出了检测算法。为减少计算量,设定关注区域作为非第一帧图像的处理范围;为去除玉米列阴影对检测结果造成的干扰,强调关注区域内 G(绿色)分量并减弱 R(红色)或 B(蓝色)分量;为加快处理速度,采用跳行累计G分量的方式确定候补点。在关注区域内对图像中去除阴影干扰后的G分量垂直累计值查找候补点,对图像上半部分收敛性好的候补点通过方差计算确定出已知点,再利用过已知点Hough变换拟合出玉米列边界所在的导航线。最后采用R分量的连续突变判断收割机是否到达田端。田间试验表明:目标直线的平均检测时间为50.13 ms/帧,对田端的检测准确可靠,满足玉米收割的作业要求。该研究成果也适用于高粱等其它高杆作物的机械化收获应用。%In a corn field with an unstructured environment, for the images collection by monocular vision, conventional path recognition algorithms are difficult to guarantee their robustness due to illumination variation, background reflection, shadow noise, and so on. In addition, the increase of the calculation amount of the algorithms caused by the complicated background information of the corn field environment affects the quickness and the real-timeliness of the corn harvester autonomous navigation, which leads to the difficulty of meeting the requirement for the operation efficiency of the corn field harvester and impedes the practical application of the mobile robot technology in agricultural production. The significant premise of visual navigation for a

  6. Real-time Risk Assessment for Aids to Navigation Using Fuzzy-FSA on Three-Dimensional Simulation System

    Directory of Open Access Journals (Sweden)

    Jinbiao Chen

    2014-06-01

    Full Text Available The risk level of the Aids to Navigation (AtoNs can reflect the ship navigation safety level in the channel to some extent. In order to appreciate the risk level of the aids to navigation (AtoNs in a navigation channel and to provide some decision-making suggestions for the AtoNs Maintenance and Management Department, the risk assessment index system of the AtoNs was built considering the advanced experience of IALA. Under the Formal Safety Assessment frame, taking the advantages of the fuzzy comprehensive evaluation method, the fuzzy-FSA model of risk assessment for aids to navigation was established. The model was implemented for the assessment of aids to navigation in Shanghai area based on the aids to navigation three-dimensional simulation system. The real-time data were extracted from the existing information system of aids to navigation, and the real-time risk assessment for aids to navigation of the chosen channel was performed on platform of the three-dimensional simulation system, with the risk assessment software. Specifically, the deep-water channel of the Yangtze River estuary was taken as an example to illustrate the general assessment procedure. The method proposed presents practical significance and application prospect on the maintenance and management of the aids to navigation.

  7. GNSS remote sensing theory, methods and applications

    CERN Document Server

    Jin, Shuanggen; Xie, Feiqin

    2014-01-01

    This book presents the theory and methods of GNSS remote sensing as well as its applications in the atmosphere, oceans, land and hydrology. It contains detailed theory and study cases to help the reader put the material into practice.

  8. 14 CFR Appendix G to Part 121 - Doppler Radar and Inertial Navigation System (INS): Request for Evaluation; Equipment and...

    Science.gov (United States)

    2010-01-01

    ... crewmembers, dispatchers, and maintenance personnel. (b) For pilots, instruction in the following: (1) Theory... latitudes, a review of navigation, flight planning, and applicable meteorology. (3) The methods for updating...

  9. Spatial Database Modeling for Indoor Navigation Systems

    Science.gov (United States)

    Gotlib, Dariusz; Gnat, Miłosz

    2013-12-01

    For many years, cartographers are involved in designing GIS and navigation systems. Most GIS applications use the outdoor data. Increasingly, similar applications are used inside buildings. Therefore it is important to find the proper model of indoor spatial database. The development of indoor navigation systems should utilize advanced teleinformation, geoinformatics, geodetic and cartographical knowledge. The authors present the fundamental requirements for the indoor data model for navigation purposes. Presenting some of the solutions adopted in the world they emphasize that navigation applications require specific data to present the navigation routes in the right way. There is presented original solution for indoor data model created by authors on the basis of BISDM model. Its purpose is to expand the opportunities for use in indoor navigation.

  10. SOME STATISTICAL SOFTWARE APPLICATIONS FOR TAGUCHI METHODS

    Directory of Open Access Journals (Sweden)

    Adrian Stere PARIS

    2016-05-01

    Full Text Available The paper details the variety of Taguchi methods, as important contribution to the quality improvement. The extended use of these methods imposes more and more complex calculi for the practical application and optimization. It should be necessary to benefit by the new software developments, assisted by the advanced statistical methods. The paper presents a few particular applications of some statistical software for the Taguchi methods as a quality enhancement insisting on the quality loss functions, the design of experiments and the new developments of statistical process control.

  11. Advanced computational electromagnetic methods and applications

    CERN Document Server

    Li, Wenxing; Elsherbeni, Atef; Rahmat-Samii, Yahya

    2015-01-01

    This new resource covers the latest developments in computational electromagnetic methods, with emphasis on cutting-edge applications. This book is designed to extend existing literature to the latest development in computational electromagnetic methods, which are of interest to readers in both academic and industrial areas. The topics include advanced techniques in MoM, FEM and FDTD, spectral domain method, GPU and Phi hardware acceleration, metamaterials, frequency and time domain integral equations, and statistics methods in bio-electromagnetics.

  12. Navigation method for reconnaissance robot based on vision object tracking%基于视觉目标跟踪的侦察机器人导航方法

    Institute of Scientific and Technical Information of China (English)

    包加桐; 宋爱国; 唐鸿儒; 熊鹏文

    2012-01-01

    Aiming at the problem of autonomous navigation of the reconnaissance robot in unknown environments, a navigation method for reconnaissance robots based on vision object tracking is proposed. First, the binary robust independent elementary features (BRIEF) extraction algorithm is employed to detect and describe the local invariant feature points in the image region of vision object to track. Based on a fast feature matching procedure, a coarse-to-fine target location method is proposed for real-time and accurate object tracking in the robot navigation process. Secondly, the autonomous navigation mission based on object tracking is decomposed into several behaviors in some of which the object tracking algorithm is integrated. Finally, the macro behavior-based robot mission execution mechanism is used to control the robot moving towards the vision target autonomously. Experimental results show that the proposed approach makes the reconnaissance robot accurately track the vision guidance object in real-time, and perform the target oriented autonomous navigation task reliably.%针对未知环境下侦察机器人的自主导航问题,提出了一种基于视觉目标跟踪的侦察机器人导航方法.首先利用二进制鲁棒独立元素特征(BRIEF)提取方法来检测和描述待跟踪视觉目标的局部不变特征点,在快速的特征匹配计算基础上提出由粗到精的目标定位两步法实现机器人导航过程中视觉目标的实时准确跟踪.其次对基于视觉目标跟踪的自主导航任务进行行为分解和实现,在行为中集成视觉目标跟踪算法.最后利用基于宏行为的机器人事务执行机制实现移向视觉目标的自主导航控制.实验结果表明,提出的方法能够使侦察机器人实时准确地跟踪视觉引导目标,在复杂障碍物环境下可靠地完成移向目标的自主导航任务.

  13. Risk assessment theory, methods, and applications

    CERN Document Server

    Rausand, Marvin

    2011-01-01

    With its balanced coverage of theory and applications along with standards and regulations, Risk Assessment: Theory, Methods, and Applications serves as a comprehensive introduction to the topic. The book serves as a practical guide to current risk analysis and risk assessment, emphasizing the possibility of sudden, major accidents across various areas of practice from machinery and manufacturing processes to nuclear power plants and transportation systems. The author applies a uniform framework to the discussion of each method, setting forth clear objectives and descriptions, while also shedding light on applications, essential resources, and advantages and disadvantages. Following an introduction that provides an overview of risk assessment, the book is organized into two sections that outline key theory, methods, and applications. * Introduction to Risk Assessment defines key concepts and details the steps of a thorough risk assessment along with the necessary quantitative risk measures. Chapters outline...

  14. MALL NAVIGATION SYSTEM USING WI-FI Router

    Directory of Open Access Journals (Sweden)

    Ankita Paul ,Rohit Das , Abhik Sarkar

    2012-12-01

    Full Text Available There have been various navigation and tracking systems being developed with the help of technologies like GPS, GSM, Bluetooth, IR, Wi-Fi and Radar. A shopping Mall is a vast place, & we often get confused with the direction of the nearest ATMs or even rest rooms. So we have simplified this method with the “Mall Navigation System”. Smart phones have become very popular these days, so we have combined the idea of a smart phone application helping you in an alienated mall. The idea revolves around our smart phones & the “WIFI” provided by the mall. An application that needs real-time, fast, & reliable data processing. The WIFI router will install NAVIGATION software by which it will detect our present location and with a view finder & our maps we detect the desired location.

  15. Systems Evaluation Methods, Models, and Applications

    CERN Document Server

    Liu, Siefeng; Xie, Naiming; Yuan, Chaoqing

    2011-01-01

    A book in the Systems Evaluation, Prediction, and Decision-Making Series, Systems Evaluation: Methods, Models, and Applications covers the evolutionary course of systems evaluation methods, clearly and concisely. Outlining a wide range of methods and models, it begins by examining the method of qualitative assessment. Next, it describes the process and methods for building an index system of evaluation and considers the compared evaluation and the logical framework approach, analytic hierarchy process (AHP), and the data envelopment analysis (DEA) relative efficiency evaluation method. Unique

  16. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Fan, Shiwei; Wang, Feixue

    2016-01-01

    These Proceedings present selected research papers from CSNC2016, held during 18th-20th May in Changsha, China. The theme of CSNC2016 is Smart Sensing, Smart Perception. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2016, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  17. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Yang, Yuanxi; Fan, Shiwei; Yu, Wenxian

    2017-01-01

    These proceedings present selected research papers from CSNC2017, held during 23th-25th May in Shanghai, China. The theme of CSNC2017 is Positioning, Connecting All. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2017, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  18. Molecular Combing of DNA: Methods and Applications

    DEFF Research Database (Denmark)

    Nazari, Zeniab Esmail; Gurevich, Leonid

    2013-01-01

    First proposed in 1994, molecular combing of DNA is a technique that allows adsorption and alignment of DNA on the surface with no need for prior modification of the molecule. Since then, many variations of the original method have been devised and used in a wide range of applications from genomic...... of the main methods in molecular combing as well as its major applications in nanotechnology....... studies to nanoelectronics. While molecular combing has been applied in a variety of DNA-related studies, no comprehensive review has been published on different combing methods proposed so far. In this review, the underlying mechanisms of molecular combing of DNA are described followed by discussion...

  19. The optimal homotopy asymptotic method engineering applications

    CERN Document Server

    Marinca, Vasile

    2015-01-01

    This book emphasizes in detail the applicability of the Optimal Homotopy Asymptotic Method to various engineering problems. It is a continuation of the book “Nonlinear Dynamical Systems in Engineering: Some Approximate Approaches”, published at Springer in 2011, and it contains a great amount of practical models from various fields of engineering such as classical and fluid mechanics, thermodynamics, nonlinear oscillations, electrical machines, and so on. The main structure of the book consists of 5 chapters. The first chapter is introductory while the second chapter is devoted to a short history of the development of homotopy methods, including the basic ideas of the Optimal Homotopy Asymptotic Method. The last three chapters, from Chapter 3 to Chapter 5, are introducing three distinct alternatives of the Optimal Homotopy Asymptotic Method with illustrative applications to nonlinear dynamical systems. The third chapter deals with the first alternative of our approach with two iterations. Five application...

  20. Navigation Lights - USACE IENC

    Data.gov (United States)

    Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  1. Applicabilities of ship emission reduction methods

    Energy Technology Data Exchange (ETDEWEB)

    Guleryuz, Adem [ARGEMAN Research Group, Marine Division (Turkey)], email: ademg@argeman.org; Kilic, Alper [Istanbul Technical University, Maritime Faculty, Marine Engineering Department (Turkey)], email: enviromarineacademic@yahoo.com

    2011-07-01

    Ships, with their high consumption of fossil fuels to power their engines, are significant air polluters. Emission reduction methods therefore need to be implemented and the aim of this paper is to assess the advantages and disadvantages of each emissions reduction method. Benefits of the different methods are compared, with their disadvantages and requirements, to determine the applicability of such solutions. The methods studied herein are direct water injection, humid air motor, sea water scrubbing, diesel particulate filter, selected catalytic reduction, design of engine components, exhaust gas recirculation and engine replacement. Results of the study showed that the usefulness of each emissions reduction method depends on the particular case and that an evaluation should be carried out for each ship. This study pointed out that methods to reduce ship emissions are available but that their applicability depends on each case.

  2. Application of meshless method to electromagnetic NDT

    Institute of Scientific and Technical Information of China (English)

    Huang Zuoying; Que Peiwen; Tao Zhengshu

    2006-01-01

    In this paper, a meshless method is introduced for NDT computation. Compared with the conventional FEM, it can avoid the onerous mesh generation and updating, only a distribution of points and the description of the boundaries are needed. The mathematical background for moving least square approximation employed in the method is given, and the numerical implementation is discussed. Application of the method for MFL computation and comparison with the results from FEM are also presented.

  3. Graphene doping methods and device applications.

    Science.gov (United States)

    Oh, Jong Sik; Kim, Kyong Nam; Yeom, Geun Young

    2014-02-01

    Graphene has recently been studied as a promising material to replace and enhance conventional electronic materials in various fields such as electronics, photovoltaics, sensors, etc. However, for the electronic applications of graphene prepared by various techniques such as chemical vapor deposition, chemical exfoliation, mechanical exfoliation, etc., critical limitations are found due to the defects in the graphene in addition to the absence of a semiconducting band gap. For that, many researchers have investigated the doped graphene which is effective to tailor its electronic property and chemical reactivity. This work presents a review of the various graphene doping methods and their device applications. As doping methods, direct synthesis method and post treatment method could be categorized. Because the latter case has been widely investigated and used in various electronic applications, we will focus on the post treatment method. Post treatment method could be further classified into wet and dry doping methods. In the case of wet doping, acid treatment, metal chloride, and organic material coating are the methods used to functionalize graphene by using dip-coating, spin coating, etc. Electron charge transfer achieved from graphene to dopants or from dopants to graphene makes p-type or n-type graphenes, respectively, with sheet resistance reduction effect. In the case of dry doping, it can be further categorized into electrostatic field method, evaporation method, thermal treatment method, plasma treatment method, etc. These doping techniques modify Fermi energy level of graphene and functionalize the property of graphene. Finally, some perspectives and device applications of doped graphene are also briefly discussed.

  4. Dynamic Transportation Navigation

    Science.gov (United States)

    Meng, Xiaofeng; Chen, Jidong

    Miniaturization of computing devices, and advances in wireless communication and sensor technology are some of the forces that are propagating computing from the stationary desktop to the mobile outdoors. Some important classes of new applications that will be enabled by this revolutionary development include intelligent traffic management, location-based services, tourist services, mobile electronic commerce, and digital battlefield. Some existing application classes that will benefit from the development include transportation and air traffic control, weather forecasting, emergency response, mobile resource management, and mobile workforce. Location management, i.e., the management of transient location information, is an enabling technology for all these applications. In this chapter, we present the applications of moving objects management and their functionalities, in particular, the application of dynamic traffic navigation, which is a challenge due to the highly variable traffic state and the requirement of fast, on-line computations.

  5. Application of a Computer-Assisted Navigation System (CANS) in the Delayed Treatment of Zygomatic Fractures: A Randomized Controlled Trial.

    Science.gov (United States)

    Gong, Xi; He, Yang; An, Jingang; Yang, Yao; Huang, Xiuling; Liu, Meng; Zhao, Yangyang; Zhang, Yi

    2017-07-01

    The delayed treatment of zygomatic complex (ZMC) fracture presents a difficult challenge to surgeons. The aim of this study was to compare the treatment effects of delayed surgery of ZMC fractures with and without a computer-assisted navigation system (CANS). In this observer-blinded single-site randomized clinical trial, patients with unilateral ZMC fracture were included and randomized 1:1 to delayed treatment with or without CANS. The primary outcome measurement was the absolute bilateral differences of the ZMC eminence and width based on computed tomographic (CT) measurements 48 to 72 hours after surgery. One hundred three patients with unilateral ZMC fracture without immediate treatment were enrolled, and 78 were randomized to each group. Postoperative CT measurements showed that the bilateral difference in ZMC eminence was significantly less for the navigation group than for the control group (1.24 vs 2.22 mm; P control group (P = .001). Photogrammetry showed that the average difference between the postoperative CT data and the preoperative design was smaller in the navigation group (1.30 vs 2.40 mm; P = .012). Use of CANS improved ZMC symmetry in patients with unilateral ZMC fracture who had delayed treatment by allowing for more accurate implementation of the preoperative plan. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  6. 导航电子地图在移动设备中的应用%The Application of Navigation Electronic Map on Mobile Devices

    Institute of Scientific and Technical Information of China (English)

    周友生

    2012-01-01

    Abstract With the development of geographic information system and mobile information technologies, they have tremendous potential support for users in the field. It is necessary for design solutions for geographical data visualization and decision system based on mobile devices. And the navigation electronic map system is the foundation for this work, which could provide field navigation and aided decision support. For this hot issue, this paper is presents its application significance from current status of research by analyzing a typical example of the field study results and explore the meaning and the current state of the application of navigation electronic map on mobile devices.%摘要移动信息技术和地理信息系统的迅猛发展为野外工作提供了巨大潜在支持,而设计基于移动设备的地理数据可视化与决策系统又是十分必要的,导航电子地图系统是完成这一工作的基础。导航电子地图能够向用户提供野外导航和辅助决策支持。针对这个热点问题,本文通过分析典型的应用实例论述了目前基于移动设备的导航电子地图的应用现状,探讨其应用意义。

  7. The Clinical Application of Digital Navigation Templates in Lumbar Spine%数字化腰椎椎弓根导航模板的临床应用

    Institute of Scientific and Technical Information of China (English)

    董乐乐; 郭鹏年; 左强; 刘瑞

    2016-01-01

    Objective:To investigate the problems of the pedicle navigation template used in lumbar surgery. Method:Retrospective study of 10 patients, with lumbar stenosis and lumbar intervertebral disc herniation, 6 male, 4 female, mean ages was 76 years, used the navigation template but failed to implanted the screws. The lumbar spines data of the patients were collected by 64-row CT scanner. Then the pedicle navigation templates were designed in mimics software. At last, the navigation templates were made by the 3D printer and were used in operations. Result:22 pedicle navigation templates were made , there were three multiple vertebral and channel navigation templates、six cover spine templates、eight bridge templates、five bridge vertebral plate spacing template . The 22 templates were used in the operation but all failed. Conclusion: There are many problems of pedicle navigation template used in lumbar degenerative disease. For example, the template attached poorly, template fracture and insufficient space. So the 3D printing pedicle navigation template used in lumbar degenerative disease need to be further revision.%目的:探讨3D打印腰椎椎弓根导航模板在腰椎退变性疾病中应用的利与弊。方法:回顾性研究10例患者,男6例,女4例,平均年龄76岁,为腰椎间盘突出伴椎管狭窄患者,均使用导航模板但未成功植入螺钉。术前行64排CT扫描采集患者腰椎数据,mimics软件中设计腰椎椎弓根导航模板,利用3D打印技术制作出实体导板并临床应用。结果:椎弓根导航模板共22只,其中多椎体多通道导航模板3只;单椎体双通道导板三种,包括覆盖棘突导板6只、桥式导板8只、桥式椎板限位导板5只。22只腰椎导航模板在术中应用时均失败。结论:3D打印椎弓根导航模板在腰椎退变性疾病中应用时仍存在诸多问题,如导板贴附不佳、导板断裂、导板置入空间不足等问题,有待进一步改善。

  8. Analysis of mixed data methods & applications

    CERN Document Server

    de Leon, Alexander R

    2013-01-01

    A comprehensive source on mixed data analysis, Analysis of Mixed Data: Methods & Applications summarizes the fundamental developments in the field. Case studies are used extensively throughout the book to illustrate interesting applications from economics, medicine and health, marketing, and genetics. Carefully edited for smooth readability and seamless transitions between chaptersAll chapters follow a common structure, with an introduction and a concluding summary, and include illustrative examples from real-life case studies in developmental toxicolog

  9. 组合导航中全球定位系统输出延迟补偿方法%Compensation Method for GPS Delay in INS/GPS Integrated Navigation

    Institute of Scientific and Technical Information of China (English)

    刘海波; 杨波; 熊陶; 郭志斌

    2014-01-01

    Under high-speed and high-dynamic flight environment,global positioning system (GPS)delay will influence the precision of inertial navigation system/global positioning system (INS/GPS)integrated navigation. Two kinds of compensation methods for GPS delay were researched in this paper,they were compensation meth-od by state propagating and compensation method by parabola fitting.State propagating of Kalman filter was used to achieve the integrated navigation result at present by propagating the integrated navigation result in the past,which was achieved by GPS present output and INS past output.The parabola function was used to de-scribe GPS output in the compensation method by parabola fitting,and then the real output at present was calcu-lated by the delay time and the parabola function.Simulation experiments show that,the compensation method by state propagating has higher precision,but it depends on INS output and large memory.The algorithm of the compensation method by parabola fitting is simpler and small computing,which could be used to compensate GPS delay without navigation equipments and be realized easily in engineering application.%针对高速高动态飞行环境下全球定位系统(GPS)导航信息输出存在延迟,进而影响惯性导航系统/全球定位系统(INS/GPS)组合导航精度的问题,提出 GPS 输出延迟补偿的两种方法:状态递推补偿法和曲线拟合补偿法。状态递推补偿法利用卡尔曼滤波状态递推,将 GPS当前输出与对应过去时刻惯导输出进行组合导航的结果递推更新到当前时刻,以获得当前时刻的组合导航结果;曲线拟合补偿法采用曲线函数来描述 GPS的输出,利用延迟时间与曲线函数计算获得当前时刻的真实输出。仿真实验表明,状态递推补偿法的补偿精度较高,但必须依赖惯导输出信息,而且计算机存储负担重;曲线拟合补偿法算法简单、计算量小,不依赖

  10. Global navigation satellite systems, inertial navigation, and integration

    CERN Document Server

    Grewal, Mohinder S; Bartone, Chris G

    2013-01-01

    An updated guide to GNSS, and INS, and solutions to real-world GNSS/INS problems with Kalman filtering Written by recognized authorities in the field, this third edition of a landmark work provides engineers, computer scientists, and others with a working familiarity of the theory and contemporary applications of Global Navigation Satellite Systems (GNSS), Inertial Navigational Systems, and Kalman filters. Throughout, the focus is on solving real-world problems, with an emphasis on the effective use of state-of-the-art integration techniques for those systems, especially the application of Kal

  11. INDOOR POSITIONING AND NAVIGATION BASED ON CONTROL SPHERECAL PANORAMIC IMAGES

    Directory of Open Access Journals (Sweden)

    T.-C. Huang

    2016-06-01

    Full Text Available Continuous indoor and outdoor positioning and navigation is the goal to achieve in the field of mobile mapping technology. However, accuracy of positioning and navigation will be largely degraded in indoor or occluded areas, due to receiving weak or less GNSS signals. Targeting the need of high accuracy indoor and outdoor positioning and navigation for mobile mapping applications, the objective of this study is to develop a novel method of indoor positioning and navigation with the use of spherical panoramic image (SPI. Two steps are planned in the technology roadmap. First, establishing a control SPI database that contains a good number of well-distributed control SPIs pre-acquired in the target space. A control SPI means an SPI with known exterior orientation parameters, which can be solved with a network bundle adjustment of SPIs. Having a control SPI database, the target space will be ready to provide the service of positioning and navigation. Secondly, the position and orientation of a newly taken SPI can be solved by using overlapped SPIs searched from the control SPI database. The method of matching SPIs and finding conjugate image features will be developed and tested. Two experiments will be planned and conducted in this paper to test the feasibility and validate the test results of the proposed methods. Analysis of appropriate number and distribution of needed control SPIs will also be included in the experiments with respect to different test cases.

  12. Indoor Positioning and Navigation Based on Control Spherecal Panoramic Images

    Science.gov (United States)

    Huang, Tsung-Che; Tseng, Yi-Hsing

    2016-06-01

    Continuous indoor and outdoor positioning and navigation is the goal to achieve in the field of mobile mapping technology. However, accuracy of positioning and navigation will be largely degraded in indoor or occluded areas, due to receiving weak or less GNSS signals. Targeting the need of high accuracy indoor and outdoor positioning and navigation for mobile mapping applications, the objective of this study is to develop a novel method of indoor positioning and navigation with the use of spherical panoramic image (SPI). Two steps are planned in the technology roadmap. First, establishing a control SPI database that contains a good number of well-distributed control SPIs pre-acquired in the target space. A control SPI means an SPI with known exterior orientation parameters, which can be solved with a network bundle adjustment of SPIs. Having a control SPI database, the target space will be ready to provide the service of positioning and navigation. Secondly, the position and orientation of a newly taken SPI can be solved by using overlapped SPIs searched from the control SPI database. The method of matching SPIs and finding conjugate image features will be developed and tested. Two experiments will be planned and conducted in this paper to test the feasibility and validate the test results of the proposed methods. Analysis of appropriate number and distribution of needed control SPIs will also be included in the experiments with respect to different test cases.

  13. Particle methods: An introduction with applications

    Directory of Open Access Journals (Sweden)

    Moral Piere Del

    2014-01-01

    Full Text Available Interacting particle methods are increasingly used to sample from complex high-dimensional distributions. They have found a wide range of applications in applied probability, Bayesian statistics and information engineering. Understanding rigorously these new Monte Carlo simulation tools leads to fascinating mathematics related to Feynman-Kac path integral theory and their interacting particle interpretations. In these lecture notes, we provide a pedagogical introduction to the stochastic modeling and the theoretical analysis of these particle algorithms. We also illustrate these methods through several applications including random walk confinements, particle absorption models, nonlinear filtering, stochastic optimization, combinatorial counting and directed polymer models.

  14. Data Analysis Techniques for a Lunar Surface Navigation System Testbed

    Science.gov (United States)

    Chelmins, David; Sands, O. Scott; Swank, Aaron

    2011-01-01

    NASA is interested in finding new methods of surface navigation to allow astronauts to navigate on the lunar surface. In support of the Vision for Space Exploration, the NASA Glenn Research Center developed the Lunar Extra-Vehicular Activity Crewmember Location Determination System and performed testing at the Desert Research and Technology Studies event in 2009. A significant amount of sensor data was recorded during nine tests performed with six test subjects. This paper provides the procedure, formulas, and techniques for data analysis, as well as commentary on applications.

  15. Multisensor robot navigation system

    Science.gov (United States)

    Persa, Stelian; Jonker, Pieter P.

    2002-02-01

    Almost all robot navigation systems work indoors. Outdoor robot navigation systems offer the potential for new application areas. The biggest single obstacle to building effective robot navigation systems is the lack of accurate wide-area sensors for trackers that report the locations and orientations of objects in an environment. Active (sensor-emitter) tracking technologies require powered-device installation, limiting their use to prepared areas that are relative free of natural or man-made interference sources. The hybrid tracker combines rate gyros and accelerometers with compass and tilt orientation sensor and DGPS system. Sensor distortions, delays and drift required compensation to achieve good results. The measurements from sensors are fused together to compensate for each other's limitations. Analysis and experimental results demonstrate the system effectiveness. The paper presents a field experiment for a low-cost strapdown-IMU (Inertial Measurement Unit)/DGPS combination, with data processing for the determination of 2-D components of position (trajectory), velocity and heading. In the present approach we have neglected earth rotation and gravity variations, because of the poor gyroscope sensitivities of our low-cost ISA (Inertial Sensor Assembly) and because of the relatively small area of the trajectory. The scope of this experiment was to test the feasibility of an integrated DGPS/IMU system of this type and to develop a field evaluation procedure for such a combination.

  16. Indoor Pedestrian Navigation Based on Hybrid Route Planning and Location Modeling

    DEFF Research Database (Denmark)

    Schougaard, Kari Rye; Grønbæk, Kaj; Scharling, Tejs

    2012-01-01

    This paper introduces methods and services called PerPosNav for development of custom indoor pedestrian navigation applications to be deployed on a variety of platforms. PerPosNav combines symbolic and geometry based modeling of buildings, and in turn combines graph-based and geometric route...... computation. The paper argues why these hybrid approaches are necessary to handle the challenges of in-door pedestrian navigation...

  17. 基于人体下肢运动学机理的行人导航方法%Pedestrian navigation method based on kinematic mechanism of human lower limb

    Institute of Scientific and Technical Information of China (English)

    钱伟行; 曾庆化; 万骏炜; 熊智

    2015-01-01

    利用人体运动特征实现行人导航是近年来导航技术领域新兴的研究方向之一。针对惯性测量组件足部安装方式在人体较高过载的运动中无法有效实现零速修正的问题,研究了一种惯性测量组件在人体下肢分布式安装,基于人体下肢运动学机理构建虚拟足部惯性测量组件,从而实现人体导航定位的方法。阐述了行人导航系统的结构与虚拟惯性传感组件的构建机理,研制了系统原理样机。实验结果表明所提出的方法在人体较高过载的行进中可有效克服测量信息超量程、冲击等因素对导航解算的影响,定位精度约为行进距离的6%,并通过分析总结了影响该类型行人导航系统性能的各项主要因素,为进一步研究提供了一定的理论与技术基础。%In recent years, using human motion characteristics to realize pedestrian navigation is one of the emerging directions of navigation technology. In view that the inertial measurement units in foot-mounted mode can not effectively achieve zero velocity update (ZUPT) in high overload of human body motion, this paper presents a novel method which adopts distributed IMUs to install in human lower limb. Virtual foot-mounted inertial sensor components are structured based on kinematic structure of human lower limb to realize the pedestrian navigation. The structure of the pedestrian navigation system and the mechanism of virtual inertial sensor components are described, and the system principle prototype is developed. The experimental results show that the proposed method can effectively overcome the influences of measurement information over-range, the impact signals and other factors in high-overload human body traveling. The positioning accuracy of the navigation solution is about 6%of the traveled distance. Finally, the major factors affecting the performance of the pedestrian navigation system is summarized to provide theoretical and

  18. Stamping Robust Design Method and Its Application

    Institute of Scientific and Technical Information of China (English)

    Z.Q. Lin; Jian Ai; Weigang Zhang; Shuhui Li

    2004-01-01

    The application of the robust design to stamping is discussed in the paper. The regression equation of the quality index and its influencing factors can be attained by using method of central composite design. Stamping computer simulation takes the place of real stamping experiments to fulfill the special experimental conditions. The real stamping experiments prove the correctness and the feasibility of the stamping robust design method-central composite design.

  19. Electromagnetic field-based navigation for percutaneous punctures on C-arm CT: experimental evaluation and clinical application.

    Science.gov (United States)

    Meyer, Bernhard C; Peter, Olaf; Nagel, Markus; Hoheisel, Martin; Frericks, Bernd B; Wolf, Karl-Jürgen; Wacker, Frank K

    2008-12-01

    The aim of this study was to prospectively evaluate the needle visualization and placement error and use of an electromagnetic field-based tracking navigation device for puncture procedures based on C-arm CT (CACT) images. A commercially available navigation device was mounted on an angiographic X-ray system setup for CACT. After the target was defined, needle placement was performed under real-time visualization of the virtual needle in CACT images. The final, real needle position was assessed by CACT. Punctures were performed in phantoms (n = 76) and in twelve patients (eight biopsies, three drainages, one injection). Procedure times, system error, user error and total error were assessed. In phantoms, mean total error was 2.3 +/- 0.9 mm, user error was 1.4 +/- 0.8 mm and system error was 1.7 +/- 0.8 mm. In the patient study, the targeted puncture was successful in all twelve cases. The mean total error was 5.4 mm +/- 1.9 mm (maximum 8.1 mm), user error was 3.7 +/- 1.7 mm, system error was 3.2 +/- 1.4 mm and mean skin-to-target time was less than 1 min. The navigation device relying on CACT was accurate in terms of needle visualization and useful for needle placement under both experimental and clinical conditions. For more complex procedures, electromagnetic field-based tracking guidance might be of help in facilitating the puncture and reducing both the puncture risk and procedure time.

  20. Electromagnetic field-based navigation for percutaneous punctures on C-arm CT: experimental evaluation and clinical application

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Bernhard C.; Peter, Olaf; Frericks, Bernd B.; Wolf, Karl-Juergen [Charite - University Hospital, Campus Benjamin Franklin, Department of Radiology and Nuclear Medicine, Berlin (Germany); Nagel, Markus [CAS innovations AG, Erlangen (Germany); Hoheisel, Martin [Siemens Healthcare, Forchheim (Germany); Wacker, Frank K. [Charite - University Hospital, Campus Benjamin Franklin, Department of Radiology and Nuclear Medicine, Berlin (Germany); The Johns Hopkins Hospital, Radiology Department, Division of Vascular and Interventional Radiology, Baltimore, MD (United States)

    2008-12-15

    The aim of this study was to prospectively evaluate the needle visualization and placement error and use of an electromagnetic field-based tracking navigation device for puncture procedures based on C-arm CT (CACT) images. A commercially available navigation device was mounted on an angiographic X-ray system setup for CACT. After the target was defined, needle placement was performed under real-time visualization of the virtual needle in CACT images. The final, real needle position was assessed by CACT. Punctures were performed in phantoms (n = 76) and in twelve patients (eight biopsies, three drainages, one injection). Procedure times, system error, user error and total error were assessed. In phantoms, mean total error was 2.3 {+-} 0.9 mm, user error was 1.4 {+-} 0.8 mm and system error was 1.7 {+-} 0.8 mm. In the patient study, the targeted puncture was successful in all twelve cases. The mean total error was 5.4 mm {+-} 1.9 mm (maximum 8.1 mm), user error was 3.7 {+-} 1.7 mm, system error was 3.2 {+-} 1.4 mm and mean skin-to-target time was less than 1 min. The navigation device relying on CACT was accurate in terms of needle visualization and useful for needle placement under both experimental and clinical conditions. For more complex procedures, electromagnetic field-based tracking guidance might be of help in facilitating the puncture and reducing both the puncture risk and procedure time. (orig.)

  1. Practical issues in automatic 3D reconstruction and navigation applications using man-portable or vehicle-mounted sensors

    Science.gov (United States)

    Harris, Chris; Stennett, Carl

    2012-09-01

    The navigation of an autonomous robot vehicle and person localisation in the absence of GPS both rely on using local sensors to build a model of the 3D environment. Accomplishing such capabilities is not straightforward - there are many choices to be made of sensor and processing algorithms. Roke Manor Research has broad experience in this field, gained from building and characterising real-time systems that operate in the real world. This includes developing localization for planetary and indoor rovers, model building of indoor and outdoor environments, and most recently, the building of texture-mapped 3D surface models.

  2. A Geometry-Based Cycle Slip Detection and Repair Method with Time-Differenced Carrier Phase (TDCP for a Single Frequency Global Position System (GPS + BeiDou Navigation Satellite System (BDS Receiver

    Directory of Open Access Journals (Sweden)

    Chuang Qian

    2016-12-01

    Full Text Available As the field of high-precision applications based on carriers continues to expand, the development of low-cost, small, modular receivers and their application in diverse scenarios and situations with complex data quality has increased the requirements of carrier-phase data preprocessing. A new geometry-based cycle slip detection and repair method based on Global Position System (GPS + BeiDou Navigation Satellite System (BDS is proposed. The method uses a Time-differenced Carrier Phase (TDCP model, which eliminates the Inner-System Bias (ISB between GPS and BDS, and it is conducive to the effective combination of GPS and BDS. It avoids the interference of the noise of the pseudo-range with cycle slip detection, while the cycle slips are preserved as integers. This method does not limit the receiver frequency number, and it is applicable to single-frequency data. The process is divided into two steps to detect and repair cycle slip. The first step is cycle slip detection, using the Improved Local Analysis Method (ILAM to find satellites that have cycle slips; The second step is to repair the cycle slips, including estimating the float solution of changes in ambiguities at the satellites that have cycle slips with the least squares method and the integer solution of the cycle slips by rounding. In the process of rounding, in addition to the success probability, a decimal test is carried out to validate the result. Finally, experiments with filed test data are carried out to prove the effectiveness of this method. The results show that the detectable cycle slips number with GPS + BDS is much greater than that with GPS. The method can also detect the non-integer outliers while fixing the cycle slip. The maximum decimal bias in repair is less than that with GPS. It implies that this method takes full advantages of multi-system.

  3. A Geometry-Based Cycle Slip Detection and Repair Method with Time-Differenced Carrier Phase (TDCP) for a Single Frequency Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) Receiver.

    Science.gov (United States)

    Qian, Chuang; Liu, Hui; Zhang, Ming; Shu, Bao; Xu, Longwei; Zhang, Rufei

    2016-12-05

    As the field of high-precision applications based on carriers continues to expand, the development of low-cost, small, modular receivers and their application in diverse scenarios and situations with complex data quality has increased the requirements of carrier-phase data preprocessing. A new geometry-based cycle slip detection and repair method based on Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) is proposed. The method uses a Time-differenced Carrier Phase (TDCP) model, which eliminates the Inner-System Bias (ISB) between GPS and BDS, and it is conducive to the effective combination of GPS and BDS. It avoids the interference of the noise of the pseudo-range with cycle slip detection, while the cycle slips are preserved as integers. This method does not limit the receiver frequency number, and it is applicable to single-frequency data. The process is divided into two steps to detect and repair cycle slip. The first step is cycle slip detection, using the Improved Local Analysis Method (ILAM) to find satellites that have cycle slips; The second step is to repair the cycle slips, including estimating the float solution of changes in ambiguities at the satellites that have cycle slips with the least squares method and the integer solution of the cycle slips by rounding. In the process of rounding, in addition to the success probability, a decimal test is carried out to validate the result. Finally, experiments with filed test data are carried out to prove the effectiveness of this method. The results show that the detectable cycle slips number with GPS + BDS is much greater than that with GPS. The method can also detect the non-integer outliers while fixing the cycle slip. The maximum decimal bias in repair is less than that with GPS. It implies that this method takes full advantages of multi-system.

  4. Apollo Onboard Navigation Techniques

    Science.gov (United States)

    Interbartolo, Michael

    2009-01-01

    This viewgraph presentation reviews basic navigation concepts, describes coordinate systems and identifies attitude determination techniques including Primary Guidance, Navigation and Control System (PGNCS) IMU management and Command and Service Module Stabilization and Control System/Lunar Module (LM) Abort Guidance System (AGS) attitude management. The presentation also identifies state vector determination techniques, including PGNCS coasting flight navigation, PGNCS powered flight navigation and LM AGS navigation.

  5. Understanding satellite navigation

    CERN Document Server

    Acharya, Rajat

    2014-01-01

    This book explains the basic principles of satellite navigation technology with the bare minimum of mathematics and without complex equations. It helps you to conceptualize the underlying theory from first principles, building up your knowledge gradually using practical demonstrations and worked examples. A full range of MATLAB simulations is used to visualize concepts and solve problems, allowing you to see what happens to signals and systems with different configurations. Implementation and applications are discussed, along with some special topics such as Kalman Filter and Ionosphere. W

  6. Multiphase lattice Boltzmann methods theory and application

    CERN Document Server

    Huang, Haibo; Lu, Xiyun

    2015-01-01

    Theory and Application of Multiphase Lattice Boltzmann Methods presents a comprehensive review of all popular multiphase Lattice Boltzmann Methods developed thus far and is aimed at researchers and practitioners within relevant Earth Science disciplines as well as Petroleum, Chemical, Mechanical and Geological Engineering. Clearly structured throughout, this book will be an invaluable reference  on the current state of all popular multiphase Lattice Boltzmann Methods (LBMs). The advantages and disadvantages of each model are presented in an accessible manner to enable the reader to choose the

  7. Underwater Navigation using Pseudolite

    Directory of Open Access Journals (Sweden)

    Krishneshwar Tiwary

    2011-07-01

    Full Text Available Using pseudolite or pseudo satellite, a proven technology for ground and space applications for the augmentation of GPS, is proposed for underwater navigation. Global positioning systems (GPS like positioning for underwater system, needs minimum of four pseudolite-ranging signals for pseudo-range and accumulated delta range measurements. Using four such measurements and using the models of underwater attenuation and delays, the navigation solution can be found. However, for application where the one-way ranging does not give good accuracy, alternative algorithms based upon the bi-directional and self-difference ranging is proposed using selfcalibrated pseudolite array algorithm. The hardware configuration is proposed for pseudolite transceiver for making the self-calibrated array. The pseudolite array, fixed or moored under the sea, can give position fixing similar to GPS for underwater applications.Defence Science Journal, 2011, 61(4, pp.331-336, DOI:http://dx.doi.org/10.14429/dsj.61.1087

  8. An improved particle filter and its application to an INS/GPS integrated navigation system in a serious noisy scenario

    Science.gov (United States)

    Wang, Xuemei; Ni, Wenbo

    2016-09-01

    For loosely coupled INS/GPS integrated navigation systems with low-cost and low-accuracy microelectromechanical device inertial sensors, in order to obtain enough accuracy, a full-state nonlinear dynamic model rather than a linearized error model is much more preferable. Particle filters are particularly for nonlinear and non-Gaussian situations, but typical bootstrap particle filters (BPFs) and some improved particle filters (IPFs) such as auxiliary particle filters (APFs) and Gaussian particle filters (GPFs) cannot solve the mismatch between the importance function and the likelihood function very well. The predicted particles propagated through inertial navigation equations cannot be scattered with certainty within the effective range of current observation when there are large drift errors of the inertial sensors. Therefore, the current observation cannot play the correction role well and these particle filters are invalid to some extent. The proposed IPF firstly estimates the corresponding state bias errors according to the current observation and then corrects the bias errors of the predicted particles before determining the weights and resampling the particles. Simulations and practical experiments both show that the proposed IPF can effectively solve the mismatch between the importance function and the likelihood function of a BPF and compensate the accumulated errors of INSs very well. It has great robustness in a serious noisy scenario.

  9. Structural equation modeling methods and applications

    CERN Document Server

    Wang, Jichuan

    2012-01-01

    A reference guide for applications of SEM using Mplus Structural Equation Modeling: Applications Using Mplus is intended as both a teaching resource and a reference guide. Written in non-mathematical terms, this book focuses on the conceptual and practical aspects of Structural Equation Modeling (SEM). Basic concepts and examples of various SEM models are demonstrated along with recently developed advanced methods, such as mixture modeling and model-based power analysis and sample size estimate for SEM. The statistical modeling program, Mplus, is also featured and provides researchers with a

  10. Study on the Mitigation Methods of Ionospheric Scintillation of Global Navigation Satellite System%卫星导航电离层闪烁环境保障方法研究

    Institute of Scientific and Technical Information of China (English)

    张红波; 盛冬生; 赵振维; 刘玉梅; 孙树计

    2015-01-01

    Ionospheric scintillation can result in larger position errors of GNSS receivers . Its worst effect is to cause a loss of lock on the signal and results in GNSS service interrup‐tion .The ionospheric scintillation has practical importance in general applications of global navigation satellite system and a few high precision applications ,including service of life safety and geodesy measurement . T he mitigation methods of ionospheric scintillation w ere analyzed from three aspects :improving the scintillation resistant capability of GNSS receiv‐ers ,manufacturing the integrated navigation and positioning equipment based on national PNT architecture and developing the forecasting and alarm system of ionospheric scintilla‐tion .%电离层闪烁会导致卫星导航接收机的导航定位误差增大,严重时会使其导航定位中断。电离层闪烁严重影响了卫星导航系统正常应用和多种高端应用,如生命安全服务、高精度测量等。从提升卫星导航接收机抗电离层闪烁能力、研制基于国家PN T 体系结构的集成导航定位装备、建立电离层闪烁预报预警保障机制三个方面探讨了电离层闪烁环境保障方法,以确保导航定位能力。

  11. Application of Sampling Methods to Geological Survey

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@There are two kinds of research methods in geological observation study. One is the remote-sensing observation. The other is the partial sampling method extensively used in every stage of the geological work, for example, in arranging the lines and points of geologic survey, and in arranging the exploration engineering. Three problems may occur in practical application of the sampling method: (1) Though we use the partial sampling method in geological work, we must make use of many labor powers, materials and money to accomplish the geological task. Is the method we use appropriate to some special geological task? (2) How many samples or observation points should be appropriate to the geological research?

  12. Quantum Navigation and Ranking in Complex Networks

    Science.gov (United States)

    Sánchez-Burillo, Eduardo; Duch, Jordi; Gómez-Gardeñes, Jesús; Zueco, David

    2012-08-01

    Complex networks are formal frameworks capturing the interdependencies between the elements of large systems and databases. This formalism allows to use network navigation methods to rank the importance that each constituent has on the global organization of the system. A key example is Pagerank navigation which is at the core of the most used search engine of the World Wide Web. Inspired in this classical algorithm, we define a quantum navigation method providing a unique ranking of the elements of a network. We analyze the convergence of quantum navigation to the stationary rank of networks and show that quantumness decreases the number of navigation steps before convergence. In addition, we show that quantum navigation allows to solve degeneracies found in classical ranks. By implementing the quantum algorithm in real networks, we confirm these improvements and show that quantum coherence unveils new hierarchical features about the global organization of complex systems.

  13. Kyphoplasty interventions using a navigation system and C-arm CT data: first clinical results

    Science.gov (United States)

    Hoheisel, Martin; Skalej, Martin; Beuing, Oliver; Bill, Ulrich; Klingenbeck-Regn, Klaus; Petzold, Ralf; Nagel, Markus H.

    2009-02-01

    This study evaluates new applications using a novel navigation system with electromagnetic (EM) tracking in clinical routine. The navigation system (iGuide CAPPA, CAS innovations, Erlangen, Germany) consists of a PC with dedicated navigation software, the AURORA tracking system (NDI, Waterloo Ontario, Canada; needles equipped with small coils in their tips for EM navigation. After patient positioning a 3D C-arm data set of the spine region of interest is acquired. The images are reconstructed and the 3D data set is directly transferred to the navigation system. Image loading and image to patient registration are performed automatically by the navigation system. For image acquisition a C-arm system with DynaCT option (AXIOM Artis, Siemens Healthcare, Forchheim, Germany) was used. As new clinical applications we performed kyphoplasty for reconstruction of collapsed vertebrae. All interventions were carried out without any complication. After a single planning scan the radiologists were able to place the needle in the designated vertebra. During needle driving 2D imaging was performed just in a few cases for control reasons. The time between planning and final needle positioning was reduced in all cases compared to conventional methods. Moreover, the number of control scans could be markedly reduced. The deviation of the needle to the planned target was less than 2 mm. The use of DynaCT images in combination with electromagnetic tracking-based navigation systems allows a precise needle positioning for kyphoplasty.

  14. Evaluation Method for Strap-down Inertial Navigation System of Multi-level Based on Gray Comprehensive Evaluation Model%基于灰色多层次综合评价模型的捷联惯性导航系统评估方法

    Institute of Scientific and Technical Information of China (English)

    石钊铭; 王文革

    2014-01-01

    The structure is complex and influence factors are too many to evaluate the performance of the strap down inertial navigation system by use of single index. Aimed at the problem, this paper puts forward an evaluation method of strap-down inertial navigation system based on multi-level gray comprehensive evaluation model. Firstly, in view of ship application, evaluation index system of the strap-down inertial navigation system is built. Then according to the structure characteristics of the strap-down inertial navigation system, the grey multi hierarchical comprehensive evaluation model is applied to the strap-down inertial navigation system. Finally, the effectiveness of the method is proved by use of simulation experiments.%针对捷联惯性导航系统层次结构复杂、影响因素较多、单一指标难以全面准确评估其综合性能的问题,提出了基于灰色多层次综合评价模型的捷联惯性导航系统评估方法。首先从舰船使用角度出发,构建了捷联惯性导航系统的评价指标体系,然后根据捷联惯性导航系统的结构特点,将灰色多层次综合评估模型应用于捷联惯性导航系统的评估中,最后仿真试验证明了方法的有效性。

  15. Advanced Methods and Applications in Computational Intelligence

    CERN Document Server

    Nikodem, Jan; Jacak, Witold; Chaczko, Zenon; ACASE 2012

    2014-01-01

    This book offers an excellent presentation of intelligent engineering and informatics foundations for researchers in this field as well as many examples with industrial application. It contains extended versions of selected papers presented at the inaugural ACASE 2012 Conference dedicated to the Applications of Systems Engineering. This conference was held from the 6th to the 8th of February 2012, at the University of Technology, Sydney, Australia, organized by the University of Technology, Sydney (Australia), Wroclaw University of Technology (Poland) and the University of Applied Sciences in Hagenberg (Austria). The  book is organized into three main parts. Part I contains papers devoted to the heuristic approaches that are applicable in situations where the problem cannot be solved by exact methods, due to various characteristics or  dimensionality problems. Part II covers essential issues of the network management, presents intelligent models of the next generation of networks and distributed systems ...

  16. Finite Element Methods and Their Applications

    CERN Document Server

    Chen, Zhangxin

    2005-01-01

    This book serves as a text for one- or two-semester courses for upper-level undergraduates and beginning graduate students and as a professional reference for people who want to solve partial differential equations (PDEs) using finite element methods. The author has attempted to introduce every concept in the simplest possible setting and maintain a level of treatment that is as rigorous as possible without being unnecessarily abstract. Quite a lot of attention is given to discontinuous finite elements, characteristic finite elements, and to the applications in fluid and solid mechanics including applications to porous media flow, and applications to semiconductor modeling. An extensive set of exercises and references in each chapter are provided.

  17. An interactive physics-based unmanned ground vehicle simulator leveraging open source gaming technology: progress in the development and application of the virtual autonomous navigation environment (VANE) desktop

    Science.gov (United States)

    Rohde, Mitchell M.; Crawford, Justin; Toschlog, Matthew; Iagnemma, Karl D.; Kewlani, Guarav; Cummins, Christopher L.; Jones, Randolph A.; Horner, David A.

    2009-05-01

    It is widely recognized that simulation is pivotal to vehicle development, whether manned or unmanned. There are few dedicated choices, however, for those wishing to perform realistic, end-to-end simulations of unmanned ground vehicles (UGVs). The Virtual Autonomous Navigation Environment (VANE), under development by US Army Engineer Research and Development Center (ERDC), provides such capabilities but utilizes a High Performance Computing (HPC) Computational Testbed (CTB) and is not intended for on-line, real-time performance. A product of the VANE HPC research is a real-time desktop simulation application under development by the authors that provides a portal into the HPC environment as well as interaction with wider-scope semi-automated force simulations (e.g. OneSAF). This VANE desktop application, dubbed the Autonomous Navigation Virtual Environment Laboratory (ANVEL), enables analysis and testing of autonomous vehicle dynamics and terrain/obstacle interaction in real-time with the capability to interact within the HPC constructive geo-environmental CTB for high fidelity sensor evaluations. ANVEL leverages rigorous physics-based vehicle and vehicle-terrain interaction models in conjunction with high-quality, multimedia visualization techniques to form an intuitive, accurate engineering tool. The system provides an adaptable and customizable simulation platform that allows developers a controlled, repeatable testbed for advanced simulations. ANVEL leverages several key technologies not common to traditional engineering simulators, including techniques from the commercial video-game industry. These enable ANVEL to run on inexpensive commercial, off-the-shelf (COTS) hardware. In this paper, the authors describe key aspects of ANVEL and its development, as well as several initial applications of the system.

  18. UKF滤波方法及其在车辆导航状态估计中的应用%Application of Unscented Kalman Filter in State Estimation for Land Vehicle Navigation System

    Institute of Scientific and Technical Information of China (English)

    张传斌; 田蔚风; 金志华

    2005-01-01

    In a land vehicle navigation system, generally the Extended Kalman Filter (EKF) is as a state estimation method to improve the accuracy of navigation. However, as defects of the EKF in nonlinear estimation, there exists estimated error, which affects the accuracy of the navigation system, when it is adopted in nonlinear estimation of a navigation system. In order to yield the higher accuracy of navigation, a novel method-Unscented Kalman Filter (UKF) was employed in state estimation for a land vehicle navigation system. For a land vehicle DR/GPS navigation system, the EKF and UKF are compared through simulation. Simulation results show that the UKF is superior to the EKF in state estimation for a land vehicle navigation system.%在车载导航系统中,通常采用EKF作为状态估计方法提高导航的精度.由于EKF进行非线性估计存在一些缺陷,因此将其用于导航系统的非线性估计时,存在估计误差,从而影响导航系统的精度.为了获得更高的导航精度,将一种新的滤波方法-UKF方法用于车载导航系统的状态估计中.对一个车载DR/GPS组合系统,将EKF和UKF方法分别进行了滤波仿真.仿真结果表明:在车载导航状态估计中,UKF方法优于EKF方法.

  19. Heat kernel method and its applications

    CERN Document Server

    Avramidi, Ivan G

    2015-01-01

    The heart of the book is the development of a short-time asymptotic expansion for the heat kernel. This is explained in detail and explicit examples of some advanced calculations are given. In addition some advanced methods and extensions, including path integrals, jump diffusion and others are presented. The book consists of four parts: Analysis, Geometry, Perturbations and Applications. The first part shortly reviews of some background material and gives an introduction to PDEs. The second part is devoted to a short introduction to various aspects of differential geometry that will be needed later. The third part and heart of the book presents a systematic development of effective methods for various approximation schemes for parabolic differential equations. The last part is devoted to applications in financial mathematics, in particular, stochastic differential equations. Although this book is intended for advanced undergraduate or beginning graduate students in, it should also provide a useful reference ...

  20. A Kalman Filter Integrated Navigation Design for the IAR Twin Otter Atmospheric Research Aircraft (Methode de Navigation Integree a Filtre de Kalman Destinee au Twin Otter de L’Ira Charge des Recherches Atmospheriques)

    Science.gov (United States)

    1991-04-01

    A FILTRE DE KALMAN DESTINEE AU TWIN OTTER DE LIRA CHARGE DES RECHERCHES ATMOSPHERIQUES A4%.’s~ion o by :Di RATAI B.W. Leach____________ Institute for...navigation ant fait I’objet de travaux ant~rieurs de mise au point qui ant ddmantr6 qu’un dispositif de navigation int~gr6e A filtre Kalman pr~sentait...I’ensembls des d6tecteurs instafls A bard du Twin Otter s’est traduite par la passibilit6 de g~n~rer, par le biais d’un filtre de Kalman , des donn~es

  1. An Analysis Method of Business Application Framework

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    We discuss the evolution of object-oriented software developmentpr o cess based on software pattern. For developing mature software fra mework and component, we advocate to elicit and incorporate software patterns fo r ensuing quality and reusability of software frameworks. On the analysis base o f requirement specification for business application domain, we present analysis method and basic role model of software framework. We also elicit analysis patt ern of framework architecture, and design basic role classes and their structure .

  2. Simulating protein dynamics: Novel methods and applications

    Science.gov (United States)

    Vishal, V.

    This Ph.D dissertation describes several methodological advances in molecular dynamics (MD) simulations. Methods like Markov State Models can be used effectively in combination with distributed computing to obtain long time scale behavior from an ensemble of short simulations. Advanced computing architectures like Graphics Processors can be used to greatly extend the scope of MD. Applications of MD techniques to problems like Alzheimer's Disease and fundamental questions in protein dynamics are described.

  3. Low temperature plasma technology methods and applications

    CERN Document Server

    Chu, Paul K

    2013-01-01

    Written by a team of pioneering scientists from around the world, Low Temperature Plasma Technology: Methods and Applications brings together recent technological advances and research in the rapidly growing field of low temperature plasmas. The book provides a comprehensive overview of related phenomena such as plasma bullets, plasma penetration into biofilms, discharge-mode transition of atmospheric pressure plasmas, and self-organization of microdischarges. It describes relevant technology and diagnostics, including nanosecond pulsed discharge, cavity ringdown spectroscopy, and laser-induce

  4. Comparison of real-time performance of Kalman filter-based slam methods for unmanned ground vehicle (UGV) navigation

    Science.gov (United States)

    Temeltaş, Hakan; Kavak, Deniz

    2009-05-01

    Simultaneous Localization and Mapping (SLAM) using for the mobile robot navigation has two main problems. First problem is the computational complexity due to the growing state vector with the added landmark in the environment. Second problem is data association which matches the observations and landmarks in the state vector. In this study, we compare Extended Kalman Filter (EKF) based SLAM which is well-developed and well-known algorithm, and Compressed Extended Kalman Filter (CEKF) based SLAM developed for decreasing of the computational complexity of the EKF based SLAM. We write two simulation program to investigate these techniques. Firts program is written for the comparison of EKF and CEKF based SLAM according to the computational complexity and covariance matrix error with the different numbers of landmarks. In the second program, EKF and CEKF based SLAM simulations are presented. For this simulation differential drive vehicle that moves in a 10m square trajectory and LMS 200 2-D laser range finder are modelled and landmarks are randomly scattered in that 10m square environment.

  5. Harmony Search Method: Theory and Applications

    Directory of Open Access Journals (Sweden)

    X. Z. Gao

    2015-01-01

    Full Text Available The Harmony Search (HS method is an emerging metaheuristic optimization algorithm, which has been employed to cope with numerous challenging tasks during the past decade. In this paper, the essential theory and applications of the HS algorithm are first described and reviewed. Several typical variants of the original HS are next briefly explained. As an example of case study, a modified HS method inspired by the idea of Pareto-dominance-based ranking is also presented. It is further applied to handle a practical wind generator optimal design problem.

  6. APPLICATION OF HOMOTOPY METHODS TO POWER SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Da-yongCai; Yu-rongChen

    2004-01-01

    In this paper, the application of homotopy methods to the load flow multi-solution problems of power systems is introduced. By the generalized Bernshtein theorem, the combinatorial number C2nm is shown to be the BKK bound of the number of isolated solutions of the polynomial system transformed from load flow equations with generically chosen coefficients. As a result of the general Bezout number, the number of paths being followed is reduced significantly in the practical load flow computation. Finally, the complete P-V cures are obtained by tracking the load flow with homotopy methods.

  7. Keller-box method and its application

    CERN Document Server

    Prasad, Kerehalli V

    2014-01-01

    Most of the problems arising in science and engineering are nonlinear. They are inherently difficult to solve. Traditional analytical approximations are valid only for weakly nonlinear problems, and often break down for problems with strong nonlinearity. This book presents the current theoretical developments and applications of Keller-Box method to nonlinear problems. The first half of the bookaddresses basic concepts to understand the theoretical framework for the method. In the second half of the book, the authorsgive a number of examples of coupled nonlinear problems that have been solved

  8. Experimental design methods for bioengineering applications.

    Science.gov (United States)

    Keskin Gündoğdu, Tuğba; Deniz, İrem; Çalışkan, Gülizar; Şahin, Erdem Sefa; Azbar, Nuri

    2016-01-01

    Experimental design is a form of process analysis in which certain factors are selected to obtain the desired responses of interest. It may also be used for the determination of the effects of various independent factors on a dependent factor. The bioengineering discipline includes many different areas of scientific interest, and each study area is affected and governed by many different factors. Briefly analyzing the important factors and selecting an experimental design for optimization are very effective tools for the design of any bioprocess under question. This review summarizes experimental design methods that can be used to investigate various factors relating to bioengineering processes. The experimental methods generally used in bioengineering are as follows: full factorial design, fractional factorial design, Plackett-Burman design, Taguchi design, Box-Behnken design and central composite design. These design methods are briefly introduced, and then the application of these design methods to study different bioengineering processes is analyzed.

  9. Surgical navigation with QR codes

    Directory of Open Access Journals (Sweden)

    Katanacho Manuel

    2016-09-01

    Full Text Available The presented work is an alternative to established measurement systems in surgical navigation. The system is based on camera based tracking of QR code markers. The application uses a single video camera, integrated in a surgical lamp, that captures the QR markers attached to surgical instruments and to the patient.

  10. Personal navigation method based on foot-mounted MEMS inertial/magnetic measurement unit%光电跟踪模型噪声卡尔曼滤波算法

    Institute of Scientific and Technical Information of China (English)

    王秋平; 李凤; 马春林

    2012-01-01

    为减小滤波性能对跟踪目标状态空间模型噪声的敏感性,提出一种基于新息同时更新系统噪声方差和测量噪声方差方法,并将其与非线性卡尔曼滤波类算法相结合,构成一类适用于光电跟踪目标的自适应非线性卡尔曼滤波算法.同时将此方法应用到非线性测量光电跟踪系统中,并与扩展卡尔曼滤波和U卡尔曼滤波进行性能对比.仿真实验结果证明该方法可以实时调整系统噪声方差和测量噪声方差,有效地避免由于系统模型噪声统计特性不准确所带来的滤波性能下降的问题,而且其性能明显优于扩展卡尔曼滤波和U卡尔曼滤波.%In order to relieve the dependence of personal navigation on global navigation satellite system (GNSS), a personal navigation method was studied based on foot-mounted MEMS inertial/ magnetic measurement unit. Navigation information including attitude, velocity and position was obtained through the data from MEMS inertial measurement unit and strapdown inertial navigation algorithm. The azimuth of the navigation system was obtained by magnetic sensors. The errors of MEMS inertial navigation system and random errors of inertial sensors were modified by applying gait phase detection and zero-velocity update, so that the accumulate speed of the positioning errors was slowed down. The navigation experiment result shows that, the navigation errors of straight line and rectangle route retain about 2 m and 6 m during about 9 minutes' walking. The errors take up 1.1% and 2.5% of the whole distances of walking respectively. The experiment conclusion proves that the proposed method can effectively improve the positioning precision of personal navigation system, and can achieve personal positioning for longer time under the environment that GNSS signal is attenuated or become failure.

  11. Autonomous Deep-Space Optical Navigation Project

    Science.gov (United States)

    D'Souza, Christopher

    2014-01-01

    This project will advance the Autonomous Deep-space navigation capability applied to Autonomous Rendezvous and Docking (AR&D) Guidance, Navigation and Control (GNC) system by testing it on hardware, particularly in a flight processor, with a goal of limited testing in the Integrated Power, Avionics and Software (IPAS) with the ARCM (Asteroid Retrieval Crewed Mission) DRO (Distant Retrograde Orbit) Autonomous Rendezvous and Docking (AR&D) scenario. The technology, which will be harnessed, is called 'optical flow', also known as 'visual odometry'. It is being matured in the automotive and SLAM (Simultaneous Localization and Mapping) applications but has yet to be applied to spacecraft navigation. In light of the tremendous potential of this technique, we believe that NASA needs to design a optical navigation architecture that will use this technique. It is flexible enough to be applicable to navigating around planetary bodies, such as asteroids.

  12. Mobile Augmented Reality enhances indoor navigation for wheelchair users

    Directory of Open Access Journals (Sweden)

    Luciene Chagas de Oliveira

    Full Text Available Introduction: Individuals with mobility impairments associated with lower limb disabilities often face enormous challenges to participate in routine activities and to move around various environments. For many, the use of wheelchairs is paramount to provide mobility and social inclusion. Nevertheless, they still face a number of challenges to properly function in our society. Among the many difficulties, one in particular stands out: navigating in complex internal environments (indoors. The main objective of this work is to propose an architecture based on Mobile Augmented Reality to support the development of indoor navigation systems dedicated to wheelchair users, that is also capable of recording CAD drawings of the buildings and dealing with accessibility issues for that population. Methods Overall, five main functional requirements are proposed: the ability to allow for indoor navigation by means of Mobile Augmented Reality techniques; the capacity to register and configure building CAD drawings and the position of fiducial markers, points of interest and obstacles to be avoided by the wheelchair user; the capacity to find the best route for wheelchair indoor navigation, taking stairs and other obstacles into account; allow for the visualization of virtual directional arrows in the smartphone displays; and incorporate touch or voice commands to interact with the application. The architecture is proposed as a combination of four layers: User interface; Control; Service; and Infrastructure. A proof-of-concept application was developed and tests were performed with disable volunteers operating manual and electric wheelchairs. Results The application was implemented in Java for the Android operational system. A local database was used to store the test building CAD drawings and the position of fiducial markers and points of interest. The Android Augmented Reality library was used to implement Augmented Reality and the Blender open source

  13. Collaborative WiFi Fingerprinting Using Sensor-Based Navigation on Smartphones

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2015-07-01

    Full Text Available This paper presents a method that trains the WiFi fingerprint database using sensor-based navigation solutions. Since micro-electromechanical systems (MEMS sensors provide only a short-term accuracy but suffer from the accuracy degradation with time, we restrict the time length of available indoor navigation trajectories, and conduct post-processing to improve the sensor-based navigation solution. Different middle-term navigation trajectories that move in and out of an indoor area are combined to make up the database. Furthermore, we evaluate the effect of WiFi database shifts on WiFi fingerprinting using the database generated by the proposed method. Results show that the fingerprinting errors will not increase linearly according to database (DB errors in smartphone-based WiFi fingerprinting applications.

  14. Collaborative WiFi Fingerprinting Using Sensor-Based Navigation on Smartphones.

    Science.gov (United States)

    Zhang, Peng; Zhao, Qile; Li, You; Niu, Xiaoji; Zhuang, Yuan; Liu, Jingnan

    2015-07-20

    This paper presents a method that trains the WiFi fingerprint database using sensor-based navigation solutions. Since micro-electromechanical systems (MEMS) sensors provide only a short-term accuracy but suffer from the accuracy degradation with time, we restrict the time length of available indoor navigation trajectories, and conduct post-processing to improve the sensor-based navigation solution. Different middle-term navigation trajectories that move in and out of an indoor area are combined to make up the database. Furthermore, we evaluate the effect of WiFi database shifts on WiFi fingerprinting using the database generated by the proposed method. Results show that the fingerprinting errors will not increase linearly according to database (DB) errors in smartphone-based WiFi fingerprinting applications.

  15. A New Navigation Strategy in Hypermedia Integral Ware Authoring System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    After analyzing the general navigation mechanisms and discussing the knowledge point card linking model which is the base of the navigation mechanism used in the Hypermedia Integral ware Authoring System(HIAS), the paper presents a new navigation strategy in HIAS. And the application trend of HIAS is discussed at last.

  16. A Situational Implementation Method for Web-based Content Management System-applications: Method Engineering and Validation in Practice

    NARCIS (Netherlands)

    Weerd, I. van de; Brinkkemper, S.; Souer, J.; Versendaal, J.M.

    2006-01-01

    The usage of data-intensive web applications raises problems concerning consistency, navigation, and data duplication. Content management systems (CMSs) can overcome these problems. In this research, we focus on special types ofweb contentmanagement systems – webbased CMS applications. Currently, no

  17. Design and Algorithm Verification of a Gyroscope-Based Inertial Navigation System for Small-Diameter Spaces in Multilateral Horizontal Drilling Applications

    Directory of Open Access Journals (Sweden)

    Tao Li

    2015-12-01

    Full Text Available In the recent years horizontal drilling (HD has become increasingly important in oil and gas exploration because it can increase the production per well and can effectively rework old and marginal vertical wells. The key element of successful HD is accurate navigation of the drill bit with advanced measurement-while-drilling (MWD tools. The size of the MWD tools is not significantly restricted in vertical wells because there is enough space for their installation in traditional well drilling, but the diameter of devices for HD must be restricted to less than 30 mm for some applications, such as lateral drilling from existing horizontal wells. Therefore, it is essential to design miniature devices for lateral HD applications. Additionally, magnetometers in traditional MWD devices are easily susceptible to complex downhole interferences, and gyroscopes have been previously suggested as the best avenue to replace magnetometers for azimuth measurements. The aim of this paper is to propose a miniature gyroscope-based MWD system which is referred to as miniature gyroscope-based while drilling (MGWD system. A prototype of such MGWD system is proposed. The device consists of a two-axis gyroscope and a three-axis accelerometer. Miniaturization design approaches for MGWD are proposed. In addition, MGWD data collection software is designed to provide real-time data display and navigation algorithm verification. A fourth-order autoregressive (AR model is introduced for stochastic noise modeling of the gyroscope and the accelerometer data. Zero velocity and position are injected into a Kalman filter as a system reference to update system states, which can effectively improve the state observability of the MGWD system and decrease estimation errors. Nevertheless, the azimuth of the proposed MGWD system is not observable in the Kalman filter, and reliable azimuth estimation remains a problem.

  18. STEPPING - Smartphone-Based Portable Pedestrian Indoor Navigation

    Science.gov (United States)

    Lukianto, C.; Sternberg, H.

    2011-12-01

    Many current smartphones are fitted with GPS receivers, which, in combination with a map application form a pedestrian navigation system for outdoor purposes. However, once an area with insufficient satellite signal coverage is entered, these navigation systems cease to function. For indoor positioning, there are already several solutions available which are usually based on measured distances to reference points. These solutions can achieve resolutions as low as the sub-millimetre range depending on the complexity of the set-up. STEPPING project, developed at HCU Hamburg Germany aims at designing an indoor navigation system consisting of a small inertial navigation system and a new, robust sensor fusion algorithm running on a current smartphone. As this system is theoretically able to integrate any available positioning method, it is independent of a particular method and can thus be realized on a smartphone without affecting user mobility. Potential applications include --but are not limited to: Large trade fairs, airports, parking decks and shopping malls, as well as ambient assisted living scenarios.

  19. Welcome to Methods and Applications in Fluorescence

    Science.gov (United States)

    Birch, David; Mély, Yves; Wolfbeis, Otto S.

    2013-03-01

    On behalf of the Editorial Board of Methods and Applications in Fluorescence and IOP Publishing we are delighted to invite you to read the first articles in our new journal. Methods and Applications in Fluorescence is forged out of the renowned MAF conference series of the same name and we fully expect the natural synergy between the two to provide the ideal platform for moving the field of fluorescence forward. Our aim is for this new journal to reflect the truly global and diverse impact fluorescence is having across many disciplines and help fluorescence achieve its full potential. Just as MAF is the leading conference in fluorescence we are confident of the high impact of this new journal. Methods and Applications in Fluorescence has a distinguished Editorial Board that is drawn from the MAF conference Permanent Steering Committee. Together with the Editorial Board and the rest of the community, the journal will closely track the very latest developments in fluorescence while delivering a fair and constructive review process. We are very pleased that this journal is backed by the Institute of Physics, one of the world's premier learned societies. IOP Publishing has a wealth of experience in science publishing that dates back to 1874. It is a not-for-profit organization that publishes over 60 journals, many on multidisciplinary topics and many including seminal contributions from Nobel Laureates. Any funding surplus generated by IOP Publishing goes directly back into science through the Institute of Physics, thus helping to nurture science for future generations. We invite submissions as regular articles, review articles and technical notes within the scope of the journal, which includes all the major aspects of fluorescence. This covers both theory and experiment across spectroscopy, imaging, materials, labels, probes and sensors. The applications of fluorescence to emerging areas in bionanotechnology, nanotechnology and medicine are very much part of the

  20. Capacitance Measurement Methods for Integrated Sensor Applications

    Directory of Open Access Journals (Sweden)

    Alireza Hassanzadeh

    2013-09-01

    Full Text Available In this paper different measurement methods that have been used for integrated capacitance measurement are reviewed and their advantage and disadvantages are discussed. For the designers of high accuracy on chip integrated circuits for capacitive sensors, it is important to know which method will provide the best approach for high accuracy, small chip area and power consumption especially for array sensors. These methods include on chip capacitive sensor and transducer measurement techniques that have been implemented for low value capacitance evaluations using CMOS technology. After the best structure is known the designer can optimize the chip for specific application. Voltage mode and current mode, linear and switched mode techniques are reviewed and a useful comparison table comparing all figures of merit including accuracy, range of measurement, chip area, speed and complexity is provided. The provided comparison table can be used as a reference for analog designers in the design of high accuracy integrated capacitive sensor interface

  1. Observability of Inertial Navigation System

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To improve the observability of strapdown inertial navigation system and the effectiveness of Kalman filter in the navigation system, the method of estimating the observability is analyzed based on eigenvalues and eigenvectors which are proved to be availabe, on this basis two-position alignment technigue is applied. The simulation shows that two-position alignment really makes the system's observability change from being incomplete to being complete, and the test method based on eigenvalues and eigenvectors is available to determine the observability of every state vector.

  2. Daytime Celestial Navigation for the Novice

    Science.gov (United States)

    Sadler, Philip M.; Night, Christopher

    2010-03-01

    What kinds of astronomical lab activities can high school and college astronomy students carry out easily in daytime? The most impressive is the determination of latitude and longitude from observations of the Sun. The ``shooting of a noon sight'' and its ``reduction to a position'' grew to become a daily practice at the start of the 19th century1 following the perfection of the marine chronometer by John Harrison and its mass production.2 This technique is still practiced by navigators in this age of GPS. Indeed, the U.S. Coast Guard exams for ocean-going licenses include celestial navigation.3 These techniques continue to be used by the military and by private sailors as a backup to all-too-fallible and jammable electronic navigation systems. A sextant, a nautical almanac,4 special sight reduction tables,5 and involved calculations are needed to determine position to the nearest mile using the Sun, Moon, stars, or planets. Yet, finding latitude and longitude to better than 30 miles from measurements of the Sun's altitude is easily within the capability of those taking astronomy or physics for the first time by applying certain basic principles. Moreover, it shows a practical application of astronomy in use the world over. The streamlined method described here takes advantage of the similar level of accuracy of its three components: 1.Observations using a homemade quadrant6 (instead of a sextant), 2. Student-made graphs of the altitude of the Sun over a day7 (replacing lengthy calculation using sight reduction tables), and 3. An averaged 20-year analemma used to find the Sun's navigational coordinates8,9 (rather than the 300+ page Nautical Almanac updated yearly).

  3. Big data analytics methods and applications

    CERN Document Server

    Rao, BLS; Rao, SB

    2016-01-01

    This book has a collection of articles written by Big Data experts to describe some of the cutting-edge methods and applications from their respective areas of interest, and provides the reader with a detailed overview of the field of Big Data Analytics as it is practiced today. The chapters cover technical aspects of key areas that generate and use Big Data such as management and finance; medicine and healthcare; genome, cytome and microbiome; graphs and networks; Internet of Things; Big Data standards; bench-marking of systems; and others. In addition to different applications, key algorithmic approaches such as graph partitioning, clustering and finite mixture modelling of high-dimensional data are also covered. The varied collection of themes in this volume introduces the reader to the richness of the emerging field of Big Data Analytics.

  4. Stein's method in high dimensions with applications

    CERN Document Server

    Röllin, Adrian

    2011-01-01

    Let $h$ be a three times partially differentiable function on $R^n$, let $X=(X_1,\\dots,X_n)$ be a collection of real-valued random variables and let $Z=(Z_1,\\dots,Z_n)$ be a multivariate Gaussian vector. In this article, we develop Stein's method to give error bounds on the difference $E h(X) - E h(Z)$ in cases where the coordinates of $X$ are not necessarily independent, focusing on the high dimensional case $n\\to\\infty$. In order to express the dependency structure we use Stein couplings, which allows for a broad range of applications, such as classic occupancy, local dependence, Curie-Weiss model etc. We will also give applications to the Sherrington-Kirkpatrick model and last passage percolation on thin rectangles.

  5. Nested partitions method, theory and applications

    CERN Document Server

    Shi, Leyuan

    2009-01-01

    There is increasing need to solve large-scale complex optimization problems in a wide variety of science and engineering applications, including designing telecommunication networks for multimedia transmission, planning and scheduling problems in manufacturing and military operations, or designing nanoscale devices and systems. Advances in technology and information systems have made such optimization problems more and more complicated in terms of size and uncertainty. Nested Partitions Method, Theory and Applications provides a cutting-edge research tool to use for large-scale, complex systems optimization. The Nested Partitions (NP) framework is an innovative mix of traditional optimization methodology and probabilistic assumptions. An important feature of the NP framework is that it combines many well-known optimization techniques, including dynamic programming, mixed integer programming, genetic algorithms and tabu search, while also integrating many problem-specific local search heuristics. The book uses...

  6. Application of Formal Methods in Software Engineering

    Directory of Open Access Journals (Sweden)

    Adriana Morales

    2011-12-01

    Full Text Available The purpose of this research work is to examine: (1 why are necessary the formal methods for software systems today, (2 high integrity systems through the methodology C-by-C –Correctness-by-Construction–, and (3 an affordable methodology to apply formal methods in software engineering. The research process included reviews of the literature through Internet, in publications and presentations in events. Among the Research results found that: (1 there is increasing the dependence that the nations have, the companies and people of software systems, (2 there is growing demand for software Engineering to increase social trust in the software systems, (3 exist methodologies, as C-by-C, that can provide that level of trust, (4 Formal Methods constitute a principle of computer science that can be applied software engineering to perform reliable process in software development, (5 software users have the responsibility to demand reliable software products, and (6 software engineers have the responsibility to develop reliable software products. Furthermore, it is concluded that: (1 it takes more research to identify and analyze other methodologies and tools that provide process to apply the Formal Software Engineering methods, (2 Formal Methods provide an unprecedented ability to increase the trust in the exactitude of the software products and (3 by development of new methodologies and tools is being achieved costs are not more a disadvantage for application of formal methods.

  7. Optical Navigation System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for a flexible navigation system for deep space operations that does not require GPS measurements. The navigation solution is computed using an...

  8. Optical Navigation System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for a flexible navigation system for deep space operations that does not require GPS measurements. The navigation solution is computed using an...

  9. Long-code Signal Waveform Monitoring Method for Navigation Satellites%卫星导航长码信号波形监测方法

    Institute of Scientific and Technical Information of China (English)

    刘建成; 王宇; 宫磊; 徐晓燕

    2016-01-01

    Due to the weakness of signal,signal waveform monitoring for navigation satellites in orbit is one of the difficulties in satellite navigation signal quality monitoring research,so a signal waveform monitoring method for navigation satellites in orbit is pro⁃posed.Based on the Vernier sampling principle,a large⁃diameter parabolic antenna is used for in⁃orbit satellite signal collection.After in⁃itial phase and residual frequency elimination,accumulation and combination,a clear chip waveform is obtained.For civilian and long⁃code signals with the same code rate,the PN code phase bias can be determined.By using a large⁃diameter parabolic antenna for COM⁃PASS satellite tracking,the civilian and long⁃code chip waveforms of several COMPASS satellites in B1 band are obtained,and the PN code phase bias of the satellite signals are got.The results show that there is little difference between the civilian signal waveform and long⁃code signal waveform,but there is a code phase bias between them.%由于信号微弱,如何获得在轨导航卫星的清晰信号波形是卫星导航信号质量监测研究中的难点之一,为此提出了一种在轨导航卫星的信号波形监测方法。该方法基于Vernier采样原理,利用大口径抛物面天线对在轨卫星进行信号采集,经过消除初相和残余频率、累加平均和数据组合等处理,获得清晰的码片波形。对于相同码速率的民用信号和长码信号,可确定民用信号和长码信号的伪码相位偏差。利用大口径抛物面天线对北斗卫星进行跟踪,获得了多颗北斗卫星B1频点民用信号和长码信号的码片波形。结果表明,民用信号和长码信号的码片波形的轮廓差异较小,但伪码相位存在偏差。

  10. Personal Navigation Algorithms Based on Wireless Networks and Inertial Sensors

    Science.gov (United States)

    Kaňa, Zdenek; Bradáč, Zdenek; Fiedler, Petr

    2014-08-01

    The work aims at a development of positioning algorithm suitable for low-cost indoor or urban pedestrian navigation application. The sensor fusion was applied to increase the localization accuracy. Due to required low application cost only low grade inertial sensors and wireless network based ranging were taken into account. The wireless network was assumed to be preinstalled due to other required functionality (for example: building control) therefore only received signal strength (RSS) range measurement technique was considered. Wireless channel loss mapping method was proposed to overcome the natural uncertainties and restrictions in the RSS range measurements The available sensor and environment models are summarized first and the most appropriate ones are selected secondly. Their effective and novel application in the navigation task, and favorable fusion (Particle filtering) of all available information are the main objectives of this thesis.

  11. Restricted Kalman Filtering Theory, Methods, and Application

    CERN Document Server

    Pizzinga, Adrian

    2012-01-01

    In statistics, the Kalman filter is a mathematical method whose purpose is to use a series of measurements observed over time, containing random variations and other inaccuracies, and produce estimates that tend to be closer to the true unknown values than those that would be based on a single measurement alone. This Brief offers developments on Kalman filtering subject to general linear constraints. There are essentially three types of contributions: new proofs for results already established; new results within the subject; and applications in investment analysis and macroeconomics, where th

  12. Exergy method technical and ecological applications

    CERN Document Server

    Szargut, J

    2005-01-01

    The exergy method makes it possible to detect and quantify the possibilities of improving thermal and chemical processes and systems. The introduction of the concept ""thermo-ecological cost"" (cumulative consumption of non-renewable natural exergy resources) generated large application possibilities of exergy in ecology. This book contains a short presentation on the basic principles of exergy analysis and discusses new achievements in the field over the last 15 years. One of the most important issues considered by the distinguished author is the economy of non-renewable natural exergy.

  13. Applicable methods for NDT of tubes

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, J.; Lipponen, A.; Kauppinen, P. [VTT Industrial Systems Espoo (Finland)

    2004-05-01

    For inside inspection of tubes, eddy current testing (ET) and internal rotating ultrasonic inspection (IRIS) are mainly used at the moment. Special eddy current method, remote field technique (RFEC) is being used to some extent, but normally only for ferritic tubes. This paper presents a review of techniques that can be used for internal inspections of tubes in boilers, heat exchangers and steam generators. Material affects the choice of the method, considering given defect type and detectability with the selected technique. In general ET methods are used for inspection of non- ferromagnetic tubes and IRIS and RFEC methods for inspection of ferromagnetic tubes. New techniques have been introduced, to determine the tube condition accurately. One of the developed techniques is for instance inspection of the internal surface by combination of dye penetrant and optical laser inspection. New applications of ultrasonic techniques include defect detection and characterisation by tip diffraction echoes, defect analysis by echo dynamics and the TOFD-technique for defect sizing. Ultrasonic guided waves have a great potential to increase inspection speed for defect detection, although sizing is still under development. For inspection of ferromagnetic tubes, a method based on magnetic flux leakage has been used. In addition to the basic techniques visualisation of the measured data is one of the. key factors for improved exploitation of the inspection results. (orig.)

  14. Intelligent numerical methods applications to fractional calculus

    CERN Document Server

    Anastassiou, George A

    2016-01-01

    In this monograph the authors present Newton-type, Newton-like and other numerical methods, which involve fractional derivatives and fractional integral operators, for the first time studied in the literature. All for the purpose to solve numerically equations whose associated functions can be also non-differentiable in the ordinary sense. That is among others extending the classical Newton method theory which requires usual differentiability of function. Chapters are self-contained and can be read independently and several advanced courses can be taught out of this book. An extensive list of references is given per chapter. The book’s results are expected to find applications in many areas of applied mathematics, stochastics, computer science and engineering. As such this monograph is suitable for researchers, graduate students, and seminars of the above subjects, also to be in all science and engineering libraries.

  15. A Toolbox of Aiding Techniques for the HUGIN AUV Integrated Inertial Navigation System

    Directory of Open Access Journals (Sweden)

    Bjørn Jalving

    2004-07-01

    Full Text Available Modern AUV designs must handle submerged autonomous operation for long periods of time. The state of the art solution embedded in the HUGIN AUVs is a Doppler Velocity Log (DVL aided Inertial Navigation System (INS that can integrate various forms of position measurement updates. In autonomous operations, position updates are only available in limited periods of time or space, thus the core velocity aided inertial navigation system must exhibit high accuracy However, position uncertainty of a DVL aided inertial navigation system will eventually drift off, compromising either mission operation or requirements for accurate positioning of payload data. To meet the requirements for a range of military and civilian AUV applications, the HUGIN vehicles come with a flexible and powerful set of navigation techniques. Methods for position updates include GPS surface fix, DGPS-USBL, Underwater Transponder Positioning (UTP and bathymetric terrain navigation. Based on synthetic aperture sonar technology, a potentially revolutionary accurate velocity measurement is under development. HUGIN also comes with a navigation post-processing system (NavLab, which can be applied to increase navigational integrity and maximize position accuracy.

  16. Learning for Autonomous Navigation

    Science.gov (United States)

    Angelova, Anelia; Howard, Andrew; Matthies, Larry; Tang, Benyang; Turmon, Michael; Mjolsness, Eric

    2005-01-01

    Robotic ground vehicles for outdoor applications have achieved some remarkable successes, notably in autonomous highway following (Dickmanns, 1987), planetary exploration (1), and off-road navigation on Earth (1). Nevertheless, major challenges remain to enable reliable, high-speed, autonomous navigation in a wide variety of complex, off-road terrain. 3-D perception of terrain geometry with imaging range sensors is the mainstay of off-road driving systems. However, the stopping distance at high speed exceeds the effective lookahead distance of existing range sensors. Prospects for extending the range of 3-D sensors is strongly limited by sensor physics, eye safety of lasers, and related issues. Range sensor limitations also allow vehicles to enter large cul-de-sacs even at low speed, leading to long detours. Moreover, sensing only terrain geometry fails to reveal mechanical properties of terrain that are critical to assessing its traversability, such as potential for slippage, sinkage, and the degree of compliance of potential obstacles. Rovers in the Mars Exploration Rover (MER) mission have got stuck in sand dunes and experienced significant downhill slippage in the vicinity of large rock hazards. Earth-based off-road robots today have very limited ability to discriminate traversable vegetation from non-traversable vegetation or rough ground. It is impossible today to preprogram a system with knowledge of these properties for all types of terrain and weather conditions that might be encountered.

  17. New color segmentation method and its applications

    Science.gov (United States)

    Wang, Jian

    1999-01-01

    Segmentation is an important step in the early stage of image analysis. Color or multi-spectral image segmentation usually involves search and clustering techniques in a three or higher dimensional spectral space - an exercise which is considered computationally expensive. This paper presents a new color segmentation method for color image analysis with its application to plant leaf area measurement. A 3D histogram for an RGB color image is established basing on an octree data structure. The histogram represents the color distribution of the image in the RGB color space on which a 3D Gaussian filter is applied to smooth out small maxima of this distribution. The color space is then searched to find out al the major maxima. Around each maxima, a covering cube with a controlled side width is established. These maxima and covering cubes are considered to be potential color classes. Each cube may expand according to the value of surrounding neighbors. Once enough modes and their cover cubes have been found, a k-means clustering algorithm is used to classify these maxima into a predetermined number of classes. Then, the classified modes and the color covered by the cubes are used as training samples for a Bayes classifier which can be used to classify all the pixels in the image. A statistical relaxation method is then sued as a find segmentation. This method can either be supervised or unsupervised, depending on the different requirements of specific applications. The octree data structure significantly reduces the color space to be searched and consequently reduces computational cost. An extension of this method can also be applied to multi-spectral image analysis.

  18. Application of Hydrocyclone and UV Radiation as a Ballast Water Treatment Method

    Directory of Open Access Journals (Sweden)

    Željko Kurtela

    2010-05-01

    Full Text Available The ballast water exchange methods in open sea are, for the time being, the prevailing procedures accepted by shipowners. However, such methods do not guarantee full efficacy in elimination of allochthonous organisms. Besides, in some navigation zones, in particular in the closed seas, not even the criteria prescribed by international regulations can be fulfilled, i.e. the position of a ship exchanging ballast must be farther than 200Nm from the shore (alternatively 50Nm at the sea depth exceeding 200m. Numerous research attempts on various treatment methods lead to the conclusion that there is still no scientific opinion on the final choice of methods for wide application on board. The treatment methods, such as hydrocyclone separation in the first stage and UV radiation in the second stage, stand a good chance for application on board. Advantages of such a combined method are in the very application of treatment that can be performed during all stages of ballast water treatment, i.e. loading ballast, voyage in ballast and discharging ballast. In closed seas and on shorter routes the operational advantages of hydrocyclone and UV radiation could be the prevailing factor for application. Within the research on the possible application of ballast water treatment by hydrocyclone and UV radiation, a pilot plant with hydrocyclone cluster and UV device was constructed. The research carried out on the pilot plant installed on board the m/v ‘’Naše more’’ proved the effectiveness of such ballast water treatment method and offered a new approach in using hydrocyclone for the inactivation of organisms by hydrodynamic forces. This approach has largely increased the efficacy of the device and a new method for utilization of hydrocyclone in ballast water treatment on board has been discovered. KEY WORDS: ballast water treatment, hydrocyclone, UV radiation, application of method, pilot plant, hydrodynamic forces

  19. Direct navigation on 3D rotational x-ray data acquired with a mobile propeller C-arm: accuracy and application in functional endoscopic sinus surgery.

    Science.gov (United States)

    van de Kraats, Everine B; Carelsen, Bart; Fokkens, Wytske J; Boon, Sjirk N; Noordhoek, Niels; Niessen, Wiro J; van Walsum, Theo

    2005-12-21

    Recently, three-dimensional (3D) rotational x-ray imaging has been combined with navigation technology, enabling direct 3D navigation for minimally invasive image guided interventions. In this study, phantom experiments are used to determine the accuracy of such a navigation set-up for a mobile C-arm with propeller motion. After calibration of the C-arm system, the accuracy is evaluated by pinpointing divots on a special-purpose phantom with known geometry. This evaluation is performed both with and without C-arm motion in between calibration and registration for navigation. The variation caused by each of the individual transformations in the calibration and registration process is also studied. The feasibility of direct navigation on 3D rotational x-ray images for functional endoscopic sinus surgery has been evaluated in a cadaver navigation experiment. Navigation accuracy was approximately 1.0 mm, which is sufficient for functional endoscopic sinus surgery. C-arm motion in between calibration and registration slightly degraded the registration accuracy by approximately 0.3 mm. Standard deviations of each of the transformations were in the range 0.15-0.31 mm. In the cadaver experiment, the navigation images were considered in good correspondence with the endoscopic images by an experienced ENT surgeon. Availability of 3D localization information provided by the navigation system was considered valuable by the ENT surgeon.

  20. Direct navigation on 3D rotational x-ray data acquired with a mobile propeller C-arm: accuracy and application in functional endoscopic sinus surgery

    Science.gov (United States)

    van de Kraats, Everine B.; Carelsen, Bart; Fokkens, Wytske J.; Boon, Sjirk N.; Noordhoek, Niels; Niessen, Wiro J.; van Walsum, Theo

    2005-12-01

    Recently, three-dimensional (3D) rotational x-ray imaging has been combined with navigation technology, enabling direct 3D navigation for minimally invasive image guided interventions. In this study, phantom experiments are used to determine the accuracy of such a navigation set-up for a mobile C-arm with propeller motion. After calibration of the C-arm system, the accuracy is evaluated by pinpointing divots on a special-purpose phantom with known geometry. This evaluation is performed both with and without C-arm motion in between calibration and registration for navigation. The variation caused by each of the individual transformations in the calibration and registration process is also studied. The feasibility of direct navigation on 3D rotational x-ray images for functional endoscopic sinus surgery has been evaluated in a cadaver navigation experiment. Navigation accuracy was approximately 1.0 mm, which is sufficient for functional endoscopic sinus surgery. C-arm motion in between calibration and registration slightly degraded the registration accuracy by approximately 0.3 mm. Standard deviations of each of the transformations were in the range 0.15-0.31 mm. In the cadaver experiment, the navigation images were considered in good correspondence with the endoscopic images by an experienced ENT surgeon. Availability of 3D localization information provided by the navigation system was considered valuable by the ENT surgeon.

  1. Direct navigation on 3D rotational x-ray data acquired with a mobile propeller C-arm: accuracy and application in functional endoscopic sinus surgery

    Energy Technology Data Exchange (ETDEWEB)

    Kraats, Everine B van de [Image Sciences Institute, University Medical Center Utrecht (Netherlands); Carelsen, Bart [Academic Medical Center Amsterdam, Medical Physics Department (Netherlands); Fokkens, Wytske J [Academic Medical Center Amsterdam, Department of Otorhinolaryngology (Netherlands); Boon, Sjirk N [Philips Medical Systems, Best (Netherlands); Noordhoek, Niels [Philips Medical Systems, Best (Netherlands); Niessen, Wiro J [Image Sciences Institute, University Medical Center Utrecht (Netherlands); Walsum, Theo van [Image Sciences Institute, University Medical Center Utrecht (Netherlands)

    2005-12-21

    Recently, three-dimensional (3D) rotational x-ray imaging has been combined with navigation technology, enabling direct 3D navigation for minimally invasive image guided interventions. In this study, phantom experiments are used to determine the accuracy of such a navigation set-up for a mobile C-arm with propeller motion. After calibration of the C-arm system, the accuracy is evaluated by pinpointing divots on a special-purpose phantom with known geometry. This evaluation is performed both with and without C-arm motion in between calibration and registration for navigation. The variation caused by each of the individual transformations in the calibration and registration process is also studied. The feasibility of direct navigation on 3D rotational x-ray images for functional endoscopic sinus surgery has been evaluated in a cadaver navigation experiment. Navigation accuracy was approximately 1.0 mm, which is sufficient for functional endoscopic sinus surgery. C-arm motion in between calibration and registration slightly degraded the registration accuracy by approximately 0.3 mm. Standard deviations of each of the transformations were in the range 0.15-0.31 mm. In the cadaver experiment, the navigation images were considered in good correspondence with the endoscopic images by an experienced ENT surgeon. Availability of 3D localization information provided by the navigation system was considered valuable by the ENT surgeon.

  2. 车辆视频导航中道路检测方法研究进展%Research progress on road detection method in video navigation for vehicle

    Institute of Scientific and Technical Information of China (English)

    高华; 刘济林

    2012-01-01

    视频导航以其获取信息丰富、对环境影响小、成本低廉等诸多优点成为了辅助车辆自动驾驶和陆地自主车( ALV)常用的一种自动导航方式,而从视频导航图像中检测出道路区域则是实现视频导航的基础和关键.对近年来车辆视频导航过程中道路检测的实现算法进行了回顾和分析,并对道路检测算法以后的研究方向进行了探讨.%Because of a great deal of advantages, such as more abundant acquired information, small influence on environment,low cost and etc,the video navigation has become a most common navigation method for vehicle. At the same time, road detection which means finding the road region from the navigation video is the basis and key of video navigation. The research of the road-detection from navigation video is summarized. The main problem and prospect of the road detection is discussed.

  3. Application of vortex method; Uzuho no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Tsukiji, T. [Ashikaga Inst. of Technology, Tochigi (Japan); Shimizu, S. [Hiroshima Univ., Hiroshima (Japan). Faculty of Engineering

    1995-07-15

    Basic jets such as two dimensional free jet, impact jet, axisymmetric circular free jet, and jet flowing out from a nozzle equipped with a collar at the outlet, as well as flow in such valves as disc valves, spool valves, and poppet valves are taken up to discuss their applications using the vortex method, and the results of studies made using vortex method on the analysis of jet and conditions inside valves are reported. The state of the development of large scale vortex structure in the shear layer can be simulated comparatively simply by using the vortex method. The effects of the radius and the lift of a valve on the fluid outlet angle of jet and on the discharge coefficient of orifice are analyzed. Although the shape of the spool valve near the throttle is very complicated, simplified models are used for numerical analysis. An example of calculated result in the case where the spool reciprocates is introduced. Actual vibrating phenomena can be simulated well by the vortex method for minute vibration of the poppet caused by the discharge of lump vortex. 17 refs., 16 figs., 1 tab.

  4. Quad-Rotor Helicopter Autonomous Navigation Based on Vanishing Point Algorithm

    Directory of Open Access Journals (Sweden)

    Jialiang Wang

    2014-01-01

    Full Text Available Quad-rotor helicopter is becoming popular increasingly as they can well implement many flight missions in more challenging environments, with lower risk of damaging itself and its surroundings. They are employed in many applications, from military operations to civilian tasks. Quad-rotor helicopter autonomous navigation based on the vanishing point fast estimation (VPFE algorithm using clustering principle is implemented in this paper. For images collected by the camera of quad-rotor helicopter, the system executes the process of preprocessing of image, deleting noise interference, edge extracting using Canny operator, and extracting straight lines by randomized hough transformation (RHT method. Then system obtains the position of vanishing point and regards it as destination point and finally controls the autonomous navigation of the quad-rotor helicopter by continuous modification according to the calculated navigation error. The experimental results show that the quad-rotor helicopter can implement the destination navigation well in the indoor environment.

  5. Radar and electronic navigation

    CERN Document Server

    Sonnenberg, G J

    2013-01-01

    Radar and Electronic Navigation, Sixth Edition discusses radar in marine navigation, underwater navigational aids, direction finding, the Decca navigator system, and the Omega system. The book also describes the Loran system for position fixing, the navy navigation satellite system, and the global positioning system (GPS). It reviews the principles, operation, presentations, specifications, and uses of radar. It also describes GPS, a real time position-fixing system in three dimensions (longitude, latitude, altitude), plus velocity information with Universal Time Coordinated (UTC). It is accur

  6. Navigation in spatial networks: A survey

    Science.gov (United States)

    Huang, Wei; Chen, Shengyong; Wang, Wanliang

    2014-01-01

    The study on the navigation process in spatial networks has attracted much attention in recent years due to the universal applications in real communication networks. This article surveys recent advances of the navigation problem in spatial networks. Due to the ability to overcome scaling limitations in utilizing geometric information for designing navigation algorithms in spatial networks, we summarize here several important navigation algorithms based on geometric information on both homogeneous and heterogeneous spatial networks. Due to the geometric distance employed, the cost associated with the lengths of additional long-range connections is also taken into account in this survey. Therefore, some contributions reporting how the distribution of long-range links’ lengths affects the average navigation time are summarized. We also briefly discuss two other related processes, i.e. the random walk process and the transportation process. Finally, a few open discussions are included at the end of this survey.

  7. Integrated Navigation System Design for Micro Planetary Rovers: Comparison of Absolute Heading Estimation Algorithms and Nonlinear Filtering.

    Science.gov (United States)

    Ilyas, Muhammad; Hong, Beomjin; Cho, Kuk; Baeg, Seung-Ho; Park, Sangdeok

    2016-05-23

    This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS) navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s) and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF) and Unscented Kalman filter (UKF) were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level.

  8. Integrated Navigation System Design for Micro Planetary Rovers: Comparison of Absolute Heading Estimation Algorithms and Nonlinear Filtering

    Directory of Open Access Journals (Sweden)

    Muhammad Ilyas

    2016-05-01

    Full Text Available This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF and Unscented Kalman filter (UKF were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level.

  9. Integrated Navigation System Design for Micro Planetary Rovers: Comparison of Absolute Heading Estimation Algorithms and Nonlinear Filtering

    Science.gov (United States)

    Ilyas, Muhammad; Hong, Beomjin; Cho, Kuk; Baeg, Seung-Ho; Park, Sangdeok

    2016-01-01

    This paper provides algorithms to fuse relative and absolute microelectromechanical systems (MEMS) navigation sensors, suitable for micro planetary rovers, to provide a more accurate estimation of navigation information, specifically, attitude and position. Planetary rovers have extremely slow speed (~1 cm/s) and lack conventional navigation sensors/systems, hence the general methods of terrestrial navigation may not be applicable to these applications. While relative attitude and position can be tracked in a way similar to those for ground robots, absolute navigation information is hard to achieve on a remote celestial body, like Moon or Mars, in contrast to terrestrial applications. In this study, two absolute attitude estimation algorithms were developed and compared for accuracy and robustness. The estimated absolute attitude was fused with the relative attitude sensors in a framework of nonlinear filters. The nonlinear Extended Kalman filter (EKF) and Unscented Kalman filter (UKF) were compared in pursuit of better accuracy and reliability in this nonlinear estimation problem, using only on-board low cost MEMS sensors. Experimental results confirmed the viability of the proposed algorithms and the sensor suite, for low cost and low weight micro planetary rovers. It is demonstrated that integrating the relative and absolute navigation MEMS sensors reduces the navigation errors to the desired level. PMID:27223293

  10. Computer navigation versus fluoroscopy-guided navigation for thoracic pedicle screw placement: a meta-analysis.

    Science.gov (United States)

    Meng, Xiao-Tong; Guan, Xiao-Fei; Zhang, Hai-Long; He, Shi-Sheng

    2016-07-01

    Although application of intraoperative computer navigation technique had been integrated into placement of pedicle screws (PSs) in thoracic fusion for years, its security and practicability remain controversial. The aim of this study is to evaluate the accuracy, the operative time consumption, the amount of intraoperative blood loss, time of pedicle insertion and the incidence of complications of thoracic pedicle screw placement in patients with thoracic diseases such as scoliosis and kyphosis. Pubmed, Web of Knowledge, and Google scholar were searched to identify comparative studies of thoracic pedicle screw placement between intraoperative computer navigation and fluoroscopy-guided navigation. Outcomes of malposition rate, operative time consumption, insertion time, intraoperative blood loss, and the incidence of complications are evaluated. Fourteen articles including 1723 patients and 9019 PSs were identified matching inclusion criteria. The malposition rate was lower (RR: 0.33, 95 % CI: 0.28-0.38, P navigation group than that in fluoroscopy-guided navigation group; the operative time was significantly longer [weighted mean difference (WMD) = 23.66, 95 % CI: 14.74-32.57, P navigation group than that in fluoroscopy-guided navigation group. The time of insertion was shorter (WMD = -1.88, 95 % CI: -2.25- -1.52, P navigation group than that in fluoroscopy-guided navigation group. The incidence of complications was lower (RR = 0. 23, 95 % CI: 0.12-0.46, P navigation group than that in the other group. The intraoperative blood loss was fewer (WMD = -167.49, 95 % CI: -266.39- -68.58, P navigation group than that in the other. In conclusion, the meta-analysis of thoracic pedicle screw placement studies clearly demonstrated lower malposition rate, less intraoperative blood loss, and fewer complications when using computer navigation. This result provides strong evidence that computer technology could be safer and more reliable than

  11. Low-Cost Navigation Sensors and Integration Technology (Capteurs de navigation a faible cout et technologie d’integration)

    Science.gov (United States)

    2010-03-01

    auditeurs soient informés sur les pratiques actuelles mais aussi sur les capteurs et leurs applications . Des orientations technologiques ont été...Mar 2010 Low-Cost Navigation Sensors and Integration Technology ( Capteurs de navigation à faible coût et technologie d’intégration) Research and...to-date with current practices, as well as, information on sensors, algorithms, and applications . Applications were described for navigating in

  12. 5th China Satellite Navigation Conference

    CERN Document Server

    Jiao, Wenhai; Wu, Haitao; Lu, Mingquan

    2014-01-01

    China Satellite Navigation Conference (CSNC) 2014 Proceedings presents selected research papers from CSNC2014, held on 21-23 May in Nanjing, China. The theme of CSNC2014 is 'BDS Application: Innovation, Integration and Sharing'. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 9 topics to match the corresponding sessions in CSNC2014, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.  SUN Jiadong is the Chief Designer of the Compass/ BDS, and the Academician of Chinese Academy of Sciences (CAS); JIAO Wenhai is a researcher at China Satellite Navigation Office; WU Haitao is a professor at Navigation Headquarters, CAS; LU Mingquan is a professor at Department of Electronic Engineering of Tsinghua University.

  13. Space Shuttle navigation validation

    Science.gov (United States)

    Ragsdale, A.

    The validation of the guidance, navigation, and control system of the Space Shuttle is explained. The functions of the ascent, on-board, and entry mission phases software of the navigation system are described. The common facility testing, which evaluates the simulations to be used in the navigation validation, is examined. The standard preflight analysis of the operational modes of the navigation software and the post-flight navigation analysis are explained. The conversion of the data into a useful reference frame and the use of orbit parameters in the analysis of the data are discussed. Upon entry the data received are converted to flags, ratios, and residuals in order to evaluate performance and detect errors. Various programs developed to support navigation validation are explained. A number of events that occurred with the Space Shuttle's navigation system are described.

  14. The driving methods of the autonomous navigated ultrasonic exploring car%超声探路车的自主导航行驶办法

    Institute of Scientific and Technical Information of China (English)

    张海鹰; 高艳丽; 张树团

    2011-01-01

    In order to increase the autonomous navigated capability of the intelligent car in absolute unknown environment,a method that using an ultrasonic sensor driven by a step motor for rotating detection is designed. It could get more exact and comprehensive environment information than the old ways. Base on this, several kinds of traveling methods including the tracking drive method are designed against different conditions. And also the setting values of the parameters and the relations between parameters in the system are analyzed. It makes the car can drive with high efficiency in ali environments.%为了加强智能车辆在全未知环境下的自主导航行驶能力,设计了使用步进电动机驱动小波束角超声传感器旋转探测的方法,获取了较以往相比更加全面准确地环境信息.在此基础上,针对不同的环境状况设计了包含循线行驶模式在内的多种行驶方法,并分析了在各种不同的行驶模式下系统相关参数的设置,和各参数之间的关系,使车辆在各类环境下都能保持较高的行驶效率.

  15. Autonomous Robot Navigation based on Visual Landmarks

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    autonomous navigation and self-localization using automatically selected landmarks. The thesis investigates autonomous robot navigation and proposes a new method which benefits from the potential of the visual sensor to provide accuracy and reliability to the navigation process while relying on naturally...... available environment features (natural landmarks). The goal is also to integrate techniques and algorithms (also related to other research field) in the same navigation system, in order to improve localization performance and system autonomy. The proposed localization strategy is based on a continuous...... update of the estimated robot position while the robot is moving. In order to make the system autonomous, both acquisition and observation of landmarks have to be carried out automatically. The thesis consequently proposes a method for learning and navigation of a working environment and it explores...

  16. Celestial navigation in a nutshell

    CERN Document Server

    Schlereth, Hewitt

    2000-01-01

    Celestial Navigation in a Nutshell demonstrates how to take sights by the sun, moon, stars, and planets, discussing the advantages and disadvantages of each method. The reader is taken carefully through several examples and situational illustrations, making this a most effective self-teaching guide. Common errors are reviewed and several tips on how to improve accuracy are given.

  17. Modelling the water mass exchange through navigational channels connecting adjacent coastal basins - application to the Channel of Potidea (North Aegean Sea

    Directory of Open Access Journals (Sweden)

    Y. G. Savvidis

    2005-02-01

    Full Text Available The research objective is the detection of the mechanism of the water mass exchange through a navigational channel connecting two adjacent coastal basins. The research involves the application of a mathematical model in parallel to in-situ measurements. The hydrodynamic circulation in the greater area of the NW Aegean Sea is modeled by means of a barotropic circulation model. Wind, Coriolis and Tide are the main forcings taken into account. The flow through the channel is resolved at a subgrid scale by means of a local open channel flow model. The comparison between field measurements, recorded during a limited period, and the model results supports the model verification. The study is integrated by an operational application of the model under various realistic forcings. The results help to gain a better understanding of the mechanisms regulating the water mass exchange and the consequent interaction between two adjacent connected coastal basins. From the case study of the Potidea channel it is revealed that the water mass exchange under mean wind forcing is of the same order as the one induced by the tidal forcing.

  18. Enabling Persistent Autonomy for Underwater Gliders with Ocean Model Predictions and Terrain Based Navigation

    Directory of Open Access Journals (Sweden)

    Andrew eStuntz

    2016-04-01

    Full Text Available Effective study of ocean processes requires sampling over the duration of long (weeks to months oscillation patterns. Such sampling requires persistent, autonomous underwater vehicles, that have a similarly long deployment duration. The spatiotemporal dynamics of the ocean environment, coupled with limited communication capabilities, make navigation and localization difficult, especially in coastal regions where the majority of interesting phenomena occur. In this paper, we consider the combination of two methods for reducing navigation and localization error; a predictive approach based on ocean model predictions and a prior information approach derived from terrain-based navigation. The motivation for this work is not only for real-time state estimation, but also for accurately reconstructing the actual path that the vehicle traversed to contextualize the gathered data, with respect to the science question at hand. We present an application for the practical use of priors and predictions for large-scale ocean sampling. This combined approach builds upon previous works by the authors, and accurately localizes the traversed path of an underwater glider over long-duration, ocean deployments. The proposed method takes advantage of the reliable, short-term predictions of an ocean model, and the utility of priors used in terrain-based navigation over areas of significant bathymetric relief to bound uncertainty error in dead-reckoning navigation. This method improves upon our previously published works by 1 demonstrating the utility of our terrain-based navigation method with multiple field trials, and 2 presenting a hybrid algorithm that combines both approaches to bound navigational error and uncertainty for long-term deployments of underwater vehicles. We demonstrate the approach by examining data from actual field trials with autonomous underwater gliders, and demonstrate an ability to estimate geographical location of an underwater glider to 2

  19. The Performance Analysis of Space Resection-Aided Pedestrian Dead Reckoning for Smartphone Navigation in a Mapped Indoor Environment

    Directory of Open Access Journals (Sweden)

    Kai-Wei Chiang

    2017-02-01

    Full Text Available Smartphones have become indispensable in our daily lives. Their various embedded sensors have inspired innovations in mobile applications—especially for indoor navigation. However, the accuracy, reliability and generalizability of navigation all continue to struggle in environments lacking a Global Navigation Satellite System (GNSS. Pedestrian Dead Reckoning (PDR is a popular method for indoor pedestrian navigation. Unfortunately, due to its fundamental principles, even a small navigation error will amplify itself, step by step, generally leading to the need for supplementary resources to maintain navigation accuracy. Virtually all mobile devices and most robots contain a basic camera sensor, which has led to the popularity of image-based localization, and vice versa. However, all of the image-based localization requires continuous images for uninterrupted positioning. Furthermore, the solutions provided by either image-based localization or a PDR are usually in a relative coordinate system. Therefore, this research proposes a system, which uses space resection-aided PDR with geo-referenced images of a previously mapped environment to enable seamless navigation and solve the shortcomings of PDR and image-based localization, and evaluates the performance of space resection with different assumptions using a smartphone. The indoor mobile mapping system (IMMS is used for the effective production of geo-referenced images. The preliminary results indicate that the proposed algorithm is suitable for universal pedestrian indoor navigation, achieving the accuracy required for commercial applications.

  20. Applications of Langevin and Molecular Dynamics methods

    Science.gov (United States)

    Lomdahl, P. S.

    Computer simulation of complex nonlinear and disordered phenomena from materials science is rapidly becoming an active and new area serving as a guide for experiments and for testing of theoretical concepts. This is especially true when novel massively parallel computer systems and techniques are used on these problems. In particular the Langevin dynamics simulation technique has proven useful in situations where the time evolution of a system in contact with a heat bath is to be studied. The traditional way to study systems in contact with a heat bath has been via the Monte Carlo method. While this method has indeed been used successfully in many applications, it has difficulty addressing true dynamical questions. Large systems of coupled stochastic ODE's (or Langevin equations) are commonly the end result of a theoretical description of higher dimensional nonlinear systems in contact with a heat bath. The coupling is often local in nature, because it reflects local interactions formulated on a lattice, the lattice for example represents the underlying discreteness of a substrate of atoms or discrete k-values in Fourier space. The fundamental unit of parallelism thus has a direct analog in the physical system the authors are interested in. In these lecture notes the authors illustrate the use of Langevin stochastic simulation techniques on a number of nonlinear problems from materials science and condensed matter physics that have attracted attention in recent years. First, the authors review the idea behind the fluctuation-dissipation theorem which forms that basis for the numerical Langevin stochastic simulation scheme. The authors then show applications of the technique to various problems from condensed matter and materials science.

  1. Solution Method and Precision Analysis of Double-difference Dynamic Precise Orbit Determination of BeiDou Navigation Satellite System

    Directory of Open Access Journals (Sweden)

    LIU Weiping

    2016-02-01

    Full Text Available To resolve the high relativity between the transverse element of GEO orbit and double-difference ambiguity, the classical double-difference dynamic method is improved and the method, which is to determine precise BeiDou satellite orbit using carrier phase and pseudo-range smoothed by phase, is proposed. The feasibility of the method is discussed and the influence of the method about ambiguity fixing is analyzed. Considering the characteristic of BeiDou, the method, which is to fix double-difference ambiguity of BeiDou satellites by QIF, is derived. The real data analysis shows that the new method, which can reduce the relativity and assure the precision, is better than the classical double-difference dynamic method. The result of ambiguity fixing is well by QIF, but the ambiguity fixing success rate is not high on the whole. So the precision of BeiDou orbit can't be improved clearly after ambiguity fixing.

  2. Real-time bladder lesion registration and navigation: a phantom study.

    Directory of Open Access Journals (Sweden)

    Michelle Agenant

    Full Text Available BACKGROUND: Bladder cancer is the fourth most common malignancy in men, with a recurrence rate of 33-64%. Tumor documentation during cystoscopy of the bladder is suboptimal and might play a role in these high recurrence rates. OBJECTIVE: In this project, a bladder registration and navigation system was developed to improve bladder tumor documentation and consequently increase reproducibility of the cystoscopy. MATERIALS/METHODS: The bladder registration and navigation system consists of a stereo-tracker that tracks the location of a newly developed target, which is attached to the endoscope during cystoscopy. With this information the urology registration and navigation software is able to register the 3D position of a lesion of interest. Simultaneously, the endoscopic image is captured in order to combine it with this 3D position. To enable navigation, navigational cues are displayed on the monitor, which subsequently direct the cystoscopist to the previously registered lesion. To test the system, a rigid and a flexible bladder phantom was developed. The system's robustness was tested by measuring the accuracy of registering and navigating the lesions. Different calibration procedures were compared. It was also tested whether system accuracy is limited by using a previously saved calibration, to avoid surgical delay due to calibration. Urological application was tested by comparing a rotational camera (fixed to the rotating endoscope to a non-rotational camera (dangling by gravity used in standard urologic practice. Finally, the influence of volume differences on registering and navigating was tested. RESULTS/CONCLUSION: The bladder registration and navigation system has an acceptable accuracy for bladder lesion registration and navigation. Limitations for patient determinants included changes in bladder volume and bladder deformation. In vivo studies are required to measure the effect of these limitations and functionality in urological

  3. 一种用于自律搬运车导航的混合式视觉方法%A Hybrid Vision Method for Autonomous Guided Vehicle Navigation

    Institute of Scientific and Technical Information of China (English)

    吕健; 池田博康; 滨岛京子

    2006-01-01

    For the autonomous guided vehicle (AGV) used mainly in unfixed work fields, a machine vision method was proposed for the navigation system, in which a series of navigation-signs are placed along the travel route. The navigation system detects and recognizes these signs, and accordingly informs the travel control system. In order for the navigation to have balanced ability of 1) covering a large area and 2) recognizing details of the sign, the proposed vision method was designed to be a hybrid one, using both the stereo vision and the traditional 2D template matching. The former implemented a coarse recognition function for above 1), and the later implemented a fine recognition function for above 2). The results from the coarse recognition were used in the fine recognition for the gaze control to input suitable 2D image of the signs. Experiments on a prototype system show the feasibility of the proposed hybrid method in achieving the objective specifications for a typical AGV.

  4. Application of numerical methods to elasticity imaging.

    Science.gov (United States)

    Castaneda, Benjamin; Ormachea, Juvenal; Rodríguez, Paul; Parker, Kevin J

    2013-03-01

    Elasticity imaging can be understood as the intersection of the study of biomechanical properties, imaging sciences, and physics. It was mainly motivated by the fact that pathological tissue presents an increased stiffness when compared to surrounding normal tissue. In the last two decades, research on elasticity imaging has been an international and interdisciplinary pursuit aiming to map the viscoelastic properties of tissue in order to provide clinically useful information. As a result, several modalities of elasticity imaging, mostly based on ultrasound but also on magnetic resonance imaging and optical coherence tomography, have been proposed and applied to a number of clinical applications: cancer diagnosis (prostate, breast, liver), hepatic cirrhosis, renal disease, thyroiditis, arterial plaque evaluation, wall stiffness in arteries, evaluation of thrombosis in veins, and many others. In this context, numerical methods are applied to solve forward and inverse problems implicit in the algorithms in order to estimate viscoelastic linear and nonlinear parameters, especially for quantitative elasticity imaging modalities. In this work, an introduction to elasticity imaging modalities is presented. The working principle of qualitative modalities (sonoelasticity, strain elastography, acoustic radiation force impulse) and quantitative modalities (Crawling Waves Sonoelastography, Spatially Modulated Ultrasound Radiation Force (SMURF), Supersonic Imaging) will be explained. Subsequently, the areas in which numerical methods can be applied to elasticity imaging are highlighted and discussed. Finally, we present a detailed example of applying total variation and AM-FM techniques to the estimation of elasticity.

  5. CSM research: Methods and application studies

    Science.gov (United States)

    Knight, Norman F., Jr.

    1989-01-01

    Computational mechanics is that discipline of applied science and engineering devoted to the study of physical phenomena by means of computational methods based on mathematical modeling and simulation, utilizing digital computers. The discipline combines theoretical and applied mechanics, approximation theory, numerical analysis, and computer science. Computational mechanics has had a major impact on engineering analysis and design. When applied to structural mechanics, the discipline is referred to herein as computational structural mechanics. Complex structures being considered by NASA for the 1990's include composite primary aircraft structures and the space station. These structures will be much more difficult to analyze than today's structures and necessitate a major upgrade in computerized structural analysis technology. NASA has initiated a research activity in structural analysis called Computational Structural Mechanics (CSM). The broad objective of the CSM activity is to develop advanced structural analysis technology that will exploit modern and emerging computers, such as those with vector and/or parallel processing capabilities. Here, the current research directions for the Methods and Application Studies Team of the Langley CSM activity are described.

  6. Risk methods and their applications in agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Ladanyi, M. [Corvinus University of Budapest (Hungary). Dept. of Mathematics and Informatics

    2008-09-30

    Considering risk in agriculture is nowadays more necessary than ever. With climate change, the consequences of all decisions are becoming more and more serious, especially in agricultural production. In this paper the author reviews some results and gives a case study. In agriculture one faces several decision problems in which, among proficiency and sustainability, the risk aspects have to be investigated more and more seriously. In Hungary the risk of production is especially meaningful as it has considerably been increased in the last few decades. In this paper the author reviews those risk analysis methods which are very useful in climate change impact research. He gives a case study of the application of the described methods in which he proves that the risk of corn and wheat production has increased between 1951 and 1990 in four Hungarian regions (Hajdu-Bihar, Bacs- Kiskun, Fejer and Gyor-Moson-Sopron), independently to the rate of absolute risk aversion. In some regions the rate of increase became even quicker.

  7. GPS navigation algorithms for Autonomous Airborne Refueling of Unmanned Air Vehicles

    Science.gov (United States)

    Khanafseh, Samer Mahmoud

    measurements as an additional inter-vehicle ranging measurement were also introduced. The algorithms and methods developed in this work are generally applicable to realize high-performance GPS-based navigation in partially obstructed environments. Navigation performance for AAR was quantified through covariance analysis, and it was shown that the stringent navigation requirements for this application are achievable. Finally, a real-time implementation of the algorithms was developed and successfully validated in autopiloted flight tests.

  8. [Clinical application of three-dimensional O-arm navigation system in treating patients with dystrophic scoliosis secondary to neurofibromatosis type Ⅰ].

    Science.gov (United States)

    Liu, Z; Qiu, Y; Li, Y; Zhao, Z H; Wang, B; Zhu, F; Yu, Y; Sun, X; Zhu, Z Z

    2017-03-01

    Objective: To investigate the clinical outcomes and the accuracy of O-arm-navigation system assisted pedicle screw insertion in dystrophic scoliosis secondary to neurofibromatosis type Ⅰ(NF-1). Methods: A retrospective study was conducted in 41 patients with dystrophic NF-1-associated thoracic scoliosis who were surgically treated at Department of Orthopaedics, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School between June 2012 and October 2014 with more than 18 months follow-up. The patients were then divided into two groups: 18 patients were under the assistance of O-arm-navigation-based pedicle screw insertion (O-arm group) and the remaining 23 patients' pedicle screws insertion were conducted by free-hand (free-hand group). The X-ray and CT were analyzed to investigate the correction rate and safety of pedicle insertion. t-test was used to analyze measurement data and χ(2) test was used to analyze accuracy of screw insertion between the two groups. Results: The mean coronal Cobb angle was 63.2°±8.7° in the O-arm group and 66.9°±7.4° in the free-hand group (P>0.05), which was then corrected into 23.1°±6.8° and 30.2°±7.6°(t=2.231, P=0.031) after surgery respectively.Operation time was (265.0±70.3)minutes and estimated blood loss was (1 024±465)ml in the O-arm group. Operation time and estimated blood loss was (243.0±49.6)minutes and (1 228±521)ml respectively in the free-hand group, which had no significant difference between the two groups. However, the implant density was higher in the O-arm group than that in the free-hand group ((64.1±10.8)% vs.(44.3±15.3)%)(t=4.652, P=0.000). The O-arm group comprised 122 screws, of which 72.9% were excellent, 22.1% were good and 4.9% were bad. The free-hand group comprised 136 screws and 48.5% of them were excellent, 33.8% were good and 17.6% were bad.Accuracy of pedicle screw insertion was higher in the O-arm group than that in the free-hand group(χ(2

  9. “CT导航”在下颌角截骨成形术中的应用%Application of CT navigation in mandibular angle plastic osteotomy

    Institute of Scientific and Technical Information of China (English)

    邢乐君; 张海钟; 陈鹏; 席庆; 戴俊峰; 文照取; 杨靖嘉; 朱凯

    2012-01-01

    Objective To summarize the use of the CT-guided mandibular angle plastic osteotomy.Methods The clinical data of mandibular angle plastic osteotomy were analyzed under the CT navigation in recent 3 years in our department.Thin-slice CT scans of the mandibular angle were performed before the operation.The CT data were input to the system of neuronavigation.The surgical procedures were then taken under the CT navigation.Results All of patients who received this new technology obtained good plastic effects and safe operation.The anatomic location accurately achieched with short operation time and less bleeding during the operation and distinct curative effect and fast recovery after operation.The effects of the treatment were fine.No visible complications occurred.Conclusions The CT navigation could fix accurately on position of important blood vessels and nerves which could be injured accidentally during operation and,of course,the safety of the operation is improved.The CT navigation can also determine the position and quantities of osteotomy from three dimensional angles,reduce effectively the surgical complications and the risk of surgery,reduce the psychological burden of patients efficiently and increase their confidence and credibility to the operation and surgeons.%目的 探讨“CT导航”技术在下颌角截骨成形术中的应用.方法 分析并总结近3年来,在“CT导航”下对46例施行下颌角截骨成形术,术前对患者头颈部行薄层CT扫描,将数据输入“CT导航”系统,术中在“CT导航”系统引导下行下颌角截骨成形术.结果 全部患者整形效果及安全性良好,术中解剖定位准确,截骨操作简便,无明显并发症发生,手术时间短,出血少,术后康复快.结论 采用“CT导航”技术不仅可精确判定重要血管、神经所在位置,避免术中误伤,提高手术安全性;而且可以从三维立体角度确定截骨的位置及骨量,有效减少并发症的发生,降低

  10. Polarization Methods of Measuring the Roll Angle of an Object in Motion in Radio Beacon Navigation Systems

    Science.gov (United States)

    Gulko, V. L.; Mescheryakov, A. A.

    2016-06-01

    Polarization methods of measuring the roll angle of an object in motion with the help of radio beacon systems are considered. The polarization properties of the beacon signals received on board the object and amplitude-phase processing of their orthogonal polarized components are used to accomplish this goal.

  11. Methods of geodiversity assessment and theirs application

    Science.gov (United States)

    Zwoliński, Zbigniew; Najwer, Alicja; Giardino, Marco

    2016-04-01

    The concept of geodiversity has rapidly gained the approval of scientists around the world (Wiedenbein 1993, Sharples 1993, Kiernan 1995, 1996, Dixon 1996, Eberhard 1997, Kostrzewski 1998, 2011, Gray 2004, 2008, 2013, Zwoliński 2004, Serrano, Ruiz- Flano 2007, Gordon et al. 2012). However, the problem recognition is still at an early stage, and in effect not explicitly understood and defined (Najwer, Zwoliński 2014). Nevertheless, despite widespread use of the concept, little progress has been made in its assessment and mapping. Less than the last decade can be observing investigation of methods for geodiversity assessment and its visualisation. Though, many have acknowledged the importance of geodiversity evaluation (Kozłowski 2004, Gray 2004, Reynard, Panizza 2005, Zouros 2007, Pereira et al. 2007, Hjort et al. 2015). Hitherto, only a few authors have undertaken that kind of methodological issues. Geodiversity maps are being created for a variety of purposes and therefore their methods are quite manifold. In the literature exists some examples of the geodiversity maps applications for the geotourism purpose, basing mainly on the geological diversity, in order to point the scale of the area's tourist attractiveness (Zwoliński 2010, Serrano and Gonzalez Trueba 2011, Zwoliński and Stachowiak 2012). In some studies, geodiversity maps were created and applied to investigate the spatial or genetic relationships with the richness of particular natural environmental components (Burnett et al. 1998, Silva 2004, Jačková, Romportl 2008, Hjort et al. 2012, 2015, Mazurek et al. 2015, Najwer et al. 2014). There are also a few examples of geodiversity assessment in order to geoconservation and efficient management and planning of the natural protected areas (Serrano and Gonzalez Trueba 2011, Pellitero et al. 2011, 2014, Jaskulska et al. 2013, Melelli 2014, Martinez-Grana et al. 2015). The most popular method of assessing the diversity of abiotic components of the natural

  12. PRIVATE GRAPHS – ACCESS RIGHTS ON GRAPHS FOR SEAMLESS NAVIGATION

    Directory of Open Access Journals (Sweden)

    W. Dorner

    2016-06-01

    Full Text Available After the success of GNSS (Global Navigational Satellite Systems and navigation services for public streets, indoor seems to be the next big development in navigational services, relying on RTLS – Real Time Locating Services (e.g. WIFI and allowing seamless navigation. In contrast to navigation and routing services on public streets, seamless navigation will cause an additional challenge: how to make routing data accessible to defined users or restrict access rights for defined areas or only to parts of the graph to a defined user group? The paper will present case studies and data from literature, where seamless and especially indoor navigation solutions are presented (hospitals, industrial complexes, building sites, but the problem of restricted access rights was only touched from a real world, but not a technical perspective. The analysis of case studies will show, that the objective of navigation and the different target groups for navigation solutions will demand well defined access rights and require solutions, how to make only parts of a graph to a user or application available to solve a navigational task. The paper will therefore introduce the concept of private graphs, which is defined as a graph for navigational purposes covering the street, road or floor network of an area behind a public street and suggest different approaches how to make graph data for navigational purposes available considering access rights and data protection, privacy and security issues as well.

  13. Private Graphs - Access Rights on Graphs for Seamless Navigation

    Science.gov (United States)

    Dorner, W.; Hau, F.; Pagany, R.

    2016-06-01

    After the success of GNSS (Global Navigational Satellite Systems) and navigation services for public streets, indoor seems to be the next big development in navigational services, relying on RTLS - Real Time Locating Services (e.g. WIFI) and allowing seamless navigation. In contrast to navigation and routing services on public streets, seamless navigation will cause an additional challenge: how to make routing data accessible to defined users or restrict access rights for defined areas or only to parts of the graph to a defined user group? The paper will present case studies and data from literature, where seamless and especially indoor navigation solutions are presented (hospitals, industrial complexes, building sites), but the problem of restricted access rights was only touched from a real world, but not a technical perspective. The analysis of case studies will show, that the objective of navigation and the different target groups for navigation solutions will demand well defined access rights and require solutions, how to make only parts of a graph to a user or application available to solve a navigational task. The paper will therefore introduce the concept of private graphs, which is defined as a graph for navigational purposes covering the street, road or floor network of an area behind a public street and suggest different approaches how to make graph data for navigational purposes available considering access rights and data protection, privacy and security issues as well.

  14. Application of computer-assisted navigation system in education of complex zygomatic fractures treatment%计算机辅助导航在复杂颧骨颧弓骨折治疗中的教学应用

    Institute of Scientific and Technical Information of China (English)

    杨荣涛; 李祖兵; 李智; 杨学文

    2016-01-01

    Complex zygomatic fracture is a difficult part in teaching maxillofacial fractures. We applied computer-assisted navigation system for the education of complex zygomatic fractures treatment , making it a bridge between theory and practice. This method greatly motivated students′participation,and promoted their learning efficiency. The application of this technique in teaching practice is improvement and innovation of traditional teaching methods,and is worth to be popularized in oral and maxillofacial surgery teaching.%复杂颧骨颧弓骨折是颌面部骨折的教学难点,将计算机辅助导航应用于复杂颧骨颧弓骨折的教学过程,使其成为理论与实践相互转化的桥梁,极大提高学生主动参与的积极性,提升学习效率.该技术在教学实践中的应用,是对传统教学模式的完善及革新,值得在口腔颌面外科教学过程中推广.

  15. Image Based Indoor Navigation

    OpenAIRE

    Noreikis, Marius

    2014-01-01

    Over the last years researchers proposed numerous indoor localisation and navigation systems. However, solutions that use WiFi or Radio Frequency Identification require infrastructure to be deployed in the navigation area and infrastructureless techniques, e.g. the ones based on mobile cell ID or dead reckoning suffer from large accuracy errors. In this Thesis, we present a novel approach of infrastructure-less indoor navigation system based on computer vision Structure from Motion techniques...

  16. Pediatric lumbar pedicle screw placement using navigation templates: A cadaveric study

    Directory of Open Access Journals (Sweden)

    Xing Wang

    2017-01-01

    Full Text Available Background: Pedicle screw technique is commonly used treatment of adult spinal trauma, tumor, degeneration. The application of pedicle screws is very challenging in children because children have a fast growing spine and spinal pedicle morphology of children and adult has large difference. 3 D reconstruction individual navigation templates improve the success rate of pediatric pedicle screw system. This study is aimed to provide a precise method for lumbar spine pedicle screw placement in children using computer-aided design and rapid prototyping technology. Materials and Methods: Computed tomography (CT scans of cadaver specimens of 4 children were obtained, and the raw data were reconstructed using three-dimensional reconstruction software. Pedicle screws were placed using the conventional method or by using individually designed navigation templates based on the principles of reverse engineering and rapid prototyping technology. Results: We evaluated the accuracy of the pedicle screws placed using the two methods by CT scan. Ten navigation templates were designed for placement of 20 lumbar pedicle screws in the navigation group, and CT scan confirmed that all the screws were placed accurately in the corresponding pedicle. Conversely, of the 20 lumbar pedicle screws placed using the conventional method, 3 screws perforated the pedicle. The findings showed that lumbar pedicle screw placement was successful using navigation templates in children. Conclusions: This technique is simple, easy to master, and allows personalized screw placement, thus providing a new and feasible method for lumbar pedicle screw placement in children.

  17. Navigating nuclear science: Enhancing analysis through visualization

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, N.H.; Berkel, J. van; Johnson, D.K.; Wylie, B.N.

    1997-09-01

    Data visualization is an emerging technology with high potential for addressing the information overload problem. This project extends the data visualization work of the Navigating Science project by coupling it with more traditional information retrieval methods. A citation-derived landscape was augmented with documents using a text-based similarity measure to show viability of extension into datasets where citation lists do not exist. Landscapes, showing hills where clusters of similar documents occur, can be navigated, manipulated and queried in this environment. The capabilities of this tool provide users with an intuitive explore-by-navigation method not currently available in today`s retrieval systems.

  18. Precise laser gyroscope for autonomous inertial navigation

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, A G; Molchanov, A V; Izmailov, E A [Joint Stock Company ' Moscow Institute of Electromechanics and Automatics' , Moscow (Russian Federation); Chirkin, M V [Ryazan State Radio Engineering University (Russian Federation)

    2015-01-31

    Requirements to gyroscopes of strapdown inertial navigation systems for aircraft application are formulated. The construction of a ring helium – neon laser designed for autonomous navigation is described. The processes that determine the laser service life and the relation between the random error of the angular velocity measurement and the surface relief features of the cavity mirrors are analysed. The results of modelling one of the promising approaches to processing the laser gyroscope signals are presented. (laser gyroscopes)

  19. Indoor wayfinding and navigation

    CERN Document Server

    2015-01-01

    Due to the widespread use of navigation systems for wayfinding and navigation in the outdoors, researchers have devoted their efforts in recent years to designing navigation systems that can be used indoors. This book is a comprehensive guide to designing and building indoor wayfinding and navigation systems. It covers all types of feasible sensors (for example, Wi-Fi, A-GPS), discussing the level of accuracy, the types of map data needed, the data sources, and the techniques for providing routes and directions within structures.

  20. USE OF ASSISTED PHOTOGRAMMETRY FOR INDOOR AND OUTDOOR NAVIGATION PURPOSES

    Directory of Open Access Journals (Sweden)

    D. Pagliari

    2015-05-01

    Full Text Available Nowadays, devices and applications that require navigation solutions are continuously growing. For instance, consider the increasing demand of mapping information or the development of applications based on users’ location. In some case it could be sufficient an approximate solution (e.g. at room level, but in the large amount of cases a better solution is required. The navigation problem has been solved from a long time using Global Navigation Satellite System (GNSS. However, it can be unless in obstructed areas, such as in urban areas or inside buildings. An interesting low cost solution is photogrammetry, assisted using additional information to scale the photogrammetric problem and recovering a solution also in critical situation for image-based methods (e.g. poor textured surfaces. In this paper, the use of assisted photogrammetry has been tested for both outdoor and indoor scenarios. Outdoor navigation problem has been faced developing a positioning system with Ground Control Points extracted from urban maps as constrain and tie points automatically extracted from the images acquired during the survey. The proposed approach has been tested under different scenarios, recovering the followed trajectory with an accuracy of 0.20 m. For indoor navigation a solution has been thought to integrate the data delivered by Microsoft Kinect, by identifying interesting features on the RGB images and re-projecting them on the point clouds generated from the delivered depth maps. Then, these points have been used to estimate the rotation matrix between subsequent point clouds and, consequently, to recover the trajectory with few centimeters of error.

  1. Use of Assisted Photogrammetry for Indoor and Outdoor Navigation Purposes

    Science.gov (United States)

    Pagliari, D.; Cazzaniga, N. E.; Pinto, L.

    2015-05-01

    Nowadays, devices and applications that require navigation solutions are continuously growing. For instance, consider the increasing demand of mapping information or the development of applications based on users' location. In some case it could be sufficient an approximate solution (e.g. at room level), but in the large amount of cases a better solution is required. The navigation problem has been solved from a long time using Global Navigation Satellite System (GNSS). However, it can be unless in obstructed areas, such as in urban areas or inside buildings. An interesting low cost solution is photogrammetry, assisted using additional information to scale the photogrammetric problem and recovering a solution also in critical situation for image-based methods (e.g. poor textured surfaces). In this paper, the use of assisted photogrammetry has been tested for both outdoor and indoor scenarios. Outdoor navigation problem has been faced developing a positioning system with Ground Control Points extracted from urban maps as constrain and tie points automatically extracted from the images acquired during the survey. The proposed approach has been tested under different scenarios, recovering the followed trajectory with an accuracy of 0.20 m. For indoor navigation a solution has been thought to integrate the data delivered by Microsoft Kinect, by identifying interesting features on the RGB images and re-projecting them on the point clouds generated from the delivered depth maps. Then, these points have been used to estimate the rotation matrix between subsequent point clouds and, consequently, to recover the trajectory with few centimeters of error.

  2. Subjective evidence based ethnography: method and applications.

    Science.gov (United States)

    Lahlou, Saadi; Le Bellu, Sophie; Boesen-Mariani, Sabine

    2015-06-01

    Subjective Evidence Based Ethnography (SEBE) is a method designed to access subjective experience. It uses First Person Perspective (FPP) digital recordings as a basis for analytic Replay Interviews (RIW) with the participants. This triggers their memory and enables a detailed step by step understanding of activity: goals, subgoals, determinants of actions, decision-making processes, etc. This paper describes the technique and two applications. First, the analysis of professional practices for know-how transferring purposes in industry is illustrated with the analysis of nuclear power-plant operators' gestures. This shows how SEBE enables modelling activity, describing good and bad practices, risky situations, and expert tacit knowledge. Second, the analysis of full days lived by Polish mothers taking care of their children is described, with a specific focus on how they manage their eating and drinking. This research has been done on a sub-sample of a large scale intervention designed to increase plain water drinking vs sweet beverages. It illustrates the interest of SEBE as an exploratory technique in complement to other more classic approaches such as questionnaires and behavioural diaries. It provides the detailed "how" of the effects that are measured at aggregate level by other techniques.

  3. Antimicrobial applications of nanotechnology: methods and literature

    Directory of Open Access Journals (Sweden)

    Seil JT

    2012-06-01

    Full Text Available Justin T Seil, Thomas J WebsterLaboratory for Nanomedicine Research, School of Engineering, Brown University, Providence, RI, USAAbstract: The need for novel antibiotics comes from the relatively high incidence of bacterial infection and the growing resistance of bacteria to conventional antibiotics. Consequently, new methods for reducing bacteria activity (and associated infections are badly needed. Nanotechnology, the use of materials with dimensions on the atomic or molecular scale, has become increasingly utilized for medical applications and is of great interest as an approach to killing or reducing the activity of numerous microorganisms. While some natural antibacterial materials, such as zinc and silver, possess greater antibacterial properties as particle size is reduced into the nanometer regime (due to the increased surface to volume ratio of a given mass of particles, the physical structure of a nanoparticle itself and the way in which it interacts with and penetrates into bacteria appears to also provide unique bactericidal mechanisms. A variety of techniques to evaluate bacteria viability, each with unique advantages and disadvantages, has been established and must be understood in order to determine the effectiveness of nanoparticles (diameter ≤100 nm as antimicrobial agents. In addition to addressing those techniques, a review of select literature and a summary of bacteriostatic and bactericidal mechanisms are covered in this manuscript.Keywords: nanomaterial, nanoparticle, nanotechnology, bacteria, antibacterial, biofilm

  4. Immunofluorescence in cytogenetic analysis: method and applications

    Directory of Open Access Journals (Sweden)

    Jeppesen Peter

    2000-01-01

    Full Text Available Control of the genetic information encoded by DNA in mammalian chromosomes is mediated by proteins, some of which are only transiently attached, although others are intrinsically associated with nucleic acid in the complex mixture known as chromatin. Chromatin-associated proteins range from the ubiquitous and abundant histones down to the most specific and rare of transcription factors. Although many chromatin proteins are probably excluded from highly condensed mitotic chromosomes, a number are retained throughout the cell cycle and can be detected on chromosomes in metaphase spreads. Comparing the distribution of a chromosomal protein with known cytogenetic markers on metaphase chromosomes can provide an important and potentially highly informative first source of data on the function of the protein under consideration. The aim of the present study is to summarize some of the principles involved in obtaining suitable chromosome preparations for subsequent immunolocalization of protein antigens. Some applications of the method will be included to illustrate how this approach has increased our understanding of chromosome structure and genetic regulation.

  5. An embedded omnidirectional vision navigator for automatic guided vehicles

    Science.gov (United States)

    Feng, Weijia; Zhang, Baofeng; Röning, Juha; Cao, Zuoliang; Zong, Xiaoning

    2011-01-01

    Omnidirectional vision appears the definite significance since its advantage of acquiring full 360° horizontal field of vision information simultaneously. In this paper, an embedded original omnidirectional vision navigator (EOVN) based on fish-eye lens and embedded technology has been researched. Fish-eye lens is one of the special ways to establish omnidirectional vision. However, it appears with an unavoidable inherent and enormous distortion. A unique integrated navigation method which is conducted on the basis of targets tracking has been proposed. It is composed of multi-target recognition and tracking, distortion rectification, spatial location and navigation control. It is called RTRLN. In order to adapt to the different indoor and outdoor navigation environments, we implant mean-shift and dynamic threshold adjustment into the Particle Filter algorithm to improve the efficiency and robustness of tracking capability. RTRLN has been implanted in an independent development embedded platform. EOVN likes a smart crammer based on COMS+FPGA+DSP. It can guide various vehicles in outdoor environments by tracking the diverse marks hanging in the air. The experiments prove that the EOVN is particularly suitable for the guidance applications which need high requirements on precision and repeatability. The research achievements have a good actual applied inspection.

  6. The occlusion-adjusted prefabricated 3D mirror image templates by computer simulation: the image-guided navigation system application in difficult cases of head and neck reconstruction.

    Science.gov (United States)

    Cheng, Hsu-Tang; Wu, Chao-I; Tseng, Ching-Shiow; Chen, Hung-Chi; Lee, Wu-Song; Chen, Philip Kuo-Ting; Chang, Sophia Chia-Ning

    2009-11-01

    Computer applications in head and neck reconstruction are rapidly emerging and create not only a virtual environment for presurgical planning, but also help in image-guided navigational surgery. This study evaluates the use of prefabricated 3-dimensional (3D) mirror image templates made by computer-simulated adjusted occlusions to assist in microvascular prefabricated flap insertion during reconstructive surgery. Five patients underwent tumor ablation surgery in 1999 and survived for 8 years. Four of the patients with malignancy received radiation therapy. All patients in this study suffered from severe malocclusion causing trismus, headache, temporomandibular joint pain, an unsymmetrical face, and the inability of further osseointegrated teeth insertion. They underwent a 3D computer tomography examination and the nonprocessed raw data were sent for computer simulation in adjusting occlusion; thus, a mirror image template could be fabricated for microsurgical flap guidance. The computer simulated occlusion was acceptable and facial symmetry obtained. The use of the template resulted in a shorter operation time and recovery was as expected. The computer-simulated occlusion-adjusted 3D mirror image templates aid in the use of free vascularized bone flaps for restoring continuity to the mandible. The coordinated arch will help with further osseointegration teeth insertion.

  7. Research on Application of Navigation Based on ARPA Algorithm%基于ARPA算法的航海应用研究

    Institute of Scientific and Technical Information of China (English)

    王斌

    2012-01-01

    Studying of how to expand the field of application in the maritime ARPA, a simple and intuitive manipulator is designed to provide vessels for the current situation, and can provide real-time for the manipulator collision avoidance radar collision avoidance algorithm for decision making. To ensure safety of navigation of the ship manipulator, it has great significance. The compass coordinates and the Carte sian coordinate system conversion algorithms are introduced. The collision avoidance and collision avoidance algorithm are designed based on the trend of analytic geometry.%研究如何拓展ARPA在航海领域的应用,设计一种操作简单且直观的为操纵者提供船舶当前态势,并能实时为操纵者提供避碰决策的雷达避碰算法,对船舶操纵者保证航行安全,有重要的意义。介绍了罗盘坐标系与笛卡尔坐标系转换的算法,设计了基于避碰解析几何的态势标绘算法和避碰标绘算法。

  8. Research on Observability Analysis-Based Autonomous Navigation Method for Deep Space%基于可观测性分析的深空自主导航方法研究

    Institute of Scientific and Technical Information of China (English)

    崔平远; 常晓华; 崔祜涛

    2011-01-01

    In this paper, the autonomous navigation approaches for different observation models are studied based on observability analysis. Based on the observability analysis of the nonlinear system, the observability matrix is derived from the theory of differential geometry. Then, a method for measuring the observability index of the system is derived, and the analytical method of the observability index for state variable is given. The principle is applied in the autonomous navigation system for deep space. The observability indexes of navigation system corresponding to different observation models are studied, and the observability indexes of the orbital elements are investigated. The result of the observability analysis is used as a selection criterion of the observation model used in the navigation system. And then, the navigation approaches under different observation models are established by utilizing the extended Kalman filter. Finally, the autonomous navigation approach presented in the paper is validated by the practical data of a deep impact mission. The relation between the observability index of the navigation system and the estimation accuracy of orbit elements is verified, and the method of observability analysis is demonstrated to be feasible.%基于可观测性分析,研究了不同观测模型下的深空自主导航算法.从非线性系统的可观测性分析出发,利用微分几何理论求解出系统的可观测矩阵,并给出了系统的可观测度定义和状态变量的可观测度分析方法;将其应用于深空自主导航系统,分析了不同观测模型下导航系统以及轨道参数的可观测度,并将其作为观测模型的选取准则;根据可观测性分析结果,结合非线性扩展卡尔曼滤波,建立了不同观测模型对应的自主导航算法.最后,以深度撞击任务的实际飞行数据对文中的自主导航算法进行数值仿真,验证了导航系统可观测度与系统状态估计精度之间的关

  9. FID navigator-based MR thermometry method to monitor small temperature changes in the brain of ventilated animals.

    Science.gov (United States)

    Boulant, Nicolas; Bottlaender, Michel; Uhrig, Lynn; Giacomini, Eric; Luong, Michel; Amadon, Alexis; Massire, Aurélien; Larrat, Benoît; Vignaud, Alexandre

    2015-01-01

    An MR thermometry method is proposed for measuring in vivo small temperature changes engendered by external RF heat sources. The method relies on reproducible and stable respiration and therefore currently applies to ventilated animals whose breathing is carefully controlled. It first consists in characterizing the stability of the main magnetic field as well as the variations induced by breathing during a first monitoring stage. Second, RF heating is applied while the phase and thus temperature evolutions are continuously measured, the corrections due to breathing and field drift being made thanks to the data accumulated during the first period. The RF heat source is finally stopped and the temperature rise likewise is continuously monitored during a third and last stage to observe the animal cooling down and to validate the assumptions made for correcting for the main field variation and the physiological noise. Experiments were performed with a clinical 7 T scanner on an anesthetized baboon and with a dedicated RF heating setup. Analysis of the data reveals a precision around 0.1°C, which allows us to reliably measure sub-degree temperature rises in the muscle and in the brain of the animal.

  10. Indoor Pedestrian Navigation Based on Hybrid Route Planning and Location Modeling

    DEFF Research Database (Denmark)

    Schougaard, Kari Rye; Grønbæk, Kaj; Scharling, Tejs

    2012-01-01

    This paper introduces methods and services called PerPosNav for development of custom indoor pedestrian navigation applications to be deployed on a variety of platforms. PerPosNav combines symbolic and geometry based modeling of buildings, and in turn combines graph-based and geometric route...

  11. Quantum control of isomerization by robust navigation in the energy spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Murgida, G. E., E-mail: murgida@tandar.cnea.gov.ar [Centro Atómico Constituyentes, GIyA, CNEA, San Martín, and Consejo Nacional de Investigaciones Científicas y Técnicas, C1033AAJ Buenos Aires (Argentina); Arranz, F. J., E-mail: fj.arranz@upm.es [Grupo de Sistemas Complejos, Universidad Politécnica de Madrid, 28040 Madrid (Spain); Borondo, F., E-mail: f.borondo@uam.es [Departamento de Química, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Instituto de Ciencias Matemáticas (ICMAT), Cantoblanco, 28049 Madrid (Spain)

    2015-12-07

    In this paper, we present a detailed study on the application of the quantum control technique of navigation in the energy spectrum to chemical isomerization processes, namely, CN–Li⇆ Li–CN. This technique is based on the controlled time variation of a Hamiltonian parameter, an external uniform electric field in our case. The main result of our work establishes that the navigation involved in the method is robust, in the sense that quite sizable deviations from a pre-established control parameter time profile can be introduced and still get good final results. This is specially relevant thinking of a experimental implementation of the method.

  12. A Method of Eliminating Noises in Web Pages by Style Tree Model and Its Applications

    Institute of Scientific and Technical Information of China (English)

    ZHAO Cheng-li; YI Dong-yun

    2004-01-01

    A Web page typically contains many information blocks.Apart from the main content blocks, it usually has such blocks as navigation panels, copyright and privacy notices, and advertisements.We call these blocks the noisy blocks.The noises in Web pages can seriously harm Web data mining.To the question of eliminating these noises, we introduce a new tree structure, called Style Tree, and study an algorithm how to construct a site style tree.The Style Tree Model is employed to detect and eliminate noises in any Web pages of the site.An information based measure to determine which element node is noisy is also constructed.In addition, the applications of this method are discussed in detail.Experimental results show that our noises elimination technique is able to improve the mining results significantly.

  13. Detecting memory and structure in human navigation patterns using Markov chain models of varying order.

    Science.gov (United States)

    Singer, Philipp; Helic, Denis; Taraghi, Behnam; Strohmaier, Markus

    2014-01-01

    One of the most frequently used models for understanding human navigation on the Web is the Markov chain model, where Web pages are represented as states and hyperlinks as probabilities of navigating from one page to another. Predominantly, human navigation on the Web has been thought to satisfy the memoryless Markov property stating that the next page a user visits only depends on her current page and not on previously visited ones. This idea has found its way in numerous applications such as Google's PageRank algorithm and others. Recently, new studies suggested that human navigation may better be modeled using higher order Markov chain models, i.e., the next page depends on a longer history of past clicks. Yet, this finding is preliminary and does not account for the higher complexity of higher order Markov chain models which is why the memoryless model is still widely used. In this work we thoroughly present a diverse array of advanced inference methods for determining the appropriate Markov chain order. We highlight strengths and weaknesses of each method and apply them for investigating memory and structure of human navigation on the Web. Our experiments reveal that the complexity of higher order models grows faster than their utility, and thus we confirm that the memoryless model represents a quite practical model for human navigation on a page level. However, when we expand our analysis to a topical level, where we abstract away from specific page transitions to transitions between topics, we find that the memoryless assumption is violated and specific regularities can be observed. We report results from experiments with two types of navigational datasets (goal-oriented vs. free form) and observe interesting structural differences that make a strong argument for more contextual studies of human navigation in future work.

  14. Methods of Real Time Image Enhancement of Flash LIDAR Data and Navigating a Vehicle Using Flash LIDAR Data

    Science.gov (United States)

    Vanek, Michael D. (Inventor)

    2014-01-01

    A method for creating a digital elevation map ("DEM") from frames of flash LIDAR data includes generating a first distance R(sub i) from a first detector i to a first point on a surface S(sub i). After defining a map with a mesh THETA having cells k, a first array S(k), a second array M(k), and a third array D(k) are initialized. The first array corresponds to the surface, the second array corresponds to the elevation map, and the third array D(k) receives an output for the DEM. The surface is projected onto the mesh THETA, so that a second distance R(sub k) from a second point on the mesh THETA to the detector can be found. From this, a height may be calculated, which permits the generation of a digital elevation map. Also, using sequential frames of flash LIDAR data, vehicle control is possible using an offset between successive frames.

  15. Doubly contracted CI method and applications

    Institute of Scientific and Technical Information of China (English)

    WANG; Yubin; HAN; Huixian; ZHAI; Gaohong; SUO; Bin; WEN; Zh

    2004-01-01

    algebras, Physica Scripta, 1980, 21: 295.[15]Shavitt, Ⅰ., Unitary group approach to configuration interaction calculations of the electronic structure of atoms and molecules,Unitary Group Approach to Configuration Interaction Calculations of the Electronic Structure of Atoms and Molecules Mathematical Frontiers in Computational Chemical Physic (ed. Trnhlar,D. G), Berlin: Springer Verlag, 1988, 299.[16]Siegbahn, P. S. M., Generalizations of the CI method, Ⅱ, J. Chem.Phys., 1980, 72: 1647.[17]Wang Yubin, Wen Zhenyi, Dou Qishi et al, New realization of loop driven direct CI, J. Comput. Chem., 1992, 13: 187.[18]Wen Zhenyi, WangYubin, Theory and Application of Unitary Group Approach (in Chinese), Shanghai: Shanghai Science and Technology Press, 1994.[19]Wang Yubin, Zhai Gaohong, Suo Binbin et al., Hole-particle correspondence in CI calculations, Chem. Phys. Letters, 2003, 375:134- 140.[20]Frisch, M. J., Trucks, G. W., Schlegel, H. B. et al., Gaussian 03,Revision A.l, Pittsburgh PA: Gaussian, Inc., 2003.[21]Dupuis, M., Farazdel, A., Karna, S. P. et al., HONDO: A general atomic and molecular electronic structure system, HONDO,Modern Techniques in Computational Chemistry (ed. Clementi,E.), Leiden: ESCOM, 1990, 277.[22]Bunker, P. R., Jensen, P., Kraemer, W. P. et al., The potential surface of x3 B1 methylene (CH2) and the singlet-triplet splitting, J.Chem. Phys, 1986, 85: 3724-3731.[23]Berkwitz, J., Greene, J. P., Cho, H. et al., Photoionization mass spectrometric studies of SiHn (n=1-4), J. Chem. Phys., 1987, 86:1235.[24]Bruna, P., Peyerimhoff, S. D., Structure and electronic spectra of small radicals by quantum mechanical methods, Bull. Soc. Chim.(Belgium), 1983, 92: 525.[25]Phillips, R. A., Bunker, R. J., Beardsworth, R. et al., An ab initio study of the rotation-vibration energy levels of germylene (GeH2)in the a3 B1 state, Chem. Phys. Letters, 1985, 118: 60.[26]Herzberg, G., Molecular Spectra and Molecular Structure Ⅲ, New

  16. Comparative Analysis of H-infinity Filtering in INS/GPS Integrated Navigation Application%H∞滤波在惯导/GPS组合导航应用的比较分析

    Institute of Scientific and Technical Information of China (English)

    魏伟; 秦永元; 张晓冬; 张亚崇

    2012-01-01

    为分析H∞滤波算法在惯性导航系统INS/GPS组合导航应用中对动态环境的自适应能力,选用卡尔曼滤波算法和Sage-Husa算法作为对照,并改进了Sage-Husa算法,构造了较为全面的惯导系统误差模型、扰动数据情形和飞行轨迹,比较分析了三种算法的自适应能力.仿真结果表明:在这种验证环境中,H∞滤波算法可调参数受到的约束较多,与改进的Sage-Husa算法相比,卡尔曼增益和估计协方误差与量测值变化的相关性较弱,导致自适应能力较弱.在这类模拟动态环境中H∞滤波算法的自适应能力要低于改进的Sage-Husa算法.方法和结果对于鲁棒的INS/GPS组合导航算法的工程化应用有较高的实用价值.%In order to compare and analyze the adaptive ability of H-infinity filtering algorithm to dynamic circumstances in INS/GPS integrated navigation application, Kalman filtering algorithm and Sage-Husa algorithm were chosen as the comparisons. Sage-Husa algorithm was improved. The more comprehensive INS error models, data disturbance circumstances and flight track were constructed. Adaptive abilities of the three algorithms were compared. The simulation results show that in the validation environment, the adjustable parameters of H-infinity filtering algorithm are subjected to more restrictions and that, compared with the improved Sage-Husa algorithm, the correlation of the Kalman gain and the estimation error covariance with the change of measurement is low, which results in the weaker adaptive ability. In the simulated dynamic environment,the adaptive ability of H-infinity filtering algorithm is weaker than the ameliorated Sage-Husa algorithm. The methods and results have higher practical value for a further study of the engineering application of the robust INS/GPS integrated navigation algorithm.

  17. On Applicability of Formal Methods and Tools to Dependable Services

    Science.gov (United States)

    Ishikawa, Fuyuki; Honiden, Shinichi

    As a variety of digital services are provided through networks, more and more efforts are made to ensure dependability of software behavior implementing services. Formal methods and tools have been considered as promising means to support dependability in complex software systems during the development. On the other hand, there have been serious doubts on practical applicability of formal methods. This paper overviews the present state of formal methods and discusses their applicability, especially focusing on two representative methods (SPIN and B Method) and their recent industrial applications. This paper also discusses applications of formal methods to dependable networked software.

  18. 一种高动态环境下卫星扩频信号的快速捕获方法研究%Research on Quickly Acquisition Method About High Dynamic Satellite Navigation Signals

    Institute of Scientific and Technical Information of China (English)

    张现宇; 郭熙业; 王跃科; 唐银银

    2014-01-01

    In the present satellite navigation applications , the global navigation satellite system ( GNSS) receiver must be able to work well at large dynamic environment .In order to capture rapidly satellite navigation signals at the large frequency deviation , this paper presents an improved Bi-Frequency domain calculation method which could parallel search code phase and Doppler shift .First, long correla-tion integral operation is divided into short correlation integration operation with double block zeros pad-ding ( DBZP) algorithm, quickly searching code phase with circular correlation combined with Fast Fou-rier Transform ( FFT) , significantly reducing the amount of computation .Then the amount of computation is largely reduced with equivalence principle of the frequency domain circular shift and time domain carri -er peeling .Compared with continuous acquisition algorithms and single frequency domain acquisition al -gorithm under the same acquisition sensitivity conditions , operation time reduces 90%.It is suitable for rapid acquisition of GPS signals under large deviation conditions .Experiments show that the method can capture GPS signal ±500kHz within 0.1s.%现代卫星导航及测控应用对接收机在高动态环境下实现测量通信提出了迫切需求。为了解决大多普勒频偏扩频信号的快速捕获问题,提出了一种在频域并行搜索码相位及多普勒频偏的双频域快速捕获方法。采用双块补零算法将长的相关积分操作分割为多个短的相关积分操作,然后采用快速傅里叶变换进行圆周相关,大大节约了处理时间,利用频域圆周移位与时域载波剥离等价的原理,大幅提高了频率搜索效率。与时域相关算法和单频域计算方法相比,在捕获灵敏度不变的条件下,该方法将计算量减少90%,显著提高了运算速度,适合高动态环境下扩频信号的快速捕获。该方案应用于星载接收机平台FPGA实现,测试

  19. Autonomous Robot Navigation based on Visual Landmarks

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    autonomous navigation and self-localization using automatically selected landmarks. The thesis investigates autonomous robot navigation and proposes a new method which benefits from the potential of the visual sensor to provide accuracy and reliability to the navigation process while relying on naturally...... update of the estimated robot position while the robot is moving. In order to make the system autonomous, both acquisition and observation of landmarks have to be carried out automatically. The thesis consequently proposes a method for learning and navigation of a working environment and it explores...... of the proposed method is based on a system with a simple setup. The novelty and potentiality, are in combining algorithms for panoramic view-synthesis, attention selection, stereo reconstruction, triangulation, optimal triplet selection, and image-based rendering. Experiments demonstrate that the system can...

  20. Cooperative Navigation Method of Multiple Autonomous Underwater Vehicles Base on Double Acoustic Measurement%双伪测量的多水下航行器移动长基线协同导航算法

    Institute of Scientific and Technical Information of China (English)

    张立川; 徐德民; 刘明雍

    2013-01-01

    用最近邻理论研究了基于移动长基线的多AUV协同导航.移动长基线多AUV协同导航结构中,主AUV内部装备高精度导航设备,从AUV内部装备低精度导航设备,外部均装备水声装置测量相对位置关系,利用协同导航融合内部和外部传感器信息,实现从AUV进行实时导航定位.基于最近邻理论,建立了双伪测量的数学模型,设计了协同导航算法,进行了数学仿真研究.研究结果表明,在双领航者结构下,通过构建双伪测量可以显著提高群体的导航定位精度.%In this paper, a moving long baseline algorithm based on double acoustic measurement for cooperative navigation and localization of multi-AUVs is proposed. In the moving long baseline structure, the master AUV is equipped with high precision navigation system, and the slaver AUV is equipped with low precision navigation system. They both are equipped with acoustic devices to measure relative location. The system model is presented, which fuses the proprioceptive and exteroceptive sensors. The analytical results derived in this paper are validated in simulation for different test cases. The research results prove that the navigation accuracy has been improved effectively by using cooperative navigation and localization method.

  1. Progress in spatial analysis methods and applications

    CERN Document Server

    Páez, Antonio; Buliung, Ron N; Dall'erba, Sandy

    2010-01-01

    This book brings together developments in spatial analysis techniques, including spatial statistics, econometrics, and spatial visualization, and applications to fields such as regional studies, transportation and land use, population and health.

  2. Augmented Reality Implementation Methods in Mainstream Applications

    CERN Document Server

    Prochazka, David

    2011-01-01

    Augmented reality has became an useful tool in many areas from space exploration to military applications. Although used theoretical principles are well known for almost a decade, the augmented reality is almost exclusively used in high budget solutions with a special hardware. However, in last few years we could see rising popularity of many projects focused on deployment of the augmented reality on different mobile devices. Our article is aimed on developers who consider development of an augmented reality application for the mainstream market. Such developers will be forced to keep the application price, therefore also the development price, at reasonable level. Usage of existing image processing software library could bring a significant cut-down of the development costs. In the theoretical part of the article is presented an overview of the augmented reality application structure. Further, an approach for selection appropriate library as well as the review of the existing software libraries focused in th...

  3. Biomedical image understanding methods and applications

    CERN Document Server

    Lim, Joo-Hwee; Xiong, Wei

    2015-01-01

    A comprehensive guide to understanding and interpreting digital images in medical and functional applications Biomedical Image Understanding focuses on image understanding and semantic interpretation, with clear introductions to related concepts, in-depth theoretical analysis, and detailed descriptions of important biomedical applications. It covers image processing, image filtering, enhancement, de-noising, restoration, and reconstruction; image segmentation and feature extraction; registration; clustering, pattern classification, and data fusion. With contributions from ex

  4. Restricted Navigation Areas - USACE IENC

    Data.gov (United States)

    Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  5. 计算机导航技术在后交叉韧带重建胫骨隧道定位中的应用%Application of computer navigation system in tibial tunnel positioning during reconstruction of posterior cruciate ligament

    Institute of Scientific and Technical Information of China (English)

    熊健斌; 赵劲民; 沙轲; 程建文; 韦庆军

    2011-01-01

    背景:后交叉韧带重建中胫骨隧道的定位一直是手术的难点,把计算机导航技术运用到后交叉韧带重建中,希望能提高胫骨隧道定位的精度.目的:采用计算机导航系统在重建膝关节后交叉韧带中准确定位胫骨隧道的方法,评价其在后交叉韧带重建中的应用价值.方法:甲醛防腐成人下肢标本50侧,切断标本后交叉韧带后分别用聚氨酯海棉粘贴包裹模拟软组织覆盖的完整标本.随机分成两组,分别采用计算机辅助导航系统(导航组)及传统关节镜(对照组)定位胫骨隧道.观察两组标本胫骨隧道的出口位置,透视后测量胫骨隧道的矢状角度及长度,记录透视次数.结果与结论:导航组胫骨虚拟隧道矢状角度和长度术中定位及术后实测比较差异均无显著性意义(P > 0.05).导航组术后实测胫骨隧道矢状角度为(61.88±0.94)°、透视次数为(3.0±0.5)次,对照组分别为(52.63±1.04)°及(9.0±2.7)次;导航组隧道出口位于后交叉韧带生理附着区23例,对照组为15例;两组比较差异均有显著性意义(P < 0.05).结果提示透视导航技术可以辅助后交叉韧带重建手术中胫骨隧道的定位,具有隧道定位准确性高、辐射及手术污染机会减少的特点.%BACKGROUND: Positioning pathway of bony tunnel in tibia during reconstructing posterior cruciate ligament is a difficult part of surgical procedure permanently. As computer assistant navigating system applied in the field of medicine rapidly, we use this technique to elevate accuracy of positioning bony tunnel in tibia and improve the operative effect in reconstruction of posterior cruciate ligament.OBJECTIVE: To investigate the rational plan of computer navigation system in the reconstruction of posterior cruciate ligament and the accurate positioning methods of tibial tunnel, and to evaluate the application of computer navigation system in the reconstruction of posterior cruciate ligament.METHODS

  6. 面向机器人导航的汉语路径自然语言组块分析方法研究%Research on the Chinese Path Natural Language Chunking Method for Robot Navigation

    Institute of Scientific and Technical Information of China (English)

    王浩; 景阳; 王鲜惠; 张超; 潘蔚; 陈奇

    2016-01-01

    Man-robot interaction by Chinese natural language is an efficient and convenient method for robot navigation. In this paper, we mainly study the natural language processing method for Chinese route language. Firstly 10 unstructured 3D environ-ments for robot navigation tasks were built, and then the natural language navigation corpus was collected based on these robot navigation tasks. The most of corpus collectors are college students, in addition to some people with different age and career. Secondly the NLPIR Chinese word segmentation system was used for segmentation and tagging. Finally in order to extract the semantic information for robot navigation, nine basic blocks were defined, and the conditional random field (CRF) model was employed to achieve the data block automatic annotation. The experimental results show that the accuracy of this chunking method is higher, which laid the foundation for further extraction of semantic navigation.%通过汉语自然语言与机器人进行人机交互无疑是一种高效便捷的导航办法。主要针对汉语路径自然语言的处理方法进行研究。首先搭建了10个非结构化的3D环境,针对所构建环境下机器人的导航任务完成了自然语言导航语料的收集,该语料库的来源以在校大学生为主体,辅以各年龄段不同职业的社会人士;然后采用NLPIR汉语分词系统对有效语料进行分词以及词性标注处理,最后为了提取用于导航的语义信息,定义了9种基本组块,并采用条件随机场(CRF)实现了语料的组块自动标注,实验结果表明该方法的组块标注准确率较高,为进一步提取导航语义打下了基础。

  7. A Method of Mobile Robot Reactive Navigation Based on Human-Robot Interaction%一种基于人机交互的移动机器人反应式导航方法

    Institute of Scientific and Technical Information of China (English)

    唐鸿儒; 包加桐; 宋爱国

    2013-01-01

    A method of mobile robot reactive navigation based on human-robot interaction is proposed to address the issue of mobile robot autonomous navigation under unknown environments. The fuzzy logic is utilized to implement the basic intelligent behaviors of the robot. The mixed behavior coordination method based on priority and finite state automata (FSA) is then used to set up the mechanism of environment stimulus-response so as to enhance the robot local autonomous ability. The mechanism of human stimulus-response which enables the robot system to understand the unknown environment well and make correct decisions is further proposed and imported in the robot system. The simulations in which the proposed navigation method is used for robot autonomous navigation toward the preset targets under various environments are performed. The effectiveness of the proposed method is validated by simulation results.%针对未知环境中移动机器人的自主导航问题,提出了一种基于人机交互的反应式导航方法.在采用模糊逻辑实现机器人基本智能行为的基础上,利用基于优先级和有限状态机的混合行为协调方法建立“环境刺激-反应”机制,提高机器人的局部自主能力.提出将“人刺激-反应”机制引入机器人系统,提高机器人系统对环境的理解与决策能力.在不同环境模型中利用提出的方法对移向指定目标的机器人自主导航进行了仿真,仿真结果验证了该方法的有效性.

  8. FM Navigator100在调频广播覆盖及非法电台排查中的应用探讨%Application of FM Navigator 100 in FM Broadcast Coverage and Illegal Radio Investigation

    Institute of Scientific and Technical Information of China (English)

    刘航航; 周悦颖

    2015-01-01

    调频广播覆盖的收测以及非法电台的监测监管在广播电视监测监管工作中发挥着非常重要的作用,对于掌握各电台布局、规划和技术标准提供了可靠的依据.本文主要根据FM Navigator 100在流动收测工作过程中积累的一些方法和经验,就调频广播覆盖情况的分析及非法电台的排查做出简单的归纳和总结.

  9. Studies on Precise Spacecraft Navigation and Positioning Using GPS

    Institute of Scientific and Technical Information of China (English)

    XiangKaiheng; QuGuangji

    2004-01-01

    GPS measurement technology, Encke method to solve satellite orbit perturbation and generalized Kalman filtering technology are organically combined together, and an innovative solution—carrier phase & pseudorange integrated dynamic orbit determination (CPPIDOD) for low earth orbit spacecraft on-board autonomous precise navigation and positioning by using GPS is presented. The difficult problems of dynamically resolving integer ambiguities and amendment of cycle slips in the application of GPS carrier phase have been solved.Based on all above, the technique of carrier phase & pseudorange integrated dynamic differential relative navigation between two spacecrafts is brought forward. Results of numerical simulation analyses and senti-physical simulation tests show that the solutions presented in this paper are feasible, which can significantly improve the performance of GPS positioning, and the models, algorithms and software are practical for engineering use.

  10. Wide-field TCSPC: methods and applications

    Science.gov (United States)

    Hirvonen, Liisa M.; Suhling, Klaus

    2017-01-01

    Time-correlated single photon counting (TCSPC) is a widely used, robust and mature technique to measure the photon arrival time in applications such as fluorescence spectroscopy and microscopy, LIDAR and optical tomography. In the past few years there have been significant developments with wide-field TCSPC detectors, which can record the position as well as the arrival time of the photon simultaneously. In this review, we summarise different approaches used in wide-field TCSPC detection, and discuss their merits for different applications, with emphasis on fluorescence lifetime imaging.

  11. 北斗在远海工程人员安全监管中的应用前景%Application prospect of BeiDou Navigation Satellite System in staff safety supervision of open- sea engineering

    Institute of Scientific and Technical Information of China (English)

    何建波; 张工; 崔银秋; 田俊峰

    2015-01-01

    北斗卫星导航系统是中国正在实施的自主发展、独立运行的全球卫星导航系统,作为先进的导航、定位、测量和授时手段,已经融入了国家建设和社会发展的各个应用领域。文章根据北斗系统的服务特色和服务优势,阐述北斗在远海工程人员安全监管的技术解决途径和应用前景,进行了有益的尝试。%China is implementing the BeiDou Navigation Satellite System, which is the independently developed and operated global navigation satellite system by China. It has been integrated into various applications of the national construction and so-cial development as the means of navigation, fixed position, measurement, and time service. Based on the service characteristics and advantages of BeiDou System, we describes the technology solutions and application prospect of BeiDou System in staff safety supervision of open-sea engineering, and carried on the beneficial attempt.

  12. [Application of Delphi method in traditional Chinese medicine clinical research].

    Science.gov (United States)

    Bi, Ying-fei; Mao, Jing-yuan

    2012-03-01

    In recent years, Delphi method has been widely applied in traditional Chinese medicine (TCM) clinical research. This article analyzed the present application situation of Delphi method in TCM clinical research, and discussed some problems presented in the choice of evaluation method, classification of observation indexes and selection of survey items. On the basis of present application of Delphi method, the author analyzed the method on questionnaire making, selection of experts, evaluation of observation indexes and selection of survey items. Furthermore, the author summarized the steps of application of Delphi method in TCM clinical research.

  13. 78 FR 68861 - Certain Navigation Products, Including GPS Devices, Navigation and Display Systems, Radar Systems...

    Science.gov (United States)

    2013-11-15

    ... COMMISSION Certain Navigation Products, Including GPS Devices, Navigation and Display Systems, Radar Systems... the United States after importation of certain navigation products, including GPS devices, navigation... products, including GPS devices, navigation and display systems, radar systems, navigational aids,...

  14. Dynamical Systems Method and Applications Theoretical Developments and Numerical Examples

    CERN Document Server

    Ramm, Alexander G

    2012-01-01

    Demonstrates the application of DSM to solve a broad range of operator equations The dynamical systems method (DSM) is a powerful computational method for solving operator equations. With this book as their guide, readers will master the application of DSM to solve a variety of linear and nonlinear problems as well as ill-posed and well-posed problems. The authors offer a clear, step-by-step, systematic development of DSM that enables readers to grasp the method's underlying logic and its numerous applications. Dynamical Systems Method and Applications begins with a general introduction and

  15. Application of FastSLAM based on simulated annealing variance reduction in navigation and localization of AUV%模拟退火方差缩减的FastSLAM算法在AUV导航定位中的应用

    Institute of Scientific and Technical Information of China (English)

    王宏健; 王晶; 曲丽萍; 刘振业

    2013-01-01

    The FastSLAM algorithm based on variance reduction of particle weight was presented in order to solve the decrease of estimated accuracy of AUV ( autonomous underwater vehicle) , location due to particles degeneracy and the sample impoverishment as a result of resampling in standard FastSLAM. The variance of particle weight was decreased by generating an adaptive exponential fading factor, which came from the thought of cooling function in simulated annealing. The effective particle number was increased by application of FastSLAM based on simulated annealing variance reduction in navigation and localization of AUV. Resampling in standard FastSLAM was replaced with it. Establish the kinematic model of AUV, feature model and measurement models of sensors, and make feature extraction with Hough transform. The experiment of AUV's simultaneous localization and mapping u-sing simulated annealing variance reduction FastSLAM was based on trial data. The results indicate that the method described in this paper maintains the diversity of the particles, however, weakens the degeneracy, while at the same time enhances the accuracy stability of AUV's navigation and localization system.%由于标准FastSLAM中存在粒子退化及重采样引起的粒子贫化,导致自主水下航行器(AUV)位置估计精度严重下降的问题,提出了一种基于粒子权值方差缩减的FastSLAM算法.利用模拟退火的降温函数产生自适应指数渐消因子来降低粒子权值的方差,进而增加有效粒子数,以此取代标准FastSLAM中的重采样步骤.建立AUV的运动学模型、特征模型及传感器的测量模型,通过霍夫变换进行特征提取.利用方差缩减FastSLAM算法,基于海试数据进行了AUV同步定位与构图仿真试验,结果表明所提方法能够保证粒子的多样性,并且降低粒子的退化程度,提高了AUV定位与地图构建系统的准确性及稳定性.

  16. Comparison of methods for intestinal histamine application

    DEFF Research Database (Denmark)

    Vind, S; Søondergaard, I; Poulsen, L K

    1991-01-01

    The study was conducted to investigate whether introduction of histamine in enterosoluble capsules produced the same amount of urinary histamine metabolites as that found after application of histamine through a duodeno-jejunal tube. Secondly, to examine whether a histamine-restrictive or a fast ...

  17. Numerical Methods for Structured Matrices and Applications

    CERN Document Server

    Bini, Dario A; Olshevsky, Vadim; Tyrtsyhnikov, Eugene; van Barel, Marc

    2010-01-01

    This cross-disciplinary volume brings together theoretical mathematicians, engineers and numerical analysts and publishes surveys and research articles related to the topics where Georg Heinig had made outstanding achievements. In particular, this includes contributions from the fields of structured matrices, fast algorithms, operator theory, and applications to system theory and signal processing.

  18. Application of Walk navigation type ADCP in tidal flow monitoring%走航式ADCP在感潮河段流量监测中的应用

    Institute of Scientific and Technical Information of China (English)

    林卫文

    2012-01-01

      Influenced by upstream runoff and tidal in the tidal reach, water level and flow rate changed fasterly, hydrological phenomena is extremely complex. represent line used the traditional routine test methods is validated, and the intensity of labor is bigger, the efficiency is lower. But walk navigation type ADCP (acoustic doppler velocity profile instrument) not only can quickly measure section flow, also can obtain the vertical ( on behalf of the line) flow rate and flow direction through the commands of the WinRiver software which controled ADCP, using the above methods,flow continuous test has been completed in the tidal reach,ShiJiao stations,beijiang river, good effect has achieved, and a new means was provided for the continuous monitoring of tidal flow section.%  在感潮河段受上游径流、潮汐的影响,水位、流速变化较快,水文现象极为复杂。采用传统的常规测验方法验证代表线,劳动强度较大,效率低下。而走航式ADCP(声学多普勒流速剖面仪)除可以快速测量断面流量外,也可以定点(固定垂线位置)通过WinRiver软件中的命令控制ADCP定时按时长获取垂线(代表线)流速、流向,应用上述方法在北江石角站完成感潮河段的流量连续测验,取得良好的效果,从而为感潮河段流量连续监测提供了一种新的手段。

  19. Algorithms for vehicle navigation

    OpenAIRE

    Storandt, Sabine

    2012-01-01

    Nowadays, navigation systems are integral parts of most cars. They allow the user to drive to a preselected destination on the shortest or quickest path by giving turn-by-turn directions. To fulfil this task the navigation system must be aware of the current position of the vehicle at any time, and has to compute the optimal route to the destination on that basis. Both of these subproblems have to be solved frequently, because the navigation system must react immediately if the vehicle leaves...

  20. Calibration of a polarization navigation sensor using the NSGA-II algorithm

    Science.gov (United States)

    Ma, Tao; Hu, Xiaoping; Zhang, Lilian; He, Xiaofeng

    2016-10-01

    A bio-inspired polarization navigation sensor is designed based on the polarization sensitivity mechanisms of insects. A new calibration model by formulating the calibration problem as a multi-objective optimization problem is presented. Unlike existing calibration models, the proposed model makes the calibration problem well-posed. The calibration parameters are optimized through Non-dominated Sorting Genetic Algorithm-II (NSGA-II) approach to minimize both angle of polarization (AOP) residuals and degree of linear polarization (DOLP) dispersions. The results of simulation and experiments show that the proposed algorithm is more stable than the compared methods for the calibration applications of polarization navigation sensors.

  1. Application of Beidou Satellite Navigation System in Ground Surveillance System%北斗卫星导航系统在地面监视系统中的应用

    Institute of Scientific and Technical Information of China (English)

    杜思良; 杨俊峰; 王德泉

    2013-01-01

    为满足部队作战训练的应用需求,对北斗卫星导航系统在地面监视系统中的应用进行研究。在简要介绍卫星导航系统国内外应用现状的基础上,结合北斗卫星导航系统提供的定位和短消息通信能力,提出系统软件应具有定位获取与导航、图上监视、数据指挥和基于北斗的信息传递等核心功能,并分析软件设计中指挥与监视一体集成、图上位置聚合解聚展现和队形偏航告警等关键技术和实现方法。该研究可为研发基于北斗卫星导航系统的地面监视系统提供参考。%To meet the application requirements of military combat training, the paper studies the application of Beidou satellite navigation system in ground surveillance system. Based on the present research of satellite navigation system at home and abroad, position and short message communication ability of Beidou satellite, the core capability of the software system is proposed, including position and navigation ability, situation monitoring ability, data commanding ability and information delivery ability. The key technologies of software design are analyzed, which are composed of commanding and monitoring, troop position aggregation and disaggregation, vehicle off-course alarm etc. The study could provide a reference for the development of ground surveillance system based on Beidou satellite navigation system.

  2. Application of 3D reconstruction navigation template in Bernese periacetabular osteotomy%3D打印导板在Bernese髋臼周围截骨术中的应用

    Institute of Scientific and Technical Information of China (English)

    周游; 徐小山; 李川; 康晓鹏; 陈昊; 王均; 朱崇涛; 李伟; 陆声

    2016-01-01

    14 right hips and 12 left ones.Preoperative patients were prepared by pelvic plain film,CT scan,CT data reconstruction and simulated acetabular osteotomy and rotation in Mimics10.1 software.According to preoperative planning,reverse engineering technology was applied to extract the pelvic anatomic morphology and the osteotomy surface of operative field.Navigation templates were designed and manufactured by 3D printing technology.In operation,the navigation template was attached onto the exposed pelvis and osteotomy surface with complete accurate rotation displacement of osteotomy and acetabular bone block.Lateral center-edge (LCE) angle,acetabular index (AC),extrusion index (EI) and femoral coverage were analyzed.Results The operation time for this group ranged from 2.7 to 4.6 hours,averaging 3.2 hours.Intraoperative bleeding ranged from 950 mL to 3,300 mL,averaging 1,630 mL.No injury to the femoral nerve or sciatic nerve was observed in this group.No serious complications like bone fragments into the hip joint occurred.Postoperative infection was not found in all the cases.Posterior column breakage occurred in only one case.There were significant differences between the preoperative and postoperative measurements regarding LCE,AC,EI and femoral coverage (P < 0.05),but there were no significant differences between the above measurements after simulated operation and actual operation (P > 0.05).Conclusion Since application of the navigation template designed based on CT 3D reconstruction in PAO can improve the surgical accuracy and safety,it is an effective method to solve the difficulties of PAO.

  3. Design and study of software reliability of cleanroom methods of integrated navigation system%组合导航系统软件的净室技术可靠性设计与研究

    Institute of Scientific and Technical Information of China (English)

    张家海; 孙枫; 张延顺; 郝燕玲

    2001-01-01

    The software design is the crux of integrated navigation system. Using the cleanroom methods, the paper gives effective reliability design of integrated navigation system is proposed. Experimental results show that the scheme design can improve the reliability of system greatly.%组合导航系统的关键是软件设计。从可靠性的角度出发,引入净室技术对组合导航系统软件进行了有效的可靠性设计。试验结果表明,该方案设计有效地提高了系统的可靠性。

  4. The Limitations and Application Methods of Suggestopedia

    Institute of Scientific and Technical Information of China (English)

    李苗苗; 宋宝梅

    2015-01-01

    For a long time,college English teaching was mainly teacher-centered.Teachers played a dominant role in the classroom whereas students played a passive role.The"Suggestopedia"theory is such an effective way.However,there exist some limitations when apply the Suggestopedia theory.Teachers must pay attention to these limitations when apply the Suggestopedia theory.This thesis not only presents the limitations but also give some advises to the proper application of Suggestopedia Theory in teaching.

  5. Numerical Methods for Equations and its Applications

    CERN Document Server

    Argyros, Ioannis K

    2012-01-01

    This book introduces advanced numerical-functional analysis to beginning computer science researchers. The reader is assumed to have had basic courses in numerical analysis, computer programming, computational linear algebra, and an introduction to real, complex, and functional analysis. Although the book is of a theoretical nature, each chapter contains several new theoretical results and important applications in engineering, in dynamic economics systems, in input-output system, in the solution of nonlinear and linear differential equations, and optimization problem.

  6. The Limitations and Application Methods of Suggestopedia

    Institute of Scientific and Technical Information of China (English)

    李苗苗; 宋宝梅

    2015-01-01

    For a long time,college English teaching was mainly teacher-centered.Teachers played a dominant role in the classroom whereas students played a passive role.The"Suggestopedia" theory is such an effective way.However,there exist some limitations when apply the Suggestopedia theory.Teachers must pay attention to these limitations when apply the Suggestopedia theory.This thesis not only presents the limitations but also give some advises to the proper application of Suggestopedia Theory in teaching.

  7. The Automatic Start Method of Application Program Using API

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This paper introduces on a method about the au-tomactic start of application program. Through defining Registryby API function, the automatic start of specified application pro-gram is fulfilled when Windows98 is taking action. It gives facil-ities to many computer application works.

  8. New methods applicable for calibration of indicator electrodes.

    Science.gov (United States)

    Michałowski, Tadeusz; Pilarski, Bogusław; Ponikvar-Svet, Maja; Asuero, Agustin G; Kukwa, Agata; Młodzianowski, Janusz

    2011-02-15

    The new methods applicable for calibration of indicator electrodes, based on standard addition and standard subtraction methods, are suggested. Some of the methods enable the slope of an indicator electrode and equivalence volume V(eq) to be determined simultaneously from a single set of potentiometric titration data. Some other methods known hitherto were also taken into account. A new model, based on a standard addition method, applicable also in nonlinear range for the ISE slope (S) is suggested, and its applicability was confirmed experimentally in calibration of calcium ISE. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. NFC Internal: An Indoor Navigation System

    Directory of Open Access Journals (Sweden)

    Busra Ozdenizci

    2015-03-01

    Full Text Available Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability.

  10. NFC Internal: An Indoor Navigation System

    Science.gov (United States)

    Ozdenizci, Busra; Coskun, Vedat; Ok, Kerem

    2015-01-01

    Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC)-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability. PMID:25825976

  11. Unmanned vehicle mobility: Limits of autonomous navigation

    Science.gov (United States)

    McCormac, A. W.; Hanna, D. M.; McFee, J.

    Considerable research is being conducted on the development of unmanned vehicles for military and civilian applications, particularly for hostile environments. It is desirable to produce a vehicle which can select its own route, not requiring remote navigation, but then it would be required to sense its surroundings. Although imaging systems and modern computers make this possible, the extreme data processing demands usually make it impractical. It is suggested that an inverse relationship exists between vehicle mobility and the complexity of the autonomous navigation system required for an unmanned vehicle. An overview of vehicle navigation is presented which shows the degree to which navigation is affected by increasing inherent mobility. If the inherent mobility of a vehicle is greatly enhanced, the scene image processing requirements and navigational computations are greatly simplified. This means the vehicle path selection and speed and steering adjustments may be made more quickly, resulting in higher vehicle speeds whenever possible. Combined with reduced deviation from the intended path, this would greatly increase the speed of the vehicle from one given point to another, suggesting that high speed autonomous navigation may be feasible.

  12. NFC internal: an indoor navigation system.

    Science.gov (United States)

    Ozdenizci, Busra; Coskun, Vedat; Ok, Kerem

    2015-03-27

    Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC)-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability.

  13. USACE Navigation Channels 2012

    Data.gov (United States)

    California Department of Resources — This dataset represents both San Francisco and Los Angeles District navigation channel lines. All San Francisco District channel lines were digitized from CAD files...

  14. LEO AUTONOMOUS NAVIGATION BASED ON IMAGE MOTION

    Institute of Scientific and Technical Information of China (English)

    DUANFang; LIUJian-ye; YUFeng

    2005-01-01

    A method of LEO autonomous navigation is presented based on the nonlinear satellite velocity relative to the earth. The velocity is detected by a high-speed camera, with the attitude information detected by a star sensor. Compared with traditional autonomous navigation by landmark identification, the satellite velocity relarive to the earth is obtained by correlativity analysis of images. It does not need to recognize ground objects or views. Since it is not necessary to pre-store the database of ground marks, lots of memory space can be saved.The state and observation equations are constructed, and the filtering is processed by the Kalman filter. Simulation results show that the system has high autonomous navigation precision in LEO autonomous navigation.

  15. Metal nitrate conversion method, patent application

    NARCIS (Netherlands)

    2008-01-01

    A method for converting a supported metal nitrate into the corresponding supported metal comprises heating the metal nitrate to effect its decomposition under a gas mixture that contains nitric oxide and has an oxygen content of

  16. Application of geophysical methods for fracture characterization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.H.; Majer, E.L. [Lawrence Berkeley Lab., CA (USA); McEvilly, T.V. [Lawrence Berkeley Lab., CA (USA)]|[California Univ., Berkeley, CA (USA). Dept. of Geology and Geophysics; Morrison, H.F. [Lawrence Berkeley Lab., CA (USA)]|[California Univ., Berkeley, CA (USA). Dept. of Materials Science and Mineral Engineering

    1990-01-01

    One of the most crucial needs in the design and implementation of an underground waste isolation facility is a reliable method for the detection and characterization of fractures in zones away from boreholes or subsurface workings. Geophysical methods may represent a solution to this problem. If fractures represent anomalies in the elastic properties or conductive properties of the rocks, then the seismic and electrical techniques may be useful in detecting and characterizing fracture properties. 7 refs., 3 figs.

  17. Coastal Navigation Portfolio Management

    Science.gov (United States)

    2015-02-19

    the entire navigation portfolio of projects , both inland and coastal. The Coastal Structures Management , Analysis, and Ranking Tool (CSMART) is a...FEB 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Coastal Navigatoin Portfolio Management 5a. CONTRACT...CIRP.aspx Coastal Inlets Research Program Coastal Navigation Portfolio Management The Coastal Navigatoin Portfolio Management work unit

  18. Economic valuation of patents methods and applications

    CERN Document Server

    Munari, F

    2011-01-01

    The Economic Valuation of Patents provides an original and essential analysis of patent valuation, presenting the main methodologies to value patents in different contexts. Starting with an analysis of the relevance of patent valuation from a strategic, economic and legal perspective, the book undertakes a thorough review of the existing financial and qualitative valuation methodologies. The contributing authors, IP experts from academia and business, discuss the application of valuation issues in various contexts such as patent portfolio management, licensing agreements, IP litigation, IP-bac

  19. Vision/INS Integrated Navigation System for Poor Vision Navigation Environments

    Directory of Open Access Journals (Sweden)

    Youngsun Kim

    2016-10-01

    Full Text Available In order to improve the performance of an inertial navigation system, many aiding sensors can be used. Among these aiding sensors, a vision sensor is of particular note due to its benefits in terms of weight, cost, and power consumption. This paper proposes an inertial and vision integrated navigation method for poor vision navigation environments. The proposed method uses focal plane measurements of landmarks in order to provide position, velocity and attitude outputs even when the number of landmarks on the focal plane is not enough for navigation. In order to verify the proposed method, computer simulations and van tests are carried out. The results show that the proposed method gives accurate and reliable position, velocity and attitude outputs when the number of landmarks is insufficient.

  20. 地磁导航基准图三分量数学仿真方法研究%Three-component Mathematic Simulation Method for Geomagnetic Navigation Reference Map

    Institute of Scientific and Technical Information of China (English)

    孙渊; 王仕成; 张金生; 乔玉坤; 张盈

    2012-01-01

    Data of geomagnetic field survey,especially the three-component data,can not meet the requirement of geomagnetic navigation research currently.A mathematic simulation method by calculating geomagnetic three-component value was proposed for geomagnetic navigation reference map in order to provide a rather real verification method for the next geomagnetic navigation technology research.Using Maxwell software to calculate the numerical value of magnetizing field about the magnetic substance,the space distributing of three-component static magnetic field was simulated.Adding geomagnetic time variation model and combinatorial error model,geomagnetic navigation reference map could be simulated after interpolated by radial basis function(RBF) method.Calculated result indicates that this simulation method has a high accuracy and can provide a verification platform for geomagnetic navigation research.%针对现有地磁场磁测数据尤其是三分量数据难以满足地磁导航技术研究需求的问题,同时为了给后续的地磁导航技术研究提供一种较为真实的仿真验证手段,提出一种使用三分量数值计算的方法用以实现地磁导航基准图的数学仿真。使用Maxwell软件对磁性体磁化磁场进行数值计算来仿真静态磁场三分量的空间分布,辅以地磁场的时间变化模型和误差组合模型,通过径向基函数法插值后,得到数学仿真的她磁导航基准图.计算结果表明该方法可以对地磁场进行高精度的数学仿真,可以为地磁导航相关技术的研究提供试验验证平台。

  1. Applications of a transonic wing design method

    Science.gov (United States)

    Campbell, Richard L.; Smith, Leigh A.

    1989-01-01

    A method for designing wings and airfoils at transonic speeds using a predictor/corrector approach was developed. The procedure iterates between an aerodynamic code, which predicts the flow about a given geometry, and the design module, which compares the calculated and target pressure distributions and modifies the geometry using an algorithm that relates differences in pressure to a change in surface curvature. The modular nature of the design method makes it relatively simple to couple it to any analysis method. The iterative approach allows the design process and aerodynamic analysis to converge in parallel, significantly reducing the time required to reach a final design. Viscous and static aeroelastic effects can also be accounted for during the design or as a post-design correction. Results from several pilot design codes indicated that the method accurately reproduced pressure distributions as well as the coordinates of a given airfoil or wing by modifying an initial contour. The codes were applied to supercritical as well as conventional airfoils, forward- and aft-swept transport wings, and moderate-to-highly swept fighter wings. The design method was found to be robust and efficient, even for cases having fairly strong shocks.

  2. GPS-Aided Gyroscope-Free Inertial Navigation Systems

    OpenAIRE

    Park, Sungsu; Tan, Chin-Woo

    2002-01-01

    A gyroscope-free inertial navigation system uses only accelerometers to compute navigation trajectories. It is a low-cost navigation system, but its output error diverges at a rate that is an order faster than that of a conventional gyroscope-based system. So integration with an external reference system, such as the Global Positioning System, is necessary for long-term navigation applications. In this pa-per, an integrated GPS and gyroscope-free INS system is designed to achieve stable long-...

  3. Application of Subgroup Method in TPFAP Library

    Institute of Scientific and Technical Information of China (English)

    LIU; Ping

    2012-01-01

    <正>TPFAP is a transmission probability fuel assembly code package for burn-up calculations on BWR and PWR. The transport calculation is started with a number of energy group calculations in the TPFAP nuclear data library by using of collision probability method. The method of calculating resonance shielding effects in TPFAP library is equivalence theory which uses the intermediate resonance approximations to derive an effective background scatter cross section sigma-p. The equivalence theory is limited by the available algorithms for determining the so-called ’equivalent’ sigma-p value in complex geometries.

  4. Application of intelligent Kalman filter to under-water terrain integrated navigation system%智能Kalman滤波在水下地形组合导航系统中的应用

    Institute of Scientific and Technical Information of China (English)

    李佩娟; 徐晓苏; 张小飞

    2011-01-01

    为了避免现实环境的动态变化对水下航行器系统模型造成的随机干扰影响,保证水下航行器长时间导航精度的稳定性,提出了利用RBF神经网络辅助联邦Kalman滤波方法对SINS /TAN/ DVL/ MCP组合导航系统进行信息融合.给出了各子导航系统的误差模型,通过足够精度的样本对前向神经网络进行离线训练,建立神经网络控制模型.仿真结果表明,该方法可使水下航行器的系统状态在较短的时间内以较高的精度达到稳定.通过与联邦Kalman滤波结果对比表明,采用智能控制方法辅助的信息融合方式的导航定位精度提高了一倍,能有效提高常规联邦Kalman滤波器的自适应能力,达到减小误差,提高精度的目的.%In order to avoid the random effects of the underwater vehicle system model caused by the real dynamics of the environment, a RBF neural network aided federated Kalman filter is proposed to fuse the navigation information from various navigation sensors (such as SINS, TAN, DVL and MCP) to improve the navigation accuracy. Error models of navigation systems are proposed and a neural network model is set up via offline training with enough precise samples. Simulation experiments prove that the AUV navigation accuracy can attain high stability in a short period by the proposed method. By comparing the filtering results with the federated Kalman filter, it is shown that the proposed method can effectively improve the adaptivity, and the navigation precision is doubled.

  5. Mobile Navigation for Sport’s Pilots

    Directory of Open Access Journals (Sweden)

    Dušan Fister

    2013-06-01

    Full Text Available Today, global object-positioning is accomplished very precisely by GPS satellite technology. Access to this information is provided globally by widespread mobile devices with integrated GPS receivers from everywhere also from airplane. This paper presents a mobile device using GPS receiver to be used by mobile navigation for sports pilots. In fact, the mobile navigation is a mobile application running on Android. Thus, the current position of the airplane is indicated on the GoogleMaps and compared with the planned direction of the flight by the pilot. In addition, this mobile application could also serve flight instructors when tracking student pilots by first independent flights. The proposed solution has shown in practice to be the cheapest substitute for expensive professional navigation devices.

  6. Web Navigation Sequences Automation in Modern Websites

    Science.gov (United States)

    Montoto, Paula; Pan, Alberto; Raposo, Juan; Bellas, Fernando; López, Javier

    Most today’s web sources are designed to be used by humans, but they do not provide suitable interfaces for software programs. That is why a growing interest has arisen in so-called web automation applications that are widely used for different purposes such as B2B integration, automated testing of web applications or technology and business watch. Previous proposals assume models for generating and reproducing navigation sequences that are not able to correctly deal with new websites using technologies such as AJAX: on one hand existing systems only allow recording simple navigation actions and, on the other hand, they are unable to detect the end of the effects caused by an user action. In this paper, we propose a set of new techniques to record and execute web navigation sequences able to deal with all the complexity existing in AJAX-based web sites. We also present an exhaustive evaluation of the proposed techniques that shows very promising results.

  7. Methods of practice and guidelines for using survey-grade global navigation satellite systems (GNSS) to establish vertical datum in the United States Geological Survey

    Science.gov (United States)

    Rydlund, Paul H.; Densmore, Brenda K.

    2012-01-01

    Geodetic surveys have evolved through the years to the use of survey-grade (centimeter level) global positioning to perpetuate and post-process vertical datum. The U.S. Geological Survey (USGS) uses Global Navigation Satellite Systems (GNSS) technology to monitor natural hazards, ensure geospatial control for climate and land use change, and gather data necessary for investigative studies related to water, the environment, energy, and ecosystems. Vertical datum is fundamental to a variety of these integrated earth sciences. Essentially GNSS surveys provide a three-dimensional position x, y, and z as a function of the North American Datum of 1983 ellipsoid and the most current hybrid geoid model. A GNSS survey may be approached with post-processed positioning for static observations related to a single point or network, or involve real-time corrections to provide positioning "on-the-fly." Field equipment required to facilitate GNSS surveys range from a single receiver, with a power source for static positioning, to an additional receiver or network communicated by radio or cellular for real-time positioning. A real-time approach in its most common form may be described as a roving receiver augmented by a single-base station receiver, known as a single-base real-time (RT) survey. More efficient real-time methods involving a Real-Time Network (RTN) permit the use of only one roving receiver that is augmented to a network of fixed receivers commonly known as Continually Operating Reference Stations (CORS). A post-processed approach in its most common form involves static data collection at a single point. Data are most commonly post-processed through a universally accepted utility maintained by the National Geodetic Survey (NGS), known as the Online Position User Service (OPUS). More complex post-processed methods involve static observations among a network of additional receivers collecting static data at known benchmarks. Both classifications provide users

  8. 33 CFR 209.325 - Navigation lights, aids to navigation, navigation charts, and related data policy, practices and...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Navigation lights, aids to navigation, navigation charts, and related data policy, practices and procedure. 209.325 Section 209.325 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF...

  9. Gas sensing method applicable to real conditions

    Science.gov (United States)

    Szczurek, A.; Maciejewska, M.

    2013-04-01

    In this work, we tested the influence of various sampling techniques and modes of operation on the response of sensor systems under real conditions. The first system was based on diffusive sampling. The second one used a dynamic method of sampling. In the third system, a stop flow mode of operation was applied. A considerable error of target gas concentration assessment was obtained in the first two cases. The error resulted from sensor signal fluctuations encountered during their exposure either to the air at the measurement point (diffusive sampling) or to the air drawn from the measurement point (dynamic sampling). The fluctuations could be attributed to the temporal variation of physical and chemical parameters of air. The main merit of the third method consists in utilizing sensor exposure under the conditions of stopped flow for the purpose of pollutant concentration assessment. While using this method, the accuracy of target gas quantification under real conditions was comparable to the one achieved when measuring standard gases. We think that the proposed method is a valuable contribution, which addresses the increasing demand for sensor systems that perform quantitative pollution assessment in workplace air, under real conditions. This paper was presented at the Conference on Optoelectronic and Electronic Sensors held in Karpacz, Poland, on 24-27 June 2012.

  10. Application of continuation methods in physical oceanography

    NARCIS (Netherlands)

    Katsman, C.A.; Dijkstra, H.A.; Schmeits, M.J.

    2001-01-01

    A specific example will be considered in which continuation methods are used to study fundamental problems in physical oceanography.The separation be- havior of the Gulf Stream in the North Atlantic is a long standing problem in dynamical oceanography,with state-of-the-art ocean models still having

  11. Translational bioinformatics in psychoneuroimmunology: methods and applications.

    Science.gov (United States)

    Yan, Qing

    2012-01-01

    Translational bioinformatics plays an indispensable role in transforming psychoneuroimmunology (PNI) into personalized medicine. It provides a powerful method to bridge the gaps between various knowledge domains in PNI and systems biology. Translational bioinformatics methods at various systems levels can facilitate pattern recognition, and expedite and validate the discovery of systemic biomarkers to allow their incorporation into clinical trials and outcome assessments. Analysis of the correlations between genotypes and phenotypes including the behavioral-based profiles will contribute to the transition from the disease-based medicine to human-centered medicine. Translational bioinformatics would also enable the establishment of predictive models for patient responses to diseases, vaccines, and drugs. In PNI research, the development of systems biology models such as those of the neurons would play a critical role. Methods based on data integration, data mining, and knowledge representation are essential elements in building health information systems such as electronic health records and computerized decision support systems. Data integration of genes, pathophysiology, and behaviors are needed for a broad range of PNI studies. Knowledge discovery approaches such as network-based systems biology methods are valuable in studying the cross-talks among pathways in various brain regions involved in disorders such as Alzheimer's disease.

  12. Study of Vehicle Navigation Method Integrating GPS and Dead Reckoning%车辆GPS/DR组合导航方法研究

    Institute of Scientific and Technical Information of China (English)

    董绪荣; 孟庆杰; 任宇飞

    2001-01-01

    The integrated navigation technology can contribute greatly to solving automatic vehicle location. At first this paper describes the theory of the vehicle integrated navigation system, and the constant-acceleration Kalman filter model with velocity observation is presented,the field test shows that the position accuracy and reliability of the system can be improved greatly.%车辆组合导航技术是解决车辆自主定位(AVL)的一个有效途径。本文介绍了车辆组合导航系统的原理,建立了采用速度观测量的定常加速度滤波模型,实验结果表明车辆组合导航定位系统的精度和可靠性得到很大提高。

  13. Navigating the challenges of digital health innovation: considerations and solutions in developing online and smartphone-application-based interventions for mental health disorders.

    Science.gov (United States)

    Hill, Claire; Martin, Jennifer L; Thomson, Simon; Scott-Ram, Nick; Penfold, Hugh; Creswell, Cathy

    2017-08-01

    This article presents an analysis of challenges and considerations when developing digital mental health innovations. Recommendations include collaborative working between clinicians, researchers, industry and service users in order to successfully navigate challenges and to ensure e-therapies are engaging, acceptable, evidence based, scalable and sustainable. © The Royal College of Psychiatrists 2017.

  14. Application of the Doppler effect in VOR navigation%多普勒效应在全向信标导航中的应用

    Institute of Scientific and Technical Information of China (English)

    王霜; 孙丽环; 王春光

    2009-01-01

    When flying, civil airplanes must receive navigation signals transmitted by the ground navigation equipment momentarily to determine their own positions. At present, the Doppler VOR navigation is used widely,in which the variable signals are generated from Doppler effect. By analyzing the process of Doppler effect and combining with the principle of Doppler VOR beacon, we can have a con-ceptual understanding about the realization of the Doppler VOR navigation.%民航飞机在飞行过程中,需要随时接收地面台发射的导航信号,以确定自己的位置.目前应用最广泛的多普勒全向信标机,其导航信号中的可变信号是通过多普勒效应产生的.通过分析多普勒效应的产生过程,结合全向信标机的工作原理,可以对全向信标导航信号的实现有一个概念性的了解.

  15. Asymmetric synthesis II more methods and applications

    CERN Document Server

    Christmann, Mathias

    2012-01-01

    After the overwhelming success of 'Asymmetric Synthesis - The Essentials', narrating the colorful history of asymmetric synthesis, this is the second edition with latest subjects and authors. While the aim of the first edition was mainly to honor the achievements of the pioneers in asymmetric syntheses, the aim of this new edition was bringing the current developments, especially from younger colleagues, to the attention of students. The format of the book remained unchanged, i.e. short conceptual overviews by young leaders in their field including a short biography of the authors. The growing multidisciplinary research within chemistry is reflected in the selection of topics including metal catalysis, organocatalysis, physical organic chemistry, analytical chemistry, and its applications in total synthesis. The prospective reader of this book is a graduate or undergraduate student of advanced organic chemistry as well as the industrial chemist who wants to get a brief update on the current developments in th...

  16. Ensemble Machine Learning Methods and Applications

    CERN Document Server

    Ma, Yunqian

    2012-01-01

    It is common wisdom that gathering a variety of views and inputs improves the process of decision making, and, indeed, underpins a democratic society. Dubbed “ensemble learning” by researchers in computational intelligence and machine learning, it is known to improve a decision system’s robustness and accuracy. Now, fresh developments are allowing researchers to unleash the power of ensemble learning in an increasing range of real-world applications. Ensemble learning algorithms such as “boosting” and “random forest” facilitate solutions to key computational issues such as face detection and are now being applied in areas as diverse as object trackingand bioinformatics.   Responding to a shortage of literature dedicated to the topic, this volume offers comprehensive coverage of state-of-the-art ensemble learning techniques, including various contributions from researchers in leading industrial research labs. At once a solid theoretical study and a practical guide, the volume is a windfall for r...

  17. Methods and Applications in Interactive Broadcasting

    Directory of Open Access Journals (Sweden)

    George Lekakos

    2007-09-01

    Full Text Available Interactive TV technology has been addressed in many previous works, but there is sparse research on the topic of interactive content broadcasting and how to support the production process. In this article, the interactive broadcasting process is broadly defined to include studio technology and digital TV applications at consumer set-top boxes. In particular, augmented reality studio technology employs smart-projectors as light sources and blends real scenes with interactive computer graphics that are controlled at end-user terminals. Moreover, TV producer-friendly multimedia authoring tools empower the development of novel TV formats. Finally, the support for user-contributed content raises the potential to revolutionize the hierarchical TV production process, by introducing the viewer as part of content delivery chain.

  18. P olar Navigation Method Based on P olar Stereographic P rojection%基于极球面投影的极区格网坐标表示方法∗

    Institute of Scientific and Technical Information of China (English)

    王海波; 张汉武; 张萍萍; 徐适

    2016-01-01

    The global climate is getting warmer and warmer, the arctic ice cover is melting more quickly which enable the whole line navigation of arctic channel in summer, the rapid convergence of geographic meridians in arctic makes the naviga⁃tion error of the traditional navigation method based on the geographic coordinate system too strong to use. In view of the a⁃bove⁃mentioned facts, the polar navigation is researched in this paper, the problem of using in arctic of the conventional chart and the traditional navigation method is analysed firstly, the polar grid coordinate representation based on the polar stereographic projection is represented, the conversion relationship between the geographical coordinates and the grid coordi⁃nates based on the polar stereographic projection is derived, the method represented in this paper can provide a precise posi⁃tion on earth for the polar navigation, and it is convenient for polar maritime jobs.%随着全球气候变暖,北极冰盖的快速消融使北极航道的夏季全线通航成为可能,但由于极区经线的快速收敛,导致基于地理坐标的传统航海导航方法误差过大而不能使用。针对这一问题引发的极区导航问题进行研究,首先对常用海图及传统航海导航方法在极区使用存在的问题进行分析,然后采用极球面投影下的极区格网坐标表示方法,给出了极球面投影格网坐标与地理坐标的转换关系,该方法能够使在极区航行的船舶便捷、准确地确定其在地球的位置,为极区航海作业提供方便。

  19. Autonomous Robot Navigation in Human-Centered Environments Based on 3D Data Fusion

    Science.gov (United States)

    Steinhaus, Peter; Strand, Marcus; Dillmann, Rüdiger

    2007-12-01

    Efficient navigation of mobile platforms in dynamic human-centered environments is still an open research topic. We have already proposed an architecture (MEPHISTO) for a navigation system that is able to fulfill the main requirements of efficient navigation: fast and reliable sensor processing, extensive global world modeling, and distributed path planning. Our architecture uses a distributed system of sensor processing, world modeling, and path planning units. In this arcticle, we present implemented methods in the context of data fusion algorithms for 3D world modeling and real-time path planning. We also show results of the prototypic application of the system at the museum ZKM (center for art and media) in Karlsruhe.

  20. Multiangle Bistatic SAR Imaging and Fusion Based on BeiDou-2 Navigation Satellite System

    Directory of Open Access Journals (Sweden)

    Zeng Tao

    2015-01-01

    Full Text Available Bistatic Synthetic Aperture Radar (BSAR based on the Global Navigation Service System (GNSSBSAR uses navigation satellites as radar transmitters, which are low in cost. However, GNSS-BSAR images have poor resolution and low Signal-to-Noise Ratios (SNR. In this paper, a multiangle observation and data processing strategy are presented based on BeiDou-2 navigation satellite imagery, from which twenty-six BSAR images in different configurations are obtained. A region-based fusion algorithm using region of interest segmentation is proposed, and a high-quality fusion image is obtained. The results reveal that the multiangle imaging method can extend the applications of GNSS-BSAR.

  1. Fuzzy Logic Navigation and Obstacle Avoidance by a Mobile Robot in an Unknown Dynamic Environment

    Directory of Open Access Journals (Sweden)

    Mohammed Faisal

    2013-01-01

    Full Text Available Mobile robot navigation has remained an open problem over the last two decades. Mobile robots are required to navigate in unknown and dynamic environments, and in recent years the use of mobile robots in material handling has considerably increased. Usually workers push carts around warehouses and manually handle orders which is not very cost‐effective. To this end, a potential method to control a swarm of mobile robots in a warehouse with static and dynamic obstacles is to use the wireless control approach. Further, to be able to control different types of mobile robots in the warehouse, the fuzzy logic control approach has been chosen. Therefore, in this paper, an on‐line navigation technique for a wheeled mobile robot (WMR in an unknown dynamic environment using fuzzy logic techniques is investigated. In this paper, we aim to use the robot in application in a warehouse. Experimental results show the effectiveness of the proposed algorithm.

  2. a Framework of Cognitive Indoor Navigation Based on Characteristics of Indoor Spatial Environment

    Science.gov (United States)

    Si, R.; Arikawa, M.

    2015-05-01

    People are easy to get confused in indoor spatial environment. Thus, indoor navigation systems on mobile devices are expected in a wide variety of application domains. Limited by the accuracy of indoor positioning, indoor navigating systems are not common in our society. However, automatic positioning is not all about location-based services (LBS), other factors, such as good map design and user interfaces, are also important to satisfy users of LBS. Indoor spatial environment and people's indoor spatial cognition are different than those in outdoor environment, which asks for different design of LBS. This paper introduces our design methods of indoor navigation system based on the characteristics of indoor spatial environment and indoor spatial cognition.

  3. Autonomous Robot Navigation in Human-Centered Environments Based on 3D Data Fusion

    Directory of Open Access Journals (Sweden)

    Rüdiger Dillmann

    2007-01-01

    Full Text Available Efficient navigation of mobile platforms in dynamic human-centered environments is still an open research topic. We have already proposed an architecture (MEPHISTO for a navigation system that is able to fulfill the main requirements of efficient navigation: fast and reliable sensor processing, extensive global world modeling, and distributed path planning. Our architecture uses a distributed system of sensor processing, world modeling, and path planning units. In this arcticle, we present implemented methods in the context of data fusion algorithms for 3D world modeling and real-time path planning. We also show results of the prototypic application of the system at the museum ZKM (center for art and media in Karlsruhe.

  4. 一种基于 Unity3D 的移动增强现实自动导览方法%An Automatic Navigation Method of Mobile Augmented Reality Based on Unity3D

    Institute of Scientific and Technical Information of China (English)

    罗永东; 张淑军

    2015-01-01

    Augmented reality(AR) based on mobile terminal is one of the current hot fields in mobile applications and human-computer interaction .The common AR techniques mostly adopt simple template matching methods to identify mark-ers which are inaccurate and easily influenced by the change of light or occlusion ,and often lead to tracking failure .An auto-matic navigation method of mobile AR is proposed based on Unity3D in this paper .Firstly ,3D models of the scene are con-structed using Unity3D and features points of the markers are detected and tracked by Vuforia engine .Then ,according to the relative positions and angles of different markers ,the 3D models can be rendered and animations or videos are played on the visual screen .Virtual buttons are used for virtual-reality interaction .Experimental results show that this method can switch seamlessly augmented reality effects during the terminal moving process and have good robustness to illumination change and occlusion .It can be applied for automatic navigation of indoor and outdoor environments including schools ,exhi-bitions ,tourist spots ,etc .%基于移动终端的增强现实是当前移动应用和人机交互领域备受关注的热点之一,现有的增强现实开发技术多采用简单的模板匹配方式进行标识物的识别,准确率较低,受光照和遮挡的影响较大,常导致跟踪失败。该文提出了一种基于 Unity3D 的移动增强现实自动导览方法,利用 Unity3D 对场景进行三维建模,由 Vuforia 引擎检测和跟踪标识物特征点,根据不同标识物的相对位置和姿态在视平面上绘制对应的3D 模型、设置动画、播放视频,采用虚拟按钮方式进行虚实交互。实验结果表明,该方法能够在终端连续移动过程中无缝切换虚实叠加的效果,对光照变化和遮挡处理的鲁棒性较好,可用于校园、展会、旅游景点等室内外环境的自动导览。

  5. Fuzzy multiple attribute decision making methods and applications

    CERN Document Server

    Chen, Shu-Jen

    1992-01-01

    This monograph is intended for an advanced undergraduate or graduate course as well as for researchers, who want a compilation of developments in this rapidly growing field of operations research. This is a sequel to our previous works: "Multiple Objective Decision Making--Methods and Applications: A state-of-the-Art Survey" (No.164 of the Lecture Notes); "Multiple Attribute Decision Making--Methods and Applications: A State-of-the-Art Survey" (No.186 of the Lecture Notes); and "Group Decision Making under Multiple Criteria--Methods and Applications" (No.281 of the Lecture Notes). In this monograph, the literature on methods of fuzzy Multiple Attribute Decision Making (MADM) has been reviewed thoroughly and critically, and classified systematically. This study provides readers with a capsule look into the existing methods, their characteristics, and applicability to the analysis of fuzzy MADM problems. The basic concepts and algorithms from the classical MADM methods have been used in the development of the f...

  6. Application of Software Safety Analysis Methods

    Energy Technology Data Exchange (ETDEWEB)

    Park, G. Y.; Hur, S.; Cheon, S. W.; Kim, D. H.; Lee, D. Y.; Kwon, K. C. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, S. J.; Koo, Y. H. [Doosan Heavy Industries and Construction Co., Daejeon (Korea, Republic of)

    2009-05-15

    A fully digitalized reactor protection system, which is called the IDiPS-RPS, was developed through the KNICS project. The IDiPS-RPS has four redundant and separated channels. Each channel is mainly composed of a group of bistable processors which redundantly compare process variables with their corresponding setpoints and a group of coincidence processors that generate a final trip signal when a trip condition is satisfied. Each channel also contains a test processor called the ATIP and a display and command processor called the COM. All the functions were implemented in software. During the development of the safety software, various software safety analysis methods were applied, in parallel to the verification and validation (V and V) activities, along the software development life cycle. The software safety analysis methods employed were the software hazard and operability (Software HAZOP) study, the software fault tree analysis (Software FTA), and the software failure modes and effects analysis (Software FMEA)

  7. Orientation in birds. Olfactory navigation.

    Science.gov (United States)

    Papi, F

    1991-01-01

    Research work on the olfactory navigation of birds, which has only recently attracted attention, has shown that many wild species rely on an osmotactic mechanism to find food sources, even at a considerable distance. The homing pigeon, the only bird to have been thoroughly investigated with respect to olfactory navigation, has been found to rely on local odours for homeward orientation, and to integrate olfactory cues perceived during passive transportation with those picked up at the release site. It is possible to design experiments in which birds are given false olfactory information, and predictions about the effects of this can be made and tested. Pigeons are able to home from unfamiliar sites because they acquire an olfactory map extending beyond the area they have flown over. The olfactory map is built up by associating wind-borne odours with the direction from which they come; this was shown by experiments which aimed to prevent, limit or alter this association. One aim of the research work has been to test whether pigeons flying over unfamiliar areas also rely or can learn to rely on non-olfactory cues, depending on their local availability, and/or on the methods of rearing and training applied to them. Various evaluations have been made of the results; the most recent experiments, however, confirm that pigeons do derive directional information from atmospheric odours. A neurobiological approach is also in progress; its results show that some telencephalic areas are involved in orientation and olfactory navigation. The lack of any knowledge about the distribution and chemical nature of the odorants which allow pigeons to navigate hinders progress in this area of research.

  8. Robust adaptive model predictive filtering algorithm and application to integrated navigation%抗差自适应模型预测滤波及其在组合导航中的应用

    Institute of Scientific and Technical Information of China (English)

    高社生; 宋飞彪; 姜微微

    2011-01-01

    is significantly superior to that of the robust adaptive filter. The results show that the proposed filtering method can effectively inhibit the impacts of model errors and abnormal observation on the navigation solution, thus improving the precision of navigation system.

  9. Extending the application of critical path methods.

    Science.gov (United States)

    Coffey, R J; Othman, J E; Walters, J I

    1995-01-01

    Most health care organizations are using critical pathways in an attempt to reduce the variation in patient care, improve quality, enhance communication, and reduce costs. Virtually all of the critical path efforts to date have developed tables of treatments, medications, and so forth by day and have displayed them in a format known as a Gantt chart. This article presents a methodology for identifying the true "time-limiting" critical path, describes three additional methods for presenting the information--the network, precedent, and resource formats--and shows how these can significantly enhance current critical path efforts.

  10. Method and Application of Comprehensive Knowledge Discovery

    Institute of Scientific and Technical Information of China (English)

    SHA Zongyao; BIAN Fuling

    2003-01-01

    This paper proposes the principle of comprehensive knowledge discovery. Unlike most of the current knowledge discovery methods, the comprehensive knowledge discovery considers both the spatial relations and attributes of spatial entities or objects. We introduce the theory of spatial knowledge expression system and some concepts including comprehensive knowledge discovery and spatial union information table(SUIT). In theory, SUIT records all information contained in the studied objects, but in reality, because of the complexity and varieties of spatial relations,only those factors of interest to us are selected. In order to find out the comprehensive knowledge from spatial databases, an efficient comprehensive knowledge discovery algorithm called recycled algorithm (RAR) is suggested.

  11. Application of DCI to the lipid method

    Energy Technology Data Exchange (ETDEWEB)

    Raffi, J.; Lesgards, G.; Pouliquen, I.; Giamarchi, P.; Fakirian, A. [Laboratoire de Recherche sur la Qualite des Aliments, Marseille (France)

    1996-12-31

    At the end of the sixties it was proposed that a cleavage point on the triglycerides which can produce alkanes and alkenes with one or two carbons less, aldehydes and free fatty acids. The first results of work on pork were extended to chicken and poultry meats. The methodology involved extraction of the lipid fraction followed by vacuum distillation and analysis by gas chromatography (GC). Other extraction and fractionation procedures have been investigated by ADMIT and BCR groups which are more appropriate for the routine examination of large numbers of samples. In the present study, the radio-induced volatile compounds were analysed with a DI200 chromatograph, used with a head-space system, also called the DCI system (Desorption, Concentration, Injection). The main advantage of the method is that it avoids the soxhlet extraction of the lipid fraction from the foodstuffs. Several products were studied; oils, poultry meat, avocado pear. It appears that the DCI is a good and fast method provided that the temperature of the oven is controlled, which is not the case with the commercial apparatus used. (author).

  12. Scheduled Relaxation Jacobi method: improvements and applications

    CERN Document Server

    Adsuara, J E; Cerdá-Durán, P; Aloy, M A

    2015-01-01

    Elliptic partial differential equations (ePDEs) appear in a wide variety of areas of mathematics, physics and engineering. Typically, ePDEs must be solved numerically, which sets an ever growing demand for efficient and highly parallel algorithms to tackle their computational solution. The Scheduled Relaxation Jacobi (SRJ) is a promising class of methods, atypical for combining simplicity and efficiency, that has been recently introduced for solving linear Poisson-like ePDEs. The SRJ methodology relies on computing the appropriate parameters of a multilevel approach with the goal of minimizing the number of iterations needed to cut down the residuals below specified tolerances. The efficiency in the reduction of the residual increases with the number of levels employed in the algorithm. Applying the original methodology to compute the algorithm parameters with more than 5 levels notably hinders obtaining optimal SRJ schemes, as the mixed (non-linear) algebraic-differential equations from which they result bec...

  13. XRSW method, its application and development

    Energy Technology Data Exchange (ETDEWEB)

    Zheludeva, S.I.; Kovalchuk, M.V. [Russian Academy of Sciences, Institute of Crystallography, Moscow (Russian Federation)

    1996-09-01

    X-Ray Standing Waves (XRSW) may be obtained under dynamical diffraction in periodic structures or under total external reflection conditions (TR) is stratified medium. As the incident angle varies, XRSW nodes and antinodes move in the direction perpendicular to the reflecting planes, leading to drastic variation of photoelectron interaction of X-ray with matter and resulting in specific angular dependencies of secondary radiation yields (photoelectrons, fluorescence, internal photoeffect, photoluminescence, Compton and thermal diffuse scattering). The structural information - the position of investigated atoms in the direction of XRSW movement (coherent position), the distribution of atoms about this position (coherent fraction) - is obtained with the accuracy about several percents from XRSW period D. The objects under investigation are: semiconductor surface layers, heterostructure, multicomponent crystals, interfaces, adsorbed layers. Besides the development of XRSW method allow to obtain structure, geometrical and optical parameters of ultrathin films (crystalline and disordered, organic and inorganic) and nanostructures on their base.

  14. Methods applicable to membrane nanodomain studies?

    Science.gov (United States)

    Ashrafzadeh, Parham; Parmryd, Ingela

    2015-01-01

    Membrane nanodomains are dynamic liquid entities surrounded by another type of dynamic liquid. Diffusion can take place inside, around and in and out of the domains, and membrane components therefore continuously shift between domains and their surroundings. In the plasma membrane, there is the further complexity of links between membrane lipids and proteins both to the extracellular matrix and to intracellular proteins such as actin filaments. In addition, new membrane components are continuously delivered and old ones removed. On top of this, cells move. Taking all of this into account imposes great methodological challenges, and in the present chapter we discuss some methods that are currently used for membrane nanodomain studies, what information they can provide and their weaknesses.

  15. Formulation and application of Russell's method

    Science.gov (United States)

    Hou, J. W.

    1985-01-01

    It is shown that the numerical technique of Russell's momentum approach can be derived by using Hamilton's principle and Vance's numerical scheme. It results in a set of first order differnce equations for solving the angular velocities. The numerical examples show that the method is reliable. The algorithm is modified next to perform the analysis of N-body systems with closed loop topology. To increase the formulation flexibility, the equations of motion are represented by using Cartesian coordinates and Lagrange multipliers. The algorithm consists of two parts, Vance's scheme and an unconstrained minimization. The Vance's scheme is used to find the angular velocities, and the unconstrained minimization is applied to provide the correct angular displacements. The proposed scheme is further extended to find the design sensitivity of an N-body system with closed loop configuration, and to carry out the design optimization as well. The numerical example of a small-scaled mechanical system is presented to verify the proposed formulation.

  16. Scheduled Relaxation Jacobi method: Improvements and applications

    Science.gov (United States)

    Adsuara, J. E.; Cordero-Carrión, I.; Cerdá-Durán, P.; Aloy, M. A.

    2016-09-01

    Elliptic partial differential equations (ePDEs) appear in a wide variety of areas of mathematics, physics and engineering. Typically, ePDEs must be solved numerically, which sets an ever growing demand for efficient and highly parallel algorithms to tackle their computational solution. The Scheduled Relaxation Jacobi (SRJ) is a promising class of methods, atypical for combining simplicity and efficiency, that has been recently introduced for solving linear Poisson-like ePDEs. The SRJ methodology relies on computing the appropriate parameters of a multilevel approach with the goal of minimizing the number of iterations needed to cut down the residuals below specified tolerances. The efficiency in the reduction of the residual increases with the number of levels employed in the algorithm. Applying the original methodology to compute the algorithm parameters with more than 5 levels notably hinders obtaining optimal SRJ schemes, as the mixed (non-linear) algebraic-differential system of equations from which they result becomes notably stiff. Here we present a new methodology for obtaining the parameters of SRJ schemes that overcomes the limitations of the original algorithm and provide parameters for SRJ schemes with up to 15 levels and resolutions of up to 215 points per dimension, allowing for acceleration factors larger than several hundreds with respect to the Jacobi method for typical resolutions and, in some high resolution cases, close to 1000. Most of the success in finding SRJ optimal schemes with more than 10 levels is based on an analytic reduction of the complexity of the previously mentioned system of equations. Furthermore, we extend the original algorithm to apply it to certain systems of non-linear ePDEs.

  17. Applications of geophysical methods to volcano monitoring

    Science.gov (United States)

    Wynn, Jeff; Dzurisin, Daniel; Finn, Carol A.; Kauahikaua, James P.; Lahusen, Richard G.

    2006-01-01

    The array of geophysical technologies used in volcano hazards studies - some developed originally only for volcano monitoring - ranges from satellite remote sensing including InSAR to leveling and EDM surveys, campaign and telemetered GPS networks, electronic tiltmeters and strainmeters, airborne magnetic and electromagnetic surveys, short-period and broadband seismic monitoring, even microphones tuned for infrasound. They include virtually every method used in resource exploration except large-scale seismic reflection. By “geophysical ” we include both active and passive methods as well as geodetic technologies. Volcano monitoring incorporates telemetry to handle high-bandwith cameras and broadband seismometers. Critical geophysical targets include the flux of magma in shallow reservoir and lava-tube systems, changes in active hydrothermal systems, volcanic edifice stability, and lahars. Since the eruption of Mount St. Helens in Washington State in 1980, and the eruption at Pu’u O’o in Hawai’i beginning in 1983 and still continuing, dramatic advances have occurred in monitoring technology such as “crisis GIS” and lahar modeling, InSAR interferograms, as well as gas emission geochemistry sampling, and hazards mapping and eruption predictions. The on-going eruption of Mount St. Helens has led to new monitoring technologies, including advances in broadband Wi-Fi and satellite telemetry as well as new instrumentation. Assessment of the gap between adequate monitoring and threat at the 169 potentially dangerous Holocene volcanoes shows where populations are dangerously exposed to volcanic catastrophes in the United States and its territories . This paper focuses primarily on Hawai’ian volcanoes and the northern Pacific and Cascades volcanoes. The US Geological Survey, the US National Park System, and the University of Utah cooperate in a program to monitor the huge Yellowstone volcanic system, and a separate observatory monitors the restive Long Valley

  18. Novel Design of Dual-Band Conformal Co-Aperture Antenna for Airborne Navigational Application%一种新型双频共形共孔径机载导航天线设计

    Institute of Scientific and Technical Information of China (English)

    王敏; 李方

    2015-01-01

    The basic design method and advantage of conformal antenna are introduced in this paper. A novel design of dual-band conformal co-aperture antenna for airborne navigational application has been completed. This antenna operates at L band and C band with two RF output ports. A new realization way of antenna aperture synthesis has been found through the comparative analysis of different ways of antenna integration. The model of the antenna is simulated, and a prototype is fabricated and measured. The simulation and measured results are in good agreement. The gain of L-band beyond -1dB at the domain range pitch angle 60°~95° and azimuth angle -45°~45° and the gain of C-band beyond -2dB at the same time.%本文阐述了共形天线的基本设计方法及其优点,设计研制了一种新型双频共形共孔径导航天线。该天线有两个射频输出端口,分别工作在L波段和C波段。通过分析对比不同形式的天线集成手段,最终提出一种性能优良的天线孔径综合实现方式并研制实物验证。仿真数据与实测结果基本吻合,在有效的工作频带和俯仰角为60°~95°、方位角为-45°~45°的角域范围内, L波段天线增益≥-1dB,C波段天线增益≥-2dB。

  19. 全球导航星座的远地/深空导航应用研究%The application research of global navigation constellation for HEO (high earth orbit) satellites and deep-space satellites

    Institute of Scientific and Technical Information of China (English)

    赵雯雯; 张立新; 蒙艳松; 宋志强

    2011-01-01

    It has been widely studied that GNSS(global navigation satellite system) offers navigation for Ground-Based users and LEO(low earth orbit.) users. At present, it mainly depends on Ground-Based measurement and control system that HEO satellites and deep-space satellites determine their orbits and attitude, and synchronize their time. The Ground-Based measurement and control system which has complex equipment and high investment can't support abundant aerocrafts at the same time, and can't operate autonomously. This article studied the possibility of orbit determination, attitude determination, and time synchronization with global navigation constellation for HEO satellites and deep-space satellites, and consequently achieved the extended applications of global navigation constellation. It found out a high efficient way for global navigation constellation to operating as time and space reference for constellation networks, in order that constellation networks autonomously operate and navigate. And it also putted forward a solution to realize passive navigation for HEO satellites and deep-space satellites by skillfully designing the links between satellites, without increasing equipment on satellites. The research focused on the number of visible satellites and GDOP(geometric dilution of precision) value. The precision of positioning and time determination was also analyzed in order to provide new ideas for the construction of global navigation constellation.%全球卫星导航系统为低轨和地面用户提供导航服务已有广泛的研究.中高轨卫星以及深空卫星的定轨、定姿和时间同步,目前主要利用地面测控系统完成,存在设备复杂、投资高、无法同时支持大量飞行器、无法自主运行等缺点.本文研究中高轨卫星和深空卫星利用全球导航星座进行定轨、定姿和授时服务的可行性,实现其扩展应用,寻求全球导航星座作为天基网时空基准的高效途径,使得天基网的

  20. Beginnings of Satellite Navigation

    Directory of Open Access Journals (Sweden)

    Miljenko Solarić

    2008-05-01

    Full Text Available The first satellite navigation system called the Navy Navigation Satellite System (NNSS or TRANSIT was planned in the USA in 1958. It consisted of 5-6 artificial Earth satellites, was set in motion for the USA military in 1964, and in 1967 for civilian purposes. The frequency shift of received radio waves emitted from the satellite and caused by the Doppler effect was measured. The TRANSIT satellite speed of approaching or moving away was derived from that; the TRANSIT satellites emmited also their own coordinates. Then the ship's position was determined by an intersection of three hyperboloids, which were determined from differences of distances in three time intervals. Maintenance of this navigation system was stopped in 1996, but it is still being used in the USA Navy for exploring the ionosphere. Furthermore, results of Doppler measurements in international projects at the Hvar Observatory from 1982 and 1983. This was the first time in Croatia and the former country that the coordinates of the Hvar Observatory were determined in the unique world coordinate system WGS'72. The paper ends with a brief representation of the Tsiklon Doppler navigation system produced in the former Soviet Union, and there is a list of some of numerous produced and designed satellite navigation systems.Ključne riječi

  1. Experience with CANDID: Comparison algorithm for navigating digital image databases

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, P.; Cannon, M.

    1994-10-01

    This paper presents results from the authors experience with CANDID (Comparison Algorithm for Navigating Digital Image Databases), which was designed to facilitate image retrieval by content using a query-by-example methodology. A global signature describing the texture, shape, or color content is first computed for every image stored in a database, and a normalized similarity measure between probability density functions of feature vectors is used to match signatures. This method can be used to retrieve images from a database that are similar to a user-provided example image. Results for three test applications are included.

  2. 一种NLOS环境下TOA与惯导信息的融合定位方法%An integrated location method of TOA/inertial navigation in NLOS environment

    Institute of Scientific and Technical Information of China (English)

    傅军; 朱涛; 李峰

    2015-01-01

    针对基于TOA(time‐of‐arrival)的无线定位系统中信号容易受到非视距传播的影响等问题,提出了一种非视距条件下TOA测量与惯导信息的融合定位方法。该方法利用 TOA定位结果对惯导系统进行误差抑制,同时利用惯导系统的定位结果对TOA测量进行滤波处理,进而有效地减小了非视距传播对定位结果的影响。仿真实验结果表明:该方法能提高定位精度,是NLOS环境下一种有效的定位方法。%In order to solve the problem that the signal of wireless location system based on TOA (time‐of‐arrival) is easily influenced by NLOS (non‐line‐of‐sight) ,a TOA/inertial navigation infor‐mation fusion location method is proposed .The method utilizes the TOA positioning result to restrain the position errors of the inertial navigation system and meanw hile uses the positioning result of iner‐tial navigation system to filter the TOA measurements so as to effectively decrease the influence of the NLOS on the positioning result .Simulations and experiments show that the method can improve the location accuracy and so it is an effective location method in the NLOS environment .

  3. Cameras Improve Navigation for Pilots, Drivers

    Science.gov (United States)

    2012-01-01

    Advanced Scientific Concepts Inc. (ASC), of Santa Barbara, California, received SBIR awards and other funding from the Jet Propulsion Laboratory, Johnson Space Center, and Langley Research Center to develop and refine its 3D flash LIDAR technologies for space applications. Today, ASC's NASA-derived technology is sold to assist with collision avoidance, navigation, and object tracking.

  4. Extraction of the 3D Free Space from Building Models for Indoor Navigation

    Science.gov (United States)

    Diakité, A. A.; Zlatanova, S.

    2016-10-01

    For several decades, indoor navigation has been exclusively investigated in a 2D perspective, based on floor plans, projection and other 2D representations of buildings. Nevertheless, 3D representations are closer to our reality and offer a more intuitive description of the space configuration. Thanks to recent advances in 3D modelling, 3D navigation is timidly but increasingly gaining in interest through the indoor applications. But, because the structure of indoor environment is often more complex than outdoor, very simplified models are used and obstacles are not considered for indoor navigation leading to limited possibilities in complex buildings. In this paper we consider the entire configuration of the indoor environment in 3D and introduce a method to extract from it the actual navigable space as a network of connected 3D spaces (volumes). We describe how to construct such 3D free spaces from semantically rich and furnished IFC models. The approach combines the geometric, the topological and the semantic information available in a 3D model to isolate the free space from the rest of the components. Furthermore, the extraction of such navigable spaces in building models lacking of semantic information is also considered. A data structure named combinatorial maps is used to support the operations required by the process while preserving the topological and semantic information of the input models.

  5. Methods and applications of HPLC-AMS

    Science.gov (United States)

    Buchholz, Bruce A.; Dueker, Stephen R.; Lin, Yumei; Clifford, Andrew J.; Vogel, John S.

    2000-10-01

    Pharmacokinetics of physiologic doses of nutrients, pesticides, and herbicides can easily be traced in humans using a 14C-labeled compound. Basic kinetics can be monitored in blood or urine by measuring the elevation in the 14C content above the control predose tissue and converting to equivalents of the parent compound. High performance liquid chromatography (HPLC) is an excellent method for the chemical separation of complex mixtures whose profiles afford estimation of biochemical pathways of metabolism. Compounds elute from the HPLC systems with characteristic retention times and can be collected in fractions that can then be graphitized for AMS measurement. Unknowns are tentatively identified by co-elution with known standards and chemical tests that reveal functional groupings. Metabolites are quantified with the 14C signal. Thoroughly accounting for the carbon inventory in the LC solvents, ion-pairing agents, samples, and carriers adds some complexity to the analysis. In most cases the total carbon inventory is dominated by carrier. Baseline background and stability need to be carefully monitored. Limits of quantitation near 10 amol of 14C per HPLC fraction are typically achieved. Baselines are maintained by limiting injected 14C activity <0.17 Bq (4.5 pCi) on the HPLC column.

  6. Formal Methods Applications in Air Transportation

    Science.gov (United States)

    Farley, Todd

    2009-01-01

    The U.S. air transportation system is the most productive in the world, moving far more people and goods than any other. It is also the safest system in the world, thanks in part to its venerable air traffic control system. But as demand for air travel continues to grow, the air traffic control system s aging infrastructure and labor-intensive procedures are impinging on its ability to keep pace with demand. And that impinges on the growth of our economy. Air traffic control modernization has long held the promise of a more efficient air transportation system. Part of NASA s current mission is to develop advanced automation and operational concepts that will expand the capacity of our national airspace system while still maintaining its excellent record for safety. It is a challenging mission, as efforts to modernize have, for decades, been hamstrung by the inability to assure safety to the satisfaction of system operators, system regulators, and/or the traveling public. In this talk, we ll provide a brief history of air traffic control, focusing on the tension between efficiency and safety assurance, and the promise of formal methods going forward.

  7. Web API for biology with a workflow navigation system.

    Science.gov (United States)

    Kwon, Yeondae; Shigemoto, Yasumasa; Kuwana, Yoshikazu; Sugawara, Hideaki

    2009-07-01

    DNA Data Bank of Japan (DDBJ) provides Web-based systems for biological analysis, called Web APIs for biology (WABI). So far, we have developed over 20 SOAP services and several workflows that consist of a series of method invocations. In this article, we present newly developed services of WABI, that is, REST-based Web services, additional workflows and a workflow navigation system. Each Web service and workflow can be used as a complete service or a building block for programmers to construct more complex information processing systems. The workflow navigation system aims to help non-programming biologists perform analysis tasks by providing next applicable services on Web browsers according to the output of a previously selected service. With this function, users can apply multiple services consecutively only by following links without any programming or manual copy-and-paste operations on Web browsers. The listed services are determined automatically by the system referring to the dictionaries of service categories, the input/output types of services and HTML tags. WABI and the workflow navigation system are freely accessible at http://www.xml.nig.ac.jp/index.html and http://cyclamen.ddbj.nig.ac.jp/, respectively.

  8. Sensor-based navigation of air duct inspection mobile robots

    Science.gov (United States)

    Koh, Kyoungchul; Choi, H. J.; Kim, Jae-Seon; Ko, Kuk Won; Cho, Hyungsuck

    2001-02-01

    12 This paper deals with an image sensor system and its position estimation algorithm for autonomous duct cleaning and inspection mobile robots. For the real application, a hierarchical control structure that consists of robot motion controller and image sensor system is designed considering the efficient and autonomous motion behaviors in narrow space such as air ducts. The sensor's system consists of a CCD camera and two laser sources to generate slit beams. The image of the structured lights is used for calculating the geometric parameters of the air ducts which are usually designed with a rectangular section. With the acquired 3D information about the environment, the mobile robot with two differential driving wheels is able to autonomously navigates along the duct path without any human intervention. For real time navigation, the relative position estimation of the robot are performed from 3D image reconstructed by the sensor system. The calibration and image processing methods used for the sensor system are presented with the experimental data. The experimental results show the possibility of the sensor based navigation which is important for effective duct cleaning by small mobile robots.

  9. Global positioning system pseudolite-based relative navigation.

    Energy Technology Data Exchange (ETDEWEB)

    Monda, Eric W. (University of Texas, Austin, TX)

    2004-03-01

    Though the Global Positioning System has revolutionized navigation in the modern age, it is limited in its capability for some applications because an unobstructed line of sight to a minimum of four satellites is required. One way of augmenting the system in small areas is by employing pseudolites to broadcast additional signals that can be used to improve the user's position solution. At the Navigation Systems Testing Laboratory (NSTL) at NASA's Johnson Space Center in Houston, TX, research has been underway on the use of pseudolites to perform precision relative navigation. Based on the findings of previous research done at the NSTL, the method used to process the pseudolite measurements is an extended Kalman filter of the double differenced carrier phase measurements. By employing simulations of the system, as well as processing previously collected data in a real time manner, sub-meter tracking of a moving receiver with carrier phase measurements in the extended Kalman filter appears to be possible.

  10. Surgeons’ Perceptions of Spinal Navigation: Analysis of Key Factors Affecting the Lack of Adoption of Spinal Navigation Technology

    OpenAIRE

    Choo, Alexander D.; Regev, Gilad; Garfin, Steven R.; Kim, Choll W.

    2008-01-01

    Background Computer-assisted spinal navigation allows for real time localization of surgical instruments in multiple views. Its use decreases radiation exposure and clears the surgical field of the C-arm fluoroscope. Despite these advantages, spinal navigation has yet to gain general acceptance among spine surgeons. The purpose of this study is to survey spine surgeons about their opinions on the strengths and weaknesses of spinal navigation. Methods Spine surgeons from the membership of the ...

  11. A Discussion on e-Navigation and Implementation in Turkey

    Directory of Open Access Journals (Sweden)

    Y.V. Aydogdu

    2014-03-01

    Full Text Available Electronic navigation, which has great important for ship management, has taken a step with technological improvements. In the result of these enhancements, new systems appeared as well as existing systems and these systems began to be integrated each other or used data of obtaining from the others like that AIS, Radar, ECDIS etc. All these and likely future systems have been put together under the roof of enhanced navigation (e-navigation is defined by organizations such as International Maritime Organization (IMO, International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA, General Lighthouse Authority (GLA etc. Especially IALA guidelines serve as model future applications in Turkish waterways. In this study aim to redefine e-navigation concept based on maritime safety awareness, maritime service portfolio (MSC 85/26 and discuss possible applications.

  12. Navigating Distributed Services

    DEFF Research Database (Denmark)

    Beute, Berco

    2002-01-01

    , to a situation where they are distributedacross the Internet. The second trend is the shift from a virtual environment that solelyconsists of distributed documents to a virtual environment that consists of bothdistributed documents and distributed services. The third and final trend is theincreasing diversity...... of devices used to access information on the Internet.The focal point of the thesis is an initial exploration of the effects of the trends onusers as they navigate the virtual environment of distributed documents and services.To begin the thesis uses scenarios as a heuristic device to identify and analyse...... themain effects of the trends. This is followed by an exploration of theory of navigationInformation Spaces, which is in turn followed by an overview of theories, and the stateof the art in navigating distributed services. These explorations of both theory andpractice resulted in a large number of topics...

  13. 46 CFR 4.05-20 - Report of accident to aid to navigation.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Report of accident to aid to navigation. 4.05-20 Section 4.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC... accident to aid to navigation. Whenever a vessel collides with a buoy, or other aid to navigation under...

  14. PulsarPlane: a feasibility study for millisecond radio pulsar navigation

    NARCIS (Netherlands)

    Buist, Peter; Hesselink, Henk; Gibbs, Alex; Keuning, Michel; Gaubitch, Nikolay; Noroozi, Arash; Verhoeven, Chris; Heusdens, Richard; Fernandes, Jorge; Kabakchiev, Hristo; Bentum, Mark; Kestilä, Antti

    2014-01-01

    Stars have been used -in what is called celestial navigation- since thousands of years by mankind. Celestial navigation was used extensively in aviation until the 1960s, and in marine navigation until recently. It has been investigated for agriculture applications, utilized for military aircraft and

  15. NEOCHIM: An electrochemical method for environmental application

    Science.gov (United States)

    Leinz, R.W.; Hoover, D.B.; Meier, A.L.

    1999-01-01

    Ion migration and electroosmosis are the principal processes underlying electrokinetic remediation of hazardous wastes from soils. These processes are a response of charged species to an applied electrical current and they are accompanied by electrolysis of water at the electrodes through which the current is applied. Electrolysis results in the formation of OH- at the cathode and H+ at the anode. The current drives the OH- and H+ thus formed from the electrodes, through the soil and to the electrode of opposite charge. Introduction of OH- and H+ into the soil being treated modifies soil chemistry and can interfere with either the collection or immobilization of hazardous waste ions. The introduction of either OH- or H+ to the soil can be problematic to electrokinetic remediation but the problem caused by OH- has been the focus of most researchers. The problem has been addressed by flushing the OH- from the soil near the cathode or treating the soil with buffers. These treatments would apply as well to soils affected by H+. With the NEOCHIM technology, developed by the U.S. Geological Survey (USGS) for use as a sampling technique in exploration for buried ore deposits, OH- and H+ are retained in the inner compartment of two-compartment electrodes and are thus prevented from reaching the soil. This enables the extraction of cations and anions, including anionic forms of toxic metals such as HAsO42-. One of the principal attributes of NEOCHIM is the large volume of soil from which ions can be extracted. It is mathematically demonstrable that NEOCHIM extraction volumes can be orders of magnitude greater than volumes typically sampled in more conventional geochemical exploration methods or for environmental sampling. The technology may also be used to introduce selected ions into the soil that affect the solubility of ceratin ions present in the soil. Although field tests for mineral exploration have shown NEOCHIM extraction efficiencies of about 25-35%, laboratory

  16. A Robust Design Method in Product Quality Applications

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shi-an

    2003-01-01

    In order to express information on the quality grade of product designed, the target value of product quality design was described with a fuzzy number in this paper. An alternative to Taguchi′s, the robustness application design method has been recently presented. However, neither Taguchi′s method nor the alternative method is capable of dealing satisfactorily with the frequently encountered situations in which all the noise variables cannot be studied simultaneously. Based on the ideas from response surface modeling, linear models theory, and random effects models, we provide a method for estimation in the robustness application design method in product quality applications. With this new method used, the high-quality ratio of the product designed could be increased, and the ability to resist the influence of various disturbing factors and noise factors could be enhanced.

  17. Une plate-forme informatique de Navigation Textuelle : modélisation, architecture, réalisation et applications de NaviTexte.

    OpenAIRE

    Couto, Javier

    2006-01-01

    Through history, search information tools based on the notion of page, such as tables of contents, index, references, etc., had been proposed. With the rise of computers, these tools, typically static in nature, had seen their power increased. In the field of digital texts, hypertext is a great achievement from a conceptual point of view, and the massive utilization of the Internet has spread his utilization at big scale.Text navigation term has many interpretations. The most known of them re...

  18. DRIFT-ARID: Application of a method for environmental water ...

    African Journals Online (AJOL)

    DRIFT-ARID: Application of a method for environmental water requirements ... of water required (EWR) to sustain ecosystem services in non-perennial rivers need ... river types, especially episodic rivers where data are scarce or non-existent.

  19. Effects of application methods and species of wood on color ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-02

    Nov 2, 2009 ... topcoat-clear, (SCPt) gave the highest metric chroma value among the three different application methods. Key words: ... gloss; and on the other side, the discoloration of the wood has to be ..... Lacquer and Related. Materials.

  20. Irrigation methods for efficient water application: 40 years of South ...

    African Journals Online (AJOL)

    Irrigation methods for efficient water application: 40 years of South African ... to a specific situation rather than by calculating various performance indicators. ... of Irrigation Water Use covers 4 levels of water-management infrastructure: the ...