Lighting energy savings potential of split-pane electrochromic windows controlled for daylighting with visual comfort

Energy Technology Data Exchange (ETDEWEB)

Software, Anyhere; Fernandes, Luis; Lee, Eleanor; Ward, Greg

2013-03-15

A simulation study was conducted to evaluate lighting energy savings of split-pane electrochromic (EC) windows controlled to satisfy key visual comfort parameters. Using the Radiance lighting simulation software, interior illuminance and luminance levels were computed for a south-facing private office illuminated by a window split into two independently-controlled EC panes. The transmittance of these was optimized hourly for a workplane illuminance target while meeting visual comfort constraints, using a least-squares algorithm with linear inequality constraints. Blinds were successively deployed until visual comfort criteria were satisfied. The energy performance of electrochromics proved to be highly dependent on how blinds were controlled. With hourly blind position adjustments, electrochromics showed significantly higher (62percent and 53percent, respectively without and with overhang) lighting energy consumption than clear glass. With a control algorithm designed to better approximate realistic manual control by an occupant, electrochromics achieved significant savings (48percent and 37percent, respectively without and with overhang). In all cases, energy consumption decreased when the workplace illuminance target was increased. In addition, the fraction of time during which the occupant had an unobstructed view of the outside was significantly greater with electrochromics: 10 months out of the year versus a handful of days for the reference case.

Efecto del uso de diferentes aditivos de panificación en la calidad de panes elaborados con harinas compuestas a base de harina de trigo y germen desgrasado de maíz

Directory of Open Access Journals (Sweden)

Marisela Granito

1997-08-01

Full Text Available Dado el alto consumo de productos alimenticios a base de trigo (HT importado y la producción industrial de subproductos del procesamiento del maíz (HGDM, ricos en fibra dietética, proteínas y minerales, en Venezuela se ha estudado la factibilidad técnica de sustituir parcialmente HT por HGDM en la elaboración de productos horneados como galletas y panes. Por otra parte, considerando las restricciones existentes en el uso del bromato de potasio (BP como aditivo de panificación y que el ácido ascórbico (AA ha sido probado exitosamente como aditivo en panes a base de HT, en este estudio se utilizaron los aditivos (BP, (AA, gluten y mezclas de ellos, en la elaboración de panes donde la HT fue sustituida por HGDM a niveles de 10% y 15%. Se encontro que las mezclas de aditivos que originaron los menores pesos específicos fueron las que contenían gluten , seguidas por 75 ppm AA y 25 ppm BP. Se observo el efecto sinergístico de estos dos aditivos, tanto en los panes control como en los que contenían HGDM. Se puede concluir que la calidad panificable y el proceso de envejecimiento en los panes donde se sustituye la HT por HGDM, a niveles de 10%, sigue patrones similares al de los panes de 100% HT, por lo que se podría considerar viable dicha sustitución. A niveles de 15% de sustitución, la presencia de fibra origina algunos cambios en el patrón de comportamiento, por lo que se sugiere el uso de hemicelulasas en las mezclas.

Navigation in musculoskeletal oncology: An overview

Directory of Open Access Journals (Sweden)

Guy Vernon Morris

2018-01-01

Full Text Available Navigation in surgery has increasingly become more commonplace. The use of this technological advancement has enabled ever more complex and detailed surgery to be performed to the benefit of surgeons and patients alike. This is particularly so when applying the use of navigation within the field of orthopedic oncology. The developments in computer processing power coupled with the improvements in scanning technologies have permitted the incorporation of navigational procedures into day-to-day practice. A comprehensive search of PubMed using the search terms “navigation”, “orthopaedic” and “oncology” yielded 97 results. After filtering for English language papers, excluding spinal surgery and review articles, this resulted in 38 clinical studies and case reports. These were analyzed in detail by the authors (GM and JS and the most relevant papers reviewed. We have sought to provide an overview of the main types of navigation systems currently available within orthopedic oncology and to assess some of the evidence behind its use.

From translation to navigation of different discourses

DEFF Research Database (Denmark)

Livonen, Mirja; Sonnenwald, Diane H.

1998-01-01

' own search experience. Data further suggest that searchers navigate these discourses dynamically and have preferences for certain discourses. Conceptualizing the selection of search terms as a meeting place of different discourses provides new insights into the complex nature of the search term...

Improved artificial bee colony algorithm based gravity matching navigation method.

Science.gov (United States)

Gao, Wei; Zhao, Bo; Zhou, Guang Tao; Wang, Qiu Ying; Yu, Chun Yang

2014-07-18

Gravity matching navigation algorithm is one of the key technologies for gravity aided inertial navigation systems. With the development of intelligent algorithms, the powerful search ability of the Artificial Bee Colony (ABC) algorithm makes it possible to be applied to the gravity matching navigation field. However, existing search mechanisms of basic ABC algorithms cannot meet the need for high accuracy in gravity aided navigation. Firstly, proper modifications are proposed to improve the performance of the basic ABC algorithm. Secondly, a new search mechanism is presented in this paper which is based on an improved ABC algorithm using external speed information. At last, modified Hausdorff distance is introduced to screen the possible matching results. Both simulations and ocean experiments verify the feasibility of the method, and results show that the matching rate of the method is high enough to obtain a precise matching position.

Proper understanding of relevant articles in RCC-M and PANE G-7-002

International Nuclear Information System (INIS)

Sun Zaozhan

2005-01-01

The French code, 'Design and construction rules for mechanical components of PWR nuclear island' RCC-M and the Russian code 'Regulations for strength analysis of equipment and pipelines of atomic power plants' PANE G-7-002, both for nuke plant design, are sometimes used in China, and discrepancies in understanding some articles of such foreign design codes will some times give different conclusions as 'acceptable' or 'unacceptable' the concerned material or product. Section IV of RCC-M concerns with qualification and performance of welding operations. Article S 3150 in this section covers the retesting procedures and article S 3152 in it relates to destructive tests. One sentence in Article S 3152 reads like this, 'Where an unsatisfactory result is due to the poor execution of the test or the presence of a defect in the specimen, the relevant result must be discarded and the test shall be repeated.' The 'presence of a defect' arose discrepancies in understanding the sentence because there is no definition in RCC-M to clarify their scopes such as how big a defect should be considered as a 'defect' that can invalidate the test results. Section 5.5 of PANE G-7-002 concerns the determination of critical brittle temperature. It stipulates that critical brittle temperature T k is a temperature at which the impact strength values must be higher than the specified ones. The specified criterion values of impact strength are related to the yield strength but it is not quite definite that the yield strength values in the table should be the documented minimum values for different materials or that they should be the tested results of the concerned lots of materials the specimen represents. The two different understandings of the yield strength values will sometimes give contrary conclusions. This paper introduces the different opinions in understanding the code texts, makes clear what it supports, and states in detail the reasons it so believes. (authors)

A personal tourism navigation system to support traveling multiple destinations with time restrictions

OpenAIRE

Maruyama, Atsushi; Shibata, Naoki; Murata, Yoshihiro; Yasumoto, Keiichi; Ito, Minoru

2004-01-01

We propose a personal navigation system (called PNS) which navigates a tourist through multiple destinations efficiently. In our PNS, a tourist can specify multiple destinations with desired arrival/stay time and preference degree. The system calculates the route including part of the destinations satisfying tourist's requirements and navigates him/her. For the above route search problem, we have developed an efficient route search algorithm using a genetic algorithm. We have designed and imp...

A Combination of Terrain Prediction and Correction for Search and Rescue Robot Autonomous Navigation

Directory of Open Access Journals (Sweden)

Yan Guo

2009-09-01

Full Text Available This paper presents a novel two-step autonomous navigation method for search and rescue robot. The algorithm based on the vision is proposed for terrain identification to give a prediction of the safest path with the support vector regression machine (SVRM trained off-line with the texture feature and color features. And correction algorithm of the prediction based the vibration information is developed during the robot traveling, using the judgment function given in the paper. The region with fault prediction will be corrected with the real traversability value and be used to update the SVRM. The experiment demonstrates that this method could help the robot to find the optimal path and be protected from the trap brought from the error between prediction and the real environment.

Seasonal shading of walls with transparent thermal insulation by means of prismatic panes; Saisonale Abschattung von transparent gedaemmten Waenden mit Hilfe von Prismenscheiben

Energy Technology Data Exchange (ETDEWEB)

Christoffers, D.; Kneser, P.; Schramm, U. [Institut fuer Solarenergieforschung GmbH Hameln/Emmerthal (ISFH), Emmerthal (Germany). Abt. Systemtechnik von Solaranlagen

1998-02-01

Using prismatic panes, a seasonal shading responsive to the sun`s position can be realized. Thus the solar gains from direct radiation can be closely matched to the annual pattern of the heating requirements of buildings. The panes are suitable for window or facade elements in applications which do not need transparency insulated walls. The direct radiation received on a vertical south-oriented facade is reduced to 10% on clear summer days, while 90% is transmitted on clear winter days. The paper reports on results from computer simulations and experiences from a one year field test. (orig.) [Deutsch] Mit Hilfe von Prismenscheiben kann eine sonnenstandsabhaengige, saisonale Verschattung realisiert werden. Damit lassen sich solare Gewinne aus direkter Einstrahlung sehr gut an den jaehrlichen Verlauf des Heizenergiebedarfs von Gebaeuden anpassen. Sie eignen sich als nach Sueden weisende Fenster- und Fassadenelemente vorzugsweise in Bereichen, die keinen freien Durchblick benoetigen, insbesondere auch fuer transparent gedaemmte Solarwaende. Die auf die Suedfassade treffende Direktstrahlung wird durch die Prismenscheibe an klaren Wintertagen auf etwa 90%, an klaren Sommertagen auf 10% reduziert. Der Beitrag beschreibt die Ergebnisse von Simulationsrechnungen und die Erfahrungen aus einem einjaehrigen Praxistest. (orig.)

Evaluation of a novel Conjunctive Exploratory Navigation Interface for consumer health information: a crowdsourced comparative study.

Science.gov (United States)

Cui, Licong; Carter, Rebecca; Zhang, Guo-Qiang

2014-02-10

Numerous consumer health information websites have been developed to provide consumers access to health information. However, lookup search is insufficient for consumers to take full advantage of these rich public information resources. Exploratory search is considered a promising complementary mechanism, but its efficacy has never before been rigorously evaluated for consumer health information retrieval interfaces. This study aims to (1) introduce a novel Conjunctive Exploratory Navigation Interface (CENI) for supporting effective consumer health information retrieval and navigation, and (2) evaluate the effectiveness of CENI through a search-interface comparative evaluation using crowdsourcing with Amazon Mechanical Turk (AMT). We collected over 60,000 consumer health questions from NetWellness, one of the first consumer health websites to provide high-quality health information. We designed and developed a novel conjunctive exploratory navigation interface to explore NetWellness health questions with health topics as dynamic and searchable menus. To investigate the effectiveness of CENI, we developed a second interface with keyword-based search only. A crowdsourcing comparative study was carefully designed to compare three search modes of interest: (A) the topic-navigation-based CENI, (B) the keyword-based lookup interface, and (C) either the most commonly available lookup search interface with Google, or the resident advanced search offered by NetWellness. To compare the effectiveness of the three search modes, 9 search tasks were designed with relevant health questions from NetWellness. Each task included a rating of difficulty level and questions for validating the quality of answers. Ninety anonymous and unique AMT workers were recruited as participants. Repeated-measures ANOVA analysis of the data showed the search modes A, B, and C had statistically significant differences among their levels of difficulty (Pconsumer health information retrieval and

A cognitive robotic system based on the Soar cognitive architecture for mobile robot navigation, search, and mapping missions

Science.gov (United States)

Hanford, Scott D.

Most unmanned vehicles used for civilian and military applications are remotely operated or are designed for specific applications. As these vehicles are used to perform more difficult missions or a larger number of missions in remote environments, there will be a great need for these vehicles to behave intelligently and autonomously. Cognitive architectures, computer programs that define mechanisms that are important for modeling and generating domain-independent intelligent behavior, have the potential for generating intelligent and autonomous behavior in unmanned vehicles. The research described in this presentation explored the use of the Soar cognitive architecture for cognitive robotics. The Cognitive Robotic System (CRS) has been developed to integrate software systems for motor control and sensor processing with Soar for unmanned vehicle control. The CRS has been tested using two mobile robot missions: outdoor navigation and search in an indoor environment. The use of the CRS for the outdoor navigation mission demonstrated that a Soar agent could autonomously navigate to a specified location while avoiding obstacles, including cul-de-sacs, with only a minimal amount of knowledge about the environment. While most systems use information from maps or long-range perceptual capabilities to avoid cul-de-sacs, a Soar agent in the CRS was able to recognize when a simple approach to avoiding obstacles was unsuccessful and switch to a different strategy for avoiding complex obstacles. During the indoor search mission, the CRS autonomously and intelligently searches a building for an object of interest and common intersection types. While searching the building, the Soar agent builds a topological map of the environment using information about the intersections the CRS detects. The agent uses this topological model (along with Soar's reasoning, planning, and learning mechanisms) to make intelligent decisions about how to effectively search the building. Once the

The EBI search engine: EBI search as a service—making biological data accessible for all

Science.gov (United States)

Park, Young M.; Squizzato, Silvano; Buso, Nicola; Gur, Tamer

2017-01-01

Abstract We present an update of the EBI Search engine, an easy-to-use fast text search and indexing system with powerful data navigation and retrieval capabilities. The interconnectivity that exists between data resources at EMBL–EBI provides easy, quick and precise navigation and a better understanding of the relationship between different data types that include nucleotide and protein sequences, genes, gene products, proteins, protein domains, protein families, enzymes and macromolecular structures, as well as the life science literature. EBI Search provides a powerful RESTful API that enables its integration into third-party portals, thus providing ‘Search as a Service’ capabilities, which are the main topic of this article. PMID:28472374

Software for Allocating Resources in the Deep Space Network

Science.gov (United States)

Wang, Yeou-Fang; Borden, Chester; Zendejas, Silvino; Baldwin, John

2003-01-01

TIGRAS 2.0 is a computer program designed to satisfy a need for improved means for analyzing the tracking demands of interplanetary space-flight missions upon the set of ground antenna resources of the Deep Space Network (DSN) and for allocating those resources. Written in Microsoft Visual C++, TIGRAS 2.0 provides a single rich graphical analysis environment for use by diverse DSN personnel, by connecting to various data sources (relational databases or files) based on the stages of the analyses being performed. Notable among the algorithms implemented by TIGRAS 2.0 are a DSN antenna-load-forecasting algorithm and a conflict-aware DSN schedule-generating algorithm. Computers running TIGRAS 2.0 can also be connected using SOAP/XML to a Web services server that provides analysis services via the World Wide Web. TIGRAS 2.0 supports multiple windows and multiple panes in each window for users to view and use information, all in the same environment, to eliminate repeated switching among various application programs and Web pages. TIGRAS 2.0 enables the use of multiple windows for various requirements, trajectory-based time intervals during which spacecraft are viewable, ground resources, forecasts, and schedules. Each window includes a time navigation pane, a selection pane, a graphical display pane, a list pane, and a statistics pane.

The EBI search engine: EBI search as a service-making biological data accessible for all.

Science.gov (United States)

Park, Young M; Squizzato, Silvano; Buso, Nicola; Gur, Tamer; Lopez, Rodrigo

2017-07-03

We present an update of the EBI Search engine, an easy-to-use fast text search and indexing system with powerful data navigation and retrieval capabilities. The interconnectivity that exists between data resources at EMBL-EBI provides easy, quick and precise navigation and a better understanding of the relationship between different data types that include nucleotide and protein sequences, genes, gene products, proteins, protein domains, protein families, enzymes and macromolecular structures, as well as the life science literature. EBI Search provides a powerful RESTful API that enables its integration into third-party portals, thus providing 'Search as a Service' capabilities, which are the main topic of this article. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Solar-based navigation for robotic explorers

Science.gov (United States)

Shillcutt, Kimberly Jo

2000-12-01

This thesis introduces the application of solar position and shadowing information to robotic exploration. Power is a critical resource for robots with remote, long-term missions, so this research focuses on the power generation capabilities of robotic explorers during navigational tasks, in addition to power consumption. Solar power is primarily considered, with the possibility of wind power also contemplated. Information about the environment, including the solar ephemeris, terrain features, time of day, and surface location, is incorporated into a planning structure, allowing robots to accurately predict shadowing and thus potential costs and gains during navigational tasks. By evaluating its potential to generate and expend power, a robot can extend its lifetime and accomplishments. The primary tasks studied are coverage patterns, with a variety of plans developed for this research. The use of sun, terrain and temporal information also enables new capabilities of identifying and following sun-synchronous and sun-seeking paths. Digital elevation maps are combined with an ephemeris algorithm to calculate the altitude and azimuth of the sun from surface locations, and to identify and map shadows. Solar navigation path simulators use this information to perform searches through two-dimensional space, while considering temporal changes. Step by step simulations of coverage patterns also incorporate time in addition to location. Evaluations of solar and wind power generation, power consumption, area coverage, area overlap, and time are generated for sets of coverage patterns, with on-board environmental information linked to the simulations. This research is implemented on the Nomad robot for the Robotic Antarctic Meteorite Search. Simulators have been developed for coverage pattern tests, as well as for sun-synchronous and sun-seeking path searches. Results of field work and simulations are reported and analyzed, with demonstrated improvements in efficiency

Science on the Web: Secondary School Students' Navigation Patterns and Preferred Pages' Characteristics

Science.gov (United States)

Dimopoulos, Kostas; Asimakopoulos, Apostolos

2010-01-01

This study aims to explore navigation patterns and preferred pages' characteristics of ten secondary school students searching the web for information about cloning. The students navigated the Web for as long as they wished in a context of minimum support of teaching staff. Their navigation patterns were analyzed using audit trail data software.…

Testing Two Tools for Multimodal Navigation

Directory of Open Access Journals (Sweden)

Mats Liljedahl

2012-01-01

Full Text Available The latest smartphones with GPS, electronic compasses, directional audio, touch screens, and so forth, hold a potential for location-based services that are easier to use and that let users focus on their activities and the environment around them. Rather than interpreting maps, users can search for information by pointing in a direction and database queries can be created from GPS location and compass data. Users can also get guidance to locations through point and sweep gestures, spatial sound, and simple graphics. This paper describes two studies testing two applications with multimodal user interfaces for navigation and information retrieval. The applications allow users to search for information and get navigation support using combinations of point and sweep gestures, nonspeech audio, graphics, and text. Tests show that users appreciated both applications for their ease of use and for allowing users to interact directly with the surrounding environment.

The EBI Search engine: providing search and retrieval functionality for biological data from EMBL-EBI.

Science.gov (United States)

Squizzato, Silvano; Park, Young Mi; Buso, Nicola; Gur, Tamer; Cowley, Andrew; Li, Weizhong; Uludag, Mahmut; Pundir, Sangya; Cham, Jennifer A; McWilliam, Hamish; Lopez, Rodrigo

2015-07-01

The European Bioinformatics Institute (EMBL-EBI-https://www.ebi.ac.uk) provides free and unrestricted access to data across all major areas of biology and biomedicine. Searching and extracting knowledge across these domains requires a fast and scalable solution that addresses the requirements of domain experts as well as casual users. We present the EBI Search engine, referred to here as 'EBI Search', an easy-to-use fast text search and indexing system with powerful data navigation and retrieval capabilities. API integration provides access to analytical tools, allowing users to further investigate the results of their search. The interconnectivity that exists between data resources at EMBL-EBI provides easy, quick and precise navigation and a better understanding of the relationship between different data types including sequences, genes, gene products, proteins, protein domains, protein families, enzymes and macromolecular structures, together with relevant life science literature. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

An Imaging Sensor-Aided Vision Navigation Approach that Uses a Geo-Referenced Image Database.

Science.gov (United States)

Li, Yan; Hu, Qingwu; Wu, Meng; Gao, Yang

2016-01-28

In determining position and attitude, vision navigation via real-time image processing of data collected from imaging sensors is advanced without a high-performance global positioning system (GPS) and an inertial measurement unit (IMU). Vision navigation is widely used in indoor navigation, far space navigation, and multiple sensor-integrated mobile mapping. This paper proposes a novel vision navigation approach aided by imaging sensors and that uses a high-accuracy geo-referenced image database (GRID) for high-precision navigation of multiple sensor platforms in environments with poor GPS. First, the framework of GRID-aided vision navigation is developed with sequence images from land-based mobile mapping systems that integrate multiple sensors. Second, a highly efficient GRID storage management model is established based on the linear index of a road segment for fast image searches and retrieval. Third, a robust image matching algorithm is presented to search and match a real-time image with the GRID. Subsequently, the image matched with the real-time scene is considered to calculate the 3D navigation parameter of multiple sensor platforms. Experimental results show that the proposed approach retrieves images efficiently and has navigation accuracies of 1.2 m in a plane and 1.8 m in height under GPS loss in 5 min and within 1500 m.

The use of x-ray pulsar-based navigation method for interplanetary flight

Science.gov (United States)

Yang, Bo; Guo, Xingcan; Yang, Yong

2009-07-01

As interplanetary missions are increasingly complex, the existing unique mature interplanetary navigation method mainly based on radiometric tracking techniques of Deep Space Network can not meet the rising demands of autonomous real-time navigation. This paper studied the applications for interplanetary flights of a new navigation technology under rapid development-the X-ray pulsar-based navigation for spacecraft (XPNAV), and valued its performance with a computer simulation. The XPNAV is an excellent autonomous real-time navigation method, and can provide comprehensive navigation information, including position, velocity, attitude, attitude rate and time. In the paper the fundamental principles and time transformation of the XPNAV were analyzed, and then the Delta-correction XPNAV blending the vehicles' trajectory dynamics with the pulse time-of-arrival differences at nominal and estimated spacecraft locations within an Unscented Kalman Filter (UKF) was discussed with a background mission of Mars Pathfinder during the heliocentric transferring orbit. The XPNAV has an intractable problem of integer pulse phase cycle ambiguities similar to the GPS carrier phase navigation. This article innovatively proposed the non-ambiguity assumption approach based on an analysis of the search space array method to resolve pulse phase cycle ambiguities between the nominal position and estimated position of the spacecraft. The simulation results show that the search space array method are computationally intensive and require long processing time when the position errors are large, and the non-ambiguity assumption method can solve ambiguity problem quickly and reliably. It is deemed that autonomous real-time integrated navigation system of the XPNAV blending with DSN, celestial navigation, inertial navigation and so on will be the development direction of interplanetary flight navigation system in the future.

Towards automated visual flexible endoscope navigation.

Science.gov (United States)

van der Stap, Nanda; van der Heijden, Ferdinand; Broeders, Ivo A M J

2013-10-01

The design of flexible endoscopes has not changed significantly in the past 50 years. A trend is observed towards a wider application of flexible endoscopes with an increasing role in complex intraluminal therapeutic procedures. The nonintuitive and nonergonomical steering mechanism now forms a barrier in the extension of flexible endoscope applications. Automating the navigation of endoscopes could be a solution for this problem. This paper summarizes the current state of the art in image-based navigation algorithms. The objectives are to find the most promising navigation system(s) to date and to indicate fields for further research. A systematic literature search was performed using three general search terms in two medical-technological literature databases. Papers were included according to the inclusion criteria. A total of 135 papers were analyzed. Ultimately, 26 were included. Navigation often is based on visual information, which means steering the endoscope using the images that the endoscope produces. Two main techniques are described: lumen centralization and visual odometry. Although the research results are promising, no successful, commercially available automated flexible endoscopy system exists to date. Automated systems that employ conventional flexible endoscopes show the most promising prospects in terms of cost and applicability. To produce such a system, the research focus should lie on finding low-cost mechatronics and technologically robust steering algorithms. Additional functionality and increased efficiency can be obtained through software development. The first priority is to find real-time, robust steering algorithms. These algorithms need to handle bubbles, motion blur, and other image artifacts without disrupting the steering process.

Growing Homophilic Networks Are Natural Navigable Small Worlds.

Science.gov (United States)

Malkov, Yury A; Ponomarenko, Alexander

2016-01-01

Navigability, an ability to find a logarithmically short path between elements using only local information, is one of the most fascinating properties of real-life networks. However, the exact mechanism responsible for the formation of navigation properties remained unknown. We show that navigability can be achieved by using only two ingredients present in the majority of networks: network growth and local homophily, giving a persuasive answer how the navigation appears in real-life networks. A very simple algorithm produces hierarchical self-similar optimally wired navigable small world networks with exponential degree distribution by using only local information. Adding preferential attachment produces a scale-free network which has shorter greedy paths, but worse (power law) scaling of the information extraction locality (algorithmic complexity of a search). Introducing saturation of the preferential attachment leads to truncated scale-free degree distribution that offers a good tradeoff between these parameters and can be useful for practical applications. Several features of the model are observed in real-life networks, in particular in the brain neural networks, supporting the earlier suggestions that they are navigable.

Growing Homophilic Networks Are Natural Navigable Small Worlds.

Directory of Open Access Journals (Sweden)

Yury A Malkov

Full Text Available Navigability, an ability to find a logarithmically short path between elements using only local information, is one of the most fascinating properties of real-life networks. However, the exact mechanism responsible for the formation of navigation properties remained unknown. We show that navigability can be achieved by using only two ingredients present in the majority of networks: network growth and local homophily, giving a persuasive answer how the navigation appears in real-life networks. A very simple algorithm produces hierarchical self-similar optimally wired navigable small world networks with exponential degree distribution by using only local information. Adding preferential attachment produces a scale-free network which has shorter greedy paths, but worse (power law scaling of the information extraction locality (algorithmic complexity of a search. Introducing saturation of the preferential attachment leads to truncated scale-free degree distribution that offers a good tradeoff between these parameters and can be useful for practical applications. Several features of the model are observed in real-life networks, in particular in the brain neural networks, supporting the earlier suggestions that they are navigable.

Transversal of Procedure Elements in a Computerized Procedure System

Energy Technology Data Exchange (ETDEWEB)

Jung, Yeonsub [KHNP Central Research Institute, Daejeon (Korea, Republic of)

2014-05-15

APR1400 MCR(Main Control Room) has introduced CPS(Computerized Procedure System). APR400 CPS is framed with overview pane, step detail pane, and monitoring pane. The overview shows the step in one dimensional array. Diagram in the step detail pane is called as flowlogic diagram. The flowlogic diagram has advantage of being intuitive and not being segmented so that the interfaces are easy to follow and understand. While developing CPS software or training operators these interfaces, however, there is still areas to refine behaviors of flowlogic diagram. If flowlogic diagram has contingency instructions, it is sometime difficult to interpret it properly. Therefore this paper is trying to explain behavior of flowlogic diagram in view of procedure elements. Procedure execution can be called as transversal of steps and instructions in flowlogic diagram. Both hierarchy of procedures elements and flowlogic diagram provides useful framework to test transversal with completeness. Navigation button behaviors are interpreted in view of flowlogic diagram. The framework and flowlogic diagram can be further applied to improve CPS user interfaces.

Realistic searches on stretched exponential networks

Indian Academy of Sciences (India)

We consider navigation or search schemes on networks which have a degree distribution of the form () ∝ exp(−). In addition, the linking probability is taken to be dependent on social distances and is governed by a parameter . The searches are realistic in the sense that not all search chains can be completed.

Path Complexity in Virtual Water Maze Navigation: Differential Associations with Age, Sex, and Regional Brain Volume.

Science.gov (United States)

Daugherty, Ana M; Yuan, Peng; Dahle, Cheryl L; Bender, Andrew R; Yang, Yiqin; Raz, Naftali

2015-09-01

Studies of human navigation in virtual maze environments have consistently linked advanced age with greater distance traveled between the start and the goal and longer duration of the search. Observations of search path geometry suggest that routes taken by older adults may be unnecessarily complex and that excessive path complexity may be an indicator of cognitive difficulties experienced by older navigators. In a sample of healthy adults, we quantify search path complexity in a virtual Morris water maze with a novel method based on fractal dimensionality. In a two-level hierarchical linear model, we estimated improvement in navigation performance across trials by a decline in route length, shortening of search time, and reduction in fractal dimensionality of the path. While replicating commonly reported age and sex differences in time and distance indices, a reduction in fractal dimension of the path accounted for improvement across trials, independent of age or sex. The volumes of brain regions associated with the establishment of cognitive maps (parahippocampal gyrus and hippocampus) were related to path dimensionality, but not to the total distance and time. Thus, fractal dimensionality of a navigational path may present a useful complementary method of quantifying performance in navigation. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Human Performance Assessments when Using Augmented Reality for Navigation

National Research Council Canada - National Science Library

Goldiez, Brian F; Saptoka, Nabin; Aedunuthula, Prashanth

2006-01-01

Human performance executing search and rescue type of navigation is one area that can benefit from augmented reality technology when the proper computer generated information is added to a real scene...

Image and information management system

Science.gov (United States)

Robertson, Tina L. (Inventor); Raney, Michael C. (Inventor); Dougherty, Dennis M. (Inventor); Kent, Peter C. (Inventor); Brucker, Russell X. (Inventor); Lampert, Daryl A. (Inventor)

2009-01-01

A system and methods through which pictorial views of an object's configuration, arranged in a hierarchical fashion, are navigated by a person to establish a visual context within the configuration. The visual context is automatically translated by the system into a set of search parameters driving retrieval of structured data and content (images, documents, multimedia, etc.) associated with the specific context. The system places ''hot spots'', or actionable regions, on various portions of the pictorials representing the object. When a user interacts with an actionable region, a more detailed pictorial from the hierarchy is presented representing that portion of the object, along with real-time feedback in the form of a popup pane containing information about that region, and counts-by-type reflecting the number of items that are available within the system associated with the specific context and search filters established at that point in time.

Metrics for evaluating patient navigation during cancer diagnosis and treatment: crafting a policy-relevant research agenda for patient navigation in cancer care.

Science.gov (United States)

Guadagnolo, B Ashleigh; Dohan, Daniel; Raich, Peter

2011-08-01

Racial and ethnic minorities as well as other vulnerable populations experience disparate cancer-related health outcomes. Patient navigation is an emerging health care delivery innovation that offers promise in improving quality of cancer care delivery to these patients who experience unique health-access barriers. Metrics are needed to evaluate whether patient navigation can improve quality of care delivery, health outcomes, and overall value in health care during diagnosis and treatment of cancer. Information regarding the current state of the science examining patient navigation interventions was gathered via search of the published scientific literature. A focus group of providers, patient navigators, and health-policy experts was convened as part of the Patient Navigation Leadership Summit sponsored by the American Cancer Society. Key metrics were identified for assessing the efficacy of patient navigation in cancer diagnosis and treatment. Patient navigation data exist for all stages of cancer care; however, the literature is more robust for its implementation during prevention, screening, and early diagnostic workup of cancer. Relatively fewer data are reported for outcomes and efficacy of patient navigation during cancer treatment. Metrics are proposed for a policy-relevant research agenda to evaluate the efficacy of patient navigation in cancer diagnosis and treatment. Patient navigation is understudied with respect to its use in cancer diagnosis and treatment. Core metrics are defined to evaluate its efficacy in improving outcomes and mitigating health-access barriers. Copyright © 2011 American Cancer Society.

Experiences of cancer patients in a patient navigation program: a qualitative systematic review.

Science.gov (United States)

Tan, Clarice Hwee Hoon; Wilson, Sally; McConigley, Ruth

2015-03-12

A patient navigation program is a model of care which entails trained personnel providing individualized and assistive care to adult oncology patients to help the patients overcome barriers. A further aim of the program is to achieve continuity of care as patients experience the complex healthcare system. Patient navigation is a new model of care in many institutions, and as such the experiences of patients in the patient navigation program remains inconclusive. The review seeks to understand the experiences of adult patients in patient navigation programs and how patient navigators impact the challenges patients encounter in the cancer care continuum. Participants of interest were adult cancer patients more than 18 years of age who are receiving or have received cancer care and are in a patient navigation program or had been in a hospital patient navigation program. Types of intervention(s)/phenomena of interest: The phenomenon of interest was the experiences of adult cancer patients who used patient navigation programs in hospital including how patient navigators impact on the challenges patients encounter in the cancer care continuum. Types of studies: This review considered studies that focused on qualitative data including, but not limited to, designs such as phenomenology, grounded theory, action research and exploratory studies. The review includes patient navigation programs within a hospital setting. Types of outcome: The review sought to understand the experiences of patients with cancer in patient navigation programs in the hospital. A three-step search strategy was used. An initial search to identify keywords was undertaken in PubMed and Science Direct followed by an expanded search using all identified keywords and index terms specific to each included database. The reference lists of included papers were then searched for any other relevant studies. Each paper was assessed independently by two reviewers for methodological quality using the Joanna

Search Analytics for Your Site

CERN Document Server

Rosenfeld, Louis

2011-01-01

Any organization that has a searchable web site or intranet is sitting on top of hugely valuable and usually under-exploited data: logs that capture what users are searching for, how often each query was searched, and how many results each query retrieved. Search queries are gold: they are real data that show us exactly what users are searching for in their own words. This book shows you how to use search analytics to carry on a conversation with your customers: listen to and understand their needs, and improve your content, navigation and search performance to meet those needs.

The AXES-lite video search engine

NARCIS (Netherlands)

Chen, Shu; McGuinness, Kevin; Aly, Robin; de Jong, Franciska M.G.; O' Connor, Noel E.

The aim of AXES is to develop tools that provide various types of users with new engaging ways to interact with audiovisual libraries, helping them discover, browse, navigate, search, and enrich archives. This paper describes the initial (lite) version of the AXES search engine, which is targeted at

The effects of link format and screen location on visual search of web pages.

Science.gov (United States)

Ling, Jonathan; Van Schaik, Paul

2004-06-22

Navigation of web pages is of critical importance to the usability of web-based systems such as the World Wide Web and intranets. The primary means of navigation is through the use of hyperlinks. However, few studies have examined the impact of the presentation format of these links on visual search. The present study used a two-factor mixed measures design to investigate whether there was an effect of link format (plain text, underlined, bold, or bold and underlined) upon speed and accuracy of visual search and subjective measures in both the navigation and content areas of web pages. An effect of link format on speed of visual search for both hits and correct rejections was found. This effect was observed in the navigation and the content areas. Link format did not influence accuracy in either screen location. Participants showed highest preference for links that were in bold and underlined, regardless of screen area. These results are discussed in the context of visual search processes and design recommendations are given.

Conceptual Grounds of Navigation Safety

Directory of Open Access Journals (Sweden)

Vladimir Torskiy

2016-04-01

Full Text Available The most important global problem being solved by the whole world community nowadays is to provide sustainable mankind development. Recent research in the field of sustainable development states that civilization safety is impossible without transfer sustainable development. At the same time, sustainable development (i.e. preservation of human culture and biosphere is impossible as a system that serves to meet economical, cultural, scientific, recreational and other human needs without safety. Safety plays an important role in sustainable development goals achievement. An essential condition of effective navigation functioning is to provide its safety. The “prescriptive” approach to the navigation safety, which is currently used in the world maritime field, is based on long-term experience and ship accidents investigation results. Thus this approach acted as an the great fact in reduction of number of accidents at sea. Having adopted the International Safety Management Code all the activities connected with navigation safety problems solution were transferred to the higher qualitative level. Search and development of new approaches and methods of ship accidents prevention during their operation have obtained greater importance. However, the maritime safety concept (i.e. the different points on ways, means and methods that should be used to achieve this goal hasn't been formed and described yet. The article contains a brief review of the main provisions of Navigation Safety Conceptions, which contribute to the number of accidents and incidents at sea reduction.

Navigation performance in virtual environments varies with fractal dimension of landscape

OpenAIRE

Juliani, Arthur W.; Bies, Alexander J.; Boydston, Cooper R.; Taylor, Richard P.; Sereno, Margaret E.

2016-01-01

Fractal geometry has been used to describe natural and built environments, but has yet to be studied in navigational research. In order to establish a relationship between the fractal dimension (D) of a natural environment and humans’ ability to navigate such spaces, we conducted two experiments using virtual environments that simulate the fractal properties of nature. In Experiment 1, participants completed a goal-driven search task either with or without a map in landscapes that varied in D...

Information Potential Fields Navigation in Wireless Ad-Hoc Sensor Networks

Directory of Open Access Journals (Sweden)

Yong Qi

2011-05-01

Full Text Available As wireless sensor networks (WSNs are increasingly being deployed in some important applications, it becomes imperative that we consider application requirements in in-network processes. We intend to use a WSN to aid information querying and navigation within a dynamic and real-time environment. We propose a novel method that relies on the heat diffusion equation to finish the navigation process conveniently and easily. From the perspective of theoretical analysis, our proposed work holds the lower constraint condition. We use multiple scales to reach the goal of accurate navigation. We present a multi-scale gradient descent method to satisfy users’ requirements in WSNs. Formula derivations and simulations show that the method is accurately and efficiently able to solve typical sensor network configuration information navigation problems. Simultaneously, the structure of heat diffusion equation allows more flexibility and adaptability in searching algorithm designs.

Sexual Orientation-Related Differences in Virtual Spatial Navigation and Spatial Search Strategies.

Science.gov (United States)

Rahman, Qazi; Sharp, Jonathan; McVeigh, Meadhbh; Ho, Man-Ling

2017-07-01

Spatial abilities are generally hypothesized to differ between men and women, and people with different sexual orientations. According to the cross-sex shift hypothesis, gay men are hypothesized to perform in the direction of heterosexual women and lesbian women in the direction of heterosexual men on cognitive tests. This study investigated sexual orientation differences in spatial navigation and strategy during a virtual Morris water maze task (VMWM). Forty-four heterosexual men, 43 heterosexual women, 39 gay men, and 34 lesbian/bisexual women (aged 18-54 years) navigated a desktop VMWM and completed measures of intelligence, handedness, and childhood gender nonconformity (CGN). We quantified spatial learning (hidden platform trials), probe trial performance, and cued navigation (visible platform trials). Spatial strategies during hidden and probe trials were classified into visual scanning, landmark use, thigmotaxis/circling, and enfilading. In general, heterosexual men scored better than women and gay men on some spatial learning and probe trial measures and used more visual scan strategies. However, some differences disappeared after controlling for age and estimated IQ (e.g., in visual scanning heterosexual men differed from women but not gay men). Heterosexual women did not differ from lesbian/bisexual women. For both sexes, visual scanning predicted probe trial performance. More feminine CGN scores were associated with lower performance among men and greater performance among women on specific spatial learning or probe trial measures. These results provide mixed evidence for the cross-sex shift hypothesis of sexual orientation-related differences in spatial cognition.

How Interface Design and Search Strategy Influence Children’s Search Performance and Evaluation

NARCIS (Netherlands)

Jochmann-Mannak, Hanna; Lentz, Leo; Huibers, Theo W.C.; Sanders, Ted

This chapter presents an experiment with 158 children, aged 10 to 12, in which search performance and attitudes towards an informational Website are investigated. The same Website was designed in 3 different types of interface design varying in playfulness of navigation structure and in playfulness

Navigation Strategy by Contact Sensing Interaction for a Biped Humanoid Robot

Directory of Open Access Journals (Sweden)

Hanafiah Yussof

2008-11-01

Full Text Available This report presents a basic contact interaction-based navigation strategy for a biped humanoid robot to support current visual-based navigation. The robot's arms were equipped with force sensors to detect physical contact with objects. We proposed a motion algorithm consisting of searching tasks, self-localization tasks, correction of locomotion direction tasks and obstacle avoidance tasks. Priority was given to right-side direction to navigate the robot locomotion. Analysis of trajectory generation, biped gait pattern, and biped walking characteristics was performed to define an efficient navigation strategy in a biped walking humanoid robot. The proposed algorithm is evaluated in an experiment with a 21-dofs humanoid robot operating in a room with walls and obstacles. The experimental results reveal good robot performance when recognizing objects by touching, grasping, and continuously generating suitable trajectories to correct direction and avoid collisions.

Towards Safe Navigation by Formalizing Navigation Rules

Directory of Open Access Journals (Sweden)

Arne Kreutzmann

2013-06-01

Full Text Available One crucial aspect of safe navigation is to obey all navigation regulations applicable, in particular the collision regulations issued by the International Maritime Organization (IMO Colregs. Therefore, decision support systems for navigation need to respect Colregs and this feature should be verifiably correct. We tackle compliancy of navigation regulations from a perspective of software verification. One common approach is to use formal logic, but it requires to bridge a wide gap between navigation concepts and simple logic. We introduce a novel domain specification language based on a spatio-temporal logic that allows us to overcome this gap. We are able to capture complex navigation concepts in an easily comprehensible representation that can direcly be utilized by various bridge systems and that allows for software verification.

Two Search Techniques within a Human Pedigree Database

OpenAIRE

Gersting, J. M.; Conneally, P. M.; Rogers, K.

1982-01-01

This paper presents the basic features of two search techniques from MEGADATS-2 (MEdical Genetics Acquisition and DAta Transfer System), a system for collecting, storing, retrieving and plotting human family pedigrees. The individual search provides a quick method for locating an individual in the pedigree database. This search uses a modified soundex coding and an inverted file structure based on a composite key. The navigational search uses a set of pedigree traversal operations (individual...

6TH Saint Petersburg International Conference on Integrated Navigation Systems. (6eme Conference Internationale de Saint Petersbourg sur les Systemes de Navigation Integree)

Science.gov (United States)

1999-10-01

Kharisov V.N., Perov A.I., Boldin V.A. (editors). 1977. The global satelllite radio-navigational system 20. Wu W.-R. Target tracking with glint...the coordinates of the OP techniques for their searching and extracting in deep seas. These techniques. have yielded Researches have shown that, an OP

Google Search Mastery Basics

Science.gov (United States)

Hill, Paul; MacArthur, Stacey; Read, Nick

2014-01-01

Effective Internet search skills are essential with the continually increasing amount of information available on the Web. Extension personnel are required to find information to answer client questions and to conduct research on programs. Unfortunately, many lack the skills necessary to effectively navigate the Internet and locate needed…

Intelligent Robot-assisted Humanitarian Search and Rescue System

Directory of Open Access Journals (Sweden)

Henry Y. K. Lau

2009-11-01

Full Text Available The unprecedented scale and number of natural and man-made disasters in the past decade has urged international emergency search and rescue communities to seek for novel technology to enhance operation efficiency. Tele-operated search and rescue robots that can navigate deep into rubble to search for victims and to transfer critical field data back to the control console has gained much interest among emergency response institutions. In response to this need, a low-cost autonomous mini robot equipped with thermal sensor, accelerometer, sonar, pin-hole camera, microphone, ultra-bright LED and wireless communication module is developed to study the control of a group of decentralized mini search and rescue robots. The robot can navigate autonomously between voids to look for living body heat and can send back audio and video information to allow the operator to determine if the found object is a living human. This paper introduces the design and control of a low-cost robotic search and rescue system based on an immuno control framework developed for controlling decentralized systems. Design and development of the physical prototype and the immunity-based control system are described in this paper.

Intelligent Robot-Assisted Humanitarian Search and Rescue System

Directory of Open Access Journals (Sweden)

Albert W. Y. Ko

2009-06-01

Full Text Available The unprecedented scale and number of natural and man-made disasters in the past decade has urged international emergency search and rescue communities to seek for novel technology to enhance operation efficiency. Tele-operated search and rescue robots that can navigate deep into rubble to search for victims and to transfer critical field data back to the control console has gained much interest among emergency response institutions. In response to this need, a low-cost autonomous mini robot equipped with thermal sensor, accelerometer, sonar, pin-hole camera, microphone, ultra-bright LED and wireless communication module is developed to study the control of a group of decentralized mini search and rescue robots. The robot can navigate autonomously between voids to look for living body heat and can send back audio and video information to allow the operator to determine if the found object is a living human. This paper introduces the design and control of a low-cost robotic search and rescue system based on an immuno control framework developed for controlling decentralized systems. Design and development of the physical prototype and the immunity-based control system are described in this paper.

6TH Saint Petersburg International Conference on Integrated Navigation Systems.

Science.gov (United States)

1999-10-01

pp. 7/1-12. 4. Kharisov V.N., Perov A.I., Boldin VA. (editors). The global satelllite radio-navigational system GLONASS [in Russian]. Moskow: IPRZhR...The need for oil and natural gas requires the techniques for their searching and extracting in deep seas. These techniques have yielded particular

Making Statistical Data More Easily Accessible on the Web Results of the StatSearch Case Study

CERN Document Server

Rajman, M; Boynton, I M; Fridlund, B; Fyhrlund, A; Sundgren, B; Lundquist, P; Thelander, H; Wänerskär, M

2005-01-01

In this paper we present the results of the StatSearch case study that aimed at providing an enhanced access to statistical data available on the Web. In the scope of this case study we developed a prototype of an information access tool combining a query-based search engine with semi-automated navigation techniques exploiting the hierarchical structuring of the available data. This tool enables a better control of the information retrieval, improving the quality and ease of the access to statistical information. The central part of the presented StatSearch tool consists in the design of an algorithm for automated navigation through a tree-like hierarchical document structure. The algorithm relies on the computation of query related relevance score distributions over the available database to identify the most relevant clusters in the data structure. These most relevant clusters are then proposed to the user for navigation, or, alternatively, are the support for the automated navigation process. Several appro...

Using Genetic Algorithms for Navigation Planning in Dynamic Environments

Directory of Open Access Journals (Sweden)

Ferhat Uçan

2012-01-01

Full Text Available Navigation planning can be considered as a combination of searching and executing the most convenient flight path from an initial waypoint to a destination waypoint. Generally the aim is to follow the flight path, which provides minimum fuel consumption for the air vehicle. For dynamic environments, constraints change dynamically during flight. This is a special case of dynamic path planning. As the main concern of this paper is flight planning, the conditions and objectives that are most probable to be used in navigation problem are considered. In this paper, the genetic algorithm solution of the dynamic flight planning problem is explained. The evolutionary dynamic navigation planning algorithm is developed for compensating the existing deficiencies of the other approaches. The existing fully dynamic algorithms process unit changes to topology one modification at a time, but when there are several such operations occurring in the environment simultaneously, the algorithms are quite inefficient. The proposed algorithm may respond to the concurrent constraint updates in a shorter time for dynamic environment. The most secure navigation of the air vehicle is planned and executed so that the fuel consumption is minimum.

Ratbot automatic navigation by electrical reward stimulation based on distance measurement in unknown environments.

Science.gov (United States)

Gao, Liqiang; Sun, Chao; Zhang, Chen; Zheng, Nenggan; Chen, Weidong; Zheng, Xiaoxiang

2013-01-01

Traditional automatic navigation methods for bio-robots are constrained to configured environments and thus can't be applied to tasks in unknown environments. With no consideration of bio-robot's own innate living ability and treating bio-robots in the same way as mechanical robots, those methods neglect the intelligence behavior of animals. This paper proposes a novel ratbot automatic navigation method in unknown environments using only reward stimulation and distance measurement. By utilizing rat's habit of thigmotaxis and its reward-seeking behavior, this method is able to incorporate rat's intrinsic intelligence of obstacle avoidance and path searching into navigation. Experiment results show that this method works robustly and can successfully navigate the ratbot to a target in the unknown environment. This work might put a solid base for application of ratbots and also has significant implication of automatic navigation for other bio-robots as well.

Geomagnetic Navigation of Autonomous Underwater Vehicle Based on Multi-objective Evolutionary Algorithm.

Science.gov (United States)

Li, Hong; Liu, Mingyong; Zhang, Feihu

2017-01-01

This paper presents a multi-objective evolutionary algorithm of bio-inspired geomagnetic navigation for Autonomous Underwater Vehicle (AUV). Inspired by the biological navigation behavior, the solution was proposed without using a priori information, simply by magnetotaxis searching. However, the existence of the geomagnetic anomalies has significant influence on the geomagnetic navigation system, which often disrupts the distribution of the geomagnetic field. An extreme value region may easily appear in abnormal regions, which makes AUV lost in the navigation phase. This paper proposes an improved bio-inspired algorithm with behavior constraints, for sake of making AUV escape from the abnormal region. First, the navigation problem is considered as the optimization problem. Second, the environmental monitoring operator is introduced, to determine whether the algorithm falls into the geomagnetic anomaly region. Then, the behavior constraint operator is employed to get out of the abnormal region. Finally, the termination condition is triggered. Compared to the state-of- the-art, the proposed approach effectively overcomes the disturbance of the geomagnetic abnormal. The simulation result demonstrates the reliability and feasibility of the proposed approach in complex environments.

Location-based Services using Image Search

DEFF Research Database (Denmark)

Vertongen, Pieter-Paulus; Hansen, Dan Witzner

2008-01-01

Recent developments in image search has made them sufficiently efficient to be used in real-time applications. GPS has become a popular navigation tool. While GPS information provide reasonably good accuracy, they are not always present in all hand held devices nor are they accurate in all situat...... of the image search engine and database image location knowledge, the location is determined of the query image and associated data can be presented to the user....

Discovering How Students Search a Library Web Site: A Usability Case Study.

Science.gov (United States)

Augustine, Susan; Greene, Courtney

2002-01-01

Discusses results of a usability study at the University of Illinois Chicago that investigated whether Internet search engines have influenced the way students search library Web sites. Results show students use the Web site's internal search engine rather than navigating through the pages; have difficulty interpreting library terminology; and…

Influence of visual clutter on the effect of navigated safety inspection: a case study on elevator installation.

Science.gov (United States)

Liao, Pin-Chao; Sun, Xinlu; Liu, Mei; Shih, Yu-Nien

2018-01-11

Navigated safety inspection based on task-specific checklists can increase the hazard detection rate, theoretically with interference from scene complexity. Visual clutter, a proxy of scene complexity, can theoretically impair visual search performance, but its impact on the effect of safety inspection performance remains to be explored for the optimization of navigated inspection. This research aims to explore whether the relationship between working memory and hazard detection rate is moderated by visual clutter. Based on a perceptive model of hazard detection, we: (a) developed a mathematical influence model for construction hazard detection; (b) designed an experiment to observe the performance of hazard detection rate with adjusted working memory under different levels of visual clutter, while using an eye-tracking device to observe participants' visual search processes; (c) utilized logistic regression to analyze the developed model under various visual clutter. The effect of a strengthened working memory on the detection rate through increased search efficiency is more apparent in high visual clutter. This study confirms the role of visual clutter in construction-navigated inspections, thus serving as a foundation for the optimization of inspection planning.

Improving Canada's Marine Navigation System through e-Navigation

Directory of Open Access Journals (Sweden)

Daniel Breton

2016-06-01

The conclusion proposed is that on-going work with key partners and stakeholders can be used as the primary mechanism to identify e-Navigation related innovation and needs, and to prioritize next steps. Moving forward in Canada, implementation of new e-navigation services will continue to be stakeholder driven, and used to drive improvements to Canada's marine navigation system.

PVR system design of advanced video navigation reinforced with audible sound

NARCIS (Netherlands)

Eerenberg, O.; Aarts, R.; De With, P.N.

2014-01-01

This paper presents an advanced video navigation concept for Personal Video Recording (PVR), based on jointly using the primary image and a Picture-in-Picture (PiP) image, featuring combined rendering of normal-play video fragments with audio and fast-search video. The hindering loss of audio during

Navigating the Path to a Biomedical Science Career

Science.gov (United States)

Zimmerman, Andrea McNeely

The number of biomedical PhD scientists being trained and graduated far exceeds the number of academic faculty positions and academic research jobs. If this trend is compelling biomedical PhD scientists to increasingly seek career paths outside of academia, then more should be known about their intentions, desires, training experiences, and career path navigation. Therefore, the purpose of this study was to understand the process through which biomedical PhD scientists are trained and supported for navigating future career paths. In addition, the study sought to determine whether career development support efforts and opportunities should be redesigned to account for the proportion of PhD scientists following non-academic career pathways. Guided by the social cognitive career theory (SCCT) framework this study sought to answer the following central research question: How does a southeastern tier 1 research university train and support its biomedical PhD scientists for navigating their career paths? Key findings are: Many factors influence PhD scientists' career sector preference and job search process, but the most influential were relationships with faculty, particularly the mentor advisor; Planned activities are a significant aspect of the training process and provide skills for career success; and Planned activities provided skills necessary for a career, but influential factors directed the career path navigated. Implications for practice and future research are discussed.

Navigating on handheld displays: Dynamic versus Static Keyhole Navigation

NARCIS (Netherlands)

Mehra, S.; Werkhoven, P.; Worring, M.

2006-01-01

Handheld displays leave little space for the visualization and navigation of spatial layouts representing rich information spaces. The most common navigation method for handheld displays is static peephole navigation: The peephole is static and we move the spatial layout behind it (scrolling). A

A model of ant route navigation driven by scene familiarity.

Directory of Open Access Journals (Sweden)

Bart Baddeley

2012-01-01

Full Text Available In this paper we propose a model of visually guided route navigation in ants that captures the known properties of real behaviour whilst retaining mechanistic simplicity and thus biological plausibility. For an ant, the coupling of movement and viewing direction means that a familiar view specifies a familiar direction of movement. Since the views experienced along a habitual route will be more familiar, route navigation can be re-cast as a search for familiar views. This search can be performed with a simple scanning routine, a behaviour that ants have been observed to perform. We test this proposed route navigation strategy in simulation, by learning a series of routes through visually cluttered environments consisting of objects that are only distinguishable as silhouettes against the sky. In the first instance we determine view familiarity by exhaustive comparison with the set of views experienced during training. In further experiments we train an artificial neural network to perform familiarity discrimination using the training views. Our results indicate that, not only is the approach successful, but also that the routes that are learnt show many of the characteristics of the routes of desert ants. As such, we believe the model represents the only detailed and complete model of insect route guidance to date. What is more, the model provides a general demonstration that visually guided routes can be produced with parsimonious mechanisms that do not specify when or what to learn, nor separate routes into sequences of waypoints.

Google and the culture of search

CERN Document Server

Hillis, Ken; Jarrett, Kylie

2013-01-01

What did you do before Google? The rise of Google as the dominant Internet search provider reflects a generationally-inflected notion that everything that matters is now on the Web, and should, in the moral sense of the verb, be accessible through search. In this theoretically nuanced study of search technology's broader implications for knowledge production and social relations, the authors shed light on a culture of search in which our increasing reliance on search engines influences not only the way we navigate, classify, and evaluate Web content, but also how we think about ourselves and the world around us, online and off. Ken Hillis, Michael Petit, and Kylie Jarrett seek to understand the ascendancy of search and its naturalization by historicizing and contextualizing Google's dominance of the search industry, and suggest that the contemporary culture of search is inextricably bound up with a metaphysical longing to manage, order, and categorize all knowledge. Calling upon this nexus between political e...

THE DEVELOPMENT OF NAVIGATION SYSTEMS IN CIVIL AVIATION

Directory of Open Access Journals (Sweden)

Anastasiya Sergeyevna Stepanenko

2017-01-01

Full Text Available The article describes the history of navigation systems formation, such as "Cicada" system, which at that time could compete with the US "Transit", European, Chinese Beidou navigation system and the Japanese Quasi-Zenit.The detailed information about improving the American GPS system, launched in 1978 and working till now is provided. The characteristics of GPS-III counterpart "Transit", which became the platform for creating such modern globalnavigation systems as GLONASS and GPS. The process of implementation of the GLONASS system in civil aviation, itssegments, functions and features are considered. The stages of GLONASS satellite system orbital grouping formation are analyzed. The author draws the analogy with the American GPS system, the GALILEO system, which has a number of additional advantages, are given. The author remarks the features of the European counterpart of the GALILEO global nav- igation system. One of the goals of this system is to provide a high-precision positioning system, which Europe can rely on regardless of the Russian GLONASS system, the US - GPS and the Chinese Beidou. GALILEO offers a unique global search and rescue function called SAR, with an important feedback function. The peculiarities of Chinese scientists’ navi- gation system, the Beidou satellite system, and the Japanese global Quasi-Zenith Satellite System are described.Global navigation systems development tendencies are considered. The author dwells upon the path to world satel- lite systems globalization, a good example of which is the trend towards GLONASS and Beidou unification. Most attention was paid to the latest development of Russian scientists’ autonomous navigation system SINS 2015, which is a strap-down inertial navigation system and allows you to navigate the aircraft without being connected to a global satellite system. The ways of navigation systems further development in Russia are determined. The two naturally opposite directions are

Theoretical Limits of Lunar Vision Aided Navigation with Inertial Navigation System

Science.gov (United States)

2015-03-26

THEORETICAL LIMITS OF LUNAR VISION AIDED NAVIGATION WITH INERTIAL NAVIGATION SYSTEM THESIS David W. Jones, Capt, USAF AFIT-ENG-MS-15-M-020 DEPARTMENT...Government and is not subject to copyright protection in the United States. AFIT-ENG-MS-15-M-020 THEORETICAL LIMITS OF LUNAR VISION AIDED NAVIGATION WITH...DISTRIBUTION UNLIMITED. AFIT-ENG-MS-15-M-020 THEORETICAL LIMITS OF LUNAR VISION AIDED NAVIGATION WITH INERTIAL NAVIGATION SYSTEM THESIS David W. Jones

Essential Annotation Schema for Ecology (EASE)-A framework supporting the efficient data annotation and faceted navigation in ecology.

Science.gov (United States)

Pfaff, Claas-Thido; Eichenberg, David; Liebergesell, Mario; König-Ries, Birgitta; Wirth, Christian

2017-01-01

Ecology has become a data intensive science over the last decades which often relies on the reuse of data in cross-experimental analyses. However, finding data which qualifies for the reuse in a specific context can be challenging. It requires good quality metadata and annotations as well as efficient search strategies. To date, full text search (often on the metadata only) is the most widely used search strategy although it is known to be inaccurate. Faceted navigation is providing a filter mechanism which is based on fine granular metadata, categorizing search objects along numeric and categorical parameters relevant for their discovery. Selecting from these parameters during a full text search creates a system of filters which allows to refine and improve the results towards more relevance. We developed a framework for the efficient annotation and faceted navigation in ecology. It consists of an XML schema for storing the annotation of search objects and is accompanied by a vocabulary focused on ecology to support the annotation process. The framework consolidates ideas which originate from widely accepted metadata standards, textbooks, scientific literature, and vocabularies as well as from expert knowledge contributed by researchers from ecology and adjacent disciplines.

Essential Annotation Schema for Ecology (EASE-A framework supporting the efficient data annotation and faceted navigation in ecology.

Directory of Open Access Journals (Sweden)

Claas-Thido Pfaff

Full Text Available Ecology has become a data intensive science over the last decades which often relies on the reuse of data in cross-experimental analyses. However, finding data which qualifies for the reuse in a specific context can be challenging. It requires good quality metadata and annotations as well as efficient search strategies. To date, full text search (often on the metadata only is the most widely used search strategy although it is known to be inaccurate. Faceted navigation is providing a filter mechanism which is based on fine granular metadata, categorizing search objects along numeric and categorical parameters relevant for their discovery. Selecting from these parameters during a full text search creates a system of filters which allows to refine and improve the results towards more relevance. We developed a framework for the efficient annotation and faceted navigation in ecology. It consists of an XML schema for storing the annotation of search objects and is accompanied by a vocabulary focused on ecology to support the annotation process. The framework consolidates ideas which originate from widely accepted metadata standards, textbooks, scientific literature, and vocabularies as well as from expert knowledge contributed by researchers from ecology and adjacent disciplines.

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.

Lost in transportation: Information measures and cognitive limits in multilayer navigation.

Science.gov (United States)

Gallotti, Riccardo; Porter, Mason A; Barthelemy, Marc

2016-02-01

Cities and their transportation systems become increasingly complex and multimodal as they grow, and it is natural to wonder whether it is possible to quantitatively characterize our difficulty navigating in them and whether such navigation exceeds our cognitive limits. A transition between different search strategies for navigating in metropolitan maps has been observed for large, complex metropolitan networks. This evidence suggests the existence of a limit associated with cognitive overload and caused by a large amount of information that needs to be processed. In this light, we analyzed the world's 15 largest metropolitan networks and estimated the information limit for determining a trip in a transportation system to be on the order of 8 bits. Similar to the "Dunbar number," which represents a limit to the size of an individual's friendship circle, our cognitive limit suggests that maps should not consist of more than 250 connection points to be easily readable. We also show that including connections with other transportation modes dramatically increases the information needed to navigate in multilayer transportation networks. In large cities such as New York, Paris, and Tokyo, more than 80% of the trips are above the 8-bit limit. Multimodal transportation systems in large cities have thus already exceeded human cognitive limits and, consequently, the traditional view of navigation in cities has to be revised substantially.

Essential Annotation Schema for Ecology (EASE)—A framework supporting the efficient data annotation and faceted navigation in ecology

Science.gov (United States)

Eichenberg, David; Liebergesell, Mario; König-Ries, Birgitta; Wirth, Christian

2017-01-01

Ecology has become a data intensive science over the last decades which often relies on the reuse of data in cross-experimental analyses. However, finding data which qualifies for the reuse in a specific context can be challenging. It requires good quality metadata and annotations as well as efficient search strategies. To date, full text search (often on the metadata only) is the most widely used search strategy although it is known to be inaccurate. Faceted navigation is providing a filter mechanism which is based on fine granular metadata, categorizing search objects along numeric and categorical parameters relevant for their discovery. Selecting from these parameters during a full text search creates a system of filters which allows to refine and improve the results towards more relevance. We developed a framework for the efficient annotation and faceted navigation in ecology. It consists of an XML schema for storing the annotation of search objects and is accompanied by a vocabulary focused on ecology to support the annotation process. The framework consolidates ideas which originate from widely accepted metadata standards, textbooks, scientific literature, and vocabularies as well as from expert knowledge contributed by researchers from ecology and adjacent disciplines. PMID:29023519

Navigation integrity monitoring and obstacle detection for enhanced-vision systems

Science.gov (United States)

Korn, Bernd; Doehler, Hans-Ullrich; Hecker, Peter

2001-08-01

Typically, Enhanced Vision (EV) systems consist of two main parts, sensor vision and synthetic vision. Synthetic vision usually generates a virtual out-the-window view using databases and accurate navigation data, e. g. provided by differential GPS (DGPS). The reliability of the synthetic vision highly depends on both, the accuracy of the used database and the integrity of the navigation data. But especially in GPS based systems, the integrity of the navigation can't be guaranteed. Furthermore, only objects that are stored in the database can be displayed to the pilot. Consequently, unexpected obstacles are invisible and this might cause severe problems. Therefore, additional information has to be extracted from sensor data to overcome these problems. In particular, the sensor data analysis has to identify obstacles and has to monitor the integrity of databases and navigation. Furthermore, if a lack of integrity arises, navigation data, e.g. the relative position of runway and aircraft, has to be extracted directly from the sensor data. The main contribution of this paper is about the realization of these three sensor data analysis tasks within our EV system, which uses the HiVision 35 GHz MMW radar of EADS, Ulm as the primary EV sensor. For the integrity monitoring, objects extracted from radar images are registered with both database objects and objects (e. g. other aircrafts) transmitted via data link. This results in a classification into known and unknown radar image objects and consequently, in a validation of the integrity of database and navigation. Furthermore, special runway structures are searched for in the radar image where they should appear. The outcome of this runway check contributes to the integrity analysis, too. Concurrent to this investigation a radar image based navigation is performed without using neither precision navigation nor detailed database information to determine the aircraft's position relative to the runway. The performance of our

33 CFR 2.36 - Navigable waters of the United States, navigable waters, and territorial waters.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Navigable waters of the United States, navigable waters, and territorial waters. 2.36 Section 2.36 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2.36 Navigable waters...

Efecto del uso de diferentes aditivos de panificación en la calidad de panes elaborados con harinas compuestas a base de harina de trigo y germen desgrasado de maíz

OpenAIRE

Granito,Marisela; Guerra,Marisa

1997-01-01

Dado el alto consumo de productos alimenticios a base de trigo (HT) importado y la producción industrial de subproductos del procesamiento del maíz (HGDM), ricos en fibra dietética, proteínas y minerales, en Venezuela se ha estudado la factibilidad técnica de sustituir parcialmente HT por HGDM en la elaboración de productos horneados como galletas y panes. Por otra parte, considerando las restricciones existentes en el uso del bromato de potasio (BP) como aditivo de panificación y que el ácid...

Telling How to Narrow it Down: Browsing Path Recommendation for Exploratory Search

NARCIS (Netherlands)

Dehghani, M.; Jagfeld, G.; Azarbonyad, H.; Olieman, A.; Kamps, J.; Marx, M.

2017-01-01

Supporting exploratory search tasks with the help of structured data is an effective way to go beyond keyword search, as it provides an overview of the data, enables users to zoom in on their intent, and provides assistance during their navigation trails. However, finding a good starting point for a

In Search of the Optimal Path: How Learners at Task Use an Online Dictionary

Science.gov (United States)

Hamel, Marie-Josee

2012-01-01

We have analyzed circa 180 navigation paths followed by six learners while they performed three language encoding tasks at the computer using an online dictionary prototype. Our hypothesis was that learners who follow an "optimal path" while navigating within the dictionary, using its search and look-up functions, would have a high chance of…

Mission Analysis, Operations, and Navigation Toolkit Environment (Monte) Version 040

Science.gov (United States)

Sunseri, Richard F.; Wu, Hsi-Cheng; Evans, Scott E.; Evans, James R.; Drain, Theodore R.; Guevara, Michelle M.

2012-01-01

Monte is a software set designed for use in mission design and spacecraft navigation operations. The system can process measurement data, design optimal trajectories and maneuvers, and do orbit determination, all in one application. For the first time, a single software set can be used for mission design and navigation operations. This eliminates problems due to different models and fidelities used in legacy mission design and navigation software. The unique features of Monte 040 include a blowdown thruster model for GRAIL (Gravity Recovery and Interior Laboratory) with associated pressure models, as well as an updated, optimalsearch capability (COSMIC) that facilitated mission design for ARTEMIS. Existing legacy software lacked the capabilities necessary for these two missions. There is also a mean orbital element propagator and an osculating to mean element converter that allows long-term orbital stability analysis for the first time in compiled code. The optimized trajectory search tool COSMIC allows users to place constraints and controls on their searches without any restrictions. Constraints may be user-defined and depend on trajectory information either forward or backwards in time. In addition, a long-term orbit stability analysis tool (morbiter) existed previously as a set of scripts on top of Monte. Monte is becoming the primary tool for navigation operations, a core competency at JPL. The mission design capabilities in Monte are becoming mature enough for use in project proposals as well as post-phase A mission design. Monte has three distinct advantages over existing software. First, it is being developed in a modern paradigm: object- oriented C++ and Python. Second, the software has been developed as a toolkit, which allows users to customize their own applications and allows the development team to implement requirements quickly, efficiently, and with minimal bugs. Finally, the software is managed in accordance with the CMMI (Capability Maturity Model

77 FR 42637 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments; Corrections

Science.gov (United States)

2012-07-20

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Parts 84 and 115 [Docket No. USCG-2012-0306] RIN 1625-AB86 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments...), the Coast Guard published a final rule entitled ``Navigation and Navigable Waters; Technical...

Multi-topic assignment for exploratory navigation of consumer health information in NetWellness using formal concept analysis.

Science.gov (United States)

Cui, Licong; Xu, Rong; Luo, Zhihui; Wentz, Susan; Scarberry, Kyle; Zhang, Guo-Qiang

2014-08-03

Finding quality consumer health information online can effectively bring important public health benefits to the general population. It can empower people with timely and current knowledge for managing their health and promoting wellbeing. Despite a popular belief that search engines such as Google can solve all information access problems, recent studies show that using search engines and simple search terms is not sufficient. Our objective is to provide an approach to organizing consumer health information for navigational exploration, complementing keyword-based direct search. Multi-topic assignment to health information, such as online questions, is a fundamental step for navigational exploration. We introduce a new multi-topic assignment method combining semantic annotation using UMLS concepts (CUIs) and Formal Concept Analysis (FCA). Each question was tagged with CUIs identified by MetaMap. The CUIs were filtered with term-frequency and a new term-strength index to construct a CUI-question context. The CUI-question context and a topic-subject context were used for multi-topic assignment, resulting in a topic-question context. The topic-question context was then directly used for constructing a prototype navigational exploration interface. Experimental evaluation was performed on the task of automatic multi-topic assignment of 99 predefined topics for about 60,000 consumer health questions from NetWellness. Using example-based metrics, suitable for multi-topic assignment problems, our method achieved a precision of 0.849, recall of 0.774, and F₁ measure of 0.782, using a reference standard of 278 questions with manually assigned topics. Compared to NetWellness' original topic assignment, a 36.5% increase in recall is achieved with virtually no sacrifice in precision. Enhancing the recall of multi-topic assignment without sacrificing precision is a prerequisite for achieving the benefits of navigational exploration. Our new multi-topic assignment method

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

Emergency Navigation without an Infrastructure

Directory of Open Access Journals (Sweden)

Erol Gelenbe

2014-08-01

Full Text Available Emergency navigation systems for buildings and other built environments, such as sport arenas or shopping centres, typically rely on simple sensor networks to detect emergencies and, then, provide automatic signs to direct the evacuees. The major drawbacks of such static wireless sensor network (WSN-based emergency navigation systems are the very limited computing capacity, which makes adaptivity very difficult, and the restricted battery power, due to the low cost of sensor nodes for unattended operation. If static wireless sensor networks and cloud-computing can be integrated, then intensive computations that are needed to determine optimal evacuation routes in the presence of time-varying hazards can be offloaded to the cloud, but the disadvantages of limited battery life-time at the client side, as well as the high likelihood of system malfunction during an emergency still remain. By making use of the powerful sensing ability of smart phones, which are increasingly ubiquitous, this paper presents a cloud-enabled indoor emergency navigation framework to direct evacuees in a coordinated fashion and to improve the reliability and resilience for both communication and localization. By combining social potential fields (SPF and a cognitive packet network (CPN-based algorithm, evacuees are guided to exits in dynamic loose clusters. Rather than relying on a conventional telecommunications infrastructure, we suggest an ad hoc cognitive packet network (AHCPN-based protocol to adaptively search optimal communication routes between portable devices and the network egress nodes that provide access to cloud servers, in a manner that spares the remaining battery power of smart phones and minimizes the time latency. Experimental results through detailed simulations indicate that smart human motion and smart network management can increase the survival rate of evacuees and reduce the number of drained smart phones in an evacuation process.

Emergency navigation without an infrastructure.

Science.gov (United States)

Gelenbe, Erol; Bi, Huibo

2014-08-18

Emergency navigation systems for buildings and other built environments, such as sport arenas or shopping centres, typically rely on simple sensor networks to detect emergencies and, then, provide automatic signs to direct the evacuees. The major drawbacks of such static wireless sensor network (WSN)-based emergency navigation systems are the very limited computing capacity, which makes adaptivity very difficult, and the restricted battery power, due to the low cost of sensor nodes for unattended operation. If static wireless sensor networks and cloud-computing can be integrated, then intensive computations that are needed to determine optimal evacuation routes in the presence of time-varying hazards can be offloaded to the cloud, but the disadvantages of limited battery life-time at the client side, as well as the high likelihood of system malfunction during an emergency still remain. By making use of the powerful sensing ability of smart phones, which are increasingly ubiquitous, this paper presents a cloud-enabled indoor emergency navigation framework to direct evacuees in a coordinated fashion and to improve the reliability and resilience for both communication and localization. By combining social potential fields (SPF) and a cognitive packet network (CPN)-based algorithm, evacuees are guided to exits in dynamic loose clusters. Rather than relying on a conventional telecommunications infrastructure, we suggest an ad hoc cognitive packet network (AHCPN)-based protocol to adaptively search optimal communication routes between portable devices and the network egress nodes that provide access to cloud servers, in a manner that spares the remaining battery power of smart phones and minimizes the time latency. Experimental results through detailed simulations indicate that smart human motion and smart network management can increase the survival rate of evacuees and reduce the number of drained smart phones in an evacuation process.

Adaptation and search: from Dexter and AHAM to GAF

NARCIS (Netherlands)

Knutov, E.; De Bra, P.M.E.; Pechenizkiy, M.; Chignell, M.H.; Toms, E.

2010-01-01

Adaptive Hypermedia Systems (AHS) have long been concentrating on adaptive guidance of links between domain concepts. Here we show parallels between navigation and linking in adaptive hypermedia on the one hand and information searching or querying on the other hand. We present a transition towards

How to find home backwards? Navigation during rearward homing of Cataglyphis fortis desert ants.

Science.gov (United States)

Pfeffer, Sarah E; Wittlinger, Matthias

2016-07-15

Cataglyphis ants are renowned for their impressive navigation skills, which have been studied in numerous experiments during forward locomotion. However, the ants' navigational performance during backward homing when dragging large food loads has not been investigated until now. During backward locomotion, the odometer has to deal with unsteady motion and irregularities in inter-leg coordination. The legs' sensory feedback during backward walking is not just a simple reversal of the forward stepping movements: compared with forward homing, ants are facing towards the opposite direction during backward dragging. Hence, the compass system has to cope with a flipped celestial view (in terms of the polarization pattern and the position of the sun) and an inverted retinotopic image of the visual panorama and landmark environment. The same is true for wind and olfactory cues. In this study we analyze for the first time backward-homing ants and evaluate their navigational performance in channel and open field experiments. Backward-homing Cataglyphis fortis desert ants show remarkable similarities in the performance of homing compared with forward-walking ants. Despite the numerous challenges emerging for the navigational system during backward walking, we show that ants perform quite well in our experiments. Direction and distance gauging was comparable to that of the forward-walking control groups. Interestingly, we found that backward-homing ants often put down the food item and performed foodless search loops around the left food item. These search loops were mainly centred around the drop-off position (and not around the nest position), and increased in length the closer the ants came to their fictive nest site. © 2016. Published by The Company of Biologists Ltd.

33 CFR 66.05-100 - Designation of navigable waters as State waters for private aids to navigation.

Science.gov (United States)

2010-07-01

... as State waters for private aids to navigation. 66.05-100 Section 66.05-100 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-100 Designation of navigable waters as State waters for private aids to...

Navigation Problems in Blind-to-Blind Pedestrians Tele-assistance Navigation

OpenAIRE

Balata , Jan; Mikovec , Zdenek; Maly , Ivo

2015-01-01

International audience; We raise a question whether it is possible to build a large-scale navigation system for blind pedestrians where a blind person navigates another blind person remotely by mobile phone. We have conducted an experiment, in which we observed blind people navigating each other in a city center in 19 sessions. We focused on problems in the navigator’s attempts to direct the traveler to the destination. We observed 96 problems in total, classified them on the basis of the typ...

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.

A Single RF Emitter-Based Indoor Navigation Method for Autonomous Service Robots.

Science.gov (United States)

Sherwin, Tyrone; Easte, Mikala; Chen, Andrew Tzer-Yeu; Wang, Kevin I-Kai; Dai, Wenbin

2018-02-14

Location-aware services are one of the key elements of modern intelligent applications. Numerous real-world applications such as factory automation, indoor delivery, and even search and rescue scenarios require autonomous robots to have the ability to navigate in an unknown environment and reach mobile targets with minimal or no prior infrastructure deployment. This research investigates and proposes a novel approach of dynamic target localisation using a single RF emitter, which will be used as the basis of allowing autonomous robots to navigate towards and reach a target. Through the use of multiple directional antennae, Received Signal Strength (RSS) is compared to determine the most probable direction of the targeted emitter, which is combined with the distance estimates to improve the localisation performance. The accuracy of the position estimate is further improved using a particle filter to mitigate the fluctuating nature of real-time RSS data. Based on the direction information, a motion control algorithm is proposed, using Simultaneous Localisation and Mapping (SLAM) and A* path planning to enable navigation through unknown complex environments. A number of navigation scenarios were developed in the context of factory automation applications to demonstrate and evaluate the functionality and performance of the proposed system.

A Single RF Emitter-Based Indoor Navigation Method for Autonomous Service Robots

Directory of Open Access Journals (Sweden)

Tyrone Sherwin

2018-02-01

Full Text Available Location-aware services are one of the key elements of modern intelligent applications. Numerous real-world applications such as factory automation, indoor delivery, and even search and rescue scenarios require autonomous robots to have the ability to navigate in an unknown environment and reach mobile targets with minimal or no prior infrastructure deployment. This research investigates and proposes a novel approach of dynamic target localisation using a single RF emitter, which will be used as the basis of allowing autonomous robots to navigate towards and reach a target. Through the use of multiple directional antennae, Received Signal Strength (RSS is compared to determine the most probable direction of the targeted emitter, which is combined with the distance estimates to improve the localisation performance. The accuracy of the position estimate is further improved using a particle filter to mitigate the fluctuating nature of real-time RSS data. Based on the direction information, a motion control algorithm is proposed, using Simultaneous Localisation and Mapping (SLAM and A* path planning to enable navigation through unknown complex environments. A number of navigation scenarios were developed in the context of factory automation applications to demonstrate and evaluate the functionality and performance of the proposed system.

A Neurocomputational Model of Goal-Directed Navigation in Insect-Inspired Artificial Agents.

Science.gov (United States)

Goldschmidt, Dennis; Manoonpong, Poramate; Dasgupta, Sakyasingha

2017-01-01

Despite their small size, insect brains are able to produce robust and efficient navigation in complex environments. Specifically in social insects, such as ants and bees, these navigational capabilities are guided by orientation directing vectors generated by a process called path integration. During this process, they integrate compass and odometric cues to estimate their current location as a vector, called the home vector for guiding them back home on a straight path. They further acquire and retrieve path integration-based vector memories globally to the nest or based on visual landmarks. Although existing computational models reproduced similar behaviors, a neurocomputational model of vector navigation including the acquisition of vector representations has not been described before. Here we present a model of neural mechanisms in a modular closed-loop control-enabling vector navigation in artificial agents. The model consists of a path integration mechanism, reward-modulated global learning, random search, and action selection. The path integration mechanism integrates compass and odometric cues to compute a vectorial representation of the agent's current location as neural activity patterns in circular arrays. A reward-modulated learning rule enables the acquisition of vector memories by associating the local food reward with the path integration state. A motor output is computed based on the combination of vector memories and random exploration. In simulation, we show that the neural mechanisms enable robust homing and localization, even in the presence of external sensory noise. The proposed learning rules lead to goal-directed navigation and route formation performed under realistic conditions. Consequently, we provide a novel approach for vector learning and navigation in a simulated, situated agent linking behavioral observations to their possible underlying neural substrates.

Changes in Search Path Complexity and Length During Learning of a Virtual Water Maze: Age Differences and Differential Associations with Hippocampal Subfield Volumes.

Science.gov (United States)

Daugherty, Ana M; Bender, Andrew R; Yuan, Peng; Raz, Naftali

2016-06-01

Impairment of hippocampus-dependent cognitive processes has been proposed to underlie age-related deficits in navigation. Animal studies suggest a differential role of hippocampal subfields in various aspects of navigation, but that hypothesis has not been tested in humans. In this study, we examined the association between volume of hippocampal subfields and age differences in virtual spatial navigation. In a sample of 65 healthy adults (age 19-75 years), advanced age was associated with a slower rate of improvement operationalized as shortening of the search path over 25 learning trials on a virtual Morris water maze task. The deficits were partially explained by greater complexity of older adults' search paths. Larger subiculum and entorhinal cortex volumes were associated with a faster decrease in search path complexity, which in turn explained faster shortening of search distance. Larger Cornu Ammonis (CA)1-2 volume was associated with faster distance shortening, but not in path complexity reduction. Age differences in regional volumes collectively accounted for 23% of the age-related variance in navigation learning. Independent of subfield volumes, advanced age was associated with poorer performance across all trials, even after reaching the asymptote. Thus, subiculum and CA1-2 volumes were associated with speed of acquisition, but not magnitude of gains in virtual maze navigation. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Memristive device based learning for navigation in robots.

Science.gov (United States)

Sarim, Mohammad; Kumar, Manish; Jha, Rashmi; Minai, Ali A

2017-11-08

Biomimetic robots have gained attention recently for various applications ranging from resource hunting to search and rescue operations during disasters. Biological species are known to intuitively learn from the environment, gather and process data, and make appropriate decisions. Such sophisticated computing capabilities in robots are difficult to achieve, especially if done in real-time with ultra-low energy consumption. Here, we present a novel memristive device based learning architecture for robots. Two terminal memristive devices with resistive switching of oxide layer are modeled in a crossbar array to develop a neuromorphic platform that can impart active real-time learning capabilities in a robot. This approach is validated by navigating a robot vehicle in an unknown environment with randomly placed obstacles. Further, the proposed scheme is compared with reinforcement learning based algorithms using local and global knowledge of the environment. The simulation as well as experimental results corroborate the validity and potential of the proposed learning scheme for robots. The results also show that our learning scheme approaches an optimal solution for some environment layouts in robot navigation.

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.

Control algorithms for autonomous robot navigation

International Nuclear Information System (INIS)

Jorgensen, C.C.

1985-01-01

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

A Spatial Cognitive Map and a Human-Like Memory Model Dedicated to Pedestrian Navigation in Virtual Urban Environments

Science.gov (United States)

Thomas, Romain; Donikian, Stéphane

Many articles dealing with agent navigation in an urban environment involve the use of various heuristics. Among them, one is prevalent: the search of the shortest path between two points. This strategy impairs the realism of the resulting behaviour. Indeed, psychological studies state that such a navigation behaviour is conditioned by the knowledge the subject has of its environment. Furthermore, the path a city dweller can follow may be influenced by many factors like his daily habits, or the path simplicity in term of minimum of direction changes. It appeared interesting to us to investigate how to mimic human navigation behavior with an autonomous agent. The solution we propose relies on an architecture based on a generic model of informed environment, a spatial cognitive map model merged with a human-like memory model, representing the agent's temporal knowledge of the environment, it gained along its experiences of navigation.

Anxiety and Search during Food Choice

DEFF Research Database (Denmark)

Hansen, Torben; Uth Thomsen, Thyra; Mukherjee, Ashkesh

2011-01-01

this type of condensed information will in fact motivate extended information search. Originality/value – This paper contributes to research in marketing on food choice and consumption: a consumption area that is important but difficult to navigate due to an increasing complexity of nutritional information......Purpose – This paper aims to investigate the effect of anxiety on information search during food choice and to test a key moderator of the effect of anxiety on search, namely attitude towards nutritional claims. Design/methodology/approach – By means of qualitative study the paper investigates...... the notion that consumers experience anxiety about health outcomes during food choice. Further, by means of structural equation modelling based on two studies with representative samples of Danish consumers, the paper investigates the effects outlined above. Findings – The authors show that anxiety during...

A Leapfrog Navigation System

Science.gov (United States)

Opshaug, Guttorm Ringstad

There are times and places where conventional navigation systems, such as the Global Positioning System (GPS), are unavailable due to anything from temporary signal occultations to lack of navigation system infrastructure altogether. The goal of the Leapfrog Navigation System (LNS) is to provide localized positioning services for such cases. The concept behind leapfrog navigation is to advance a group of navigation units teamwise into an area of interest. In a practical 2-D case, leapfrogging assumes known initial positions of at least two currently stationary navigation units. Two or more mobile units can then start to advance into the area of interest. The positions of the mobiles are constantly being calculated based on cross-range distance measurements to the stationary units, as well as cross-ranges among the mobiles themselves. At some point the mobile units stop, and the stationary units are released to move. This second team of units (now mobile) can then overtake the first team (now stationary) and travel even further towards the common goal of the group. Since there always is one stationary team, the position of any unit can be referenced back to the initial positions. Thus, LNS provides absolute positioning. I developed navigation algorithms needed to solve leapfrog positions based on cross-range measurements. I used statistical tools to predict how position errors would grow as a function of navigation unit geometry, cross-range measurement accuracy and previous position errors. Using this knowledge I predicted that a 4-unit Leapfrog Navigation System using 100 m baselines and 200 m leap distances could travel almost 15 km before accumulating absolute position errors of 10 m (1sigma). Finally, I built a prototype leapfrog navigation system using 4 GPS transceiver ranging units. I placed the 4 units in the vertices a 10m x 10m square, and leapfrogged the group 20 meters forwards, and then back again (40 m total travel). Average horizontal RMS position

A study on PubMed search tag usage pattern: association rule mining of a full-day PubMed query log.

Science.gov (United States)

Mosa, Abu Saleh Mohammad; Yoo, Illhoi

2013-01-09

The practice of evidence-based medicine requires efficient biomedical literature search such as PubMed/MEDLINE. Retrieval performance relies highly on the efficient use of search field tags. The purpose of this study was to analyze PubMed log data in order to understand the usage pattern of search tags by the end user in PubMed/MEDLINE search. A PubMed query log file was obtained from the National Library of Medicine containing anonymous user identification, timestamp, and query text. Inconsistent records were removed from the dataset and the search tags were extracted from the query texts. A total of 2,917,159 queries were selected for this study issued by a total of 613,061 users. The analysis of frequent co-occurrences and usage patterns of the search tags was conducted using an association mining algorithm. The percentage of search tag usage was low (11.38% of the total queries) and only 2.95% of queries contained two or more tags. Three out of four users used no search tag and about two-third of them issued less than four queries. Among the queries containing at least one tagged search term, the average number of search tags was almost half of the number of total search terms. Navigational search tags are more frequently used than informational search tags. While no strong association was observed between informational and navigational tags, six (out of 19) informational tags and six (out of 29) navigational tags showed strong associations in PubMed searches. The low percentage of search tag usage implies that PubMed/MEDLINE users do not utilize the features of PubMed/MEDLINE widely or they are not aware of such features or solely depend on the high recall focused query translation by the PubMed's Automatic Term Mapping. The users need further education and interactive search application for effective use of the search tags in order to fulfill their biomedical information needs from PubMed/MEDLINE.

Navigational challenges in the oceanic migrations of leatherback sea turtles

Science.gov (United States)

Sale, Alessandro; Luschi, Paolo

2009-01-01

The open-sea movements of marine animals are affected by the drifting action of currents that, if not compensated for, can produce non-negligible deviations from the correct route towards a given target. Marine turtles are paradigmatic skilful oceanic navigators that are able to reach remote goals at the end of long-distance migrations, apparently overcoming current drift effects. Particularly relevant is the case of leatherback turtles (Dermochelys coriacea), which spend entire years in the ocean, wandering in search of planktonic prey. Recent analyses have revealed how the movements of satellite-tracked leatherbacks in the Indian, Atlantic and Pacific Oceans are strongly dependent on the oceanic currents, up to the point that turtles are often passively transported over long distances. However, leatherbacks are known to return to specific areas to breed every 2–3 years, thus finding their way back home after long periods in the oceanic environment. Here we examine the navigational consequences of the leatherbacks' close association with currents and discuss how the combined reliance on mechanisms of map-based navigation and local orientation cues close to the target may allow leatherbacks to accomplish the difficult task of returning to specific sites after years spent wandering in a moving medium. PMID:19625321

Optimal motion planning using navigation measure

Science.gov (United States)

Vaidya, Umesh

2018-05-01

We introduce navigation measure as a new tool to solve the motion planning problem in the presence of static obstacles. Existence of navigation measure guarantees collision-free convergence at the final destination set beginning with almost every initial condition with respect to the Lebesgue measure. Navigation measure can be viewed as a dual to the navigation function. While the navigation function has its minimum at the final destination set and peaks at the obstacle set, navigation measure takes the maximum value at the destination set and is zero at the obstacle set. A linear programming formalism is proposed for the construction of navigation measure. Set-oriented numerical methods are utilised to obtain finite dimensional approximation of this navigation measure. Application of the proposed navigation measure-based theoretical and computational framework is demonstrated for a motion planning problem in a complex fluid flow.

Integrated navigation method of a marine strapdown inertial navigation system using a star sensor

International Nuclear Information System (INIS)

Wang, Qiuying; Diao, Ming; Gao, Wei; Zhu, Minghong; Xiao, Shu

2015-01-01

This paper presents an integrated navigation method of the strapdown inertial navigation system (SINS) using a star sensor. According to the principle of SINS, its own navigation information contains an error that increases with time. Hence, the inertial attitude matrix from the star sensor is introduced as the reference information to correct the SINS increases error. For the integrated navigation method, the vehicle’s attitude can be obtained in two ways: one is calculated from SINS; the other, which we have called star sensor attitude, is obtained as the product between the SINS position and the inertial attitude matrix from the star sensor. Therefore, the SINS position error is introduced in the star sensor attitude error. Based on the characteristics of star sensor attitude error and the mathematical derivation, the SINS navigation errors can be obtained by the coupling calculation between the SINS attitude and the star sensor attitude. Unlike several current techniques, the navigation process of this method is non-radiating and invulnerable to jamming. The effectiveness of this approach was demonstrated by simulation and experimental study. The results show that this integrated navigation method can estimate the attitude error and the position error of SINS. Therefore, the SINS navigation accuracy is improved. (paper)

The History of the Internet Search Engine: Navigational Media and the Traffic Commodity

Science.gov (United States)

van Couvering, E.

This chapter traces the economic development of the search engine industry over time, beginning with the earliest Web search engines and ending with the domination of the market by Google, Yahoo! and MSN. Specifically, it focuses on the ways in which search engines are similar to and different from traditional media institutions, and how the relations between traditional and Internet media have changed over time. In addition to its historical overview, a core contribution of this chapter is the analysis of the industry using a media value chain based on audiences rather than on content, and the development of traffic as the core unit of exchange. It shows that traditional media companies failed when they attempted to create vertically integrated portals in the late 1990s, based on the idea of controlling Internet content, while search engines succeeded in creating huge "virtually integrated" networks based on control of Internet traffic rather than Internet content.

Navigation as a New Form of Search for Agricultural Learning Resources in Semantic Repositories

Science.gov (United States)

Cano, Ramiro; Abián, Alberto; Mena, Elena

Education is essential when it comes to raise public awareness on the environmental and economic benefits of organic agriculture and agroecology (OA & AE). Organic.Edunet, an EU funded project, aims at providing a freely-available portal where learning contents on OA & AE can be published and accessed through specialized technologies. This paper describes a novel mechanism for providing semantic capabilities (such as semantic navigational queries) to an arbitrary set of agricultural learning resources, in the context of the Organic.Edunet initiative.

SUBSTITUSI TEPUNG LABU KUNING (Cucurbits moschata, Durch TERHADAP KANDUNGAN VITAMIN A DAN DAYA TERIMA PANELIS PADA SOSIS IKAN NILA (Oreochromis niloticus

Directory of Open Access Journals (Sweden)

Fu'ad Hasyim Asyngari

2017-02-01

Full Text Available Labu kuning merupakan sayuran yang kaya akan beta karoten sebagai prekursor vitamin A. Labu kuning dapat diolah menjadi tepung, yang kemudian disubstitusikan pada produk sosis ikan untuk meningkatkan nilai gizinya. Penelitian ini bertujuan untuk mendapatkan persentase substitusi tepung labu kuning yang tepat, mempelajari pengaruh substitusi tepung labu kuning terhadap kandungan vitamin A dan daya terima panelis produk sosis ikan nila. Tahapan pertama adalah pembuatan tepung labu kuning dengan pengeringan menggunakan sinar matahari selama 2-3 hari yang dilanjutkan dengan proses penepungan. Selanjutnya tepung labu kuning disubstitusikan pada sosis ikan nila dengan persentase 0%, 10%, 15% dan 20% dari total keseluruhan adonan sosis ikan. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL dengan 4 perlakuan dan 3 ulangan. Hasil penelitian menunjukkan bahwa sosis ikan nila dengan persentase substitusi tepung labu kuning 20% merupakan perlakuan terbaik ditinjau dari kandungan vitamin A. Persentase substitusi tepung labu kuning dapat meningkatkan kandungan vitamin A pada sosis ikan nila. Kandungan vitamin A sosis ikan nila dengan subtitusi tepung labu kuning dengan persentase 0%, 10%, 15% dan 20% berturut-turut yaitu < 0,01 μg/g, 0,9825 μg/g, 1,5025 μg/g dan 1,5375 μg/g. Hasil uji organoleptik menunjukkan daya terima panelis terhadap sosis ikan nila dengan substitusi tepung labu kuning berkisar antara 5 (agak suka sampai dengan 6,8 (suka. Pumpkin is vegetable that rich in beta carotene as a precursor of vitamin A. Pumpkin can be processed into flour, which is then substitution on fish sausage products to improve the nutritional value. The purpose of this study was get precise percentage substitution of pumpkin flour, to know the effect of pumpkin flour substitution on the content of vitamin A and the panelist acceptance on tilapia sausage product. The first stage was manufacturing of pumpkin flour with drying using sunlight for 2-3 days

Health literacy and usability of clinical trial search engines.

Science.gov (United States)

Utami, Dina; Bickmore, Timothy W; Barry, Barbara; Paasche-Orlow, Michael K

2014-01-01

Several web-based search engines have been developed to assist individuals to find clinical trials for which they may be interested in volunteering. However, these search engines may be difficult for individuals with low health and computer literacy to navigate. The authors present findings from a usability evaluation of clinical trial search tools with 41 participants across the health and computer literacy spectrum. The study consisted of 3 parts: (a) a usability study of an existing web-based clinical trial search tool; (b) a usability study of a keyword-based clinical trial search tool; and (c) an exploratory study investigating users' information needs when deciding among 2 or more candidate clinical trials. From the first 2 studies, the authors found that users with low health literacy have difficulty forming queries using keywords and have significantly more difficulty using a standard web-based clinical trial search tool compared with users with adequate health literacy. From the third study, the authors identified the search factors most important to individuals searching for clinical trials and how these varied by health literacy level.

Lunar Navigation Architecture Design Considerations

Science.gov (United States)

D'Souza, Christopher; Getchius, Joel; Holt, Greg; Moreau, Michael

2009-01-01

The NASA Constellation Program is aiming to establish a long-term presence on the lunar surface. The Constellation elements (Orion, Altair, Earth Departure Stage, and Ares launch vehicles) will require a lunar navigation architecture for navigation state updates during lunar-class missions. Orion in particular has baselined earth-based ground direct tracking as the primary source for much of its absolute navigation needs. However, due to the uncertainty in the lunar navigation architecture, the Orion program has had to make certain assumptions on the capabilities of such architectures in order to adequately scale the vehicle design trade space. The following paper outlines lunar navigation requirements, the Orion program assumptions, and the impacts of these assumptions to the lunar navigation architecture design. The selection of potential sites was based upon geometric baselines, logistical feasibility, redundancy, and abort support capability. Simulated navigation covariances mapped to entry interface flightpath- angle uncertainties were used to evaluate knowledge errors. A minimum ground station architecture was identified consisting of Goldstone, Madrid, Canberra, Santiago, Hartebeeshoek, Dongora, Hawaii, Guam, and Ascension Island (or the geometric equivalent).

E-navigation Services for Non-SOLAS Ships

Directory of Open Access Journals (Sweden)

Kwang An

2016-06-01

Full Text Available It is clearly understood that the main benefits of e-navigation are improved safety and better protection of the environment through the promotion of standards of navigational system and a reduction in human error. In order to meet the expectations on the benefit of e-navigation, e-navigation services should be more focused on non-SOLAS ships. The purpose of this paper is to present necessary e-navigation services for non-SOLAS ships in order to prevent marine accidents in Korean coastal waters. To meet the objectives of the study, an examination on the present navigation and communication system for non-SOLAS ships was performed. Based on the IMO's e-navigation Strategy Implementation Plan (SIP and Korea's national SIP for e-navigation, future trends for the development and implementation of e-navigation were discussed. Consequently, Electronic Navigational Chart (ENC download and ENC up-date service, ENC streaming service, route support service and communication support service based on Maritime Cloud were presented as essential e-navigation services for non-SOLAS ships. This study will help for the planning and designing of the Korean e-navigation system. It is expected that the further researches on the navigation support systems based on e-navigation will be carried out in order to implement the essential e-navigation services for non-SOLAS ships.

World Wide Web Metaphors for Search Mission Data

Science.gov (United States)

Norris, Jeffrey S.; Wallick, Michael N.; Joswig, Joseph C.; Powell, Mark W.; Torres, Recaredo J.; Mittman, David S.; Abramyan, Lucy; Crockett, Thomas M.; Shams, Khawaja S.; Fox, Jason M.;

Structure and navigation for electronic publishing

Science.gov (United States)

Tillinghast, John; Beretta, Giordano B.

1998-01-01

The sudden explosion of the World Wide Web as a new publication medium has given a dramatic boost to the electronic publishing industry, which previously was a limited market centered around CD-ROMs and on-line databases. While the phenomenon has parallels to the advent of the tabloid press in the middle of last century, the electronic nature of the medium brings with it the typical characteristic of 4th wave media, namely the acceleration in its propagation speed and the volume of information. Consequently, e-publications are even flatter than print media; Shakespeare's Romeo and Juliet share the same computer screen with a home-made plagiarized copy of Deep Throat. The most touted tool for locating useful information on the World Wide Web is the search engine. However, due to the medium's flatness, sought information is drowned in a sea of useless information. A better solution is to build tools that allow authors to structure information so that it can easily be navigated. We experimented with the use of ontologies as a tool to formulate structures for information about a specific topic, so that related concepts are placed in adjacent locations and can easily be navigated using simple and ergonomic user models. We describe our effort in building a World Wide Web based photo album that is shared among a small network of people.

Indoor navigation by image recognition

Science.gov (United States)

Choi, Io Teng; Leong, Chi Chong; Hong, Ka Wo; Pun, Chi-Man

2017-07-01

With the progress of smartphones hardware, it is simple on smartphone using image recognition technique such as face detection. In addition, indoor navigation system development is much slower than outdoor navigation system. Hence, this research proves a usage of image recognition technique for navigation in indoor environment. In this paper, we introduced an indoor navigation application that uses the indoor environment features to locate user's location and a route calculating algorithm to generate an appropriate path for user. The application is implemented on Android smartphone rather than iPhone. Yet, the application design can also be applied on iOS because the design is implemented without using special features only for Android. We found that digital navigation system provides better and clearer location information than paper map. Also, the indoor environment is ideal for Image recognition processing. Hence, the results motivate us to design an indoor navigation system using image recognition.

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...

Surface navigation on Mars with a Navigation Satellite

Science.gov (United States)

Vijayaraghavan, A.; Thurman, Sam W.; Kahn, Robert D.; Hastrup, Rolf C.

Radiometric navigation data from the Deep Space Network (DSN) stations on the earth to transponders and other surface elements such as rovers and landers on Mars, can determine their positions to only within a kilometer in inertial space. The positional error is mostly in the z-component of the surface element parallel to the Martian spin-axis. However, with Doppler and differenced-Doppler data from a Navigation Satellite in orbit around Mars to two or more of such transponders on the planetary surface, their positions can be determined to within 15 meters (or 20 meters for one-way Doppler beacons on Mars) in inertial space. In this case, the transponders (or other vehicles) on Mars need not even be capable of directly communicating to the earth. When the Navigation Satellite data is complemented by radiometric observations from the DSN stations also, directly to the surface elements on Mars, their positions can be determined to within 3 meters in inertial space. The relative positions of such surface elements on Mars (relative to one another) in Mars-fixed coordinates, however, can be determined to within 5 meters from simply range and Doppler data from the DSN stations to the surface elements. These results are obtained from covariance studies assuming X-band data noise levels and data-arcs not exceeding 10 days. They are significant in the planning and deployment of a Mars-based navigation network necessary to support real-time operations during critical phases of manned exploration of Mars.

Semiotic resources for navigation

DEFF Research Database (Denmark)

Due, Brian Lystgaard; Lange, Simon Bierring

2018-01-01

This paper describes two typical semiotic resources blind people use when navigating in urban areas. Everyone makes use of a variety of interpretive semiotic resources and senses when navigating. For sighted individuals, this especially involves sight. Blind people, however, must rely on everything...... else than sight, thereby substituting sight with other modalities and distributing the navigational work to other semiotic resources. Based on a large corpus of fieldwork among blind people in Denmark, undertaking observations, interviews, and video recordings of their naturally occurring practices...... of walking and navigating, this paper shows how two prototypical types of semiotic resources function as helpful cognitive extensions: the guide dog and the white cane. This paper takes its theoretical and methodological perspective from EMCA multimodal interaction analysis....

EnEx-RANGE - Robust autonomous Acoustic Navigation in Glacial icE

Science.gov (United States)

Heinen, Dirk; Eliseev, Dmitry; Henke, Christoph; Jeschke, Sabina; Linder, Peter; Reuter, Sebastian; Schönitz, Sebastian; Scholz, Franziska; Weinstock, Lars Steffen; Wickmann, Stefan; Wiebusch, Christopher; Zierke, Simon

2017-03-01

Within the Enceladus Explorer Initiative of the DLR Space Administration navigation technologies for a future space mission are in development. Those technologies are the basis for the search for extraterrestrial life on the Saturn moon Enceladus. An autonomous melting probe, the EnEx probe, aims to extract a liquid sample from a water reservoir below the icy crust. A first EnEx probe was developed and demonstrated in a terrestrial scenario at the Bloodfalls, Taylor Glacier, Antarctica in November 2014. To enable navigation in glacier ice two acoustic systems were integrated into the probe in addition to conventional navigation technologies. The first acoustic system determines the position of the probe during the run based on propagation times of acoustic signals from emitters at reference positions at the glacier surface to receivers in the probe. The second system provides information about the forefield of the probe. It is based on sonographic principles with phased array technology integrated in the probe's melting head. Information about obstacles or sampling regions in the probe's forefield can be acquired. The development of both systems is now continued in the project EnEx-RANGE. The emitters of the localization system are replaced by a network of intelligent acoustic enabled melting probes. These localize each other by means of acoustic signals and create the reference system for the EnEx probe. This presentation includes the discussion of the intelligent acoustic network, the acoustic navigation systems of the EnEx probe and results of terrestrial tests.

Exposure to arousal-inducing sounds facilitates visual search.

Science.gov (United States)

Asutay, Erkin; Västfjäll, Daniel

2017-09-04

Exposure to affective stimuli could enhance perception and facilitate attention via increasing alertness, vigilance, and by decreasing attentional thresholds. However, evidence on the impact of affective sounds on perception and attention is scant. Here, a novel aspect of affective facilitation of attention is studied: whether arousal induced by task-irrelevant auditory stimuli could modulate attention in a visual search. In two experiments, participants performed a visual search task with and without auditory-cues that preceded the search. Participants were faster in locating high-salient targets compared to low-salient targets. Critically, search times and search slopes decreased with increasing auditory-induced arousal while searching for low-salient targets. Taken together, these findings suggest that arousal induced by sounds can facilitate attention in a subsequent visual search. This novel finding provides support for the alerting function of the auditory system by showing an auditory-phasic alerting effect in visual attention. The results also indicate that stimulus arousal modulates the alerting effect. Attention and perception are our everyday tools to navigate our surrounding world and the current findings showing that affective sounds could influence visual attention provide evidence that we make use of affective information during perceptual processing.

33 CFR 401.54 - Interference with navigation aids.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b) No...

Search, Read and Write: An Inquiry into Web Accessibility for People with Dyslexia.

Science.gov (United States)

Berget, Gerd; Herstad, Jo; Sandnes, Frode Eika

2016-01-01

Universal design in context of digitalisation has become an integrated part of international conventions and national legislations. A goal is to make the Web accessible for people of different genders, ages, backgrounds, cultures and physical, sensory and cognitive abilities. Political demands for universally designed solutions have raised questions about how it is achieved in practice. Developers, designers and legislators have looked towards the Web Content Accessibility Guidelines (WCAG) for answers. WCAG 2.0 has become the de facto standard for universal design on the Web. Some of the guidelines are directed at the general population, while others are targeted at more specific user groups, such as the visually impaired or hearing impaired. Issues related to cognitive impairments such as dyslexia receive less attention, although dyslexia is prevalent in at least 5-10% of the population. Navigation and search are two common ways of using the Web. However, while navigation has received a fair amount of attention, search systems are not explicitly included, although search has become an important part of people's daily routines. This paper discusses WCAG in the context of dyslexia for the Web in general and search user interfaces specifically. Although certain guidelines address topics that affect dyslexia, WCAG does not seem to fully accommodate users with dyslexia.

Navigation performance in virtual environments varies with fractal dimension of landscape.

Science.gov (United States)

Juliani, Arthur W; Bies, Alexander J; Boydston, Cooper R; Taylor, Richard P; Sereno, Margaret E

2016-09-01

Fractal geometry has been used to describe natural and built environments, but has yet to be studied in navigational research. In order to establish a relationship between the fractal dimension (D) of a natural environment and humans' ability to navigate such spaces, we conducted two experiments using virtual environments that simulate the fractal properties of nature. In Experiment 1, participants completed a goal-driven search task either with or without a map in landscapes that varied in D. In Experiment 2, participants completed a map-reading and location-judgment task in separate sets of fractal landscapes. In both experiments, task performance was highest at the low-to-mid range of D, which was previously reported as most preferred and discriminable in studies of fractal aesthetics and discrimination, respectively, supporting a theory of visual fluency. The applicability of these findings to architecture, urban planning, and the general design of constructed spaces is discussed.

Thumbnail Images:Uncertainties, Infrastructures and Search Engines

OpenAIRE

Thylstrup, Nanna; Teilmann, Stina

2017-01-01

This article argues that thumbnail images are infrastructural images that raise issues of uncertainty in two distinct, but interrelated, areas: a legal question of how to define, understand and govern visual information infrastructures, in particular image search systems in epistemological and strategic terms; and a cultural question of how human-computer interaction design works with navigational uncertainty, both as an experience to be managed and a resource to be exploited. This paper cons...

Real-time precision pedestrian navigation solution using Inertial Navigation System and Global Positioning System

OpenAIRE

Yong-Jin Yoon; King Ho Holden Li; Jiahe Steven Lee; Woo-Tae Park

2015-01-01

Global Positioning System and Inertial Navigation System can be used to determine position and velocity. A Global Positioning System module is able to accurately determine position without sensor drift, but its usage is limited in heavily urbanized environments and heavy vegetation. While high-cost tactical-grade Inertial Navigation System can determine position accurately, low-cost micro-electro-mechanical system Inertial Navigation System sensors are plagued by significant errors. Global Po...

The Navigation Guide—Evidence-Based Medicine Meets Environmental Health: Systematic Review of Nonhuman Evidence for PFOA Effects on Fetal Growth

Science.gov (United States)

Lam, Juleen; Sutton, Patrice; Johnson, Paula I.; Atchley, Dylan S.; Sen, Saunak; Robinson, Karen A.; Axelrad, Daniel A.; Woodruff, Tracey J.

2014-01-01

Background: In contrast to current methods of expert-based narrative review, the Navigation Guide is a systematic and transparent method for synthesizing environmental health research from multiple evidence streams. The Navigation Guide was developed to effectively and efficiently translate the available scientific evidence into timely prevention-oriented action. Objectives: We applied the Navigation Guide systematic review method to answer the question “Does fetal developmental exposure to perfluorooctanoic acid (PFOA) or its salts affect fetal growth in animals ?” and to rate the strength of the experimental animal evidence. Methods: We conducted a comprehensive search of the literature, applied prespecified criteria to the search results to identify relevant studies, extracted data from studies, obtained additional information from study authors, conducted meta-analyses, and rated the overall quality and strength of the evidence. Results: Twenty-one studies met the inclusion criteria. From the meta-analysis of eight mouse gavage data sets, we estimated that exposure of pregnant mice to increasing concentrations of PFOA was associated with a change in mean pup birth weight of –0.023 g (95% CI: –0.029, –0.016) per 1-unit increase in dose (milligrams per kilogram body weight per day). The evidence, consisting of 15 mammalian and 6 nonmammalian studies, was rated as “moderate” and “low” quality, respectively. Conclusion: Based on this first application of the Navigation Guide methodology, we found sufficient evidence that fetal developmental exposure to PFOA reduces fetal growth in animals. Citation: Koustas E, Lam J, Sutton P, Johnson PI, Atchley DS, Sen S, Robinson KA, Axelrad DA, Woodruff TJ. 2014. The Navigation Guide—evidence-based medicine meets environmental health: systematic review of nonhuman evidence for PFOA effects on fetal growth. Environ Health Perspect 122:1015–1027; http://dx.doi.org/10.1289/ehp.1307177 PMID:24968374

Navigating oceans and cultures: Polynesian and European navigation systems in the late eighteenth century

Science.gov (United States)

Walker, M.

2012-05-01

Significant differences in the rotation of the celestial dome between the tropical and temperate zones did not stop the peoples of either the tropical Pacific or temperate Europe from using geocentric astronomy to guide exploration of the oceans. Although the differences in the night sky contributed to differences between the Pacific Island and European systems for navigation at sea, the two navigation systems exhibit substantial similarities. Both systems define positions on the surface of the Earth using two coordinates that vary at right angles to each other and use stars, and to a lesser extent the sun, to determine directions. This essay explores similarities and differences in the use of geocentric astronomy for navigation at sea by the peoples of Polynesia and Europe in the late eighteenth century. Captain Cook's orders to discover the unknown southern continent after observing the transit of Venus combined with differences in language and culture to obscure the deeper similarities between the navigation systems used by Cook and the Polynesians. Although it was a further 200 years before anthropologists studied Pacific navigation, collaborations in voyaging with communities in Oceania demonstrated the effectiveness of Pacific navigation systems, revived interest in traditional voyaging in island communities around the Pacific, and potentially open the way for further collaborations in other areas.

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.

Usability Testing of Two Ambulatory EHR Navigators.

Science.gov (United States)

Hultman, Gretchen; Marquard, Jenna; Arsoniadis, Elliot; Mink, Pamela; Rizvi, Rubina; Ramer, Tim; Khairat, Saif; Fickau, Keri; Melton, Genevieve B

2016-01-01

Despite widespread electronic health record (EHR) adoption, poor EHR system usability continues to be a significant barrier to effective system use for end users. One key to addressing usability problems is to employ user testing and user-centered design. To understand if redesigning an EHR-based navigation tool with clinician input improved user performance and satisfaction. A usability evaluation was conducted to compare two versions of a redesigned ambulatory navigator. Participants completed tasks for five patient cases using the navigators, while employing a think-aloud protocol. The tasks were based on Meaningful Use (MU) requirements. The version of navigator did not affect perceived workload, and time to complete tasks was longer in the redesigned navigator. A relatively small portion of navigator content was used to complete the MU-related tasks, though navigation patterns were highly variable across participants for both navigators. Preferences for EHR navigation structures appeared to be individualized. This study demonstrates the importance of EHR usability assessments to evaluate group and individual performance of different interfaces and preferences for each design.

75 FR 50884 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector...

Science.gov (United States)

2010-08-18

... 3 and 165 to reflect changes in Coast Guard internal organizational structure. Sector Portland and... 1625-ZA25 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector... Waters; Technical, Organizational, and Conforming Amendments, Sector Columbia River.'' 2. On page 48564...

Getting Lost Through Navigation

DEFF Research Database (Denmark)

Debus, Michael S.

2017-01-01

In this presentation, I argued two things. First, that it is navigation that lies at the core of contemporary (3D-) videogames and that its analysis is of utmost importance. Second, that this analysis needs a more rigorous differentiation between specific acts of navigation. Considering the Oxford...... in videogames is a configurational rather than an interpretational one (Eskelinen 2001). Especially in the case of game spaces, navigation appears to be of importance (Wolf 2009; Flynn 2008). Further, it does not only play a crucial role for the games themselves, but also for the experience of the player...

Inertial navigation without accelerometers

Science.gov (United States)

Boehm, M.

The Kennedy-Thorndike (1932) experiment points to the feasibility of fiber-optic inertial velocimeters, to which state-of-the-art technology could furnish substantial sensitivity and accuracy improvements. Velocimeters of this type would obviate the use of both gyros and accelerometers, and allow inertial navigation to be conducted together with vehicle attitude control, through the derivation of rotation rates from the ratios of the three possible velocimeter pairs. An inertial navigator and reference system based on this approach would probably have both fewer components and simpler algorithms, due to the obviation of the first level of integration in classic inertial navigators.

78 FR 41304 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments; Correction

Science.gov (United States)

2013-07-10

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 105 [Docket No. USCG-2013-0397] RIN 1625-AC06 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments; Correction AGENCY: Coast Guard, DHS. ACTION: Final rule; correction. SUMMARY: The Coast Guard published a final rule...

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...

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

75 FR 48564 - Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector...

Science.gov (United States)

2010-08-11

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Parts 3 and 165 [Docket No. USCG-2010-0351] RIN 1625-ZA25 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector Columbia River, WA AGENCY: Coast Guard, DHS. ACTION: Final rule. SUMMARY: This rule makes non-substantive...

Sex differences in navigation strategy and efficiency.

Science.gov (United States)

Boone, Alexander P; Gong, Xinyi; Hegarty, Mary

2018-05-22

Research on human navigation has indicated that males and females differ in self-reported navigation strategy as well as objective measures of navigation efficiency. In two experiments, we investigated sex differences in navigation strategy and efficiency using an objective measure of strategy, the dual-solution paradigm (DSP; Marchette, Bakker, & Shelton, 2011). Although navigation by shortcuts and learned routes were the primary strategies used in both experiments, as in previous research on the DSP, individuals also utilized route reversals and sometimes found the goal location as a result of wandering. Importantly, sex differences were found in measures of both route selection and navigation efficiency. In particular, males were more likely to take shortcuts and reached their goal location faster than females, while females were more likely to follow learned routes and wander. Self-report measures of strategy were only weakly correlated with objective measures of strategy, casting doubt on their usefulness. This research indicates that the sex difference in navigation efficiency is large, and only partially related to an individual's navigation strategy as measured by the dual-solution paradigm.

Celestial Navigation in the USA, Fiji, and Tunisia

Science.gov (United States)

Holbrook, Jarita C.

2015-05-01

Today there are many coastal communities that are home to navigators who use stars for position finding at night; I was, however, unaware of this fact when I began researching celestial navigation practices in 1997. My project focused on three communities: the Moce Islanders of Fiji, the Kerkennah Islanders in Tunisia, and the U.S. Navy officers and students at the United States Naval Academy, Annapolis, Maryland. My goal was to answer the question of why people continue to navigate by the stars, but also to understand the role of technology in their navigation practices. Using anthropology techniques of ethnography including participant observation, formal and informal interviews, audio and videotaping, I gathered data over five years at the three communities. I began by learning the details of how they use the stars for navigation. Next, I learned about who did the navigation and where they learned to navigate. I gathered opinions on various navigation aids and instruments, and opinions about the future of using the stars for navigation. I listened to the stories that they told about navigating. In the United States I worked in English, in Fiji, in Fijian and English, and in Tunisia, French and English. For the formal interviews I worked with translators. The navigators use stars for navigating today but the future of their techniques is not certain. Though practiced today, these celestial navigation traditions have undergone and continue to undergo changes. New navigational technologies are part of the stimulation for change, thus 'a meeting of different worlds' is symbolized by peoples encounters with these technologies.

Nautical Navigation Aids (NAVAID) Locations

Data.gov (United States)

Department of Homeland Security — Structures intended to assist a navigator to determine position or safe course, or to warn of dangers or obstructions to navigation. This dataset includes lights,...

Design of all-weather celestial navigation system

Science.gov (United States)

Sun, Hongchi; Mu, Rongjun; Du, Huajun; Wu, Peng

2018-03-01

In order to realize autonomous navigation in the atmosphere, an all-weather celestial navigation system is designed. The research of celestial navigation system include discrimination method of comentropy and the adaptive navigation algorithm based on the P value. The discrimination method of comentropy is studied to realize the independent switching of two celestial navigation modes, starlight and radio. Finally, an adaptive filtering algorithm based on P value is proposed, which can greatly improve the disturbance rejection capability of the system. The experimental results show that the accuracy of the three axis attitude is better than 10″, and it can work all weather. In perturbation environment, the position accuracy of the integrated navigation system can be increased 20% comparing with the traditional method. It basically meets the requirements of the all-weather celestial navigation system, and it has the ability of stability, reliability, high accuracy and strong anti-interference.

An on-line monitoring system for navigation equipment

Science.gov (United States)

Wang, Bo; Yang, Ping; Liu, Jing; Yang, Zhengbo; Liang, Fei

2017-10-01

Civil air navigation equipment is the most important infrastructure of Civil Aviation, which is closely related to flight safety. In addition to regular flight inspection, navigation equipment's patrol measuring, maintenance measuring, running measuring under special weather conditions are the important means of ensuring aviation flight safety. According to the safety maintenance requirements of Civil Aviation Air Traffic Control navigation equipment, this paper developed one on-line monitoring system with independent intellectual property rights for navigation equipment, the system breakthroughs the key technologies of measuring navigation equipment on-line including Instrument Landing System (ILS) and VHF Omni-directional Range (VOR), which also meets the requirements of navigation equipment ground measurement set by the ICAO DOC 8071, it provides technical means of the ground on-line measurement for navigation equipment, improves the safety of navigation equipment operation, and reduces the impact of measuring navigation equipment on airport operation.

Positioning performance improvements with European multiple-frequency satellite navigation - Galileo

Science.gov (United States)

Ji, Shengyue

2008-10-01

The rapid development of Global Positioning System has demonstrated the advantages of satellite based navigation systems. In near future, there will be a number of Global Navigation Satellite System (GNSS) available, i.e. modernized GPS, Galileo, restored GLONASS, BeiDou and many other regional GNSS augmentation systems. Undoubtedly, the new GNSS systems will significantly improve navigation performance over current GPS, with a better satellite coverage and multiple satellite signal bands. In this dissertation, the positioning performance improvement of new GNSS has been investigated based on both theoretical analysis and numerical study. First of all, the navigation performance of new GNSS systems has been analyzed, particularly for urban applications. The study has demonstrated that Receiver Autonomous Integrity Monitoring (RAIM) performance can be significantly improved with multiple satellite constellations, although the position accuracy improvement is limited. Based on a three-dimensional urban building model in Hong Kong streets, it is found that positioning availability is still very low in high-rising urban areas, even with three GNSS systems. On the other hand, the discontinuity of navigation solutions is significantly reduced with the combined constellations. Therefore, it is possible to use cheap DR systems to bridge the gaps of GNSS positioning, with high accuracy. Secondly, the ambiguity resolution performance has been investigated with Galileo multiple frequency band signals. The ambiguity resolution performance of three different algorithms is compared, including CAR, ILS and improved CAR methods (a new method proposed in this study). For short baselines, with four frequency Galileo data, it is highly possible to achieve reliable single epoch ambiguity resolution, when the carrier phase noise level is reasonably low (i.e. less than 6mm). For long baselines (up to 800 km), the integer ambiguity can be determined within 1 min on average. Ambiguity

32 CFR 644.3 - Navigation Projects.

Science.gov (United States)

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Navigation Projects. 644.3 Section 644.3 National... HANDBOOK Project Planning Civil Works § 644.3 Navigation Projects. (a) Land to be acquired in fee. All... construction and borrow areas. (3) In navigation-only projects, the right to permanently flood should be...

Advantages and limitations of navigation-based multicriteria optimization (MCO) for localized prostate cancer IMRT planning

International Nuclear Information System (INIS)

McGarry, Conor K.; Bokrantz, Rasmus; O’Sullivan, Joe M.; Hounsell, Alan R.

2014-01-01

Efficacy of inverse planning is becoming increasingly important for advanced radiotherapy techniques. This study’s aims were to validate multicriteria optimization (MCO) in RayStation (v2.4, RaySearch Laboratories, Sweden) against standard intensity-modulated radiation therapy (IMRT) optimization in Oncentra (v4.1, Nucletron BV, the Netherlands) and characterize dose differences due to conversion of navigated MCO plans into deliverable multileaf collimator apertures. Step-and-shoot IMRT plans were created for 10 patients with localized prostate cancer using both standard optimization and MCO. Acceptable standard IMRT plans with minimal average rectal dose were chosen for comparison with deliverable MCO plans. The trade-off was, for the MCO plans, managed through a user interface that permits continuous navigation between fluence-based plans. Navigated MCO plans were made deliverable at incremental steps along a trajectory between maximal target homogeneity and maximal rectal sparing. Dosimetric differences between navigated and deliverable MCO plans were also quantified. MCO plans, chosen as acceptable under navigated and deliverable conditions resulted in similar rectal sparing compared with standard optimization (33.7 ± 1.8 Gy vs 35.5 ± 4.2 Gy, p = 0.117). The dose differences between navigated and deliverable MCO plans increased as higher priority was placed on rectal avoidance. If the best possible deliverable MCO was chosen, a significant reduction in rectal dose was observed in comparison with standard optimization (30.6 ± 1.4 Gy vs 35.5 ± 4.2 Gy, p = 0.047). Improvements were, however, to some extent, at the expense of less conformal dose distributions, which resulted in significantly higher doses to the bladder for 2 of the 3 tolerance levels. In conclusion, similar IMRT plans can be created for patients with prostate cancer using MCO compared with standard optimization. Limitations exist within MCO regarding conversion of navigated plans to

14 CFR 121.349 - Communication and navigation equipment for operations under VFR over routes not navigated by...

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Communication and navigation equipment for... § 121.349 Communication and navigation equipment for operations under VFR over routes not navigated by... receiver providing visual and aural signals; and (iii) One ILS receiver; and (3) Any RNAV system used to...

Quantum imaging for underwater arctic navigation

Science.gov (United States)

Lanzagorta, Marco

2017-05-01

The precise navigation of underwater vehicles is a difficult task due to the challenges imposed by the variable oceanic environment. It is particularly difficult if the underwater vehicle is trying to navigate under the Arctic ice shelf. Indeed, in this scenario traditional navigation devices such as GPS, compasses and gyrocompasses are unavailable or unreliable. In addition, the shape and thickness of the ice shelf is variable throughout the year. Current Arctic underwater navigation systems include sonar arrays to detect the proximity to the ice. However, these systems are undesirable in a wartime environment, as the sound gives away the position of the underwater vehicle. In this paper we briefly describe the theoretical design of a quantum imaging system that could allow the safe and stealthy navigation of underwater Arctic vehicles.

Autonomous Robot Navigation based on Visual Landmarks

DEFF Research Database (Denmark)

Livatino, Salvatore

2005-01-01

The use of landmarks for robot navigation is a popular alternative to having a geometrical model of the environment through which to navigate and monitor self-localization. If the landmarks are defined as special visual structures already in the environment then we have the possibility of fully a...... automatically learn and store visual landmarks, and later recognize these landmarks from arbitrary positions and thus estimate robot position and heading.......The use of landmarks for robot navigation is a popular alternative to having a geometrical model of the environment through which to navigate and monitor self-localization. If the landmarks are defined as special visual structures already in the environment then we have the possibility of fully...... 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...

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.

Inland Electronic Navigational Charts (IENC)

Data.gov (United States)

Army Corps of Engineers, Department of the Army, Department of Defense — These Inland Electronic Navigational Charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

Pengaruh Penggunaan Talas (Xanthosoma sagittifolium Terhadap Mutu dan Tingkat Penerimaan Panelis pada Produk Roti, Pastel, Pancake, Cookies, dan Bubur Talas

Directory of Open Access Journals (Sweden)

Wilsa Hermianti

2016-06-01

dilakukan teknologi pembuatan talas blok (Hermianti et al, 2010. Pada penelitian ini dilakukan  penggunaan talas blok untuk pembuatan aneka produk makanan basah, semi basah, dan makanan kering seperti roti, pastel, cookies, pancake, dan bubur talas dengan mensubstitusi tepung terigu dan tepung beras. Penelitian ini  bertujuan untuk mengetahui jumlah penggunaan talas yang memberikan hasil yang optimal dalam pembuatan beberapa produk tersebut sehingga dihasilkan pangan dengan mutu yang baik dan disukai.  Penelitian substitusi terigu dengan talas  yang dilakukan dalam pembuatan roti, pastel, dan cookies 0% (kontrol/ tanpa talas blok, 25%, 50% dan 75%, untuk pancake dengan formula talas dengan terigu  0% (kontrol/tanpa talas blok, 30%, 50%,100%, sedangkan untuk bubur talas dengan formula talas dengan tepung beras 0% (kontrol/tanpa talas blok, 30%, 50%, dan 100%. Analisis  kimia dilakukan  terhadap bahan baku talas blok meliputi kadar air, kadar abu, kadar pati, dan protein sedangkan untuk produk olahan pangan dilakukan uji organoleptik (warna, aroma, rasa dan tekstur berdasarkan tingkat penerimaan panelis. Produk cookies talas dan roti talas yang paling disukai panelis dianalisis kandungan lemak, protein, karbohidrat dan kalorinya serta daya simpan untuk produk makanan kering (cookies. Hasil penelitian menunjukkan talas blok mengandung kadar air 12,40%, kadar abu 1,12%, kadar pati 73,37%, amilosa 2,88%, amilopektin 70,49% dan protein 3,4%. Hasil  uji organoleptik dengan hasil yang optimal dan lebih disukai adalah roti dan pastel dengan penggunaan 25% talas, cookies dengan penggunaan 50% talas, pancake dengan formula talas  dengan tepung 50% dan bubur dengan pemakaian talas blok 30%.

Low Cost Integrated Navigation System for Unmanned Vessel

Directory of Open Access Journals (Sweden)

Yang Changsong

2017-11-01

Full Text Available Large errors of low-cost MEMS inertial measurement unit (MIMU lead to huge navigation errors, even wrong navigation information. An integrated navigation system for unmanned vessel is proposed. It consists of a low-cost MIMU and Doppler velocity sonar (DVS. This paper presents an integrated navigation method, to improve the performance of navigation system. The integrated navigation system is tested using simulation and semi-physical simulation experiments, whose results show that attitude, velocity and position accuracy has improved awfully, giving exactly accurate navigation results. By means of the combination of low-cost MIMU and DVS, the proposed system is able to overcome fast drift problems of the low cost IMU.

Intelligent personal navigator supported by knowledge-based systems for estimating dead reckoning navigation parameters

Science.gov (United States)

Moafipoor, Shahram

Personal navigators (PN) have been studied for about a decade in different fields and applications, such as safety and rescue operations, security and emergency services, and police and military applications. The common goal of all these applications is to provide precise and reliable position, velocity, and heading information of each individual in various environments. In the PN system developed in this dissertation, the underlying assumption is that the system does not require pre-existing infrastructure to enable pedestrian navigation. To facilitate this capability, a multisensor system concept, based on the Global Positioning System (GPS), inertial navigation, barometer, magnetometer, and a human pedometry model has been developed. An important aspect of this design is to use the human body as navigation sensor to facilitate Dead Reckoning (DR) navigation in GPS-challenged environments. The system is designed predominantly for outdoor environments, where occasional loss of GPS lock may happen; however, testing and performance demonstration have been extended to indoor environments. DR navigation is based on a relative-measurement approach, with the key idea of integrating the incremental motion information in the form of step direction (SD) and step length (SL) over time. The foundation of the intelligent navigation system concept proposed here rests in exploiting the human locomotion pattern, as well as change of locomotion in varying environments. In this context, the term intelligent navigation represents the transition from the conventional point-to-point DR to dynamic navigation using the knowledge about the mechanism of the moving person. This approach increasingly relies on integrating knowledge-based systems (KBS) and artificial intelligence (AI) methodologies, including artificial neural networks (ANN) and fuzzy logic (FL). In addition, a general framework of the quality control for the real-time validation of the DR processing is proposed, based on a

Development of field navigation system; Field navigation system no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Ibara, S; Minode, M; Nishioka, K [Daihatsu Motor Co. Ltd., Osaka (Japan)

1995-04-20

This paper describes the following matters on a field navigation system developed for the purpose of covering a field of several kilometer square. This system consists of a center system and a vehicle system, and the center system comprises a map information computer and a communication data controlling computer; since the accuracy for a vehicle position detected by a GPS is not sufficient, an attempt of increasing the accuracy of vehicle position detection is made by means of a hybrid system; the hybrid system uses a satellite navigation method of differential system in which the error components in the GPS are transmitted from the center, and also uses a self-contained navigation method which performs an auxiliary function when the accuracy in the GPS has dropped; corrected GPS values, emergency messages to all of the vehicles and data of each vehicle position are communicated by wireless transmission in two ways between the center and vehicles; and accommodation of the map data adopted a system that can respond quickly to any change in roads and facilities. 3 refs., 13 figs., 1 tab.

Compact autonomous navigation system (CANS)

Science.gov (United States)

Hao, Y. C.; Ying, L.; Xiong, K.; Cheng, H. Y.; Qiao, G. D.

2017-11-01

Autonomous navigation of Satellite and constellation has series of benefits, such as to reduce operation cost and ground station workload, to avoid the event of crises of war and natural disaster, to increase spacecraft autonomy, and so on. Autonomous navigation satellite is independent of ground station support. Many systems are developed for autonomous navigation of satellite in the past 20 years. Along them American MANS (Microcosm Autonomous Navigation System) [1] of Microcosm Inc. and ERADS [2] [3] (Earth Reference Attitude Determination System) of Honeywell Inc. are well known. The systems anticipate a series of good features of autonomous navigation and aim low cost, integrated structure, low power consumption and compact layout. The ERADS is an integrated small 3-axis attitude sensor system with low cost and small volume. It has the Earth center measurement accuracy higher than the common IR sensor because the detected ultraviolet radiation zone of the atmosphere has a brightness gradient larger than that of the IR zone. But the ERADS is still a complex system because it has to eliminate many problems such as making of the sapphire sphere lens, birefringence effect of sapphire, high precision image transfer optical fiber flattener, ultraviolet intensifier noise, and so on. The marginal sphere FOV of the sphere lens of the ERADS is used to star imaging that may be bring some disadvantages., i.e. , the image energy and attitude measurements accuracy may be reduced due to the tilt image acceptance end of the fiber flattener in the FOV. Besides Japan, Germany and Russia developed visible earth sensor for GEO [4] [5]. Do we have a way to develop a cheaper/easier and more accurate autonomous navigation system that can be used to all LEO spacecraft, especially, to LEO small and micro satellites? To return this problem we provide a new type of the system—CANS (Compact Autonomous Navigation System) [6].

Parsimonious Ways to Use Vision for Navigation

Directory of Open Access Journals (Sweden)

Paul Graham

2012-05-01

Full Text Available The use of visual information for navigation appears to be a universal strategy for sighted animals, amongst which, one particular group of expert navigators are the ants. The broad interest in studies of ant navigation is in part due to their small brains, thus biomimetic engineers expect to be impressed by elegant control solutions, and psychologists might hope for a description of the minimal cognitive requirements for complex spatial behaviours. In this spirit, we have been taking an interdisciplinary approach to the visual guided navigation of ants in their natural habitat. Behavioural experiments and natural image statistics show that visual navigation need not depend on the remembering or recognition of objects. Further modelling work suggests how simple behavioural routines might enable navigation using familiarity detection rather than explicit recall, and we present a proof of concept that visual navigation using familiarity can be achieved without specifying when or what to learn, nor separating routes into sequences of waypoints. We suggest that our current model represents the only detailed and complete model of insect route guidance to date. What's more, we believe the suggested mechanisms represent useful parsimonious hypotheses for the visually guided navigation in larger-brain animals.

Risk management model of winter navigation operations

International Nuclear Information System (INIS)

Valdez Banda, Osiris A.; Goerlandt, Floris; Kuzmin, Vladimir; Kujala, Pentti; Montewka, Jakub

2016-01-01

The wintertime maritime traffic operations in the Gulf of Finland are managed through the Finnish–Swedish Winter Navigation System. This establishes the requirements and limitations for the vessels navigating when ice covers this area. During winter navigation in the Gulf of Finland, the largest risk stems from accidental ship collisions which may also trigger oil spills. In this article, a model for managing the risk of winter navigation operations is presented. The model analyses the probability of oil spills derived from collisions involving oil tanker vessels and other vessel types. The model structure is based on the steps provided in the Formal Safety Assessment (FSA) by the International Maritime Organization (IMO) and adapted into a Bayesian Network model. The results indicate that ship independent navigation and convoys are the operations with higher probability of oil spills. Minor spills are most probable, while major oil spills found very unlikely but possible. - Highlights: •A model to assess and manage the risk of winter navigation operations is proposed. •The risks of oil spills in winter navigation in the Gulf of Finland are analysed. •The model assesses and prioritizes actions to control the risk of the operations. •The model suggests navigational training as the most efficient risk control option.

Adaptive Landmark-Based Navigation System Using Learning Techniques

DEFF Research Database (Denmark)

Zeidan, Bassel; Dasgupta, Sakyasingha; Wörgötter, Florentin

2014-01-01

The goal-directed navigational ability of animals is an essential prerequisite for them to survive. They can learn to navigate to a distal goal in a complex environment. During this long-distance navigation, they exploit environmental features, like landmarks, to guide them towards their goal. In...... hexapod robots. As a result, it allows the robots to successfully learn to navigate to distal goals in complex environments.......The goal-directed navigational ability of animals is an essential prerequisite for them to survive. They can learn to navigate to a distal goal in a complex environment. During this long-distance navigation, they exploit environmental features, like landmarks, to guide them towards their goal....... Inspired by this, we develop an adaptive landmark-based navigation system based on sequential reinforcement learning. In addition, correlation-based learning is also integrated into the system to improve learning performance. The proposed system has been applied to simulated simple wheeled and more complex...

A navigational evaluation model for content management systems

International Nuclear Information System (INIS)

Gilani, S.; Majeed, A.

2016-01-01

Web applications are widely used world-wide, however it is important that the navigation of these websites is effective, to enhance usability. Navigation is not limited to links between pages, it is also how we complete a task. Navigational structure presented as hypertext is one of the most important component of the Web application besides content and presentation. The main objective of this paper is to explore the navigational structure of various open source Content Management Systems from the developer's perspective. For this purpose three CMS are chosen which are WordPress, Joomla, and Drupal. Objective of the research is to identify the important navigational aspects present in these CMSs. Moreover, a comparative study of these CMSs in terms of navigational support is required. For this purpose an industrial survey is conducted based on our proposed navigational evaluation model. The results shows that there exist correlation between the identified factors and these CMSs provide helpful and effective navigational support to their users. (author)

Improved Range Searching Lower Bounds

DEFF Research Database (Denmark)

Larsen, Kasper Green; Nguyen, Huy L.

2012-01-01

by constructing a hard input set and query set, and then invoking Chazelle and Rosenberg's [CGTA'96] general theorem on the complexity of navigation in the pointer machine. For the group model, we show that input sets and query sets that are hard for range reporting in the pointer machine (i.e. by Chazelle...... and Rosenberg's theorem), are also hard for dynamic range searching in the group model. This theorem allows us to reuse decades of research on range reporting lower bounds to immediately obtain a range of new group model lower bounds. Amongst others, this includes an improved lower bound for the fundamental...

Interactive navigation-guided ophthalmic plastic surgery: navigation enabling of telescopes and their use in endoscopic lacrimal surgeries

Directory of Open Access Journals (Sweden)

Ali MJ

2016-11-01

Full Text Available Mohammad Javed Ali,1 Swati Singh,1 Milind N Naik,1 Swathi Kaliki,2 Tarjani Vivek Dave1 1The Institute of Dacryology, 2The Operation Eyesight Universal Institute for Eye Cancer, L.V. Prasad Eye Institute, Hyderabad, India Purpose: The aims of this study were to report the preliminary experience of using telescopes, which were enabled for navigation guidance, and their utility in complex endoscopic lacrimal surgeries. Methods: Navigation enabling of the telescope was achieved by using the AxiEM™ malleable neuronavigation shunt stylet. Image-guided dacryolocalization was performed in five patients using the intraoperative image-guided StealthStation™ system in the electromagnetic mode. The “look ahead” protocol software was used to assist the surgeon in assessing the intraoperative geometric location of the endoscope and what lies ahead in real time. All patients underwent navigation-guided powered endoscopic dacryocystorhinostomy. The utility of uninterrupted navigation guidance throughout the surgery with the endoscope as the navigating tool was noted. Results: Intraoperative geometric localization of the lacrimal sac and the nasolacrimal duct could be easily deciphered. Constant orientation of the lacrimal drainage system and the peri-lacrimal anatomy was possible without the need for repeated point localizations throughout the surgery. The “look ahead” features could accurately alert the surgeon of anatomical structures that exists at 5, 10 and 15 mm in front of the endoscope. Good securing of the shunt stylet with the telescope was found to be essential for constant and accurate navigation. Conclusion: Navigation-enabled endoscopes provide the surgeon with the advantage of sustained stereotactic anatomical awareness at all times during the surgery. Keywords: telescope, endoscope, image guidance, navigation, lacrimal surgery, powered endoscopic DCR

Vibrotactile in-vehicle navigation system

NARCIS (Netherlands)

Erp, J.B.F. van; Veen, H.J. van

2004-01-01

A vibrotactile display, consisting ofeight vibrating elements or tactors mounted in a driver's seat, was tested in a driving simulator. Participants drove with visual, tactile and multimodal navigation displays through a built-up area. Workload and the reaction time to navigation messages were

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...

ANALYSIS OF FREE ROUTE AIRSPACE AND PERFORMANCE BASED NAVIGATION IMPLEMENTATION IN THE EUROPEAN AIR NAVIGATION SYSTEM

Directory of Open Access Journals (Sweden)

Svetlana Pavlova

2014-12-01

Full Text Available European Air Traffic Management system requires continuous improvements as air traffic is increasingday by day. For this purpose it was developed by international organizations Free Route Airspace and PerformanceBased Navigation concepts that allow to offer a required level of safety, capacity, environmental performance alongwith cost-effectiveness. The aim of the article is to provide detailed analysis of Free Route Airspace and PerformanceBased Navigation implementation status within European region including Ukrainian air navigation system.

Qatari Women Navigating Gendered Space

Directory of Open Access Journals (Sweden)

Krystyna Golkowska

2017-10-01

Full Text Available ADespite growing interest in the lived experience of Muslim women in Arab countries, there is still a dearth of studies on the Gulf region. This article focuses on Qatar, a Gulf Corporation Council (GCC country, to explore its changing sociocultural landscape and reflect on Qatari women’s agency within the framework of the traditional gendered space model. Applying Grounded Theory methodology to data collected from a variety of scholarly and non-scholarly sources, the author offers a themed overview of factors that facilitate and constrain Qatari women’s mobility. The findings testify to a significant increase in female presence and visibility in the public sphere—specifically in the spaces of education, employment, and sports. They also show that young Qatari women exercise agency through navigating the existing systems rather than question traditional socio-cultural norms. The paper identifies this search for a middle ground between tradition and modernity and its ideological underpinnings as the area of future research that should be led by Qatari women themselves.

SLS Model Based Design: A Navigation Perspective

Science.gov (United States)

Oliver, T. Emerson; Anzalone, Evan; Park, Thomas; Geohagan, Kevin

2018-01-01

The SLS Program has implemented a Model-based Design (MBD) and Model-based Requirements approach for managing component design information and system requirements. This approach differs from previous large-scale design efforts at Marshall Space Flight Center where design documentation alone conveyed information required for vehicle design and analysis and where extensive requirements sets were used to scope and constrain the design. The SLS Navigation Team is responsible for the Program-controlled Design Math Models (DMMs) which describe and represent the performance of the Inertial Navigation System (INS) and the Rate Gyro Assemblies (RGAs) used by Guidance, Navigation, and Controls (GN&C). The SLS Navigation Team is also responsible for navigation algorithms. The navigation algorithms are delivered for implementation on the flight hardware as a DMM. For the SLS Block 1B design, the additional GPS Receiver hardware model is managed as a DMM at the vehicle design level. This paper describes the models, and discusses the processes and methods used to engineer, design, and coordinate engineering trades and performance assessments using SLS practices as applied to the GN&C system, with a particular focus on the navigation components.

Through the Google Goggles: Sociopolitical Bias in Search Engine Design

Science.gov (United States)

Diaz, A.

Search engines like Google are essential to navigating the Web's endless supply of news, political information, and citizen discourse. The mechanisms and conditions under which search results are selected should therefore be of considerable interest to media scholars, political theorists, and citizens alike. In this chapter, I adopt a "deliberative" ideal for search engines and examine whether Google exhibits the "same old" media biases of mainstreaming, hypercommercialism, and industry consolidation. In the end, serious objections to Google are raised: Google may favor popularity over richness; it provides advertising that competes directly with "editorial" content; it so overwhelmingly dominates the industry that users seldom get a second opinion, and this is unlikely to change. Ultimately, however, the results of this analysis may speak less about Google than about contradictions in the deliberative ideal and the so-called "inherently democratic" nature of the Web.

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. Copyright © 2014 Elsevier Inc. All rights reserved.

The Gaze of the Perfect Search Engine: Google as an Infrastructure of Dataveillance

Science.gov (United States)

Zimmer, M.

Web search engines have emerged as a ubiquitous and vital tool for the successful navigation of the growing online informational sphere. The goal of the world's largest search engine, Google, is to "organize the world's information and make it universally accessible and useful" and to create the "perfect search engine" that provides only intuitive, personalized, and relevant results. While intended to enhance intellectual mobility in the online sphere, this chapter reveals that the quest for the perfect search engine requires the widespread monitoring and aggregation of a users' online personal and intellectual activities, threatening the values the perfect search engines were designed to sustain. It argues that these search-based infrastructures of dataveillance contribute to a rapidly emerging "soft cage" of everyday digital surveillance, where they, like other dataveillance technologies before them, contribute to the curtailing of individual freedom, affect users' sense of self, and present issues of deep discrimination and social justice.

Collective navigation of complex networks: Participatory greedy routing.

Science.gov (United States)

Kleineberg, Kaj-Kolja; Helbing, Dirk

2017-06-06

Many networks are used to transfer information or goods, in other words, they are navigated. The larger the network, the more difficult it is to navigate efficiently. Indeed, information routing in the Internet faces serious scalability problems due to its rapid growth, recently accelerated by the rise of the Internet of Things. Large networks like the Internet can be navigated efficiently if nodes, or agents, actively forward information based on hidden maps underlying these systems. However, in reality most agents will deny to forward messages, which has a cost, and navigation is impossible. Can we design appropriate incentives that lead to participation and global navigability? Here, we present an evolutionary game where agents share the value generated by successful delivery of information or goods. We show that global navigability can emerge, but its complete breakdown is possible as well. Furthermore, we show that the system tends to self-organize into local clusters of agents who participate in the navigation. This organizational principle can be exploited to favor the emergence of global navigability in the system.

Navigating the fifth dimension: new concepts in interactive multimodality and multidimensional image navigation

Science.gov (United States)

Ratib, Osman; Rosset, Antoine; Dahlbom, Magnus; Czernin, Johannes

2005-04-01

Display and interpretation of multi dimensional data obtained from the combination of 3D data acquired from different modalities (such as PET-CT) require complex software tools allowing the user to navigate and modify the different image parameters. With faster scanners it is now possible to acquire dynamic images of a beating heart or the transit of a contrast agent adding a fifth dimension to the data. We developed a DICOM-compliant software for real time navigation in very large sets of 5 dimensional data based on an intuitive multidimensional jog-wheel widely used by the video-editing industry. The software, provided under open source licensing, allows interactive, single-handed, navigation through 3D images while adjusting blending of image modalities, image contrast and intensity and the rate of cine display of dynamic images. In this study we focused our effort on the user interface and means for interactively navigating in these large data sets while easily and rapidly changing multiple parameters such as image position, contrast, intensity, blending of colors, magnification etc. Conventional mouse-driven user interface requiring the user to manipulate cursors and sliders on the screen are too cumbersome and slow. We evaluated several hardware devices and identified a category of multipurpose jogwheel device that is used in the video-editing industry that is particularly suitable for rapidly navigating in five dimensions while adjusting several display parameters interactively. The application of this tool will be demonstrated in cardiac PET-CT imaging and functional cardiac MRI studies.

Target relative navigation results from hardware-in-the-loop tests using the sinplex navigation system

NARCIS (Netherlands)

Steffes, S.; Dumke, M.; Heise, D.; Sagliano, M.; Samaan, M.; Theil, S.; Boslooper, E.C.; Oosterling, J.A.J.; Schulte, J.; Skaborn, D.; Söderholm, S.; Conticello, S.; Esposito, M.; Yanson, Y.; Monna, B.; Stelwagen, F.; Visee, R.

2014-01-01

The goal of the SINPLEX project is to develop an innovative solution to significantly reduce the mass of the navigation subsystem for exploration missions which include landing and/or rendezvous and capture phases. The system mass is reduced while still maintaining good navigation performance as

Time and Motion Study of a Community Patient Navigator

Directory of Open Access Journals (Sweden)

Sara S. Phillips

2014-04-01

Full Text Available Research on patient navigation has focused on validating the utility of navigators by defining their roles and analyzing their effects on patient outcomes, patient satisfaction, and cost effectiveness. Patient navigators are increasingly used outside the research context, and their roles without research responsibilities may look very different. This pilot study captured the activities of a community patient navigator for uninsured women with a positive screening test for breast cancer, using a time and motion approach over a period of three days. We followed the actions of this navigator minute by minute to assess the relative ratios of actions performed and to identify areas for time efficiency improvement to increase direct time with patients. This novel approach depicts the duties of a community patient navigator no longer fettered by navigation logs, research team meetings, surveys, and the consent process. We found that the community patient navigator was able to spend more time with patients in the clinical context relative to performing paperwork or logging communication with patients as a result of her lack of research responsibilities. By illuminating how community patient navigation functions as separate from the research setting, our results will inform future hiring and training of community patient navigators, system design and operations for improving the efficiency and efficacy of navigators, and our understanding of what community patient navigators do in the absence of research responsibilities.

Optical surgical navigation system causes pulse oximeter malfunction.

Science.gov (United States)

Satoh, Masaaki; Hara, Tetsuhito; Tamai, Kenji; Shiba, Juntaro; Hotta, Kunihisa; Takeuchi, Mamoru; Watanabe, Eiju

2015-01-01

An optical surgical navigation system is used as a navigator to facilitate surgical approaches, and pulse oximeters provide valuable information for anesthetic management. However, saw-tooth waves on the monitor of a pulse oximeter and the inability of the pulse oximeter to accurately record the saturation of a percutaneous artery were observed when a surgeon started an optical navigation system. The current case is thought to be the first report of this navigation system interfering with pulse oximetry. The causes of pulse jamming and how to manage an optical navigation system are discussed.

33 CFR 117.458 - Inner Harbor Navigation Canal, New Orleans.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Inner Harbor Navigation Canal, New Orleans. 117.458 Section 117.458 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Harbor Navigation Canal, New Orleans. (a) The draws of the SR 46 (St. Claude Avenue) bridge, mile 0.5...

33 CFR 209.170 - Violations of laws protecting navigable waters.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Violations of laws protecting navigable waters. 209.170 Section 209.170 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF... navigable waters. (a) [Reserved] (b) Injuries to Government works. Section 14 of the River and Harbor Act of...

Characterizing the Processes for Navigating Internet Health Information Using Real-Time Observations: A Mixed-Methods Approach.

Science.gov (United States)

Perez, Susan L; Paterniti, Debora A; Wilson, Machelle; Bell, Robert A; Chan, Man Shan; Villareal, Chloe C; Nguyen, Hien Huy; Kravitz, Richard L

2015-07-20

Little is known about the processes people use to find health-related information on the Internet or the individual characteristics that shape selection of information-seeking approaches. Our aim was to describe the processes by which users navigate the Internet for information about a hypothetical acute illness and to identify individual characteristics predictive of their information-seeking strategies. Study participants were recruited from public settings and agencies. Interested individuals were screened for eligibility using an online questionnaire. Participants listened to one of two clinical scenarios—consistent with influenza or bacterial meningitis—and then conducted an Internet search. Screen-capture video software captured Internet search mouse clicks and keystrokes. Each step of the search was coded as hypothesis testing (etiology), evidence gathering (symptoms), or action/treatment seeking (behavior). The coded steps were used to form a step-by-step pattern of each participant's information-seeking process. A total of 78 Internet health information seekers ranging from 21-35 years of age and who experienced barriers to accessing health care services participated. We identified 27 unique patterns of information seeking, which were grouped into four overarching classifications based on the number of steps taken during the search, whether a pattern consisted of developing a hypothesis and exploring symptoms before ending the search or searching an action/treatment, and whether a pattern ended with action/treatment seeking. Applying dual-processing theory, we categorized the four overarching pattern classifications as either System 1 (41%, 32/78), unconscious, rapid, automatic, and high capacity processing; or System 2 (59%, 46/78), conscious, slow, and deliberative processing. Using multivariate regression, we found that System 2 processing was associated with higher education and younger age. We identified and classified two approaches to processing

Fault-tolerant and Diagnostic Methods for Navigation

DEFF Research Database (Denmark)

Blanke, Mogens

2003-01-01

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......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...

Navigating ‘riskscapes’

DEFF Research Database (Denmark)

Gee, Stephanie; Skovdal, Morten

2017-01-01

This paper draws on interview data to examine how international health care workers navigated risk during the unprecedented Ebola outbreak in West Africa. It identifies the importance of place in risk perception, including how different spatial localities give rise to different feelings of threat...... or safety, some from the construction of physical boundaries, and others mediated through aspects of social relations, such as trust, communication and team dynamics. Referring to these spatial localities as ‘riskscapes’, the paper calls for greater recognition of the role of place in understanding risk...... perception, and how people navigate risk....

Camera Based Navigation System with Augmented Reality

Directory of Open Access Journals (Sweden)

M. Marcu

2012-06-01

Full Text Available Nowadays smart mobile devices have enough processing power, memory, storage and always connected wireless communication bandwidth that makes them available for any type of application. Augmented reality (AR proposes a new type of applications that tries to enhance the real world by superimposing or combining virtual objects or computer generated information with it. In this paper we present a camera based navigation system with augmented reality integration. The proposed system aims to the following: the user points the camera of the smartphone towards a point of interest, like a building or any other place, and the application searches for relevant information about that specific place and superimposes the data over the video feed on the display. When the user moves the camera away, changing its orientation, the data changes as well, in real-time, with the proper information about the place that is now in the camera view.

Hänsel, Gretel and the slime mould—how an external spatial memory aids navigation in complex environments

International Nuclear Information System (INIS)

Smith-Ferguson, Jules; Latty, Tanya; Beekman, Madeleine; Reid, Chris R

2017-01-01

The ability to navigate through an environment is critical to most organisms’ ability to survive and reproduce. The presence of a memory system greatly enhances navigational success. Therefore, natural selection is likely to drive the creation of memory systems, even in non-neuronal organisms, if having such a system is adaptive. Here we examine if the external spatial memory system present in the acellular slime mould, Physarum polycephalum , provides an adaptive advantage for resource acquisition. P. polycephalum lays tracks of extracellular slime as it moves through its environment. Previous work has shown that the presence of extracellular slime allows the organism to escape from a trap in laboratory experiments simply by avoiding areas previously explored. Here we further investigate the benefits of using extracellular slime as an external spatial memory by testing the organism’s ability to navigate through environments of differing complexity with and without the ability to use its external memory. Our results suggest that the external memory has an adaptive advantage in ‘open’ and simple bounded environments. However, in a complex bounded environment, the extracellular slime provides no advantage, and may even negatively affect the organism’s navigational abilities. Our results indicate that the exact experimental set up matters if one wants to fully understand how the presence of extracellular slime affects the slime mould’s search behaviour. (paper)

Hänsel, Gretel and the slime mould—how an external spatial memory aids navigation in complex environments

Science.gov (United States)

Smith-Ferguson, Jules; Reid, Chris R.; Latty, Tanya; Beekman, Madeleine

2017-10-01

The ability to navigate through an environment is critical to most organisms’ ability to survive and reproduce. The presence of a memory system greatly enhances navigational success. Therefore, natural selection is likely to drive the creation of memory systems, even in non-neuronal organisms, if having such a system is adaptive. Here we examine if the external spatial memory system present in the acellular slime mould, Physarum polycephalum, provides an adaptive advantage for resource acquisition. P. polycephalum lays tracks of extracellular slime as it moves through its environment. Previous work has shown that the presence of extracellular slime allows the organism to escape from a trap in laboratory experiments simply by avoiding areas previously explored. Here we further investigate the benefits of using extracellular slime as an external spatial memory by testing the organism’s ability to navigate through environments of differing complexity with and without the ability to use its external memory. Our results suggest that the external memory has an adaptive advantage in ‘open’ and simple bounded environments. However, in a complex bounded environment, the extracellular slime provides no advantage, and may even negatively affect the organism’s navigational abilities. Our results indicate that the exact experimental set up matters if one wants to fully understand how the presence of extracellular slime affects the slime mould’s search behaviour.

Self-navigation of a scanning tunneling microscope tip toward a micron-sized graphene sample.

Science.gov (United States)

Li, Guohong; Luican, Adina; Andrei, Eva Y

2011-07-01

We demonstrate a simple capacitance-based method to quickly and efficiently locate micron-sized conductive samples, such as graphene flakes, on insulating substrates in a scanning tunneling microscope (STM). By using edge recognition, the method is designed to locate and to identify small features when the STM tip is far above the surface, allowing for crash-free search and navigation. The method can be implemented in any STM environment, even at low temperatures and in strong magnetic field, with minimal or no hardware modifications.

Magnetic navigation in a coronary phantom: experimental results.

Science.gov (United States)

García-García, Héctor M; Tsuchida, Keiichi; Meulenbrug, Hans; Ong, Andrew T L; Van der Giessen, Willem J; Serruys, Patrick W

2005-11-01

The objective was to investigate the efficacy of a magnetic navigation system (MNS) in a coronary phantom. The number of coronary interventional procedures performed is steadily increasing with the availability of new devices to treat more complex lesions. Vessel tortuosity remains an important limiting factor in percutaneous coronary intervention. The MNS can orient the tip of magnetized wire. The coronary phantom is a representation of the coronary tree. Two operators using both a magnetic wire and a standard wire, measured the procedural time (PT), the fluoroscopic time (FT) and the radiation exposure/area product (DAP) required to navigate through to fourteen segments. Ten wire advancements were performed per segment. In all but two segments, the PT was significantly longer using magnetic navigation than using manual navigation. The median FT in the left main artery (LMA) - first septal segment was 7 seconds vs. 18 seconds, with magnetic and manual navigation respectively, (p=0.05); in the LMA - obtuse marginal segment the median FT was 15 seconds with magnetic navigation vs. 29.5 seconds with manual navigation, (p=0.01); in the segment from proximal right coronary artery (RCA1) to the acute marginal branch, the median FT was 8 seconds with magnetic vs. 11 seconds with manual navigation, (p=0.05); and in the RCA1 -posterior descending segment the median FT was 9.5 seconds with magnetic vs. 15 seconds with manual navigation, (p=0.006). The MNS facilitates wire access to distal segments in a coronary phantom, with a reduction in FT and radiation exposure using magnetic navigation in tortuous segments.

Integrated INS/GPS Navigation from a Popular Perspective

Science.gov (United States)

Omerbashich, Mensur

2002-01-01

Inertial navigation, blended with other navigation aids, Global Positioning System (GPS) in particular, has gained significance due to enhanced navigation and inertial reference performance and dissimilarity for fault tolerance and anti-jamming. Relatively new concepts based upon using Differential GPS (DGPS) blended with Inertial (and visual) Navigation Sensors (INS) offer the possibility of low cost, autonomous aircraft landing. The FAA has decided to implement the system in a sophisticated form as a new standard navigation tool during this decade. There have been a number of new inertial sensor concepts in the recent past that emphasize increased accuracy of INS/GPS versus INS and reliability of navigation, as well as lower size and weight, and higher power, fault tolerance, and long life. The principles of GPS are not discussed; rather the attention is directed towards general concepts and comparative advantages. A short introduction to the problems faced in kinematics is presented. The intention is to relate the basic principles of kinematics to probably the most used navigation method in the future-INS/GPS. An example of the airborne INS is presented, with emphasis on how it works. The discussion of the error types and sources in navigation, and of the role of filters in optimal estimation of the errors then follows. The main question this paper is trying to answer is 'What are the benefits of the integration of INS and GPS and how is this, navigation concept of the future achieved in reality?' The main goal is to communicate the idea about what stands behind a modern navigation method.

Determination of critical breakage conditions for double glazing in fire

International Nuclear Information System (INIS)

Wang, Yu; Li, Ke; Su, Yanfei; Lu, Wei; Wang, Qingsong; Sun, Jinhua; He, Linghui; Liew, K.M.

2017-01-01

Highlights: • Critical heat fluxes of exposed and ambient panes are 6 kW/m"2 and 25 kW/m"2. • Critical temperature difference of fire side pane is around 60 °C. • The ambient pane survives three times longer due to radiation filter and air gap. • Heat transfer in double glazing is revealed by a heat flux based theoretical model. - Abstract: Double glazing unit normally demonstrates better fire resistance than single glazing, but the knowledge on its thermal behavior and heat transfer mechanism during fire is limited. In this work, nine double glazing units were heated by a 500 × 500 mm"2 pool fire. The incident heat flux, temperature on four surfaces, breakage time and cracking behavior were obtained. The critical breakage conditions for interior and exterior panes were determined through gradually decreasing the glass-burner distance from 750 mm to 450 mm. It is established that in double glazing the pane at ambient side can withstand significantly more time than the pane exposed to fire. The critical temperature difference for interior pane is 60 °C; the critical temperature of exterior pane breakage is much higher due to no frame-covered area. In addition, the heat flux at the time of crack initiation is 6 kW/m"2 for the pane at fire side, while more than 25 kW/m"2 for ambient side pane. To reveal the heat transfer mechanism in glazing-air-glazing, theoretical and numerical investigations are also performed, which agrees well with the experimental results.

Piles, tabs and overlaps in navigation among documents

DEFF Research Database (Denmark)

Jakobsen, Mikkel Rønne; Hornbæk, Kasper

2010-01-01

Navigation among documents is a frequent, but ill supported activity. Overlapping or tabbed documents are widespread, but they offer limited visibility of their content. We explore variations on navigation support: arranging documents with tabs, as overlapping windows, and in piles. In an experim......Navigation among documents is a frequent, but ill supported activity. Overlapping or tabbed documents are widespread, but they offer limited visibility of their content. We explore variations on navigation support: arranging documents with tabs, as overlapping windows, and in piles....... In an experiment we compared 11 participants’ navigation with these variations and found strong task effects. Overall, overlapping windows were preferred and their structured layout worked well with some tasks. Surprisingly, tabbed documents were efficient in tasks requiring simply finding a document. Piled...... on document navigation and its support by piling....

An Integrated Approach to Electronic Navigation

National Research Council Canada - National Science Library

Shaw, Peter; Pettus, Bill

2001-01-01

While the Global Positioning System (GPS) is and will continue to be an excellent navigation system, it is neither flawless nor is it the only system employed in the navigation of today's seagoing warfighters...

Fault-tolerant Sensor Fusion for Marine Navigation

DEFF Research Database (Denmark)

Blanke, Mogens

2006-01-01

Reliability of navigation data are critical for steering and manoeuvring control, and in particular so at high speed or in critical phases of a mission. Should faults occur, faulty instruments need be autonomously isolated and faulty information discarded. This paper designs a navigation solution...... where essential navigation information is provided even with multiple faults in instrumentation. The paper proposes a provable correct implementation through auto-generated state-event logics in a supervisory part of the algorithms. Test results from naval vessels document the performance and shows...... events where the fault-tolerant sensor fusion provided uninterrupted navigation data despite temporal instrument defects...

Wayfinding search strategies and matching familiarity in the built environment through virtual navigation

NARCIS (Netherlands)

Dijkstra, J.; Vries, de B.; Jessurun, A.J.

2014-01-01

There is an underestimation of the conscious and unconscious wayfinding search strategies in a virtual built environment without signage information. Wayfinding is the process of determining and following a path or route between an origin and destination.This is the base of the experiment discussed

Navigating the black hole: explicating layers of job search context and adaptational responses

NARCIS (Netherlands)

Wanberg, C.; Basbug, G.; van Hooft, E.A.J.; Samtani, A.

2012-01-01

Via a qualitative study, we introduce and elucidate 5 layers of context-related job search demands (omnibus, organizational, social, task, and personal) that are encountered by both employed and unemployed job seekers. We develop a process model to portray the mechanisms (managing mood and

Navigation in Cross-cultural business relationships

DEFF Research Database (Denmark)

Andersen, Poul Houman

2001-01-01

Cross-cultural business navigation concerns the process of handling the complexity of several interacting cultural spheres of influence......Cross-cultural business navigation concerns the process of handling the complexity of several interacting cultural spheres of influence...

Comparative advantage between traditional and smart navigation systems

Science.gov (United States)

Shin, Jeongkyu; Kim, Pan-Jun; Kim, Seunghwan

2013-03-01

The smart navigation system that refers to real-time traffic data is believed to be superior to traditional navigation systems. To verify this belief, we created an agent-based traffic model and examined the effect of changing market share of the traditional shortest-travel-time algorithm based navigation and the smart navigation system. We tested our model on the grid and actual metropolitan road network structures. The result reveals that the traditional navigation system have better performance than the smart one as the market share of the smart navigation system exceeds a critical value, which is contrary to conventional expectation. We suggest that the superiority inversion between agent groups is strongly related to the traffic weight function form, and is general. We also found that the relationship of market share, traffic flow density and travel time is determined by the combination of congestion avoidance behavior of the smartly navigated agents and the inefficiency of shortest-travel-time based navigated agents. Our results can be interpreted with the minority game and extended to the diverse topics of opinion dynamics. This work was supported by the Original Technology Research Program for Brain Science through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology(No. 2010-0018847).

Navigation of autonomous vehicles for oil spill cleaning in dynamic and uncertain environments

Science.gov (United States)

Jin, Xin; Ray, Asok

2014-04-01

In the context of oil spill cleaning by autonomous vehicles in dynamic and uncertain environments, this paper presents a multi-resolution algorithm that seamlessly integrates the concepts of local navigation and global navigation based on the sensory information; the objective here is to enable adaptive decision making and online replanning of vehicle paths. The proposed algorithm provides a complete coverage of the search area for clean-up of the oil spills and does not suffer from the problem of having local minima, which is commonly encountered in potential-field-based methods. The efficacy of the algorithm is tested on a high-fidelity player/stage simulator for oil spill cleaning in a harbour, where the underlying oil weathering process is modelled as 2D random-walk particle tracking. A preliminary version of this paper was presented by X. Jin and A. Ray as 'Coverage Control of Autonomous Vehicles for Oil Spill Cleaning in Dynamic and Uncertain Environments', Proceedings of the American Control Conference, Washington, DC, June 2013, pp. 2600-2605.

A fuzzy logic based navigation for mobile robot

International Nuclear Information System (INIS)

Adel Ali S Al-Jumaily; Shamsudin M Amin; Mohamed Khalil

1998-01-01

The main issue of intelligent robot is how to reach its goal safely in real time when it moves in unknown environment. The navigational planning is becoming the central issue in development of real-time autonomous mobile robots. Behaviour based robots have been successful in reacting with dynamic environment but still there are some complexity and challenging problems. Fuzzy based behaviours present as powerful method to solve the real time reactive navigation problems in unknown environment. We shall classify the navigation generation methods, five some characteristics of these methods, explain why fuzzy logic is suitable for the navigation of mobile robot and automated guided vehicle, and describe a reactive navigation that is flexible to react through their behaviours to the change of the environment. Some simulation results will be presented to show the navigation of the robot. (Author)

Footprints: A Visual Search Tool that Supports Discovery and Coverage Tracking.

Science.gov (United States)

Isaacs, Ellen; Domico, Kelly; Ahern, Shane; Bart, Eugene; Singhal, Mudita

2014-12-01

Searching a large document collection to learn about a broad subject involves the iterative process of figuring out what to ask, filtering the results, identifying useful documents, and deciding when one has covered enough material to stop searching. We are calling this activity "discoverage," discovery of relevant material and tracking coverage of that material. We built a visual analytic tool called Footprints that uses multiple coordinated visualizations to help users navigate through the discoverage process. To support discovery, Footprints displays topics extracted from documents that provide an overview of the search space and are used to construct searches visuospatially. Footprints allows users to triage their search results by assigning a status to each document (To Read, Read, Useful), and those status markings are shown on interactive histograms depicting the user's coverage through the documents across dates, sources, and topics. Coverage histograms help users notice biases in their search and fill any gaps in their analytic process. To create Footprints, we used a highly iterative, user-centered approach in which we conducted many evaluations during both the design and implementation stages and continually modified the design in response to feedback.

Intelligent navigation to improve obstetrical sonography.

Science.gov (United States)

Yeo, Lami; Romero, Roberto

2016-04-01

'Manual navigation' by the operator is the standard method used to obtain information from two-dimensional and volumetric sonography. Two-dimensional sonography is highly operator dependent and requires extensive training and expertise to assess fetal anatomy properly. Most of the sonographic examination time is devoted to acquisition of images, while 'retrieval' and display of diagnostic planes occurs rapidly (essentially instantaneously). In contrast, volumetric sonography has a rapid acquisition phase, but the retrieval and display of relevant diagnostic planes is often time-consuming, tedious and challenging. We propose the term 'intelligent navigation' to refer to a new method of interrogation of a volume dataset whereby identification and selection of key anatomical landmarks allow the system to: 1) generate a geometrical reconstruction of the organ of interest; and 2) automatically navigate, find, extract and display specific diagnostic planes. This is accomplished using operator-independent algorithms that are both predictable and adaptive. Virtual Intelligent Sonographer Assistance (VIS-Assistance®) is a tool that allows operator-independent sonographic navigation and exploration of the surrounding structures in previously identified diagnostic planes. The advantage of intelligent (over manual) navigation in volumetric sonography is the short time required for both acquisition and retrieval and display of diagnostic planes. Intelligent navigation technology automatically realigns the volume, and reorients and standardizes the anatomical position, so that the fetus and the diagnostic planes are consistently displayed in the same manner each time, regardless of the fetal position or the initial orientation. Automatic labeling of anatomical structures, subject orientation and each of the diagnostic planes is also possible. Intelligent navigation technology can operate on conventional computers, and is not dependent on specific ultrasound platforms or on the

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...

A virtual water maze revisited: Two-year changes in navigation performance and their neural correlates in healthy adults.

Science.gov (United States)

Daugherty, Ana M; Raz, Naftali

2017-02-01

Age-related declines in spatial navigation are associated with deficits in procedural and episodic memory and deterioration of their neural substrates. For the lack of longitudinal evidence, the pace and magnitude of these declines and their neural mediators remain unclear. Here we examined virtual navigation in healthy adults (N=213, age 18-77 years) tested twice, two years apart, with complementary indices of navigation performance (path length and complexity) measured over six learning trials at each occasion. Slopes of skill acquisition curves and longitudinal change therein were estimated in structural equation modeling, together with change in regional brain volumes and iron content (R2* relaxometry). Although performance on the first trial did not differ between occasions separated by two years, the slope of path length improvement over trials was shallower and end-of-session performance worse at follow-up. Advanced age, higher pulse pressure, smaller cerebellar and caudate volumes, and greater caudate iron content were associated with longer search paths, i.e. poorer navigation performance. In contrast, path complexity diminished faster over trials at follow-up, albeit less so in older adults. Improvement in path complexity after two years was predicted by lower baseline hippocampal iron content and larger parahippocampal volume. Thus, navigation path length behaves as an index of perceptual-motor skill that is vulnerable to age-related decline, whereas path complexity may reflect cognitive mapping in episodic memory that improves with repeated testing, although not enough to overcome age-related deficits. Copyright © 2016 Elsevier Inc. All rights reserved.

Shape Perception and Navigation in Blind Adults

Science.gov (United States)

Gori, Monica; Cappagli, Giulia; Baud-Bovy, Gabriel; Finocchietti, Sara

2017-01-01

Different sensory systems interact to generate a representation of space and to navigate. Vision plays a critical role in the representation of space development. During navigation, vision is integrated with auditory and mobility cues. In blind individuals, visual experience is not available and navigation therefore lacks this important sensory signal. In blind individuals, compensatory mechanisms can be adopted to improve spatial and navigation skills. On the other hand, the limitations of these compensatory mechanisms are not completely clear. Both enhanced and impaired reliance on auditory cues in blind individuals have been reported. Here, we develop a new paradigm to test both auditory perception and navigation skills in blind and sighted individuals and to investigate the effect that visual experience has on the ability to reproduce simple and complex paths. During the navigation task, early blind, late blind and sighted individuals were required first to listen to an audio shape and then to recognize and reproduce it by walking. After each audio shape was presented, a static sound was played and the participants were asked to reach it. Movements were recorded with a motion tracking system. Our results show three main impairments specific to early blind individuals. The first is the tendency to compress the shapes reproduced during navigation. The second is the difficulty to recognize complex audio stimuli, and finally, the third is the difficulty in reproducing the desired shape: early blind participants occasionally reported perceiving a square but they actually reproduced a circle during the navigation task. We discuss these results in terms of compromised spatial reference frames due to lack of visual input during the early period of development. PMID:28144226

A simultaneous navigation and radiation evasion algorithm (SNARE)

Energy Technology Data Exchange (ETDEWEB)

Khasawneh, Mohammed A., E-mail: mkha@ieee.org [Department of Electrical Engineering, Jordan University of Science and Technology, Irbid 221 10 (Jordan); Jaradat, Mohammad A., E-mail: majaradat@just.edu.jo [Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid 221 10 (Jordan); Al-Shboul, Zeina Aman M., E-mail: xeinaaman@gmail.com [Department of Electrical Engineering, Jordan University of Science and Technology, Irbid 221 10 (Jordan)

2013-12-15

Highlights: • A new navigation algorithm for radiation evasion around nuclear facilities. • An optimization criteria minimized under algorithm operation. • A man-borne device guiding the occupational worker towards paths that warrant least radiation × time products. • Benefits of using localized navigation as opposed to global navigation schemas. • A path discrimination function for finding the navigational paths exhibiting the least amounts of radiation. - Abstract: In this paper, we address the issue of localization as pertains to indoor navigation under radiation contaminated environments. In this context, navigation, in the absence of any GPS signals, is guided by the location of the sensors that make up the entire wireless sensor network in a given locality within a nuclear facility. It, also, draws on the radiation levels as measured by the sensors around a given locale. Here, localization is inherently embedded into the algorithm presented in (Khasawneh et al., 2011a, 2011b) which was designed to provide navigational guidance to optimize any of two criteria: “Radiation Evasion” and “Nearest Exit”. As such, the algorithm can either be applied to setting a navigational “lowest” radiation exposure path from an initial point A to some other point B; a case typical of occupational workers performing maintenance operations around the facility; or providing a radiation-safe passage from point A to the nearest exit. Algorithm's navigational performance is tested under statistical reference, wherein for a given number of runs (trials) algorithm performance is evaluated as a function of the number of steps of look-ahead it uses to acquire navigational information, and is compared against the performance of the renowned Dijkstra global navigation algorithm. This is done with reference to the amount of (radiation × time) product and that of the time needed to reach an exit point, under the two optimization criteria. To evaluate algorithm

A simultaneous navigation and radiation evasion algorithm (SNARE)

International Nuclear Information System (INIS)

Khasawneh, Mohammed A.; Jaradat, Mohammad A.; Al-Shboul, Zeina Aman M.

2013-01-01

Highlights: • A new navigation algorithm for radiation evasion around nuclear facilities. • An optimization criteria minimized under algorithm operation. • A man-borne device guiding the occupational worker towards paths that warrant least radiation × time products. • Benefits of using localized navigation as opposed to global navigation schemas. • A path discrimination function for finding the navigational paths exhibiting the least amounts of radiation. - Abstract: In this paper, we address the issue of localization as pertains to indoor navigation under radiation contaminated environments. In this context, navigation, in the absence of any GPS signals, is guided by the location of the sensors that make up the entire wireless sensor network in a given locality within a nuclear facility. It, also, draws on the radiation levels as measured by the sensors around a given locale. Here, localization is inherently embedded into the algorithm presented in (Khasawneh et al., 2011a, 2011b) which was designed to provide navigational guidance to optimize any of two criteria: “Radiation Evasion” and “Nearest Exit”. As such, the algorithm can either be applied to setting a navigational “lowest” radiation exposure path from an initial point A to some other point B; a case typical of occupational workers performing maintenance operations around the facility; or providing a radiation-safe passage from point A to the nearest exit. Algorithm's navigational performance is tested under statistical reference, wherein for a given number of runs (trials) algorithm performance is evaluated as a function of the number of steps of look-ahead it uses to acquire navigational information, and is compared against the performance of the renowned Dijkstra global navigation algorithm. This is done with reference to the amount of (radiation × time) product and that of the time needed to reach an exit point, under the two optimization criteria. To evaluate algorithm

Off the Beaten tracks: Exploring Three Aspects of Web Navigation

NARCIS (Netherlands)

Weinreich, H.; Obendorf, H.; Herder, E.; Mayer, M.; Edmonds, H.; Hawkey, K.; Kellar, M.; Turnbull, D.

2006-01-01

This paper presents results of a long-term client-side Web usage study, updating previous studies that range in age from five to ten years. We focus on three aspects of Web navigation: changes in the distribution of navigation actions, speed of navigation and within-page navigation. “Navigation

Responsibility navigator

NARCIS (Netherlands)

Kuhlmann, Stefan; Edler, Jakob; Ordonez Matamoros, Hector Gonzalo; Randles, Sally; Walhout, Bart; Walhout, Bart; Gough, Clair; Lindner, Ralf; Lindner, Ralf; Kuhlmann, Stefan; Randles, Sally; Bedsted, Bjorn; Gorgoni, Guido; Griessler, Erich; Loconto, Allison; Mejlgaard, Niels

2016-01-01

Research and innovation activities need to become more responsive to societal challenges and concerns. The Responsibility Navigator, developed in the Res-AGorA project, supports decision-makers to govern such activities towards more conscious responsibility. What is considered “responsible” will

Letting in-vehicle navigation lead the way: Older drivers' perceptions of and ability to follow a GPS navigation system.

Science.gov (United States)

Stinchcombe, Arne; Gagnon, Sylvain; Kateb, Matthew; Curtis, Meredith; Porter, Michelle M; Polgar, Jan; Bédard, Michel

2017-09-01

In-vehicle navigation systems have the potential to simplify the driving task by reducing the drivers' need to engage in wayfinding, especially in unfamiliar environments. This study sought to characterize older drivers' overall assessment of using in-vehicle GPS technology as part of a research study and to explore whether the use of this technology has an impact on participants' driving behaviour. Forty-seven older drivers completed an on-road evaluation where directions were provided by an in-vehicle GPS navigation system and their behaviour was recorded using video technology. They later completed a questionnaire to assess their perception of the navigation system. After the study, participants were grouped based on whether they were able to accurately follow the instructions provided by the navigation system. The results indicated that most drivers were satisfied with the navigation technology and found the directions it provided to be clear. There were no statistically significant differences in the number of on-road errors committed by drivers who did not follow the directions from the navigation system in comparison to drivers who did follow the directions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cloud Absorption Radiometer Autonomous Navigation System - CANS

Science.gov (United States)

Kahle, Duncan; Gatebe, Charles; McCune, Bill; Hellwig, Dustan

2013-01-01

CAR (cloud absorption radiometer) acquires spatial reference data from host aircraft navigation systems. This poses various problems during CAR data reduction, including navigation data format, accuracy of position data, accuracy of airframe inertial data, and navigation data rate. Incorporating its own navigation system, which included GPS (Global Positioning System), roll axis inertia and rates, and three axis acceleration, CANS expedites data reduction and increases the accuracy of the CAR end data product. CANS provides a self-contained navigation system for the CAR, using inertial reference and GPS positional information. The intent of the software application was to correct the sensor with respect to aircraft roll in real time based upon inputs from a precision navigation sensor. In addition, the navigation information (including GPS position), attitude data, and sensor position details are all streamed to a remote system for recording and later analysis. CANS comprises a commercially available inertial navigation system with integral GPS capability (Attitude Heading Reference System AHRS) integrated into the CAR support structure and data system. The unit is attached to the bottom of the tripod support structure. The related GPS antenna is located on the P-3 radome immediately above the CAR. The AHRS unit provides a RS-232 data stream containing global position and inertial attitude and velocity data to the CAR, which is recorded concurrently with the CAR data. This independence from aircraft navigation input provides for position and inertial state data that accounts for very small changes in aircraft attitude and position, sensed at the CAR location as opposed to aircraft state sensors typically installed close to the aircraft center of gravity. More accurate positional data enables quicker CAR data reduction with better resolution. The CANS software operates in two modes: initialization/calibration and operational. In the initialization/calibration mode

Ballistic Aspects of Feasibility for Prospective Satellite Navigation Technologies

Directory of Open Access Journals (Sweden)

L. N. Lysenko

2015-01-01

Full Text Available When modeling the operating processes of ballistics and navigation support it is expedient to make decomposition of the general problem of coordinate-time and navigation support into the typical options of its engineering implementation.As the satellite navigation technologies the paper considers inter-satellite measurement and autonomous navigation mode of differential correction. It also assesses the possibility of their application to improve the accuracy of navigation determinations.Technologies using inter-satellite measurement tools such as GLONASS / GPS equipment, equipment of inter-satellite radio link, astro-optical space based devices are an independent class of navigation technologies.However, each of these options has both advantages and disadvantages that affect the eva luation of the appropriateness and feasibility of their use.The paper separately considers the problem of increasing survivability of space systems and conservation of ground control complex due to introduction of requirements to ensure the independent functioning of spacecraft and application of technologies of ballistics and navigation support, supposing to involve minimum means of automated ground control complex for these purposes.Currently, there is a completely developed theory of autonomous navigation based on astronomical positional gauges, which are used as onboard optical sensors of orientation and stabilization systems.To date, the differential navigation mode is, virtually, the only approach that can allow the olution of tasks in terms of increased accuracy, but with some restrictions.The implementation of differential mode of treatment is carried out through the creation of differential subsystems of the satellite navigation systems. These subsystems are usually divided into wide-range, regional and local ones.Analysis of ballistic aspects to implement discussed navigation technologies allowed us to identify constraints for improving accuracy to define

Surgical Navigation

DEFF Research Database (Denmark)

Azarmehr, Iman; Stokbro, Kasper; Bell, R. Bryan

2017-01-01

Purpose: This systematic review investigates the most common indications, treatments, and outcomes of surgical navigation (SN) published from 2010 to 2015. The evolution of SN and its application in oral and maxillofacial surgery have rapidly developed over recent years, and therapeutic indicatio...

Computer Navigation-aided Resection of Sacral Chordomas

Directory of Open Access Journals (Sweden)

Yong-Kun Yang

2016-01-01

Full Text Available Background: Resection of sacral chordomas is challenging. The anatomy is complex, and there are often no bony landmarks to guide the resection. Achieving adequate surgical margins is, therefore, difficult, and the recurrence rate is high. Use of computer navigation may allow optimal preoperative planning and improve precision in tumor resection. The purpose of this study was to evaluate the safety and feasibility of computer navigation-aided resection of sacral chordomas. Methods: Between 2007 and 2013, a total of 26 patients with sacral chordoma underwent computer navigation-aided surgery were included and followed for a minimum of 18 months. There were 21 primary cases and 5 recurrent cases, with a mean age of 55.8 years old (range: 35-84 years old. Tumors were located above the level of the S3 neural foramen in 23 patients and below the level of the S3 neural foramen in 3 patients. Three-dimensional images were reconstructed with a computed tomography-based navigation system combined with the magnetic resonance images using the navigation software. Tumors were resected via a posterior approach assisted by the computer navigation. Mean follow-up was 38.6 months (range: 18-84 months. Results: Mean operative time was 307 min. Mean intraoperative blood loss was 3065 ml. For computer navigation, the mean registration deviation during surgery was 1.7 mm. There were 18 wide resections, 4 marginal resections, and 4 intralesional resections. All patients were alive at the final follow-up, with 2 (7.7% exhibiting tumor recurrence. The other 24 patients were tumor-free. The mean Musculoskeletal Tumor Society Score was 27.3 (range: 19-30. Conclusions: Computer-assisted navigation can be safely applied to the resection of the sacral chordomas, allowing execution of preoperative plans, and achieving good oncological outcomes. Nevertheless, this needs to be accomplished by surgeons with adequate experience and skill.

Clinical applications of virtual navigation bronchial intervention.

Science.gov (United States)

Kajiwara, Naohiro; Maehara, Sachio; Maeda, Junichi; Hagiwara, Masaru; Okano, Tetsuya; Kakihana, Masatoshi; Ohira, Tatsuo; Kawate, Norihiko; Ikeda, Norihiko

2018-01-01

In patients with bronchial tumors, we frequently consider endoscopic treatment as the first treatment of choice. All computed tomography (CT) must satisfy several conditions necessary to analyze images by Synapse Vincent. To select safer and more precise approaches for patients with bronchial tumors, we determined the indications and efficacy of virtual navigation intervention for the treatment of bronchial tumors. We examined the efficacy of virtual navigation bronchial intervention for the treatment of bronchial tumors located at a variety of sites in the tracheobronchial tree using a high-speed 3-dimensional (3D) image analysis system, Synapse Vincent. Constructed images can be utilized to decide on the simulation and interventional strategy as well as for navigation during interventional manipulation in two cases. Synapse Vincent was used to determine the optimal planning of virtual navigation bronchial intervention. Moreover, this system can detect tumor location and alsodepict surrounding tissues, quickly, accurately, and safely. The feasibility and safety of Synapse Vincent in performing useful preoperative simulation and navigation of surgical procedures can lead to safer, more precise, and less invasion for the patient, and makes it easy to construct an image, depending on the purpose, in 5-10 minutes using Synapse Vincent. Moreover, if the lesion is in the parenchyma or sub-bronchial lumen, it helps to perform simulation with virtual skeletal subtraction to estimate potential lesion movement. By using virtual navigation system for simulation, bronchial intervention was performed with no complications safely and precisely. Preoperative simulation using virtual navigation bronchial intervention reduces the surgeon's stress levels, particularly when highly skilled techniques are needed to operate on lesions. This task, including both preoperative simulation and intraoperative navigation, leads to greater safety and precision. These technological instruments

Incidental memory and navigation in panoramic virtual reality for electronic commerce.

Science.gov (United States)

Howes, A; Miles, G E; Payne, S J; Mitchell, C D; Davies, A J

2001-01-01

Recently much effort has been dedicated to designing and implementing World Wide Web sites for virtual shopping and e-commerce. Despite this effort, relatively little empirical work has been done to determine the effectiveness with which different site designs sell products. We report three experiments in which participants were asked to search for products in various experimental e-commerce sites. Across the experiments participants were asked to search in either QTVR (QuickTime Virtual Reality), hypertext, or pictorially rich hypertext environments; they were then tested for their ability to recall the products seen and to recognize product locations. The experiments demonstrated that when using QTVR (Experiments 1, 2, and 3) or pictorial environments (Experiment 2), participants retained more information about products that were incidental to their goals. In two of the experiments it was shown that participants navigated more efficiently when using a QTVR environment. The costs and benefits of using 3D virtual environments for on-line shops are discussed. Actual or potential applications of this research include support for the development of e-commerce design guidelines.

Requirements for e-Navigation Architectures

Directory of Open Access Journals (Sweden)

Axel Hahn

2016-12-01

Full Text Available Technology is changing the way of navigation. New technologies for communication and navigation can be found on virtually every vessel. System architectures define structure and cooperation of components and subsystems. IMO, IALA, costal authorities, technology provider and many more actually propose new architectures for e-Navigation. This paper looks at other transportation domains and technical as normative requirements for e-Navigation architectures. With the aim of identifying possible synergies in the research, development, certification and standardization, this paper sets out to compare requirements and approaches of these two domains with respect to safety and security aspects. Since from an autonomy perspective, the automotive domain has started earlier and therefore has achieved a higher degree of technical progress, we will start with an overview of the developments in this domain. After that, the paper discusses the requirements on automation and assistance systems in the maritime domain and gives an overview of the developments into this direction within the maritime domain. This then allows us to compare developments in both domains and to derive recommendations for further developments in the maritime domain at the end of this paper.

Mars rover local navigation and hazard avoidance

Science.gov (United States)

Wilcox, B. H.; Gennery, D. B.; Mishkin, A. H.

1989-01-01

A Mars rover sample return mission has been proposed for the late 1990's. Due to the long speed-of-light delays between earth and Mars, some autonomy on the rover is highly desirable. JPL has been conducting research in two possible modes of rover operation, Computer-Aided Remote Driving and Semiautonomous Navigation. A recently-completed research program used a half-scale testbed vehicle to explore several of the concepts in semiautonomous navigation. A new, full-scale vehicle with all computational and power resources on-board will be used in the coming year to demonstrate relatively fast semiautonomous navigation. The computational and power requirements for Mars rover local navigation and hazard avoidance are discussed.

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.

Categorization and Searching of Color Images Using Mean Shift Algorithm

Directory of Open Access Journals (Sweden)

Prakash PANDEY

2009-07-01

Full Text Available Now a day’s Image Searching is still a challenging problem in content based image retrieval (CBIR system. Most CBIR system operates on all images without pre-sorting the images. The image search result contains many unrelated image. The aim of this research is to propose a new object based indexing system Based on extracting salient region representative from the image, categorizing the image into different types and search images that are similar to given query images.In our approach, the color features are extracted using the mean shift algorithm, a robust clustering technique, Dominant objects are obtained by performing region grouping of segmented thumbnails. The category for an image is generated automatically by analyzing the image for the presence of a dominant object. The images in the database are clustered based on region feature similarity using Euclidian distance. Placing an image into a category can help the user to navigate retrieval results more effectively. Extensive experimental results illustrate excellent performance.

Navigation System of Marks 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...

Navigating in higher education

DEFF Research Database (Denmark)

Thingholm, Hanne Balsby; Reimer, David; Keiding, Tina Bering

Denne rapport er skrevet på baggrund af spørgeskemaundersøgelsen – Navigating in Higher Education (NiHE) – der rummer besvarelser fra 1410 bachelorstuderende og 283 undervisere fordelt på ni uddannelser fra Aarhus Universitet: Uddannelsesvidenskab, Historie, Nordisk sprog og litteratur, Informati......Denne rapport er skrevet på baggrund af spørgeskemaundersøgelsen – Navigating in Higher Education (NiHE) – der rummer besvarelser fra 1410 bachelorstuderende og 283 undervisere fordelt på ni uddannelser fra Aarhus Universitet: Uddannelsesvidenskab, Historie, Nordisk sprog og litteratur...

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.

THE ROLE OF NAVIGATIONAL AIDS IN FLIGHT SAFETY MANAGEMENT WITHIN ICAO GLOBAL AIR NAVIGATION PLAN

Directory of Open Access Journals (Sweden)

Vadim V. Vurobyov

2017-01-01

Full Text Available The development of the global civil aviation is provided on the basis of the ICAO Communication and Surveillance/Air Traffic Management Concept, which has determined the basic strategy for further commercial flight management effectiveness improvement. On the basis of this concept a Global Air Navigation Plan has been developed by ICAO recently. The core strategies of CNS/ATM concept were specified and combined into so-called blocks. Thus the term Global Aviation System block upgrade has been introduced. At the same time, GANP states that the introduction of new procedures and flight management systems will inevitably affect flight safety. Accordingly, there is a task of flight safety management level maintaining, or even increasing within the Global Air Navigation Plan implementation. Various air navigational aids play a significant role in the process as they are directly associated with the new systems and structures introduction.This breeds the new global challenge of flight safety management level change assessment during the introduction of new procedures and systems connected with the use of both navigational aids and instruments. Some aspects of this problem solution are covered in the article.

GPS Navigation and Tracking Device

Directory of Open Access Journals (Sweden)

Yahya Salameh Khraisat

2011-10-01

Full Text Available Since the introduction of GPS Navigation systems in the marketplace, consumers and businesses have been coming up with innovative ways to use the technology in their everyday life. GPS Navigation and Tracking systems keep us from getting lost when we are in strange locations, they monitor children when they are away from home, keep track of business vehicles and can even let us know where a philandering partner is at all times. Because of this we attend to build a GPS tracking device to solve the mentioned problems. Our work consists of the GPS module that collects data from satellites and calculates the position information before transmitting them to the user’s PC (of Navigation system or observers (of Tracking System using wireless technology (GSM.

Evaluation of User Interface of DL + Federated Search Engine from the Perspective of M.A / M.S.C Students in Al-Zahra University in order to Provide Federated Search Engines User Interface Pattern

Directory of Open Access Journals (Sweden)

Amir Ghaebi

2014-02-01

The results showed that the major component from graduate students' perspective is guidance and navigation and searched filter components. Results indicate that more than 50 percent of students the importance of 74 criteria of 96 criteria considered high and very high and, (therefore the majority of the criteria in the study from the viewpoints are acceptable. However, findings also showed that among the four components of this study, the search filter, display and record review, consolidation and guidance is a positive relation, and between the views of different faculties is not significant difference about the importance of criterias and components.

A Qualitative Approach to Mobile Robot Navigation Using RFID

International Nuclear Information System (INIS)

Hossain, M; Rashid, M M; Bhuiyan, M M I; Ahmed, S; Akhtaruzzaman, M

2013-01-01

Radio Frequency Identification (RFID) system allows automatic identification of items with RFID tags using radio-waves. As the RFID tag has its unique identification number, it is also possible to detect a specific region where the RFID tag lies in. Recently it is widely been used in mobile robot navigation, localization, and mapping both in indoor and outdoor environment. This paper represents a navigation strategy for autonomous mobile robot using passive RFID system. Conventional approaches, such as landmark or dead-reckoning with excessive number of sensors, have complexities in establishing the navigation and localization process. The proposed method satisfies less complexity in navigation strategy as well as estimation of not only the position but also the orientation of the autonomous robot. In this research, polar coordinate system is adopted on the navigation surface where RFID tags are places in a grid with constant displacements. This paper also presents the performance comparisons among various grid architectures through simulation to establish a better solution of the navigation system. In addition, some stationary obstacles are introduced in the navigation environment to satisfy the viability of the navigation process of the autonomous mobile robot

A navigator-based rigid body motion correction for magnetic resonance imaging

International Nuclear Information System (INIS)

Ullisch, Marcus Goerge

2012-01-01

A novel three-dimensional navigator k-space trajectory for rigid body motion detection for Magnetic Resonance Imaging (MRI) - the Lissajous navigator - was developed and quantitatively compared to the existing spherical navigator trajectory [1]. The spherical navigator cannot sample the complete spherical surface due to slew rate limitations of the scanner hardware. By utilizing a two dimensional Lissajous figure which is projected onto the spherical surface, the Lissajous navigator overcomes this limitation. The complete sampling of the sphere consequently leads to rotation estimates with higher and more isotropic accuracy. Simulations and phantom measurements were performed for both navigators. Both simulations and measurements show a significantly higher overall accuracy of the Lissajous navigator and a higher isotropy of the rotation estimates. Measured under identical conditions with identical postprocessing, the measured mean absolute error of the rotation estimates for the Lissajous navigator was 38% lower (0.3 ) than for the spherical navigator (0.5 ). The maximum error of the Lissajous navigator was reduced by 48% relative to the spherical navigator. The Lissajous navigator delivers higher accuracy of rotation estimation and a higher degree of isotropy than the spherical navigator with no evident drawbacks; these are two decisive advantages, especially for high-resolution anatomical imaging.

A navigator-based rigid body motion correction for magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Ullisch, Marcus Goerge

2012-01-24

A novel three-dimensional navigator k-space trajectory for rigid body motion detection for Magnetic Resonance Imaging (MRI) - the Lissajous navigator - was developed and quantitatively compared to the existing spherical navigator trajectory [1]. The spherical navigator cannot sample the complete spherical surface due to slew rate limitations of the scanner hardware. By utilizing a two dimensional Lissajous figure which is projected onto the spherical surface, the Lissajous navigator overcomes this limitation. The complete sampling of the sphere consequently leads to rotation estimates with higher and more isotropic accuracy. Simulations and phantom measurements were performed for both navigators. Both simulations and measurements show a significantly higher overall accuracy of the Lissajous navigator and a higher isotropy of the rotation estimates. Measured under identical conditions with identical postprocessing, the measured mean absolute error of the rotation estimates for the Lissajous navigator was 38% lower (0.3 ) than for the spherical navigator (0.5 ). The maximum error of the Lissajous navigator was reduced by 48% relative to the spherical navigator. The Lissajous navigator delivers higher accuracy of rotation estimation and a higher degree of isotropy than the spherical navigator with no evident drawbacks; these are two decisive advantages, especially for high-resolution anatomical imaging.

SU-F-P-42: “To Navigate, Or Not to Navigate: HDR BT in Recurrent Spine Lesions”

Energy Technology Data Exchange (ETDEWEB)

Voros, L; Cohen, G; Zaider, M; Yamada, Y [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

2016-06-15

Purpose: We compare the accuracy of HDR catheter placement for paraspinal lesions using O-arm CBCT imaging combined with StealthStation navigation and traditional fluoroscopically guided catheter placement. Methods: CT and MRI scans were acquired pre-treatment to outline the lesions and design treatment plans (pre-plans) to meet dosimetric constrains. The pre-planned catheter trajectories were transferred into the StealthStation Navigation system prior to the surgery. The StealthStation is an infra red (IR) optical navigation system used for guidance of surgical instruments. An intraoperative CBCT scan (O-arm) was acquired with reference IR optical fiducials anchored onto the patient and registered with the preplan image study to guide surgical instruments in relation to the patients’ anatomy and to place the brachytherapy catheters along the pre-planned trajectories. The final treatment plan was generated based on a 2nd intraoperative CBCT scan reflecting achieved implant geometry. The 2nd CBCT was later registered with the initial CT scan to compare the preplanned dwell positions with actual dwell positions (catheter placements). Similar workflow was used in placement of 8 catheters (1 patient) without navigation, but under fluoroscopy guidance in an interventional radiology suite. Results: A total of 18 catheters (3 patients) were placed using navigation assisted surgery. Average displacement of 0.66 cm (STD=0.37cm) was observed between the pre-plan source positions and actual source positions in the 3 dimensional space. This translates into an average 0.38 cm positioning error in one direction including registration errors, digitization errors, and the surgeons ability to follow the planned trajectory. In comparison, average displacement of non-navigated catheters was 0.50 cm (STD=0.22cm). Conclusion: Spinal lesion HDR brachytherapy planning is a difficult task. Catheter placement has a direct impact on target coverage and dose to critical structures. While

Ego-motion based on EM for bionic navigation

Science.gov (United States)

Yue, Xiaofeng; Wang, L. J.; Liu, J. G.

2015-12-01

Researches have proved that flying insects such as bees can achieve efficient and robust flight control, and biologists have explored some biomimetic principles regarding how they control flight. Based on those basic studies and principles acquired from the flying insects, this paper proposes a different solution of recovering ego-motion for low level navigation. Firstly, a new type of entropy flow is provided to calculate the motion parameters. Secondly, EKF, which has been used for navigation for some years to correct accumulated error, and estimation-Maximization, which is always used to estimate parameters, are put together to determine the ego-motion estimation of aerial vehicles. Numerical simulation on MATLAB has proved that this navigation system provides more accurate position and smaller mean absolute error than pure optical flow navigation. This paper has done pioneering work in bionic mechanism to space navigation.

Cancer Patient Navigator Tasks across the Cancer Care Continuum

Science.gov (United States)

Braun, Kathryn L.; Kagawa-Singer, Marjorie; Holden, Alan E. C.; Burhansstipanov, Linda; Tran, Jacqueline H.; Seals, Brenda F.; Corbie-Smith, Giselle; Tsark, JoAnn U.; Harjo, Lisa; Foo, Mary Anne; Ramirez, Amelie G.

2011-01-01

Cancer patient navigation (PN) programs have been shown to increase access to and utilization of cancer care for poor and underserved individuals. Despite mounting evidence of its value, cancer patient navigation is not universally understood or provided. We describe five PN programs and the range of tasks their navigators provide across the cancer care continuum (education and outreach, screening, diagnosis and staging, treatment, survivorship, and end-of-life). Tasks are organized by their potential to make cancer services understandable, available, accessible, affordable, appropriate, and accountable. Although navigators perform similar tasks across the five programs, their specific approaches reflect differences in community culture, context, program setting, and funding. Task lists can inform the development of programs, job descriptions, training, and evaluation. They also may be useful in the move to certify navigators and establish mechanisms for reimbursement for navigation services. PMID:22423178

Rosetta Star Tracker and Navigation Camera

DEFF Research Database (Denmark)

Thuesen, Gøsta

1998-01-01

Proposal in response to the Invitation to Tender (ITT) issued by Matra Marconi Space (MSS) for the procurement of the ROSETTA Star Tracker and Navigation Camera.......Proposal in response to the Invitation to Tender (ITT) issued by Matra Marconi Space (MSS) for the procurement of the ROSETTA Star Tracker and Navigation Camera....

Visual navigation using edge curve matching for pinpoint planetary landing

Science.gov (United States)

Cui, Pingyuan; Gao, Xizhen; Zhu, Shengying; Shao, Wei

2018-05-01

Pinpoint landing is challenging for future Mars and asteroid exploration missions. Vision-based navigation scheme based on feature detection and matching is practical and can achieve the required precision. However, existing algorithms are computationally prohibitive and utilize poor-performance measurements, which pose great challenges for the application of visual navigation. This paper proposes an innovative visual navigation scheme using crater edge curves during descent and landing phase. In the algorithm, the edge curves of the craters tracked from two sequential images are utilized to determine the relative attitude and position of the lander through a normalized method. Then, considering error accumulation of relative navigation, a method is developed. That is to integrate the crater-based relative navigation method with crater-based absolute navigation method that identifies craters using a georeferenced database for continuous estimation of absolute states. In addition, expressions of the relative state estimate bias are derived. Novel necessary and sufficient observability criteria based on error analysis are provided to improve the navigation performance, which hold true for similar navigation systems. Simulation results demonstrate the effectiveness and high accuracy of the proposed navigation method.

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.

76 FR 27337 - Houston/Galveston Navigation Safety Advisory Committee

Science.gov (United States)

2011-05-11

... DEPARTMENT OF HOMELAND SECURITY Coast Guard [USCG-2010-1116] Houston/Galveston Navigation Safety...: The Houston/Galveston Navigation Safety Advisory Committee postponed its originally scheduled February... Houston Ship Channel, and various other navigation safety matters in the Galveston Bay area. The meeting...

Visual Guided Navigation

National Research Council Canada - National Science Library

Banks, Martin

1999-01-01

.... Similarly, the problem of visual navigation is the recovery of an observer's self-motion with respect to the environment from the moving pattern of light reaching the eyes and the complex of extra...

Paediatric patient navigation models of care in Canada: An environmental scan.

Science.gov (United States)

Luke, Alison; Doucet, Shelley; Azar, Rima

2018-05-01

(1) To provide other organizations with useful information when implementing paediatric navigation programs and (2) to inform the implementation of a navigation care centre in New Brunswick for children with complex health conditions. This environmental scan consisted of a literature review of published and grey literature for paediatric patient navigation programs across Canada. Additional programs were found following discussions with program coordinators and navigators. Interviews were conducted with key staff from each program and included questions related to patient condition; target population and location; method delivery; navigator background; and navigator roles. Data analysis included analysis of interviews and identification of common themes across the different programs. We interviewed staff from 19 paediatric navigation programs across Canada. Programs varied across a number of different themes, including: condition and disease type, program location (e.g., hospital or clinic), navigator background (e.g., registered nurse or peer/lay navigator) and method of delivery (e.g., phone or face-to-face). Overall, navigator roles are similar across all programs, including advocacy, education, support and assistance in accessing resources from both within and outside the health care system. This scan offers a road map of Canadian paediatric navigation programs. Knowledge learned from this scan will inform stakeholders who are either involved in the delivery of paediatric patient navigation programs or planning to implement such a program. Specifically, our scan informed the development of a navigation centre for children with complex health conditions in New Brunswick.

Flexible edge seal for vacuum insulating glazing units

Science.gov (United States)

Bettger, Kenneth J.; Stark, David H.

2012-12-11

A flexible edge seal is provided for a vacuum insulating glazing unit having a first glass pane and a second glass pane spaced-apart from the first. The edge seal comprises a seal member formed of a hermetically bondable material and having a first end, a second end and a center section disposed therebetween. The first end is hermetically bondable to a first glass pane. The second end is hermetically bondable to a second glass pane. The center section comprises a plurality of convolutes.

SOLERAS - Solar Controlled Environment Agriculture Project. Final report, Volume 1. Project summary

Energy Technology Data Exchange (ETDEWEB)

1985-12-30

A summary of the Solar Controlled Environment Agriculture Project is presented. The design of the greenhouses include transparent double pane glass roof with channels for fluid between the panes, inner pane tinted and double pane extruded acrylic aluminized mylar shade and diffuser. Solar energy technologies provide power for water desalination, for pumping irrigation water, and for cooling and heating the controlled environment space so that crops can grow in arid lands. The project is a joint effort between the United States and Saudi Arabia. (BCS)

Tinnitus Patient Navigator

Science.gov (United States)

... Cure About Us Initiatives News & Events Professional Resources Tinnitus Patient Navigator Want to get started on the ... unique and may require a different treatment workflow. Tinnitus Health-Care Providers If you, or someone you ...

Design Issues for MEMS-Based Pedestrian Inertial Navigation Systems

Directory of Open Access Journals (Sweden)

P. S. Marinushkin

2015-01-01

Full Text Available The paper describes design issues for MEMS-based pedestrian inertial navigation systems. By now the algorithms to estimate navigation parameters for strap-down inertial navigation systems on the basis of plural observations have been already well developed. At the same time mathematical and software processing of information in the case of pedestrian inertial navigation systems has its specificity, due to the peculiarities of their functioning and exploitation. Therefore, there is an urgent task to enhance existing fusion algorithms for use in pedestrian navigation systems. For this purpose the article analyzes the characteristics of the hardware composition and configuration of existing systems of this class. The paper shows advantages of various technical solutions. Relying on their main features it justifies a choice of the navigation system architecture and hardware composition enabling improvement of the estimation accuracy of user position as compared to the systems using only inertial sensors. The next point concerns the development of algorithms for complex processing of heterogeneous information. To increase an accuracy of the free running pedestrian inertial navigation system we propose an adaptive algorithm for joint processing of heterogeneous information based on the fusion of inertial info rmation with magnetometer measurements using EKF approach. Modeling of the algorithm was carried out using a specially developed functional prototype of pedestrian inertial navigation system, implemented as a hardware/software complex in Matlab environment. The functional prototype tests of the developed system demonstrated an improvement of the navigation parameters estimation compared to the systems based on inertial sensors only. It enables to draw a conclusion that the synthesized algorithm provides satisfactory accuracy for calculating the trajectory of motion even when using low-grade inertial MEMS sensors. The developed algorithm can be

Ground-Based Global Navigation Satellite System GLONASS (GLObal NAvigation Satellite System) Combined Broadcast Ephemeris Data (daily files) from NASA CDDIS

Data.gov (United States)

National Aeronautics and Space Administration — This dataset consists of ground-based Global Navigation Satellite System (GNSS) GLONASS Combined Broadcast Ephemeris Data (daily files of all distinct navigation...

33 CFR 207.580 - Buffalo Harbor, N.Y.; use, administration, and navigation.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Buffalo Harbor, N.Y.; use, administration, and navigation. 207.580 Section 207.580 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE NAVIGATION REGULATIONS § 207.580 Buffalo Harbor, N.Y.; use...

Navigation system for interstitial brachytherapy

International Nuclear Information System (INIS)

Strassmann, G.; Kolotas, C.; Heyd, R.

2000-01-01

The purpose of the stud was to develop a computed tomography (CT) based electromagnetic navigation system for interstitial brachytherapy. This is especially designed for situations when needles have to be positioned adjacent to or within critical anatomical structures. In such instances interactive 3D visualisation of the needle positions is essential. The material consisted of a Polhemus electromagnetic 3D digitizer, a Pentium 200 MHz laptop and a voice recognition for continuous speech. In addition, we developed an external reference system constructed of Perspex which could be positioned above the tumour region and attached to the patient using a non-invasive fixation method. A specially designed needle holder and patient bed were also developed. Measurements were made on a series of phantoms in order to study the efficacy and accuracy of the navigation system. The mean navigation accuracy of positioning the 20.0 cm length metallic needles within the phantoms was in the range 2.0-4.1 mm with a maximum of 5.4 mm. This is an improvement on the accuracy of a CT-guided technique which was in the range 6.1-11.3 mm with a maximum of 19.4 mm. The mean reconstruction accuracy of the implant geometry was 3.2 mm within a non-ferromagnetic environment. We found that although the needles were metallic this did not have a significant influence. We also found for our experimental setups that the CT table and operation table non-ferromagnetic parts had no significant influence on the navigation accuracy. This navigation system will be a very useful clinical tool for interstitial brachytherapy applications, particularly when critical structures have to be avoided. It also should provide a significant improvement on our existing technique

Benefits of multisensory presentation on perception, memory and navigation

NARCIS (Netherlands)

Philippi, T.G.|info:eu-repo/dai/nl/313711577

2012-01-01

Navigation is the process of planning and following routes to travel from the current location to a target location. In comparison with real world navigation, we have considerable difficulty with navigation in virtual environments. An important cause is that less information is presented in a

3D-navigation for interstitial stereotactic brachytherapy; 3D-Navigation in der interstitiellen stereotaktischen Brachytherapie

Energy Technology Data Exchange (ETDEWEB)

Auer, T.; Hensler, E.; Eichberger, P.; Bluhm, A.; Lukas, P. [Innsbruck Univ. (Austria). Klinik fuer Strahlentherapie und Radioonkologie; Gunkel, A.; Freysinger, W.; Bale, R.; Thumfart, W.F. [Innsbruck Univ. (Austria). Klinik fuer HNO-Krankheiten; Gaber, O. [Innsbruck Univ. (Austria). Inst. fuer Anatomie

1998-02-01

The aim of this paper is to describe the adaption of 3D-navigation for interstitial brachytherapy. The new method leads to prospective and therefore improved planning of the therapy (position of the needle and dose distribution) and to the possibility of a virtual simulation (control if vessels or nerves are on the pathway of the needle). The EasyGuide Neuro {sup trademark} navigation system (Philips) was adapted in the way, that needles for interstitial bracachytherapy were made connectable to the pointer and correctly displayed on the screen. To determine the positioning accuracy, several attempts were performed to hit defined targets on phantoms. Two methods were used: `Free navigation`, where the needle was under control of the navigation system, and the `guided navigation` where an aligned template was used additionally to lead the needle to the target. In addition a mask system was tested, whether it met the requirements of stable and reproducible positioning. The potential of applying this method is clinical practice was tested with an anatomical specimen. About 91% of all attempts lied within 5 mm. There were even better results on the more rigid table (94%<4 mm). No difference could be seen between both application methods (`free navigation` and `navigation with template`), they showed the same accuracy. (orig./MG) [Deutsch] Es war das Ziel dieser Arbeit, ein 3D-Infrarotnavigationssystem fuer die Anforderungen der interstitiellen stereotaktischen Brachytherapie zu adaptieren. Damit wird die Planung der Therapie verbessert (prospektive Planung der Nadelpositionen und der Dosisverteilung), und eine virtuelle Simulation wird realisierbar (Kontrolle des vorgeplanten Zugangs bezueglich Verletzungsmoeglichkeit von Gefaessen oder Nerven). Das EasyGuide-Neuro {sup trademark} -Navigagationssystem (Philips) wurde so veraendert, dass Nadeln, die in der Brachytherapie Verwendung finden, am Pointer befestigt werden konnten und am Bildschirm angezeigt wurden. Um die

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.

Survey of computer vision technology for UVA navigation

Science.gov (United States)

Xie, Bo; Fan, Xiang; Li, Sijian

2017-11-01

Navigation based on computer version technology, which has the characteristics of strong independence, high precision and is not susceptible to electrical interference, has attracted more and more attention in the filed of UAV navigation research. Early navigation project based on computer version technology mainly applied to autonomous ground robot. In recent years, the visual navigation system is widely applied to unmanned machine, deep space detector and underwater robot. That further stimulate the research of integrated navigation algorithm based on computer version technology. In China, with many types of UAV development and two lunar exploration, the three phase of the project started, there has been significant progress in the study of visual navigation. The paper expounds the development of navigation based on computer version technology in the filed of UAV navigation research and draw a conclusion that visual navigation is mainly applied to three aspects as follows.(1) Acquisition of UAV navigation parameters. The parameters, including UAV attitude, position and velocity information could be got according to the relationship between the images from sensors and carrier's attitude, the relationship between instant matching images and the reference images and the relationship between carrier's velocity and characteristics of sequential images.(2) Autonomous obstacle avoidance. There are many ways to achieve obstacle avoidance in UAV navigation. The methods based on computer version technology ,including feature matching, template matching, image frames and so on, are mainly introduced. (3) The target tracking, positioning. Using the obtained images, UAV position is calculated by using optical flow method, MeanShift algorithm, CamShift algorithm, Kalman filtering and particle filter algotithm. The paper expounds three kinds of mainstream visual system. (1) High speed visual system. It uses parallel structure, with which image detection and processing are

Navigation in space by X-ray pulsars

CERN Document Server

Emadzadeh, Amir Abbas

2011-01-01

This book covers modeling of X-ray pulsar signals and explains how X-ray pulsar signals can be used to solve the relative navigation problem. It formulates the problem, proposes a recursive solution and analyzes different aspects of the navigation system.

A framework and methodology for navigating disaster and global health in crisis literature.

Science.gov (United States)

Chan, Jennifer L; Burkle, Frederick M

2013-04-04

Both 'disasters' and 'global health in crisis' research has dramatically grown due to the ever-increasing frequency and magnitude of crises around the world. Large volumes of peer-reviewed literature are not only a testament to the field's value and evolution, but also present an unprecedented outpouring of seemingly unmanageable information across a wide array of crises and disciplines. Disaster medicine, health and humanitarian assistance, global health and public health disaster literature all lie within the disaster and global health in crisis literature spectrum and are increasingly accepted as multidisciplinary and transdisciplinary disciplines. Researchers, policy makers, and practitioners now face a new challenge; that of accessing this expansive literature for decision-making and exploring new areas of research. Individuals are also reaching beyond the peer-reviewed environment to grey literature using search engines like Google Scholar to access policy documents, consensus reports and conference proceedings. What is needed is a method and mechanism with which to search and retrieve relevant articles from this expansive body of literature. This manuscript presents both a framework and workable process for a diverse group of users to navigate the growing peer-reviewed and grey disaster and global health in crises literature. Disaster terms from textbooks, peer-reviewed and grey literature were used to design a framework of thematic clusters and subject matter 'nodes'. A set of 84 terms, selected from 143 curated terms was organized within each node reflecting topics within the disaster and global health in crisis literature. Terms were crossed with one another and the term 'disaster'. The results were formatted into tables and matrices. This process created a roadmap of search terms that could be applied to the PubMed database. Each search in the matrix or table results in a listed number of articles. This process was applied to literature from PubMed from

SLS Navigation Model-Based Design Approach

Science.gov (United States)

Oliver, T. Emerson; Anzalone, Evan; Geohagan, Kevin; Bernard, Bill; Park, Thomas

2018-01-01

The SLS Program chose to implement a Model-based Design and Model-based Requirements approach for managing component design information and system requirements. This approach differs from previous large-scale design efforts at Marshall Space Flight Center where design documentation alone conveyed information required for vehicle design and analysis and where extensive requirements sets were used to scope and constrain the design. The SLS Navigation Team has been responsible for the Program-controlled Design Math Models (DMMs) which describe and represent the performance of the Inertial Navigation System (INS) and the Rate Gyro Assemblies (RGAs) used by Guidance, Navigation, and Controls (GN&C). The SLS Navigation Team is also responsible for the navigation algorithms. The navigation algorithms are delivered for implementation on the flight hardware as a DMM. For the SLS Block 1-B design, the additional GPS Receiver hardware is managed as a DMM at the vehicle design level. This paper provides a discussion of the processes and methods used to engineer, design, and coordinate engineering trades and performance assessments using SLS practices as applied to the GN&C system, with a particular focus on the Navigation components. These include composing system requirements, requirements verification, model development, model verification and validation, and modeling and analysis approaches. The Model-based Design and Requirements approach does not reduce the effort associated with the design process versus previous processes used at Marshall Space Flight Center. Instead, the approach takes advantage of overlap between the requirements development and management process, and the design and analysis process by efficiently combining the control (i.e. the requirement) and the design mechanisms. The design mechanism is the representation of the component behavior and performance in design and analysis tools. The focus in the early design process shifts from the development and

The Navigation Metaphor in Security Economics

DEFF Research Database (Denmark)

Pieters, Wolter; Barendse, Jeroen; Ford, Margaret

2016-01-01

The navigation metaphor for cybersecurity merges security architecture models and security economics. By identifying the most efficient routes for gaining access to assets from an attacker's viewpoint, an organization can optimize its defenses along these routes. The well-understood concept of na...... of navigation makes it easier to motivate and explain security investment to a wide audience, encouraging strategic security decisions....

Navigational Strategies of Migrating Monarch Butterflies

Science.gov (United States)

2014-11-10

AFRL-OSR-VA-TR-2014-0339 NAVIGATIONAL STRATEGIES OF MIGRATING MONARCH BUTTERFLIES Steven Reppert UNIVERSITY OF MASSACHUSETTS Final Report 11/10/2014...Final Progress Statement to (Dr. Patrick Bradshaw) Contract/Grant Title: Navigational Strategies of Migrating Monarch Butterflies Contract...Grant #: FA9550-10-1-0480 Reporting Period: 01-Sept-10 to 31-Aug-14 Overview of accomplishments: Migrating monarch butterflies (Danaus

PERFORMANCE CHARACTERISTIC MEMS-BASED IMUs FOR UAVs NAVIGATION

Directory of Open Access Journals (Sweden)

H. A. Mohamed

2015-08-01

Full Text Available Accurate 3D reconstruction has become essential for non-traditional mapping applications such as urban planning, mining industry, environmental monitoring, navigation, surveillance, pipeline inspection, infrastructure monitoring, landslide hazard analysis, indoor localization, and military simulation. The needs of these applications cannot be satisfied by traditional mapping, which is based on dedicated data acquisition systems designed for mapping purposes. Recent advances in hardware and software development have made it possible to conduct accurate 3D mapping without using costly and high-end data acquisition systems. Low-cost digital cameras, laser scanners, and navigation systems can provide accurate mapping if they are properly integrated at the hardware and software levels. Unmanned Aerial Vehicles (UAVs are emerging as a mobile mapping platform that can provide additional economical and practical advantages. However, such economical and practical requirements need navigation systems that can provide uninterrupted navigation solution. Hence, testing the performance characteristics of Micro-Electro-Mechanical Systems (MEMS or low cost navigation sensors for various UAV applications is important research. This work focuses on studying the performance characteristics under different manoeuvres using inertial measurements integrated with single point positioning, Real-Time-Kinematic (RTK, and additional navigational aiding sensors. Furthermore, the performance of the inertial sensors is tested during Global Positioning System (GPS signal outage.

Model-base visual navigation of a mobile robot

International Nuclear Information System (INIS)

Roening, J.

1992-08-01

The thesis considers the problems of visual guidance of a mobile robot. A visual navigation system is formalized consisting of four basic components: world modelling, navigation sensing, navigation and action. According to this formalization an experimental system is designed and realized enabling real-world navigation experiments. A priori knowledge of the world is used for global path finding, aiding scene analysis and providing feedback information to the close the control loop between planned and actual movements. Two world models were developed. The first approach was a map-based model especially designed for low-level description of indoor environments. The other was a higher level and more symbolic representation of the surroundings utilizing the spatial graph concept. Two passive vision approaches were developed to extract navigation information. With passive three- camera stereovision a sparse depth map of the scene was produced. Another approach employed a fish-eye lens to map the entire scene of the surroundings without camera scanning. The local path planning of the system is supported by three-dimensional scene interpreter providing a partial understanding of scene contents. The interpreter consists of data-driven low-level stages and a model-driven high-level stage. Experiments were carried out in a simulator and test vehicle constructed in the laboratory. The test vehicle successfully navigated indoors

Performance Characteristic Mems-Based IMUs for UAVs Navigation

Science.gov (United States)

Mohamed, H. A.; Hansen, J. M.; Elhabiby, M. M.; El-Sheimy, N.; Sesay, A. B.

2015-08-01

Accurate 3D reconstruction has become essential for non-traditional mapping applications such as urban planning, mining industry, environmental monitoring, navigation, surveillance, pipeline inspection, infrastructure monitoring, landslide hazard analysis, indoor localization, and military simulation. The needs of these applications cannot be satisfied by traditional mapping, which is based on dedicated data acquisition systems designed for mapping purposes. Recent advances in hardware and software development have made it possible to conduct accurate 3D mapping without using costly and high-end data acquisition systems. Low-cost digital cameras, laser scanners, and navigation systems can provide accurate mapping if they are properly integrated at the hardware and software levels. Unmanned Aerial Vehicles (UAVs) are emerging as a mobile mapping platform that can provide additional economical and practical advantages. However, such economical and practical requirements need navigation systems that can provide uninterrupted navigation solution. Hence, testing the performance characteristics of Micro-Electro-Mechanical Systems (MEMS) or low cost navigation sensors for various UAV applications is important research. This work focuses on studying the performance characteristics under different manoeuvres using inertial measurements integrated with single point positioning, Real-Time-Kinematic (RTK), and additional navigational aiding sensors. Furthermore, the performance of the inertial sensors is tested during Global Positioning System (GPS) signal outage.

22 CFR 401.25 - Government brief regarding navigable waters.

Science.gov (United States)

2010-04-01

... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Government brief regarding navigable waters. 401... PROCEDURE Applications § 401.25 Government brief regarding navigable waters. When in the opinion of the Commission it is desirable that a decision should be rendered which affects navigable waters in a manner or...

Mobile Robot Navigation

DEFF Research Database (Denmark)

Andersen, Jens Christian

2007-01-01

the current position to a desired destination. This thesis presents and experimentally validates solutions for road classification, obstacle avoidance and mission execution. The road classification is based on laser scanner measurements and supported at longer ranges by vision. The road classification...... is sufficiently sensitive to separate the road from flat roadsides, and to distinguish asphalt roads from gravelled roads. The vision-based road detection uses a combination of chromaticity and edge detection to outline the traversable part of the road based on a laser scanner classified sample area....... The perception of these two sensors are utilised by a path planner to allow a number of drive modes, and especially the ability to follow road edges are investigated. The navigation mission is controlled by a script language. The navigation script controls route sequencing, junction detection, junction crossing...

Categorizing words through semantic memory navigation

Science.gov (United States)

Borge-Holthoefer, J.; Arenas, A.

2010-03-01

Semantic memory is the cognitive system devoted to storage and retrieval of conceptual knowledge. Empirical data indicate that semantic memory is organized in a network structure. Everyday experience shows that word search and retrieval processes provide fluent and coherent speech, i.e. are efficient. This implies either that semantic memory encodes, besides thousands of words, different kind of links for different relationships (introducing greater complexity and storage costs), or that the structure evolves facilitating the differentiation between long-lasting semantic relations from incidental, phenomenological ones. Assuming the latter possibility, we explore a mechanism to disentangle the underlying semantic backbone which comprises conceptual structure (extraction of categorical relations between pairs of words), from the rest of information present in the structure. To this end, we first present and characterize an empirical data set modeled as a network, then we simulate a stochastic cognitive navigation on this topology. We schematize this latter process as uncorrelated random walks from node to node, which converge to a feature vectors network. By doing so we both introduce a novel mechanism for information retrieval, and point at the problem of category formation in close connection to linguistic and non-linguistic experience.

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.

The Programmer's Guide to iSeries Navigator

CERN Document Server

Touhy, Paul

2012-01-01

iSeries Navigator is a favorite tool of operators and administrators-who use it with great success-but many programmers have missed the great programming tools that is provides! This book introduces you to iSeries Navigator along with all the powerful tools and interfaces that will expand your programming horizons. As iSeries applications continue to move toward a graphical user interface (GUI), so does the development environment. Programs such as CODE and WDSC may fill the need for the programming environment, but iSeries Navigator fills the programmer's need for general system access as wel

Neurosurgical robotic arm drilling navigation system.

Science.gov (United States)

Lin, Chung-Chih; Lin, Hsin-Cheng; Lee, Wen-Yo; Lee, Shih-Tseng; Wu, Chieh-Tsai

2017-09-01

The aim of this work was to develop a neurosurgical robotic arm drilling navigation system that provides assistance throughout the complete bone drilling process. The system comprised neurosurgical robotic arm navigation combining robotic and surgical navigation, 3D medical imaging based surgical planning that could identify lesion location and plan the surgical path on 3D images, and automatic bone drilling control that would stop drilling when the bone was to be drilled-through. Three kinds of experiment were designed. The average positioning error deduced from 3D images of the robotic arm was 0.502 ± 0.069 mm. The correlation between automatically and manually planned paths was 0.975. The average distance error between automatically planned paths and risky zones was 0.279 ± 0.401 mm. The drilling auto-stopping algorithm had 0.00% unstopped cases (26.32% in control group 1) and 70.53% non-drilled-through cases (8.42% and 4.21% in control groups 1 and 2). The system may be useful for neurosurgical robotic arm drilling navigation. Copyright © 2016 John Wiley & Sons, Ltd.

Navigable windows of the Northwest Passage

Science.gov (United States)

Liu, Xing-he; Ma, Long; Wang, Jia-yue; Wang, Ye; Wang, Li-na

2017-09-01

Artic sea ice loss trends support a greater potential for Arctic shipping. The information of sea ice conditions is important for utilizing Arctic passages. Based on the shipping routes given by ;Arctic Marine Shipping Assessment 2009 Report;, the navigable windows of these routes and the constituent legs were calculated by using sea ice concentration product data from 2006 to 2015, by which a comprehensive knowledge of the sea ice condition of the Northwest Passage was achieved. The results showed that Route 4 (Lancaster Sound - Barrow Strait - Prince Regent Inlet and Bellot Strait - Franklin Strait - Larsen Sound - Victoria Strait - Queen Maud Gulf - Dease Strait - Coronation Gulf - Dolphin and Union Strait - Amundsen Gulf) had the best navigable expectation, Route 2 (Parry Channel - M'Clure Strait) had the worst, and the critical legs affecting the navigation of Northwest Passage were Viscount Melville Sound, Franklin Strait, Victoria Strait, Bellot Strait, M'Clure Strait and Prince of Wales Strait. The shortest navigable period of the routes of Northwest Passage was up to 69 days. The methods used and the results of the study can help the selection and evaluation of Arctic commercial routes.

Examining care navigation: librarian participation in a teambased approach?

Directory of Open Access Journals (Sweden)

A. Tyler Nix, MSLS

2016-11-01

Full Text Available Objective: This study investigated responsibilities, skill sets, degrees, and certifications required of health care navigators in order to identify areas of potential overlap with health sciences librarianship. Method: The authors conducted a content analysis of health care navigator position announcements and developed and assigned forty-eight category terms to represent the sample’s responsibilities and skill sets. Results: Coordination of patient care and a bachelor’s degree were the most common responsibility and degree requirements, respectively. Results also suggest that managing and providing health information resources is an area of overlap between health care navigators and health sciences librarians, and that librarians are well suited to serve on navigation teams. Conclusion: Such overlap may provide an avenue for collaboration between navigators and health sciences librarians.

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.

Evolved Navigation Theory and Horizontal Visual Illusions

Science.gov (United States)

Jackson, Russell E.; Willey, Chela R.

2011-01-01

Environmental perception is prerequisite to most vertebrate behavior and its modern investigation initiated the founding of experimental psychology. Navigation costs may affect environmental perception, such as overestimating distances while encumbered (Solomon, 1949). However, little is known about how this occurs in real-world navigation or how…

Mapping, Navigation, and Learning for Off-Road Traversal

DEFF Research Database (Denmark)

Konolige, Kurt; Agrawal, Motilal; Blas, Morten Rufus

2009-01-01

The challenge in the DARPA Learning Applied to Ground Robots (LAGR) project is to autonomously navigate a small robot using stereo vision as the main sensor. During this project, we demonstrated a complete autonomous system for off-road navigation in unstructured environments, using stereo vision......, online terrain traversability learning, visual odometry, map registration, planning, and control. At the end of 3 years, the system we developed outperformed all nine other teams in final blind tests over previously unseen terrain.......The challenge in the DARPA Learning Applied to Ground Robots (LAGR) project is to autonomously navigate a small robot using stereo vision as the main sensor. During this project, we demonstrated a complete autonomous system for off-road navigation in unstructured environments, using stereo vision...

Lost in Virtual Space: Studies in Human and Ideal Spatial Navigation

Science.gov (United States)

Stankiewicz, Brian J.; Legge, Gordon E.; Mansfield, J. Stephen; Schlicht, Erik J.

2006-01-01

The authors describe 3 human spatial navigation experiments that investigate how limitations of perception, memory, uncertainty, and decision strategy affect human spatial navigation performance. To better understand the effect of these variables on human navigation performance, the authors developed an ideal-navigator model for indoor navigation…

Cislunar navigation

Science.gov (United States)

Cesarone, R. J.; Burke, J. D.; Hastrup, R. C.; Lo, M. W.

2003-01-01

In the future, navigation and communication in Earth-Moon space and on the Moon will differ from past practice due to evolving technology and new requirements. Here we describe likely requirements, discuss options for meeting them, and advocate steps that can be taken now to begin building the navcom systems needed in coming years for exploring and using the moon.

Natural Language Navigation Support in Virtual Reality

NARCIS (Netherlands)

van Luin, J.; Nijholt, Antinus; op den Akker, Hendrikus J.A.; Giagourta, V.; Strintzis, M.G.

2001-01-01

We describe our work on designing a natural language accessible navigation agent for a virtual reality (VR) environment. The agent is part of an agent framework, which means that it can communicate with other agents. Its navigation task consists of guiding the visitors in the environment and to

Autonomous Vehicles Navigation with Visual Target Tracking: Technical Approaches

Directory of Open Access Journals (Sweden)

Zhen Jia

2008-12-01

Full Text Available This paper surveys the developments of last 10 years in the area of vision based target tracking for autonomous vehicles navigation. First, the motivations and applications of using vision based target tracking for autonomous vehicles navigation are presented in the introduction section. It can be concluded that it is very necessary to develop robust visual target tracking based navigation algorithms for the broad applications of autonomous vehicles. Then this paper reviews the recent techniques in three different categories: vision based target tracking for the applications of land, underwater and aerial vehicles navigation. Next, the increasing trends of using data fusion for visual target tracking based autonomous vehicles navigation are discussed. Through data fusion the tracking performance is improved and becomes more robust. Based on the review, the remaining research challenges are summarized and future research directions are investigated.

33 CFR 64.16 - Duration of marking on sunken vessels in navigable waters.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Duration of marking on sunken vessels in navigable waters. 64.16 Section 64.16 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... Sunken Vessels and Other Obstructions § 64.16 Duration of marking on sunken vessels in navigable waters...

33 CFR 207.600 - Rochester (Charlotte) Harbor, N.Y.; use, administration, and navigation.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Rochester (Charlotte) Harbor, N.Y.; use, administration, and navigation. 207.600 Section 207.600 Navigation and Navigable Waters CORPS OF... (Charlotte) Harbor, N.Y.; use, administration, and navigation. (a)-(b) [Reserved] (c) No vessel shall moor or...

Benchmark Framework for Mobile Robots Navigation Algorithms

Directory of Open Access Journals (Sweden)

Nelson David Muñoz-Ceballos

2014-01-01

Full Text Available Despite the wide variety of studies and research on mobile robot systems, performance metrics are not often examined. This makes difficult to establish an objective comparison of achievements. In this paper, the navigation of an autonomous mobile robot is evaluated. Several metrics are described. These metrics, collectively, provide an indication of navigation quality, useful for comparing and analyzing navigation algorithms of mobile robots. This method is suggested as an educational tool, which allows the student to optimize the algorithms quality, relating to important aspectsof science, technology and engineering teaching, as energy consumption, optimization and design.

Global search tool for the Advanced Photon Source Integrated Relational Model of Installed Systems (IRMIS) database

International Nuclear Information System (INIS)

Quock, D.E.R.; Cianciarulo, M.B.

2007-01-01

The Integrated Relational Model of Installed Systems (IRMIS) is a relational database tool that has been implemented at the Advanced Photon Source to maintain an updated account of approximately 600 control system software applications, 400,000 process variables, and 30,000 control system hardware components. To effectively display this large amount of control system information to operators and engineers, IRMIS was initially built with nine Web-based viewers: Applications Organizing Index, IOC, PLC, Component Type, Installed Components, Network, Controls Spares, Process Variables, and Cables. However, since each viewer is designed to provide details from only one major category of the control system, the necessity for a one-stop global search tool for the entire database became apparent. The user requirements for extremely fast database search time and ease of navigation through search results led to the choice of Asynchronous JavaScript and XML (AJAX) technology in the implementation of the IRMIS global search tool. Unique features of the global search tool include a two-tier level of displayed search results, and a database data integrity validation and reporting mechanism.

33 CFR 165.1402 - Apra Outer Harbor, Guam-regulated navigation area.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Apra Outer Harbor, Guam-regulated....1402 Apra Outer Harbor, Guam—regulated navigation area. (a) The following is a regulated navigation area—The waters of the Pacific Ocean and Apra Outer Harbor enclosed by a line beginning at latitude 13...

Human-robot collaborative navigation for autonomous maintenance management of nuclear installation

International Nuclear Information System (INIS)

Nugroho, Djoko Hari

2002-01-01

Development of human and robot collaborative navigation for autonomous maintenance management of nuclear installation has been conducted. The human-robot collaborative system is performed using a switching command between autonomous navigation and manual navigation that incorporate a human intervention. The autonomous navigation path is conducted using a novel algorithm of MLG method based on Lozano-Perez s visibility graph. The MLG optimizes the shortest distance and safe constraints. While the manual navigation is performed using manual robot tele operation tools. Experiment in the MLG autonomous navigation system is conducted for six times with 3-D starting point and destination point coordinate variation. The experiment shows a good performance of autonomous robot maneuver to avoid collision with obstacle. The switching navigation is well interpreted using open or close command to RS-232C constructed using LabVIEW

Gray and White Matter Correlates of Navigational Ability in Humans

NARCIS (Netherlands)

Wegman, J.B.T.; Fonteijn, H.M.; Ekert, J. van; Tyborowska, A.B.; Jansen, C.; Janzen, G.

2014-01-01

Humans differ widely in their navigational abilities. Studies have shown that self-reports on navigational abilities are good predictors of performance on navigation tasks in real and virtual environments. The caudate nucleus and medial temporal lobe regions have been suggested to subserve different

New reference trajectory optimization algorithm for a flight management system inspired in beam search

Directory of Open Access Journals (Sweden)

Alejandro MURRIETA-MENDOZA

2017-08-01

Full Text Available With the objective of reducing the flight cost and the amount of polluting emissions released in the atmosphere, a new optimization algorithm considering the climb, cruise and descent phases is presented for the reference vertical flight trajectory. The selection of the reference vertical navigation speeds and altitudes was solved as a discrete combinatory problem by means of a graph-tree passing through nodes using the beam search optimization technique. To achieve a compromise between the execution time and the algorithm’s ability to find the global optimal solution, a heuristic methodology introducing a parameter called “optimism coefficient was used in order to estimate the trajectory’s flight cost at every node. The optimal trajectory cost obtained with the developed algorithm was compared with the cost of the optimal trajectory provided by a commercial flight management system(FMS. The global optimal solution was validated against an exhaustive search algorithm(ESA, other than the proposed algorithm. The developed algorithm takes into account weather effects, step climbs during cruise and air traffic management constraints such as constant altitude segments, constant cruise Mach, and a pre-defined reference lateral navigation route. The aircraft fuel burn was computed using a numerical performance model which was created and validated using flight test experimental data.

Test-retest reliability of Physical Activity Neighborhood Environment Scale among urban men and women in Nanjing, China.

Science.gov (United States)

Zhao, L; Wang, Z; Qin, Z; Leslie, E; He, J; Xiong, Y; Xu, F

2018-03-01

The identification of physical-activity-friendly built environment (BE) constructs is highly useful for physical activity promotion and maintenance. The Physical Activity Neighborhood Environment Scale (PANES) was developed for assessing BE correlates. However, PANES reliability has not been investigated among adults in China. A cross-sectional study. With multistage sampling approaches, 1568 urban adults (aged 35-74 years) were recruited for the initial survey on all 17 items of PANES Chinese version (PANES-CHN), with the survey repeated 7 days later for each participant. Intraclass correlation coefficient (ICC) was used to assess the test-retest reliability of PANES-CHN for each item. Totally, 1551 participants completed both surveys (follow-up rate = 98.9%). Among participants (mean age: 54.7 ± 11.1 years), 47.8% were men, 22.1% were elders, and 22.7% had ≥13 years of education. Overall, the PANES-CHN demonstrated at least substantial reliability with ICCs ranging from 0.66 to 0.95 (core items), from 0.75 to 0.95 (recommended items), and from 0.78 to 0.87 (optional items). Similar outcomes were observed when data were analyzed by gender or age groups. The PANES-CHN has excellent test-retest reliability and thus has valuable utility for assessing urban BE attributes among Chinese adults. Copyright © 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Pareto navigation-algorithmic foundation of interactive multi-criteria IMRT planning

International Nuclear Information System (INIS)

Monz, M; Kuefer, K H; Bortfeld, T R; Thieke, C

2008-01-01

Inherently, IMRT treatment planning involves compromising between different planning goals. Multi-criteria IMRT planning directly addresses this compromising and thus makes it more systematic. Usually, several plans are computed from which the planner selects the most promising following a certain procedure. Applying Pareto navigation for this selection step simultaneously increases the variety of planning options and eases the identification of the most promising plan. Pareto navigation is an interactive multi-criteria optimization method that consists of the two navigation mechanisms 'selection' and 'restriction'. The former allows the formulation of wishes whereas the latter allows the exclusion of unwanted plans. They are realized as optimization problems on the so-called plan bundle-a set constructed from pre-computed plans. They can be approximately reformulated so that their solution time is a small fraction of a second. Thus, the user can be provided with immediate feedback regarding his or her decisions. Pareto navigation was implemented in the MIRA navigator software and allows real-time manipulation of the current plan and the set of considered plans. The changes are triggered by simple mouse operations on the so-called navigation star and lead to real-time updates of the navigation star and the dose visualizations. Since any Pareto-optimal plan in the plan bundle can be found with just a few navigation operations the MIRA navigator allows a fast and directed plan determination. Besides, the concept allows for a refinement of the plan bundle, thus offering a middle course between single plan computation and multi-criteria optimization. Pareto navigation offers so far unmatched real-time interactions, ease of use and plan variety, setting it apart from the multi-criteria IMRT planning methods proposed so far

Pareto navigation: algorithmic foundation of interactive multi-criteria IMRT planning.

Science.gov (United States)

Monz, M; Küfer, K H; Bortfeld, T R; Thieke, C

2008-02-21

Inherently, IMRT treatment planning involves compromising between different planning goals. Multi-criteria IMRT planning directly addresses this compromising and thus makes it more systematic. Usually, several plans are computed from which the planner selects the most promising following a certain procedure. Applying Pareto navigation for this selection step simultaneously increases the variety of planning options and eases the identification of the most promising plan. Pareto navigation is an interactive multi-criteria optimization method that consists of the two navigation mechanisms 'selection' and 'restriction'. The former allows the formulation of wishes whereas the latter allows the exclusion of unwanted plans. They are realized as optimization problems on the so-called plan bundle -- a set constructed from pre-computed plans. They can be approximately reformulated so that their solution time is a small fraction of a second. Thus, the user can be provided with immediate feedback regarding his or her decisions. Pareto navigation was implemented in the MIRA navigator software and allows real-time manipulation of the current plan and the set of considered plans. The changes are triggered by simple mouse operations on the so-called navigation star and lead to real-time updates of the navigation star and the dose visualizations. Since any Pareto-optimal plan in the plan bundle can be found with just a few navigation operations the MIRA navigator allows a fast and directed plan determination. Besides, the concept allows for a refinement of the plan bundle, thus offering a middle course between single plan computation and multi-criteria optimization. Pareto navigation offers so far unmatched real-time interactions, ease of use and plan variety, setting it apart from the multi-criteria IMRT planning methods proposed so far.

USACE Navigation Channels 2012

Data.gov (United States)

California Natural Resource Agency — This dataset represents both San Francisco and Los Angeles District navigation channel lines. All San Francisco District channel lines were digitized from CAD files...

Enabling Autonomous Navigation for Affordable Scooters.

Science.gov (United States)

Liu, Kaikai; Mulky, Rajathswaroop

2018-06-05

Despite the technical success of existing assistive technologies, for example, electric wheelchairs and scooters, they are still far from effective enough in helping those in need navigate to their destinations in a hassle-free manner. In this paper, we propose to improve the safety and autonomy of navigation by designing a cutting-edge autonomous scooter, thus allowing people with mobility challenges to ambulate independently and safely in possibly unfamiliar surroundings. We focus on indoor navigation scenarios for the autonomous scooter where the current location, maps, and nearby obstacles are unknown. To achieve semi-LiDAR functionality, we leverage the gyros-based pose data to compensate the laser motion in real time and create synthetic mapping of simple environments with regular shapes and deep hallways. Laser range finders are suitable for long ranges with limited resolution. Stereo vision, on the other hand, provides 3D structural data of nearby complex objects. To achieve simultaneous fine-grained resolution and long range coverage in the mapping of cluttered and complex environments, we dynamically fuse the measurements from the stereo vision camera system, the synthetic laser scanner, and the LiDAR. We propose solutions to self-correct errors in data fusion and create a hybrid map to assist the scooter in achieving collision-free navigation in an indoor environment.

A Semantic Navigation Model for Video Games

Science.gov (United States)

van Driel, Leonard; Bidarra, Rafael

Navigational performance of artificial intelligence (AI) characters in computer games is gaining an increasingly important role in the perception of their behavior. While recent games successfully solve some complex navigation problems, there is little known or documented on the underlying approaches, often resembling a primitive conglomerate of ad-hoc algorithms for specific situations.

Navigator. Volume 45, Number 2, Winter 2009

Science.gov (United States)

National Science Education Leadership Association, 2009

2009-01-01

The National Science Education Leadership Association (NSELA) was formed in 1959 to meet a need to develop science education leadership for K-16 school systems. "Navigator" is published by NSELA to provide the latest NSELA events. This issue of "Navigator" contains the following reports: (1) A Message from the President: Creating Networks of…

Autonomous navigation - The ARMMS concept. [Autonomous Redundancy and Maintenance Management Subsystem

Science.gov (United States)

Wood, L. J.; Jones, J. B.; Mease, K. D.; Kwok, J. H.; Goltz, G. L.; Kechichian, J. A.

1984-01-01

A conceptual design is outlined for the navigation subsystem of the Autonomous Redundancy and Maintenance Management Subsystem (ARMMS). The principal function of this navigation subsystem is to maintain the spacecraft over a specified equatorial longitude to within + or - 3 deg. In addition, the navigation subsystem must detect and correct internal faults. It comprises elements for a navigation executive and for orbit determination, trajectory, maneuver planning, and maneuver command. Each of these elements is described. The navigation subsystem is to be used in the DSCS III spacecraft.

Examining care navigation: librarian participation in a team-based approach?

Science.gov (United States)

Nix, A Tyler; Huber, Jeffrey T; Shapiro, Robert M; Pfeifle, Andrea

2016-04-01

This study investigated responsibilities, skill sets, degrees, and certifications required of health care navigators in order to identify areas of potential overlap with health sciences librarianship. The authors conducted a content analysis of health care navigator position announcements and developed and assigned forty-eight category terms to represent the sample's responsibilities and skill sets. Coordination of patient care and a bachelor's degree were the most common responsibility and degree requirements, respectively. Results also suggest that managing and providing health information resources is an area of overlap between health care navigators and health sciences librarians, and that librarians are well suited to serve on navigation teams. Such overlap may provide an avenue for collaboration between navigators and health sciences librarians.

19 CFR 4.66b - Pollution of coastal and navigable waters.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Pollution of coastal and navigable waters. 4.66b... coastal and navigable waters. (a) If any Customs officer has reason to believe that any refuse matter is being or has been deposited in navigable waters or any tributary of any navigable waters in violation of...

PulsarPlane: a feasibility study for millisecond radio pulsar navigation

NARCIS (Netherlands)

Buist, Peter; Hesselink, Henk; Gibbs, Alex; Keuning, Michel; Gaubitch, Nikolay; Noroozi, Arash; Bentum, Marinus Jan; Verhoeven, Chris; Heusdens, Richard; Fernandes, Jorge; Kabakchiev, Hristo; 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

Environmental layout complexity affects neural activity during navigation in humans.

Science.gov (United States)

Slone, Edward; Burles, Ford; Iaria, Giuseppe

2016-05-01

Navigating large-scale surroundings is a fundamental ability. In humans, it is commonly assumed that navigational performance is affected by individual differences, such as age, sex, and cognitive strategies adopted for orientation. We recently showed that the layout of the environment itself also influences how well people are able to find their way within it, yet it remains unclear whether differences in environmental complexity are associated with changes in brain activity during navigation. We used functional magnetic resonance imaging to investigate how the brain responds to a change in environmental complexity by asking participants to perform a navigation task in two large-scale virtual environments that differed solely in interconnection density, a measure of complexity defined as the average number of directional choices at decision points. The results showed that navigation in the simpler, less interconnected environment was faster and more accurate relative to the complex environment, and such performance was associated with increased activity in a number of brain areas (i.e. precuneus, retrosplenial cortex, and hippocampus) known to be involved in mental imagery, navigation, and memory. These findings provide novel evidence that environmental complexity not only affects navigational behaviour, but also modulates activity in brain regions that are important for successful orientation and navigation. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Unraveling navigational strategies in migratory insects

OpenAIRE

Merlin, Christine; Heinze, Stanley; Reppert, Steven M.

2011-01-01

Long-distance migration is a strategy some animals use to survive a seasonally changing environment. To reach favorable grounds, migratory animals have evolved sophisticated navigational mechanisms that rely on a map and compasses. In migratory insects, the existence of a map sense (sense of position) remains poorly understood, but recent work has provided new insights into the mechanisms some compasses use for maintaining a constant bearing during long-distance navigation. The best-studied d...

GPS surveying method applied to terminal area navigation flight experiments

Energy Technology Data Exchange (ETDEWEB)

Murata, M; Shingu, H; Satsushima, K; Tsuji, T; Ishikawa, K; Miyazawa, Y; Uchida, T [National Aerospace Laboratory, Tokyo (Japan)

1993-03-01

With an objective of evaluating accuracy of new landing and navigation systems such as microwave landing guidance system and global positioning satellite (GPS) system, flight experiments are being carried out using experimental aircraft. This aircraft mounts a GPS and evaluates its accuracy by comparing the standard orbits spotted by a Kalman filter from the laser tracing data on the aircraft with the navigation results. The GPS outputs position and speed information from an earth-centered-earth-fixed system called the World Geodetic System, 1984 (WGS84). However, in order to compare the navigation results with output from a reference orbit sensor or other navigation sensor, it is necessary to structure a high-precision reference coordinates system based on the WGS84. A method that applies the GPS phase interference measurement for this problem was proposed, and used actually in analyzing a flight experiment data. As referred to a case of the method having been applied to evaluating an independent navigation accuracy, the method was verified sufficiently effective and reliable not only in navigation method analysis, but also in the aspect of navigational operations. 12 refs., 10 figs., 5 tabs.

Acoustic Communications and Navigation for Mobile Under-Ice Sensors

Science.gov (United States)

2017-02-04

contact below the ice. 15. SUBJECT TERMS Arctic Ocean , Undersea Workstations & Vehicles, Signal Processing, Navigation , Underwater Acoustics 16...Partan, Peter Koski, and Sandipa Singh, "Long Range Acoustic Communications and Navigation in the Arctic", Proc. IEEE/MTS Oceans Conf., Washington, DC...Oct. 2015. Freitag, L., P. Koski, A. Morozov, S. Singh, J. Partan, "Acoustic Communications and Navigation Under Arctic Ice", OCEANS , 2012

Navigator. Volume 45, Number 3, Spring 2009

Science.gov (United States)

National Science Education Leadership Association, 2009

2009-01-01

The National Science Education Leadership Association (NSELA) was formed in 1959 to meet a need to develop science education leadership for K-16 school systems. "Navigator" is published by NSELA to provide the latest NSELA events. This issue of "Navigator" includes the following items: (1) A Message from the President (Brenda Wojnowski); (2) NSELA…

Gender differences in navigational memory: pilots vs. nonpilots.

Science.gov (United States)

Verde, Paola; Piccardi, Laura; Bianchini, Filippo; Guariglia, Cecilia; Carrozzo, Paolo; Morgagni, Fabio; Boccia, Maddalena; Di Fiore, Giacomo; Tomao, Enrico

2015-02-01

The coding of space as near and far is not only determined by arm-reaching distance, but is also dependent on how the brain represents the extension of the body space. Recent reports suggest that the dissociation between reaching and navigational space is not limited to perception and action but also involves memory systems. It has been reported that gender differences emerged only in adverse learning conditions that required strong spatial ability. In this study we investigated navigational versus reaching memory in air force pilots and a control group without flight experience. We took into account temporal duration (working memory and long-term memory) and focused on working memory, which is considered critical in the gender differences literature. We found no gender effects or flight hour effects in pilots but observed gender effects in working memory (but not in learning and delayed recall) in the nonpilot population (Women's mean = 5.33; SD= 0.90; Men's mean = 5.54; SD= 0.90). We also observed a difference between pilots and nonpilots in the maintenance of on-line reaching information: pilots (mean = 5.85; SD=0.76) were more efficient than nonpilots (mean = 5.21; SD=0.83) and managed this type of information similarly to that concerning navigational space. In the navigational learning phase they also showed better navigational memory (mean = 137.83; SD=5.81) than nonpilots (mean = 126.96; SD=15.81) and were significantly more proficient than the latter group. There is no gender difference in a population of pilots in terms of navigational abilities, while it emerges in a control group without flight experience. We found also that pilots performed better than nonpilots. This study suggests that once selected, male and female pilots do not differ from each other in visuo-spatial abilities and spatial navigation.

An autonomous organic reaction search engine for chemical reactivity

Science.gov (United States)

Dragone, Vincenza; Sans, Victor; Henson, Alon B.; Granda, Jaroslaw M.; Cronin, Leroy

2017-06-01

The exploration of chemical space for new reactivity, reactions and molecules is limited by the need for separate work-up-separation steps searching for molecules rather than reactivity. Herein we present a system that can autonomously evaluate chemical reactivity within a network of 64 possible reaction combinations and aims for new reactivity, rather than a predefined set of targets. The robotic system combines chemical handling, in-line spectroscopy and real-time feedback and analysis with an algorithm that is able to distinguish and select the most reactive pathways, generating a reaction selection index (RSI) without need for separate work-up or purification steps. This allows the automatic navigation of a chemical network, leading to previously unreported molecules while needing only to do a fraction of the total possible reactions without any prior knowledge of the chemistry. We show the RSI correlates with reactivity and is able to search chemical space using the most reactive pathways.

76 FR 58105 - Regulated Navigation Area; Saugus River, Lynn, MA

Science.gov (United States)

2011-09-20

... final rule. SUMMARY: The Coast Guard is establishing a Regulated Navigation Area (RNA) on the navigable... INFORMATION: Regulatory Information The Coast Guard is issuing this temporary rule without prior notice and... Pipeline bridge poses to the navigational channel necessitates that all mariners comply with this RNA...

Satellite Imagery Assisted Road-Based Visual Navigation System

Science.gov (United States)

Volkova, A.; Gibbens, P. W.

2016-06-01

There is a growing demand for unmanned aerial systems as autonomous surveillance, exploration and remote sensing solutions. Among the key concerns for robust operation of these systems is the need to reliably navigate the environment without reliance on global navigation satellite system (GNSS). This is of particular concern in Defence circles, but is also a major safety issue for commercial operations. In these circumstances, the aircraft needs to navigate relying only on information from on-board passive sensors such as digital cameras. An autonomous feature-based visual system presented in this work offers a novel integral approach to the modelling and registration of visual features that responds to the specific needs of the navigation system. It detects visual features from Google Earth* build a feature database. The same algorithm then detects features in an on-board cameras video stream. On one level this serves to localise the vehicle relative to the environment using Simultaneous Localisation and Mapping (SLAM). On a second level it correlates them with the database to localise the vehicle with respect to the inertial frame. The performance of the presented visual navigation system was compared using the satellite imagery from different years. Based on comparison results, an analysis of the effects of seasonal, structural and qualitative changes of the imagery source on the performance of the navigation algorithm is presented. * The algorithm is independent of the source of satellite imagery and another provider can be used

Neural-network-based depth computation for blind navigation

Science.gov (United States)

Wong, Farrah; Nagarajan, Ramachandran R.; Yaacob, Sazali

2004-12-01

A research undertaken to help blind people to navigate autonomously or with minimum assistance is termed as "Blind Navigation". In this research, an aid that could help blind people in their navigation is proposed. Distance serves as an important clue during our navigation. A stereovision navigation aid implemented with two digital video cameras that are spaced apart and fixed on a headgear to obtain the distance information is presented. In this paper, a neural network methodology is used to obtain the required parameters of the camera which is known as camera calibration. These parameters are not known but obtained by adjusting the weights in the network. The inputs to the network consist of the matching features in the stereo pair images. A back propagation network with 16-input neurons, 3 hidden neurons and 1 output neuron, which gives depth, is created. The distance information is incorporated into the final processed image as four gray levels such as white, light gray, dark gray and black. Preliminary results have shown that the percentage errors fall below 10%. It is envisaged that the distance provided by neural network shall enable blind individuals to go near and pick up an object of interest.

Mobile Robot Designed with Autonomous Navigation System

Science.gov (United States)

An, Feng; Chen, Qiang; Zha, Yanfang; Tao, Wenyin

2017-10-01

With the rapid development of robot technology, robots appear more and more in all aspects of life and social production, people also ask more requirements for the robot, one is that robot capable of autonomous navigation, can recognize the road. Take the common household sweeping robot as an example, which could avoid obstacles, clean the ground and automatically find the charging place; Another example is AGV tracking car, which can following the route and reach the destination successfully. This paper introduces a new type of robot navigation scheme: SLAM, which can build the environment map in a totally strange environment, and at the same time, locate its own position, so as to achieve autonomous navigation function.

Accuracy of the hypothetical sky-polarimetric Viking navigation versus sky conditions: revealing solar elevations and cloudinesses favourable for this navigation method

Science.gov (United States)

Száz, Dénes; Farkas, Alexandra; Barta, András; Kretzer, Balázs; Blahó, Miklós; Egri, Ádám; Szabó, Gyula; Horváth, Gábor

2017-09-01

According to Thorkild Ramskou's theory proposed in 1967, under overcast and foggy skies, Viking seafarers might have used skylight polarization analysed with special crystals called sunstones to determine the position of the invisible Sun. After finding the occluded Sun with sunstones, its elevation angle had to be measured and its shadow had to be projected onto the horizontal surface of a sun compass. According to Ramskou's theory, these sunstones might have been birefringent calcite or dichroic cordierite or tourmaline crystals working as polarizers. It has frequently been claimed that this method might have been suitable for navigation even in cloudy weather. This hypothesis has been accepted and frequently cited for decades without any experimental support. In this work, we determined the accuracy of this hypothetical sky-polarimetric Viking navigation for 1080 different sky situations characterized by solar elevation θ and cloudiness ρ, the sky polarization patterns of which were measured by full-sky imaging polarimetry. We used the earlier measured uncertainty functions of the navigation steps 1, 2 and 3 for calcite, cordierite and tourmaline sunstone crystals, respectively, and the newly measured uncertainty function of step 4 presented here. As a result, we revealed the meteorological conditions under which Vikings could have used this hypothetical navigation method. We determined the solar elevations at which the navigation uncertainties are minimal at summer solstice and spring equinox for all three sunstone types. On average, calcite sunstone ensures a more accurate sky-polarimetric navigation than tourmaline and cordierite. However, in some special cases (generally at 35° ≤ θ ≤ 40°, 1 okta ≤ ρ ≤ 6 oktas for summer solstice, and at 20° ≤ θ ≤ 25°, 0 okta ≤ ρ ≤ 4 oktas for spring equinox), the use of tourmaline and cordierite results in smaller navigation uncertainties than that of calcite. Generally, under clear or less cloudy

Social networks improve leaderless group navigation by facilitating long-distance communication

Directory of Open Access Journals (Sweden)

Nikolai W. F. BODE, A. Jamie WOOD, Daniel W. FRANKS

2012-04-01

Full Text Available Group navigation is of great importance for many animals, such as migrating flocks of birds or shoals of fish. One theory states that group membership can improve navigational accuracy compared to limited or less accurate individual navigational ability in groups without leaders (“Many-wrongs principle”. Here, we simulate leaderless group navigation that includes social connections as preferential interactions between individuals. Our results suggest that underlying social networks can reduce navigational errors of groups and increase group cohesion. We use network summary statistics, in particular network motifs, to study which characteristics of networks lead to these improvements. It is networks in which preferences between individuals are not clustered, but spread evenly across the group that are advantageous in group navigation by effectively enhancing long-distance information exchange within groups. We suggest that our work predicts a base-line for the type of social structure we might expect to find in group-living animals that navigate without leaders [Current Zoology 58 (2: 329-341, 2012].

Vision Based Navigation for Autonomous Cooperative Docking of CubeSats

Science.gov (United States)

Pirat, Camille; Ankersen, Finn; Walker, Roger; Gass, Volker

2018-05-01

A realistic rendezvous and docking navigation solution applicable to CubeSats is investigated. The scalability analysis of the ESA Autonomous Transfer Vehicle Guidance, Navigation & Control (GNC) performances and the Russian docking system, shows that the docking of two CubeSats would require a lateral control performance of the order of 1 cm. Line of sight constraints and multipath effects affecting Global Navigation Satellite System (GNSS) measurements in close proximity prevent the use of this sensor for the final approach. This consideration and the high control accuracy requirement led to the use of vision sensors for the final 10 m of the rendezvous and docking sequence. A single monocular camera on the chaser satellite and various sets of Light-Emitting Diodes (LEDs) on the target vehicle ensure the observability of the system throughout the approach trajectory. The simple and novel formulation of the measurement equations allows differentiating unambiguously rotations from translations between the target and chaser docking port and allows a navigation performance better than 1 mm at docking. Furthermore, the non-linear measurement equations can be solved in order to provide an analytic navigation solution. This solution can be used to monitor the navigation filter solution and ensure its stability, adding an extra layer of robustness for autonomous rendezvous and docking. The navigation filter initialization is addressed in detail. The proposed method is able to differentiate LEDs signals from Sun reflections as demonstrated by experimental data. The navigation filter uses a comprehensive linearised coupled rotation/translation dynamics, describing the chaser to target docking port motion. The handover, between GNSS and vision sensor measurements, is assessed. The performances of the navigation function along the approach trajectory is discussed.

Sagace: A web-based search engine for biomedical databases in Japan

Directory of Open Access Journals (Sweden)

Morita Mizuki

2012-10-01

Full Text Available Abstract Background In the big data era, biomedical research continues to generate a large amount of data, and the generated information is often stored in a database and made publicly available. Although combining data from multiple databases should accelerate further studies, the current number of life sciences databases is too large to grasp features and contents of each database. Findings We have developed Sagace, a web-based search engine that enables users to retrieve information from a range of biological databases (such as gene expression profiles and proteomics data and biological resource banks (such as mouse models of disease and cell lines. With Sagace, users can search more than 300 databases in Japan. Sagace offers features tailored to biomedical research, including manually tuned ranking, a faceted navigation to refine search results, and rich snippets constructed with retrieved metadata for each database entry. Conclusions Sagace will be valuable for experts who are involved in biomedical research and drug development in both academia and industry. Sagace is freely available at http://sagace.nibio.go.jp/en/.

X-ray Pulsar Navigation Algorithms and Testbed for SEXTANT

Science.gov (United States)

Winternitz, Luke M. B.; Hasouneh, Monther A.; Mitchell, Jason W.; Valdez, Jennifer E.; Price, Samuel R.; Semper, Sean R.; Yu, Wayne H.; Ray, Paul S.; Wood, Kent S.; Arzoumanian, Zaven;

Current use of navigation system in ACL surgery: a historical review.

Science.gov (United States)

Zaffagnini, S; Urrizola, F; Signorelli, C; Grassi, A; Di Sarsina, T Roberti; Lucidi, G A; Marcheggiani Muccioli, G M; Bonanzinga, T; Marcacci, M

2016-11-01

The present review aims to analyse the available literature regarding the use of navigation systems in ACL reconstructive surgery underling the evolution during the years. A research of indexed scientific papers was performed on PubMed and Cochrane Library database. The research was performed in December 2015 with no publication year restriction. Only English-written papers and related to the terms ACL, NAVIGATION, CAOS and CAS were considered. Two reviewers independently selected only those manuscripts that presented at least the application of navigation system for ACL reconstructive surgery. One hundred and forty-six of 394 articles were finally selected. In this analysis, it was possible to review the main uses of navigation system in ACL surgery including tunnel positioning for primary and revision surgery and kinematic assessment of knee laxity before and after different surgical procedures. In the early years, until 2006, navigation system was mainly used to improve tunnel positioning, but since the last decade, this tool has been principally used for kinematics evaluation. Increased accuracy of tunnel placement was observed using navigation surgery, especially, regarding femoral, 42 of 146 articles used navigation to guide tunnel positioning. During the following years, 82 of 146 articles have used navigation system to evaluate intraoperative knee kinematic. In particular, the importance of controlling rotatory laxity to achieve better surgical outcomes has been underlined. Several applications have been described and despite the contribution of navigation systems, its potential uses and theoretical advantages, there are still controversies about its clinical benefit. The present papers summarize the most relevant studies that have used navigation system in ACL reconstruction. In particular, the analysis identified four main applications of the navigation systems during ACL reconstructive surgery have been identified: (1) technical assistance for tunnel

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.

Comparing two types of navigational interfaces for Virtual Reality.

Science.gov (United States)

Teixeira, Luís; Vilar, Elisângela; Duarte, Emília; Rebelo, Francisco; da Silva, Fernando Moreira

2012-01-01

Previous studies suggest significant differences between navigating virtual environments in a life-like walking manner (i.e., using treadmills or walk-in-place techniques) and virtual navigation (i.e., flying while really standing). The latter option, which usually involves hand-centric devices (e.g., joysticks), is the most common in Virtual Reality-based studies, mostly due to low costs, less space and technology demands. However, recently, new interaction devices, originally conceived for videogames have become available offering interesting potentialities for research. This study aimed to explore the potentialities of the Nintendo Wii Balance Board as a navigation interface in a Virtual Environment presented in an immersive Virtual Reality system. Comparing participants' performance while engaged in a simulated emergency egress allows determining the adequacy of such alternative navigation interface on the basis of empirical results. Forty university students participated in this study. Results show that participants were more efficient when performing navigation tasks using the Joystick than with the Balance Board. However there were no significantly differences in the behavioral compliance with exit signs. Therefore, this study suggests that, at least for tasks similar to the studied, the Balance Board have good potentiality to be used as a navigation interface for Virtual Reality systems.

On-board landmark navigation and attitude reference parallel processor system

Science.gov (United States)

Gilbert, L. E.; Mahajan, D. T.

1978-01-01

An approach to autonomous navigation and attitude reference for earth observing spacecraft is described along with the landmark identification technique based on a sequential similarity detection algorithm (SSDA). Laboratory experiments undertaken to determine if better than one pixel accuracy in registration can be achieved consistent with onboard processor timing and capacity constraints are included. The SSDA is implemented using a multi-microprocessor system including synchronization logic and chip library. The data is processed in parallel stages, effectively reducing the time to match the small known image within a larger image as seen by the onboard image system. Shared memory is incorporated in the system to help communicate intermediate results among microprocessors. The functions include finding mean values and summation of absolute differences over the image search area. The hardware is a low power, compact unit suitable to onboard application with the flexibility to provide for different parameters depending upon the environment.

Bio-robots automatic navigation with electrical reward stimulation.

Science.gov (United States)

Sun, Chao; Zhang, Xinlu; Zheng, Nenggan; Chen, Weidong; Zheng, Xiaoxiang

2012-01-01

Bio-robots that controlled by outer stimulation through brain computer interface (BCI) suffer from the dependence on realtime guidance of human operators. Current automatic navigation methods for bio-robots focus on the controlling rules to force animals to obey man-made commands, with animals' intelligence ignored. This paper proposes a new method to realize the automatic navigation for bio-robots with electrical micro-stimulation as real-time rewards. Due to the reward-seeking instinct and trial-and-error capability, bio-robot can be steered to keep walking along the right route with rewards and correct its direction spontaneously when rewards are deprived. In navigation experiments, rat-robots learn the controlling methods in short time. The results show that our method simplifies the controlling logic and realizes the automatic navigation for rat-robots successfully. Our work might have significant implication for the further development of bio-robots with hybrid intelligence.

GeNemo: a search engine for web-based functional genomic data.

Science.gov (United States)

Zhang, Yongqing; Cao, Xiaoyi; Zhong, Sheng

2016-07-08

A set of new data types emerged from functional genomic assays, including ChIP-seq, DNase-seq, FAIRE-seq and others. The results are typically stored as genome-wide intensities (WIG/bigWig files) or functional genomic regions (peak/BED files). These data types present new challenges to big data science. Here, we present GeNemo, a web-based search engine for functional genomic data. GeNemo searches user-input data against online functional genomic datasets, including the entire collection of ENCODE and mouse ENCODE datasets. Unlike text-based search engines, GeNemo's searches are based on pattern matching of functional genomic regions. This distinguishes GeNemo from text or DNA sequence searches. The user can input any complete or partial functional genomic dataset, for example, a binding intensity file (bigWig) or a peak file. GeNemo reports any genomic regions, ranging from hundred bases to hundred thousand bases, from any of the online ENCODE datasets that share similar functional (binding, modification, accessibility) patterns. This is enabled by a Markov Chain Monte Carlo-based maximization process, executed on up to 24 parallel computing threads. By clicking on a search result, the user can visually compare her/his data with the found datasets and navigate the identified genomic regions. GeNemo is available at www.genemo.org. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Enabling Autonomous Navigation for Affordable Scooters

Directory of Open Access Journals (Sweden)

Kaikai Liu

2018-06-01

Full Text Available Despite the technical success of existing assistive technologies, for example, electric wheelchairs and scooters, they are still far from effective enough in helping those in need navigate to their destinations in a hassle-free manner. In this paper, we propose to improve the safety and autonomy of navigation by designing a cutting-edge autonomous scooter, thus allowing people with mobility challenges to ambulate independently and safely in possibly unfamiliar surroundings. We focus on indoor navigation scenarios for the autonomous scooter where the current location, maps, and nearby obstacles are unknown. To achieve semi-LiDAR functionality, we leverage the gyros-based pose data to compensate the laser motion in real time and create synthetic mapping of simple environments with regular shapes and deep hallways. Laser range finders are suitable for long ranges with limited resolution. Stereo vision, on the other hand, provides 3D structural data of nearby complex objects. To achieve simultaneous fine-grained resolution and long range coverage in the mapping of cluttered and complex environments, we dynamically fuse the measurements from the stereo vision camera system, the synthetic laser scanner, and the LiDAR. We propose solutions to self-correct errors in data fusion and create a hybrid map to assist the scooter in achieving collision-free navigation in an indoor environment.

Research on Navigation Path Planning for An Underground Load Haul Dump

Directory of Open Access Journals (Sweden)

Qi Yulong

2015-11-01

Full Text Available The improved A * algorithm is a method of navigation path planning for articulated underground scrapers. Firstly, an environment model based on a mining Geographic Information System (GIS map is established, and then combined with improved A * algorithm, the underground global path planning problem of the intelligent Load Haul Dump (LHD is solved. In this paper, for the articulated structure, the method of expanding nodes by articulation angle is adopted to make expanded nodes meet the trajectory characteristics. In addition, collision threat cost is introduced in the evaluation function to avoid collisions between the LHD and the tunnel walls. As peran analysis of the simulation test to verify the effectiveness of the improved A * algorithm and a comparison with the traditional A * algorithm, the improved A * algorithm can enhance search efficiency. Acontrast of multiple sets of test parameters suggests that when the price weighted coefficient of collision is 0.2, the shortest path can be derived to avoid impact. Finally, tracking results indicate that the proposed algorithm for navigation path planning can maintain the tracking error to within 0.2 m in line with the structural characteristics of the scraper in the laboratory environment to realize the path planning of unmanned scrapers and trajectory tracking. Moreover, the algorithm can enhance the safety of scrapers and prevent roadway collisions. The feasibility and practicality of the proposed method is verified in this work.

Error Analysis of Inertial Navigation Systems Using Test Algorithms

OpenAIRE

Vaispacher, Tomáš; Bréda, Róbert; Adamčík, František

2015-01-01

Content of this contribution is an issue of inertial sensors errors, specification of inertial measurement units and generating of test signals for Inertial Navigation System (INS). Given the different levels of navigation tasks, part of this contribution is comparison of the actual types of Inertial Measurement Units. Considering this comparison, there is proposed the way of solving inertial sensors errors and their modelling for low – cost inertial navigation applications. The last part is ...

Wavefront Propagation and Fuzzy Based Autonomous Navigation

Directory of Open Access Journals (Sweden)

Adel Al-Jumaily

2005-06-01

Full Text Available Path planning and obstacle avoidance are the two major issues in any navigation system. Wavefront propagation algorithm, as a good path planner, can be used to determine an optimal path. Obstacle avoidance can be achieved using possibility theory. Combining these two functions enable a robot to autonomously navigate to its destination. This paper presents the approach and results in implementing an autonomous navigation system for an indoor mobile robot. The system developed is based on a laser sensor used to retrieve data to update a two dimensional world model of therobot environment. Waypoints in the path are incorporated into the obstacle avoidance. Features such as ageing of objects and smooth motion planning are implemented to enhance efficiency and also to cater for dynamic environments.

Kilohoku Ho`okele Wa`a : Astronomy of the Hawaiian Navigators

Science.gov (United States)

Slater, Stephanie; Slater, Timothy F.; Baybayan, Kalepa C.

2016-01-01

This poster provides an introduction to the astronomy of the Hawaiian wayfinders, Kilohoku Ho`okele Wa`a. Rooted in a legacy of navigation across the Polynesian triangle, wayfinding astronomy has been part of a suite of skills that allows navigators to deliberately hop between the small islands of the Pacific, for thousands of years. Forty years ago, in one manifestation of the Hawaiian Renaissance, our teachers demonstrated that ancient Hawaiians were capable of traversing the wide Pacific to settle and trade on islands separated by thousands of miles. Today those same mentors train a new generation of navigators, making Hawaiian voyaging a living, evolving, sustainable endeavor. This poster presents two components of astronomical knowledge that all crewmen, but particularly those in training to become navigators, learn early in their training. Na Ohana Hoku, the Hawaiian Star Families constitute the basic units of the Hawaiian sky. In contrast to the Western system of 88 constellations, Na Ohana Hoku divides the sky into four sections that each run from the northern to the southern poles. This configuration reduces cognitive load, allowing the navigator to preserve working memory for other complex tasks. In addition, these configurations of stars support the navigator in finding and generatively using hundreds of individual, and navigationally important pairs of stars. The Hawaiian Star Compass divides the celestial sphere into a directional system that uses 32 rather than 8 cardinal points. Within the tropics, the rising and setting of celestial objects are consistent within the Hawaiian Star Compass, providing for extremely reliable direction finding. Together, Na Ohana Hoku and the Hawaiian Star Compass provide the tropical navigator with astronomical assistance that is not available to, and would have been unknown to Western navigators trained at higher latitudes.

Navigated Waterways of Louisiana, Geographic NAD83, LOSCO (1999) [navigated_waterways_LOSCO_1999

Data.gov (United States)

Louisiana Geographic Information Center — This is a line dataset of navigated waterways fitting the LOSCO definition: it has been traveled by vessels transporting 10,000 gallons of oil or fuel as determined...

Ultrasound-Aided Pedestrian Dead Reckoning for Indoor Navigation

NARCIS (Netherlands)

Fischer, C.; Kavitha Muthukrishnan, K.; Hazas, M.; Gellersen, H.

2008-01-01

Ad hoc solutions for tracking and providing navigation support to emergency response teams is an important and safety-critical challenge. We propose a navigation system based on a combination of foot-mounted inertial sensors and ultrasound beacons. We evaluate experimentally the performance of our

Determining navigability of terrain using point cloud data.

Science.gov (United States)

Cockrell, Stephanie; Lee, Gregory; Newman, Wyatt

2013-06-01

This paper presents an algorithm to identify features of the navigation surface in front of a wheeled robot. Recent advances in mobile robotics have brought about the development of smart wheelchairs to assist disabled people, allowing them to be more independent. These robots have a human occupant and operate in real environments where they must be able to detect hazards like holes, stairs, or obstacles. Furthermore, to ensure safe navigation, wheelchairs often need to locate and navigate on ramps. The algorithm is implemented on data from a Kinect and can effectively identify these features, increasing occupant safety and allowing for a smoother ride.

Absolute Navigation Information Estimation for Micro Planetary Rovers

Directory of Open Access Journals (Sweden)

Muhammad Ilyas

2016-03-01

Full Text Available This paper provides algorithms to estimate absolute navigation information, e.g., absolute attitude and position, by using low power, weight and volume Microelectromechanical Systems-type (MEMS sensors that are suitable for micro planetary rovers. Planetary rovers appear to be easily navigable robots due to their extreme slow speed and rotation but, unfortunately, the sensor suites available for terrestrial robots are not always available for planetary rover navigation. This makes them difficult to navigate in a completely unexplored, harsh and complex environment. Whereas the relative attitude and position can be tracked in a similar way as for ground robots, absolute navigation information, unlike in terrestrial applications, is difficult to obtain for a remote celestial body, such as Mars or the Moon. In this paper, an algorithm called the EASI algorithm (Estimation of Attitude using Sun sensor and Inclinometer is presented to estimate the absolute attitude using a MEMS-type sun sensor and inclinometer, only. Moreover, the output of the EASI algorithm is fused with MEMS gyros to produce more accurate and reliable attitude estimates. An absolute position estimation algorithm has also been presented based on these on-board sensors. Experimental results demonstrate the viability of the proposed algorithms and the sensor suite for low-cost and low-weight micro planetary rovers.

Navigational efficiency of nocturnal Myrmecia ants suffers at low light levels.

Directory of Open Access Journals (Sweden)

Ajay Narendra

Full Text Available Insects face the challenge of navigating to specific goals in both bright sun-lit and dim-lit environments. Both diurnal and nocturnal insects use quite similar navigation strategies. This is despite the signal-to-noise ratio of the navigational cues being poor at low light conditions. To better understand the evolution of nocturnal life, we investigated the navigational efficiency of a nocturnal ant, Myrmecia pyriformis, at different light levels. Workers of M. pyriformis leave the nest individually in a narrow light-window in the evening twilight to forage on nest-specific Eucalyptus trees. The majority of foragers return to the nest in the morning twilight, while few attempt to return to the nest throughout the night. We found that as light levels dropped, ants paused for longer, walked more slowly, the success in finding the nest reduced and their paths became less straight. We found that in both bright and dark conditions ants relied predominantly on visual landmark information for navigation and that landmark guidance became less reliable at low light conditions. It is perhaps due to the poor navigational efficiency at low light levels that the majority of foragers restrict navigational tasks to the twilight periods, where sufficient navigational information is still available.

Patterns of task and network actions performed by navigators to facilitate cancer care.

Science.gov (United States)

Clark, Jack A; Parker, Victoria A; Battaglia, Tracy A; Freund, Karen M

2014-01-01

Patient navigation is a widely implemented intervention to facilitate access to care and reduce disparities in cancer care, but the activities of navigators are not well characterized. The aim of this study is to describe what patient navigators actually do and explore patterns of activity that clarify the roles they perform in facilitating cancer care. We conducted field observations of nine patient navigation programs operating in diverse health settings of the national patient navigation research program, including 34 patient navigators, each observed an average of four times. Trained observers used a structured observation protocol to code as they recorded navigator actions and write qualitative field notes capturing all activities in 15-minute intervals during observations ranging from 2 to 7 hours; yielding a total of 133 observations. Rates of coded activity were analyzed using numerical cluster analysis of identified patterns, informed by qualitative analysis of field notes. Six distinct patterns of navigator activity were identified, which differed most relative to how much time navigators spent directly interacting with patients and how much time they spent dealing with medical records and documentation tasks. Navigator actions reveal a complex set of roles in which navigators both provide the direct help to patients denoted by their title and also carry out a variety of actions that function to keep the health system operating smoothly. Working to navigate patients through complex health services entails working to repair the persistent challenges of health services that can render them inhospitable to patients. The organizations that deploy navigators might learn from navigators' efforts and explore alternative approaches, structures, or systems of care in addressing both the barriers patients face and the complex solutions navigators create in helping patients.

Addressing the Influence of Space Weather on Airline Navigation

Science.gov (United States)

Sparks, Lawrence

2012-01-01

The advent of satellite-based augmentation systems has made it possible to navigate aircraft safely using radio signals emitted by global navigation satellite systems (GNSS) such as the Global Positioning System. As a signal propagates through the earth's ionosphere, it suffers delay that is proportional to the total electron content encountered along the raypath. Since the magnitude of this total electron content is strongly influenced by space weather, the safety and reliability of GNSS for airline navigation requires continual monitoring of the state of the ionosphere and calibration of ionospheric delay. This paper examines the impact of space weather on GNSS-based navigation and provides an overview of how the Wide Area Augmentation System protects its users from positioning error due to ionospheric disturbances

Polar Cooperative Navigation Algorithm for Multi-Unmanned Underwater Vehicles Considering Communication Delays

Directory of Open Access Journals (Sweden)

Zheping Yan

2018-03-01

Full Text Available To solve the navigation accuracy problems of multi-Unmanned Underwater Vehicles (multi-UUVs in the polar region, a polar cooperative navigation algorithm for multi-UUVs considering communication delays is proposed in this paper. UUVs are important pieces of equipment in ocean engineering for marine development. For UUVs to complete missions, precise navigation is necessary. It is difficult for UUVs to establish true headings because of the rapid convergence of Earth meridians and the severe polar environment. Based on the polar grid navigation algorithm, UUV navigation in the polar region can be accomplished with the Strapdown Inertial Navigation System (SINS in the grid frame. To save costs, a leader-follower type of system is introduced in this paper. The leader UUV helps the follower UUVs to achieve high navigation accuracy. Follower UUVs correct their own states based on the information sent by the leader UUV and the relative position measured by ultra-short baseline (USBL acoustic positioning. The underwater acoustic communication delay is quantized by the model. In this paper, considering underwater acoustic communication delay, the conventional adaptive Kalman filter (AKF is modified to adapt to polar cooperative navigation. The results demonstrate that the polar cooperative navigation algorithm for multi-UUVs that considers communication delays can effectively navigate the sailing of multi-UUVs in the polar region.

Celestial Navigation on the Surface of Mars

Science.gov (United States)

Malay, Benjamin P.

2001-05-01

A simple, accurate, and autonomous method of finding position on the surface of Mars currently does not exist. The goal of this project is to develop a celestial navigation process that will fix a position on Mars with 100-meter accuracy. This method requires knowing the position of the stars and planets referenced to the Martian surface with one arcsecond accuracy. This information is contained in an ephemeris known as the Aeronautical Almanac (from Ares, the god of war) . Naval Observatory Vector Astrometry Subroutines (NOVAS) form the basis of the code used to generate the almanac. Planetary position data come the JPL DE405 Planetary Ephemeris. The theoretical accuracy of the almanac is determined mathematically and compared with the Ephemeris for Physical Observations of Mars contained in the Astronautical Almanac. A preliminary design of an autonomous celestial navigation system is presented. Recommendations of how to integrate celestial navigation into NASA=s current Mars exploration program are also discussed. This project is a useful and much-needed first step towards establishing celestial navigation as a practical way to find position on the surface of Mars.

'Outsmarting Traffic, Together': Driving as Social Navigation

Directory of Open Access Journals (Sweden)

Sam Hind

2014-04-01

Full Text Available The automotive world is evolving. Ten years ago Nigel Thrift (2004: 41 made the claim that the experience of driving was slipping into our 'technological unconscious'. Only recently the New York Times suggested that with the rise of automated driving, standalone navigation tools as we know them would cease to exist, instead being 'fully absorbed into the machine' (Fisher, 2013. But in order to bridge the gap between past and future driving worlds, another technological evolution is emerging. This short, critical piece charts the rise of what has been called 'social navigation' in the industry; the development of digital mapping platforms designed to foster automotive sociality. It makes two provisional points. Firstly, that 'ludic' conceptualisations can shed light on the ongoing reconfiguration of drivers, vehicles, roads and technological aids such as touch-screen satellite navigation platforms. And secondly, that as a result of this, there is a coming-into-being of a new kind of driving politics; a 'casual politicking' centred on an engagement with digital interfaces. We explicate both by turning our attention towards Waze; a social navigation application that encourages users to interact with various driving dynamics.

The impact of navigation systems on traffic safety

NARCIS (Netherlands)

Rooijen, T. van; Vonk, T.

2007-01-01

This paper studies the impact of navigation systems on traffic safety in the Netherlands. This study consists of four analyses: a literature survey, a database analysis, a user survey and an instrumented vehicle study. The results of the four sections show that navigation systems have a positive

The impact of navigation systems on traffic safety

NARCIS (Netherlands)

Rooijen, T. van; Vonk, T.

2008-01-01

This paper studies the impact of navigation systems on traffic safety in the Netherlands. This study consists of four analyses: a literature survey, a database analysis, a user survey and an instrumented vehicle study. The results of the four sections show that navigation systems have a positive

14 CFR 125.203 - Communication and navigation equipment.

Science.gov (United States)

2010-01-01

... within the degree of accuracy required for ATC; (ii) One marker beacon receiver providing visual and... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Communication and navigation equipment. 125... Equipment Requirements § 125.203 Communication and navigation equipment. (a) Communication equipment—general...

Vision Based Autonomous Robot Navigation Algorithms and Implementations

CERN Document Server

Chatterjee, Amitava; Nirmal Singh, N

2013-01-01

This book is devoted to the theory and development of autonomous navigation of mobile robots using computer vision based sensing mechanism. The conventional robot navigation systems, utilizing traditional sensors like ultrasonic, IR, GPS, laser sensors etc., suffer several drawbacks related to either the physical limitations of the sensor or incur high cost. Vision sensing has emerged as a popular alternative where cameras can be used to reduce the overall cost, maintaining high degree of intelligence, flexibility and robustness. This book includes a detailed description of several new approaches for real life vision based autonomous navigation algorithms and SLAM. It presents the concept of how subgoal based goal-driven navigation can be carried out using vision sensing. The development concept of vision based robots for path/line tracking using fuzzy logic is presented, as well as how a low-cost robot can be indigenously developed in the laboratory with microcontroller based sensor systems. The book descri...

Comparison of three filters in asteroid-based autonomous navigation

International Nuclear Information System (INIS)

Cui Wen; Zhu Kai-Jian

2014-01-01

At present, optical autonomous navigation has become a key technology in deep space exploration programs. Recent studies focus on the problem of orbit determination using autonomous navigation, and the choice of filter is one of the main issues. To prepare for a possible exploration mission to Mars, the primary emphasis of this paper is to evaluate the capability of three filters, the extended Kalman filter (EKF), unscented Kalman filter (UKF) and weighted least-squares (WLS) algorithm, which have different initial states during the cruise phase. One initial state is assumed to have high accuracy with the support of ground tracking when autonomous navigation is operating; for the other state, errors are set to be large without this support. In addition, the method of selecting asteroids that can be used for navigation from known lists of asteroids to form a sequence is also presented in this study. The simulation results show that WLS and UKF should be the first choice for optical autonomous navigation during the cruise phase to Mars

Aging specifically impairs switching to an allocentric navigational strategy.

Science.gov (United States)

Harris, Mathew A; Wiener, Jan M; Wolbers, Thomas

2012-01-01

Navigation abilities decline with age, partly due to deficits in numerous component processes. Impaired switching between these various processes (i.e., switching navigational strategies) is also likely to contribute to age-related navigational impairments. We tested young and old participants on a virtual plus maze task (VPM), expecting older participants to exhibit a specific strategy switching deficit, despite unimpaired learning of allocentric (place) and egocentric (response) strategies following reversals within each strategy. Our initial results suggested that older participants performed worse during place trial blocks but not response trial blocks, as well as in trial blocks following a strategy switch but not those following a reversal. However, we then separated trial blocks by both strategy and change type, revealing that these initial results were due to a more specific deficit in switching to the place strategy. Place reversals and switches to response, as well as response reversals, were unaffected. We argue that this specific "switch-to-place" deficit could account for apparent impairments in both navigational strategy switching and allocentric processing and contributes more generally to age-related decline in navigation.

Navigation of Pedicle Screws in the Thoracic Spine with a New Electromagnetic Navigation System: A Human Cadaver Study

Directory of Open Access Journals (Sweden)

Patrick Hahn

2015-01-01

Full Text Available Introduction. Posterior stabilization of the spine is a standard procedure in spinal surgery. In addition to the standard techniques, several new techniques have been developed. The objective of this cadaveric study was to examine the accuracy of a new electromagnetic navigation system for instrumentation of pedicle screws in the spine. Material and Method. Forty-eight pedicle screws were inserted in the thoracic spine of human cadavers using EMF navigation and instruments developed especially for electromagnetic navigation. The screw position was assessed postoperatively by a CT scan. Results. The screws were classified into 3 groups: grade 1 = ideal position; grade 2 = cortical penetration <2 mm; grade 3 = cortical penetration ≥2 mm. The initial evaluation of the system showed satisfied positioning for the thoracic spine; 37 of 48 screws (77.1%, 95% confidence interval [62.7%, 88%] were classified as group 1 or 2. Discussion. The screw placement was satisfactory. The initial results show that there is room for improvement with some changes needed. The ease of use and short setup times should be pointed out. Instrumentation is achieved without restricting the operator’s mobility during navigation. Conclusion. The results indicate a good placement technique for pedicle screws. Big advantages are the easy handling of the system.

Navigation Architecture for a Space Mobile Network

Science.gov (United States)

Valdez, Jennifer E.; Ashman, Benjamin; Gramling, Cheryl; Heckler, Gregory W.; Carpenter, Russell

2016-01-01

The Tracking and Data Relay Satellite System (TDRSS) Augmentation Service for Satellites (TASS) is a proposed beacon service to provide a global, space based GPS augmentation service based on the NASA Global Differential GPS (GDGPS) System. The TASS signal will be tied to the GPS time system and usable as an additional ranging and Doppler radiometric source. Additionally, it will provide data vital to autonomous navigation in the near Earth regime, including space weather information, TDRS ephemerides, Earth Orientation Parameters (EOP), and forward commanding capability. TASS benefits include enhancing situational awareness, enabling increased autonomy, and providing near real-time command access for user platforms. As NASA Headquarters' Space Communication and Navigation Office (SCaN) begins to move away from a centralized network architecture and towards a Space Mobile Network (SMN) that allows for user initiated services, autonomous navigation will be a key part of such a system. This paper explores how a TASS beacon service enables the Space Mobile Networking paradigm, what a typical user platform would require, and provides an in-depth analysis of several navigation scenarios and operations concepts. This paper provides an overview of the TASS beacon and its role within the SMN and user community. Supporting navigation analysis is presented for two user mission scenarios: an Earth observing spacecraft in low earth orbit (LEO), and a highly elliptical spacecraft in a lunar resonance orbit. These diverse flight scenarios indicate the breadth of applicability of the TASS beacon for upcoming users within the current network architecture and in the SMN.

Evaluation of navigation interfaces in virtual environments

Science.gov (United States)

Mestre, Daniel R.

2014-02-01

When users are immersed in cave-like virtual reality systems, navigational interfaces have to be used when the size of the virtual environment becomes larger than the physical extent of the cave floor. However, using navigation interfaces, physically static users experience self-motion (visually-induced vection). As a consequence, sensorial incoherence between vision (indicating self-motion) and other proprioceptive inputs (indicating immobility) can make them feel dizzy and disoriented. We tested, in two experimental studies, different locomotion interfaces. The objective was twofold: testing spatial learning and cybersickness. In a first experiment, using first-person navigation with a flystick ®, we tested the effect of sensorial aids, a spatialized sound or guiding arrows on the ground, attracting the user toward the goal of the navigation task. Results revealed that sensorial aids tended to impact negatively spatial learning. Moreover, subjects reported significant levels of cybersickness. In a second experiment, we tested whether such negative effects could be due to poorly controlled rotational motion during simulated self-motion. Subjects used a gamepad, in which rotational and translational displacements were independently controlled by two joysticks. Furthermore, we tested first- versus third-person navigation. No significant difference was observed between these two conditions. Overall, cybersickness tended to be lower, as compared to experiment 1, but the difference was not significant. Future research should evaluate further the hypothesis of the role of passively perceived optical flow in cybersickness, but manipulating the virtual environment'sperrot structure. It also seems that video-gaming experience might be involved in the user's sensitivity to cybersickness.

GRIP DC-8 NAVIGATION AND HOUSEKEEPING DATA V1

Data.gov (United States)

National Aeronautics and Space Administration — This dataset contains aircraft navigational data obtained during the GRIP campaign (15 Aug 2010 - 30 Sep 2010). The NASA DC-8 is outfitted with a navigational...

The Navigation Guide - evidence-based medicine meets environmental health: systematic review of human evidence for PFOA effects on fetal growth.

Science.gov (United States)

Johnson, Paula I; Sutton, Patrice; Atchley, Dylan S; Koustas, Erica; Lam, Juleen; Sen, Saunak; Robinson, Karen A; Axelrad, Daniel A; Woodruff, Tracey J

2014-10-01

The Navigation Guide methodology was developed to meet the need for a robust method of systematic and transparent research synthesis in environmental health science. We conducted a case study systematic review to support proof of concept of the method. We applied the Navigation Guide systematic review methodology to determine whether developmental exposure to perfluorooctanoic acid (PFOA) affects fetal growth in humans. We applied the first 3 steps of the Navigation Guide methodology to human epidemiological data: 1) specify the study question, 2) select the evidence, and 3) rate the quality and strength of the evidence. We developed a protocol, conducted a comprehensive search of the literature, and identified relevant studies using prespecified criteria. We evaluated each study for risk of bias and conducted meta-analyses on a subset of studies. We rated quality and strength of the entire body of human evidence. We identified 18 human studies that met our inclusion criteria, and 9 of these were combined through meta-analysis. Through meta-analysis, we estimated that a 1-ng/mL increase in serum or plasma PFOA was associated with a -18.9 g (95% CI: -29.8, -7.9) difference in birth weight. We concluded that the risk of bias across studies was low, and we assigned a "moderate" quality rating to the overall body of human evidence. On the basis of this first application of the Navigation Guide systematic review methodology, we concluded that there is "sufficient" human evidence that developmental exposure to PFOA reduces fetal growth.

Performance Evaluation and Requirements Assessment for Gravity Gradient Referenced Navigation

Directory of Open Access Journals (Sweden)

Jisun Lee

2015-07-01

Full Text Available In this study, simulation tests for gravity gradient referenced navigation (GGRN are conducted to verify the effects of various factors such as database (DB and sensor errors, flight altitude, DB resolution, initial errors, and measurement update rates on the navigation performance. Based on the simulation results, requirements for GGRN are established for position determination with certain target accuracies. It is found that DB and sensor errors and flight altitude have strong effects on the navigation performance. In particular, a DB and sensor with accuracies of 0.1 E and 0.01 E, respectively, are required to determine the position more accurately than or at a level similar to the navigation performance of terrain referenced navigation (TRN. In most cases, the horizontal position error of GGRN is less than 100 m. However, the navigation performance of GGRN is similar to or worse than that of a pure inertial navigation system when the DB and sensor errors are 3 E or 5 E each and the flight altitude is 3000 m. Considering that the accuracy of currently available gradiometers is about 3 E or 5 E, GGRN does not show much advantage over TRN at present. However, GGRN is expected to exhibit much better performance in the near future when accurate DBs and gravity gradiometer are available.

Image-based path planning for automated virtual colonoscopy navigation

Science.gov (United States)

Hong, Wei

2008-03-01

Virtual colonoscopy (VC) is a noninvasive method for colonic polyp screening, by reconstructing three-dimensional models of the colon using computerized tomography (CT). In virtual colonoscopy fly-through navigation, it is crucial to generate an optimal camera path for efficient clinical examination. In conventional methods, the centerline of the colon lumen is usually used as the camera path. In order to extract colon centerline, some time consuming pre-processing algorithms must be performed before the fly-through navigation, such as colon segmentation, distance transformation, or topological thinning. In this paper, we present an efficient image-based path planning algorithm for automated virtual colonoscopy fly-through navigation without the requirement of any pre-processing. Our algorithm only needs the physician to provide a seed point as the starting camera position using 2D axial CT images. A wide angle fisheye camera model is used to generate a depth image from the current camera position. Two types of navigational landmarks, safe regions and target regions are extracted from the depth images. Camera position and its corresponding view direction are then determined using these landmarks. The experimental results show that the generated paths are accurate and increase the user comfort during the fly-through navigation. Moreover, because of the efficiency of our path planning algorithm and rendering algorithm, our VC fly-through navigation system can still guarantee 30 FPS.

VISION-AIDED CONTEXT-AWARE FRAMEWORK FOR PERSONAL NAVIGATION SERVICES

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S. Saeedi

2012-07-01

Full Text Available The ubiquity of mobile devices (such as smartphones and tablet-PCs has encouraged the use of location-based services (LBS that are relevant to the current location and context of a mobile user. The main challenge of LBS is to find a pervasive and accurate personal navigation system (PNS in different situations of a mobile user. In this paper, we propose a method of personal navigation for pedestrians that allows a user to freely move in outdoor environments. This system aims at detection of the context information which is useful for improving personal navigation. The context information for a PNS consists of user activity modes (e.g. walking, stationary, driving, and etc. and the mobile device orientation and placement with respect to the user. After detecting the context information, a low-cost integrated positioning algorithm has been employed to estimate pedestrian navigation parameters. The method is based on the integration of the relative user’s motion (changes of velocity and heading angle estimation based on the video image matching and absolute position information provided by GPS. A Kalman filter (KF has been used to improve the navigation solution when the user is walking and the phone is in his/her hand. The Experimental results demonstrate the capabilities of this method for outdoor personal navigation systems.

Olfaction Contributes to Pelagic Navigation in a Coastal Shark.

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Nosal, Andrew P; Chao, Yi; Farrara, John D; Chai, Fei; Hastings, Philip A

2016-01-01

How animals navigate the constantly moving and visually uniform pelagic realm, often along straight paths between distant sites, is an enduring mystery. The mechanisms enabling pelagic navigation in cartilaginous fishes are particularly understudied. We used shoreward navigation by leopard sharks (Triakis semifasciata) as a model system to test whether olfaction contributes to pelagic navigation. Leopard sharks were captured alongshore, transported 9 km offshore, released, and acoustically tracked for approximately 4 h each until the transmitter released. Eleven sharks were rendered anosmic (nares occluded with cotton wool soaked in petroleum jelly); fifteen were sham controls. Mean swimming depth was 28.7 m. On average, tracks of control sharks ended 62.6% closer to shore, following relatively straight paths that were significantly directed over spatial scales exceeding 1600 m. In contrast, tracks of anosmic sharks ended 37.2% closer to shore, following significantly more tortuous paths that approximated correlated random walks. These results held after swimming paths were adjusted for current drift. This is the first study to demonstrate experimentally that olfaction contributes to pelagic navigation in sharks, likely mediated by chemical gradients as has been hypothesized for birds. Given the similarities between the fluid three-dimensional chemical atmosphere and ocean, further research comparing swimming and flying animals may lead to a unifying paradigm explaining their extraordinary navigational abilities.

GRIP DC-8 NAVIGATION AND HOUSEKEEPING DATA V1

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National Aeronautics and Space Administration — The GRIP DC-8 Navigation and Housekeeping Data contains aircraft navigational data obtained during the GRIP campaign (15 Aug 2010 - 30 Sep 2010). The major goal was...

Current Role of Computer Navigation in Total Knee Arthroplasty.

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Jones, Christopher W; Jerabek, Seth A

2018-01-31

Computer-assisted surgical (CAS) navigation has been developed with the aim of improving the accuracy and precision of total knee arthroplasty (TKA) component positioning and therefore overall limb alignment. The historical goal of knee arthroplasty has been to restore the mechanical alignment of the lower limb by aligning the femoral and tibial components perpendicular to the mechanical axis of the femur and tibia. Despite over 4 decades of TKA component development and nearly 2 decades of interest in CAS, the fundamental question remains; does the alignment goal and/or the method of achieving that goal affect the outcome of the TKA in terms of patient-reported outcome measures and/or overall survivorship? The quest for reliable and reproducible achievement of the intraoperative alignment goal has been the primary motivator for the introduction, development, and refinement of CAS navigation. Numerous proprietary systems now exist, and rapid technological advancements in computer processing power are stimulating further development of robotic surgical systems. Three categories of CAS can be defined: image-based large-console navigation; imageless large-console navigation, and more recently, accelerometer-based handheld navigation systems have been developed. A review of the current literature demonstrates that there are enough well-designed studies to conclude that both large-console CAS and handheld navigation systems improve the accuracy and precision of component alignment in TKA. However, missing from the evidence base, other than the subgroup analysis provided by the Australian Orthopaedic Association National Joint Replacement Registry, are any conclusive demonstrations of a clinical superiority in terms of improved patient-reported outcome measures and/or decreased cumulative revision rates in the long term. Few authors would argue that accuracy of alignment is a goal to ignore; therefore, in the absence of clinical evidence, many of the arguments against

Navigation of robotic system using cricket motes

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Patil, Yogendra J.; Baine, Nicholas A.; Rattan, Kuldip S.

2011-06-01

This paper presents a novel algorithm for self-mapping of the cricket motes that can be used for indoor navigation of autonomous robotic systems. The cricket system is a wireless sensor network that can provide indoor localization service to its user via acoustic ranging techniques. The behavior of the ultrasonic transducer on the cricket mote is studied and the regions where satisfactorily distance measurements can be obtained are recorded. Placing the motes in these regions results fine-grain mapping of the cricket motes. Trilateration is used to obtain a rigid coordinate system, but is insufficient if the network is to be used for navigation. A modified SLAM algorithm is applied to overcome the shortcomings of trilateration. Finally, the self-mapped cricket motes can be used for navigation of autonomous robotic systems in an indoor location.

33 CFR 207.50 - Hudson River Lock at Troy, N.Y.; navigation.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Hudson River Lock at Troy, N.Y..., DEPARTMENT OF DEFENSE NAVIGATION REGULATIONS § 207.50 Hudson River Lock at Troy, N.Y.; navigation. (a...) [Reserved] (n) Trespass on U.S. property. Trespass on U.S. property, or willful injury to the banks, masonry...

Spatial navigation by congenitally blind individuals.

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Schinazi, Victor R; Thrash, Tyler; Chebat, Daniel-Robert

2016-01-01

Spatial navigation in the absence of vision has been investigated from a variety of perspectives and disciplines. These different approaches have progressed our understanding of spatial knowledge acquisition by blind individuals, including their abilities, strategies, and corresponding mental representations. In this review, we propose a framework for investigating differences in spatial knowledge acquisition by blind and sighted people consisting of three longitudinal models (i.e., convergent, cumulative, and persistent). Recent advances in neuroscience and technological devices have provided novel insights into the different neural mechanisms underlying spatial navigation by blind and sighted people and the potential for functional reorganization. Despite these advances, there is still a lack of consensus regarding the extent to which locomotion and wayfinding depend on amodal spatial representations. This challenge largely stems from methodological limitations such as heterogeneity in the blind population and terminological ambiguity related to the concept of cognitive maps. Coupled with an over-reliance on potential technological solutions, the field has diffused into theoretical and applied branches that do not always communicate. Here, we review research on navigation by congenitally blind individuals with an emphasis on behavioral and neuroscientific evidence, as well as the potential of technological assistance. Throughout the article, we emphasize the need to disentangle strategy choice and performance when discussing the navigation abilities of the blind population. For further resources related to this article, please visit the WIREs website. © 2015 The Authors. WIREs Cognitive Science published by Wiley Periodicals, Inc.

Using noun phrases for navigating biomedical literature on Pubmed: how many updates are we losing track of?

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Srikrishna, Devabhaktuni; Coram, Marc A

2011-01-01

Author-supplied citations are a fraction of the related literature for a paper. The "related citations" on PubMed is typically dozens or hundreds of results long, and does not offer hints why these results are related. Using noun phrases derived from the sentences of the paper, we show it is possible to more transparently navigate to PubMed updates through search terms that can associate a paper with its citations. The algorithm to generate these search terms involved automatically extracting noun phrases from the paper using natural language processing tools, and ranking them by the number of occurrences in the paper compared to the number of occurrences on the web. We define search queries having at least one instance of overlap between the author-supplied citations of the paper and the top 20 search results as citation validated (CV). When the overlapping citations were written by same authors as the paper itself, we define it as CV-S and different authors is defined as CV-D. For a systematic sample of 883 papers on PubMed Central, at least one of the search terms for 86% of the papers is CV-D versus 65% for the top 20 PubMed "related citations." We hypothesize these quantities computed for the 20 million papers on PubMed to differ within 5% of these percentages. Averaged across all 883 papers, 5 search terms are CV-D, and 10 search terms are CV-S, and 6 unique citations validate these searches. Potentially related literature uncovered by citation-validated searches (either CV-S or CV-D) are on the order of ten per paper--many more if the remaining searches that are not citation-validated are taken into account. The significance and relationship of each search result to the paper can only be vetted and explained by a researcher with knowledge of or interest in that paper.

Navigating across Cultures: Narrative Constructions of Lived Experience

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Pufall-Jones, Elizabeth; Mistry, Jayanthi

2010-01-01

In this study, we investigated how individuals from diverse backgrounds learn to navigate the many worlds in which they live and explore how variations in life experiences are associated with aspects of navigating across cultures. We conducted the study using a phenomenological approach based on retrospective personal narratives from 19 young…

GPS Navigation Above 76,000 km for the MMS Mission

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Winternitz, Luke; Bamford, Bill; Price, Samuel; Long, Anne; Farahmand, Mitra; Carpenter, Russell

2016-01-01

NASA's MMS mission, launched in March of 2015,consists of a controlled formation of four spin-stabilized spacecraft in similar highly elliptic orbits reaching apogee at radial distances of 12and 25 Earth radii in the first and second phases of the mission. Navigation for MMS is achieved independently onboard each spacecraft by processing GPS observables using NASA GSFC's Navigator GPS receiver and the Goddard Enhanced Onboard Navigation System (GEONS) extended Kalman filter software. To our knowledge, MMS constitutes, by far, the highest-altitude operational use of GPS to date and represents the culmination of over a decade of high-altitude GPS navigation research and development at NASA GSFC. In this paper we will briefly describe past and ongoing high-altitude GPS research efforts at NASA GSFC and elsewhere, provide details on the design of the MMS GPS navigation system, and present on-orbit performance data. We extrapolate these results to predict performance in the Phase 2b mission orbit, and conclude with a discussion of the implications of the MMS results for future high-altitude GPS navigation, which we believe to be broad and far-reaching.

Biologically inspired autonomous agent navigation using an integrated polarization analyzing CMOS image sensor

NARCIS (Netherlands)

Sarkaer, M.; San Segundo Bello, D.; Van Hoof, C.; Theuwissen, A.

2010-01-01

The navigational strategies of insects using skylight polarization are interesting for applications in autonomous agent navigation because they rely on very little information for navigation. A polarization navigation sensor using the Stokes parameters to determine the orientation is presented. The

Expected Navigation Flight Performance for the Magnetospheric Multiscale (MMS) Mission

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Olson, Corwin; Wright, Cinnamon; Long, Anne

2012-01-01

The Magnetospheric Multiscale (MMS) mission consists of four formation-flying spacecraft placed in highly eccentric elliptical orbits about the Earth. The primary scientific mission objective is to study magnetic reconnection within the Earth s magnetosphere. The baseline navigation concept is the independent estimation of each spacecraft state using GPS pseudorange measurements (referenced to an onboard Ultra Stable Oscillator) and accelerometer measurements during maneuvers. State estimation for the MMS spacecraft is performed onboard each vehicle using the Goddard Enhanced Onboard Navigation System, which is embedded in the Navigator GPS receiver. This paper describes the latest efforts to characterize expected navigation flight performance using upgraded simulation models derived from recent analyses.

Neurobiologically inspired mobile robot navigation and planning

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Mathias Quoy

2007-11-01

Full Text Available After a short review of biologically inspired navigation architectures, mainly relying on modeling the hippocampal anatomy, or at least some of its functions, we present a navigation and planning model for mobile robots. This architecture is based on a model of the hippocampal and prefrontal interactions. In particular, the system relies on the definition of a new cell type “transition cells” that encompasses traditional “place cells”.

Advanced Navigation Aids System based on Augmented Reality

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Jaeyong OH

2016-12-01

Full Text Available Many maritime accidents have been caused by human-error including such things as inadequate watch keeping and/or mistakes in ship handling. Also, new navigational equipment has been developed using Information Technology (IT technology to provide various kinds of information for safe navigation. Despite these efforts, the reduction of maritime accidents has not occurred to the degree expected because, navigational equipment provides too much information, and this information is not well organized, such that users feel it to be complicated rather than helpful. In this point of view, the method of representation of navigational information is more important than the quantity of that information and research is required on the representation of information to make that information more easily understood and to allow decisions to be made correctly and promptly. In this paper, we adopt Augmented Reality (AR technologies for the representation of information. AR is a 3D computer graphics technology that blends virtual reality and the real world. Recently, this technology has been widely applied in our daily lives because it can provide information more effectively to users. Therefore, we propose a new concept, a navigational system based on AR technology; we review experimental results from a ship-handling simulator and from an open sea test to verify the efficiency of the proposed system.

Structured Kernel Subspace Learning for Autonomous Robot Navigation.

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Kim, Eunwoo; Choi, Sungjoon; Oh, Songhwai

2018-02-14

This paper considers two important problems for autonomous robot navigation in a dynamic environment, where the goal is to predict pedestrian motion and control a robot with the prediction for safe navigation. While there are several methods for predicting the motion of a pedestrian and controlling a robot to avoid incoming pedestrians, it is still difficult to safely navigate in a dynamic environment due to challenges, such as the varying quality and complexity of training data with unwanted noises. This paper addresses these challenges simultaneously by proposing a robust kernel subspace learning algorithm based on the recent advances in nuclear-norm and l 1 -norm minimization. We model the motion of a pedestrian and the robot controller using Gaussian processes. The proposed method efficiently approximates a kernel matrix used in Gaussian process regression by learning low-rank structured matrix (with symmetric positive semi-definiteness) to find an orthogonal basis, which eliminates the effects of erroneous and inconsistent data. Based on structured kernel subspace learning, we propose a robust motion model and motion controller for safe navigation in dynamic environments. We evaluate the proposed robust kernel learning in various tasks, including regression, motion prediction, and motion control problems, and demonstrate that the proposed learning-based systems are robust against outliers and outperform existing regression and navigation methods.

Using neural networks to understand the information that guides behavior: a case study in visual navigation.

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Philippides, Andrew; Graham, Paul; Baddeley, Bart; Husbands, Philip

2015-01-01

To behave in a robust and adaptive way, animals must extract task-relevant sensory information efficiently. One way to understand how they achieve this is to explore regularities within the information animals perceive during natural behavior. In this chapter, we describe how we have used artificial neural networks (ANNs) to explore efficiencies in vision and memory that might underpin visually guided route navigation in complex worlds. Specifically, we use three types of neural network to learn the regularities within a series of views encountered during a single route traversal (the training route), in such a way that the networks output the familiarity of novel views presented to them. The problem of navigation is then reframed in terms of a search for familiar views, that is, views similar to those associated with the route. This approach has two major benefits. First, the ANN provides a compact holistic representation of the data and is thus an efficient way to encode a large set of views. Second, as we do not store the training views, we are not limited in the number of training views we use and the agent does not need to decide which views to learn.

Navigating the massive world of reddit: using backbone networks to map user interests in social media

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Randal S. Olson

2015-05-01

Full Text Available In the massive online worlds of social media, users frequently rely on organizing themselves around specific topics of interest to find and engage with like-minded people. However, navigating these massive worlds and finding topics of specific interest often proves difficult because the worlds are mostly organized haphazardly, leaving users to find relevant interests by word of mouth or using a basic search feature. Here, we report on a method using the backbone of a network to create a map of the primary topics of interest in any social network. To demonstrate the method, we build an interest map for the social news web site reddit and show how such a map could be used to navigate a social media world. Moreover, we analyze the network properties of the reddit social network and find that it has a scale-free, small-world, and modular community structure, much like other online social networks such as Facebook and Twitter. We suggest that the integration of interest maps into popular social media platforms will assist users in organizing themselves into more specific interest groups, which will help alleviate the overcrowding effect often observed in large online communities.

Engineering satellite-based navigation and timing global navigation satellite systems, signals, and receivers

CERN Document Server

Betz, J

2016-01-01

This book describes the design and performance analysis of satnav systems, signals, and receivers. It also provides succinct descriptions and comparisons of all the world’s satnav systems. Its comprehensive and logical structure addresses all satnav signals and systems in operation and being developed. Engineering Satellite-Based Navigation and Timing: Global Navigation Satellite Systems, Signals, and Receivers provides the technical foundation for designing and analyzing satnav signals, systems, and receivers. Its contents and structure address all satnav systems and signals: legacy, modernized, and new. It combines qualitative information with detailed techniques and analyses, providing a comprehensive set of insights and engineering tools for this complex multidisciplinary field. Part I describes system and signal engineering including orbital mechanics and constellation design, signal design principles and underlying considerations, link budgets, qua tifying receiver performance in interference, and e...

Interference and deception detection technology of satellite navigation based on deep learning

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Chen, Weiyi; Deng, Pingke; Qu, Yi; Zhang, Xiaoguang; Li, Yaping

2017-10-01

Satellite navigation system plays an important role in people's daily life and war. The strategic position of satellite navigation system is prominent, so it is very important to ensure that the satellite navigation system is not disturbed or destroyed. It is a critical means to detect the jamming signal to avoid the accident in a navigation system. At present, the detection technology of jamming signal in satellite navigation system is not intelligent , mainly relying on artificial decision and experience. For this issue, the paper proposes a method based on deep learning to monitor the interference source in a satellite navigation. By training the interference signal data, and extracting the features of the interference signal, the detection sys tem model is constructed. The simulation results show that, the detection accuracy of our detection system can reach nearly 70%. The method in our paper provides a new idea for the research on intelligent detection of interference and deception signal in a satellite navigation system.

Development of a new automotive navigation system; Shingata navigation system no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Sone, M; Nakano, H; Nakayama, O; Tanemura, E; Yoshitsugu, N; Watanabe, M [Nissan Motor Co. Ltd., Tokyo (Japan)

1996-01-31

An automotive navigation system was outlined. Features of this system are described below: map display called `Bird View` extending up to the horizon was commercialized; accuracy of determining the vehicle`s present position was realized using new algorithm; and automatic route selection was adopted. Human machine interface of this system also was completely reviewed. `Bird View` was realized by reading plane map data out from CD-ROM and converting them onto the coordinate on the virtual screen in front of the view point. Automatic selection which depends mostly on self-contained navigation adopts the certain way in comparison of the computation position in GPS. To assume vehicle advancing direction, employed were optical fiber gyroscope, geomagnetic sensor, and Karman filter making a good use of advantages of GPS, for the improvement of accuracy. For the automatic distance correction, a function of correcting pulse-distance conversion coefficient was employed, and the free maintenance was realized. 5 figs.

Client-server Approach in the Navigation System for the Blind

Directory of Open Access Journals (Sweden)

Lukasz Markiewicz

2013-09-01

Full Text Available The article presents the client-server approach in the navigation system for the blind - “Voice Maps”. The authors were among the main creators of the prototype and currently the commercialization phase is being finished. In the implemented prototype only exemplary, limited spatial data were used, therefore they could be stored and analyzed (for pathfinding process in the mobile device’s memory without any difficulties. The resulting increase of spatial data scale and complexity required a modification of the data storage and operation. Consequently, the decision was made to maintain a central spatial database, which is accessed remotely. After that modification, the mobile application fetches the required batch of spatial data (with the pathfinding and search results from the central server through the mobile internet connection, which has also become necessary for other purposes (e.g. voice recognition. The authors present the advantages and disadvantages of this new approach along with the results of the server operational tests.

Electrophysiological correlates of mental navigation in blind and sighted people.

Science.gov (United States)

Kober, Silvia Erika; Wood, Guilherme; Kampl, Christiane; Neuper, Christa; Ischebeck, Anja

2014-10-15

The aim of the present study was to investigate functional reorganization of the occipital cortex for a mental navigation task in blind people. Eight completely blind adults and eight sighted matched controls performed a mental navigation task, in which they mentally imagined to walk along familiar routes of their hometown during a multi-channel EEG measurement. A motor imagery task was used as control condition. Furthermore, electrophysiological activation patterns during a resting measurement with open and closed eyes were compared between blind and sighted participants. During the resting measurement with open eyes, no differences in EEG power were observed between groups, whereas sighted participants showed higher alpha (8-12Hz) activity at occipital sites compared to blind participants during an eyes-closed resting condition. During the mental navigation task, blind participants showed a stronger event-related desynchronization in the alpha band over the visual cortex compared to sighted controls indicating a stronger activation in this brain region in the blind. Furthermore, groups showed differences in functional brain connectivity between fronto-central and parietal-occipital brain networks during mental navigation indicating stronger visuo-spatial processing in sighted than in blind people during mental navigation. Differences in electrophysiological parameters between groups were specific for mental navigation since no group differences were observed during motor imagery. These results indicate that in the absence of vision the visual cortex takes over other functions such as spatial navigation. Copyright © 2014 Elsevier B.V. All rights reserved.

Advancements in Optical Navigation Capabilities

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National Aeronautics and Space Administration — The Goddard Image Analysis and Navigation Tool (GIANT) is a tool that was developed for the Origins, Spectral Interpretation, Resource Identification,...

Using a sand wave model for optimal monitoring of navigation depth

NARCIS (Netherlands)

Knaapen, Michiel; Hulscher, Suzanne J.M.H.; Tiessen, Meinard C.H.; van den Berg, J.; Parker, G.; García, M.H.

2005-01-01

In the Euro Channel to Rotterdam Harbor, sand waves reduce the navigable depth to an unacceptable level. To avoid the risk of grounding, the navigation depth is monitored and sand waves that reduce the navigation depth unacceptably are dredged. After the dredging, the sand waves slowly regain their

Screen Miniatures as Icons for Backward Navigation in Content-Based Software.

Science.gov (United States)

Boling, Elizabeth; Ma, Guoping; Tao, Chia-Wen; Askun, Cengiz; Green, Tim; Frick, Theodore; Schaumburg, Heike

Users of content-based software programs, including hypertexts and instructional multimedia, rely on the navigation functions provided by the designers of those program. Typical navigation schemes use abstract symbols (arrows) to label basic navigational functions like moving forward or backward through screen displays. In a previous study, the…

Navigation Operations with Prototype Components of an Automated Real-Time Spacecraft Navigation System

Science.gov (United States)

Cangahuala, L.; Drain, T. R.

1999-01-01

At present, ground navigation support for interplanetary spacecraft requires human intervention for data pre-processing, filtering, and post-processing activities; these actions must be repeated each time a new batch of data is collected by the ground data system.

Navigation by environmental geometry: the use of zebrafish as a model.

Science.gov (United States)

Lee, Sang Ah; Vallortigara, Giorgio; Flore, Michele; Spelke, Elizabeth S; Sovrano, Valeria A

2013-10-01

Sensitivity to environmental shape in spatial navigation has been found, at both behavioural and neural levels, in virtually every species tested, starting early in development. Moreover, evidence that genetic deletions can cause selective deficits in such navigation behaviours suggests a genetic basis to navigation by environmental geometry. Nevertheless, the geometric computations underlying navigation have not been specified in any species. The present study teases apart the geometric components within the traditionally used rectangular enclosure and finds that zebrafish selectively represent distance and directional relationships between extended boundary surfaces. Similar behavioural results in geometric navigation tasks with human children provide prima facie evidence for similar underlying cognitive computations and open new doors for probing the genetic foundations that give rise to these computations.

Navigation concepts for MR image-guided interventions.

Science.gov (United States)

Moche, Michael; Trampel, Robert; Kahn, Thomas; Busse, Harald

2008-02-01

The ongoing development of powerful magnetic resonance imaging techniques also allows for advanced possibilities to guide and control minimally invasive interventions. Various navigation concepts have been described for practically all regions of the body. The specific advantages and limitations of these concepts largely depend on the magnet design of the MR scanner and the interventional environment. Open MR scanners involve minimal patient transfer, which improves the interventional workflow and reduces the need for coregistration, ie, the mapping of spatial coordinates between imaging and intervention position. Most diagnostic scanners, in contrast, do not allow the physician to guide his instrument inside the magnet and, consequently, the patient needs to be moved out of the bore. Although adequate coregistration and navigation concepts for closed-bore scanners are technically more challenging, many developments are driven by the well-known capabilities of high-field systems and their better economic value. Advanced concepts such as multimodal overlays, augmented reality displays, and robotic assistance devices are still in their infancy but might propel the use of intraoperative navigation. The goal of this work is to give an update on MRI-based navigation and related techniques and to briefly discuss the clinical experience and limitations of some selected systems. (Copyright) 2008 Wiley-Liss, Inc.

Performance Improvement of Inertial Navigation System by Using Magnetometer with Vehicle Dynamic Constraints

Directory of Open Access Journals (Sweden)

Daehee Won

2015-01-01

Full Text Available A navigation algorithm is proposed to increase the inertial navigation performance of a ground vehicle using magnetic measurements and dynamic constraints. The navigation solutions are estimated based on inertial measurements such as acceleration and angular velocity measurements. To improve the inertial navigation performance, a three-axis magnetometer is used to provide the heading angle, and nonholonomic constraints (NHCs are introduced to increase the correlation between the velocity and the attitude equation. The NHCs provide a velocity feedback to the attitude, which makes the navigation solution more robust. Additionally, an acceleration-based roll and pitch estimation is applied to decrease the drift when the acceleration is within certain boundaries. The magnetometer and NHCs are combined with an extended Kalman filter. An experimental test was conducted to verify the proposed method, and a comprehensive analysis of the performance in terms of the position, velocity, and attitude showed that the navigation performance could be improved by using the magnetometer and NHCs. Moreover, the proposed method could improve the estimation performance for the position, velocity, and attitude without any additional hardware except an inertial sensor and magnetometer. Therefore, this method would be effective for ground vehicles, indoor navigation, mobile robots, vehicle navigation in urban canyons, or navigation in any global navigation satellite system-denied environment.

Multitarget Approaches to Robust Navigation

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National Aeronautics and Space Administration — The performance, stability, and statistical consistency of a vehicle's navigation algorithm are vitally important to the success and safety of its mission....

Autonomous GPS/INS navigation experiment for Space Transfer Vehicle

Science.gov (United States)

Upadhyay, Triveni N.; Cotterill, Stephen; Deaton, A. W.

1993-01-01

An experiment to validate the concept of developing an autonomous integrated spacecraft navigation system using on board Global Positioning System (GPS) and Inertial Navigation System (INS) measurements is described. The feasibility of integrating GPS measurements with INS measurements to provide a total improvement in spacecraft navigation performance, i.e. improvement in position, velocity and attitude information, was previously demonstrated. An important aspect of this research is the automatic real time reconfiguration capability of the system designed to respond to changes in a spacecraft mission under the control of an expert system.

How Marginalized Young People Access, Engage With, and Navigate Health-Care Systems in the Digital Age: Systematic Review.

Science.gov (United States)

Robards, Fiona; Kang, Melissa; Usherwood, Tim; Sanci, Lena

2018-04-01

This systematic review examines how marginalized young people access and engage with health services and navigate health-care systems in high-income countries. Medline, CINAHL, PsychInfo, The University of Sydney Library database, and Google Scholar were searched to identify qualitative and quantitative original research, published from 2006 to 2017, that focused on selected definitions of marginalized young people (12 to 24 years), their parents/carers, and/or health professionals working with these populations. A thematic synthesis was undertaken identifying themes across and between groups on barriers and/or facilitators to access, engagement, and/or navigation of health-care systems. Of 1,796 articles identified, 68 studies in the final selection focused on marginalized young people who were homeless (n = 20), living in rural areas (n = 14), of refugee background (n = 11), gender and/or sexuality diverse (n = 11), indigenous (n = 4), low income (n = 4), young offenders (n = 2), or living with a disability (n = 2). Studies were from the United States, Australia, Canada, United Kingdom, New Zealand, and Portugal, including 44 qualitative, 16 quantitative, and 8 mixed-method study types. Sample sizes ranged from 3 to 1,388. Eight themes were identified relating to ability to recognize and understand health issues; service knowledge and attitudes toward help seeking; structural barriers; professionals' knowledge, skills, attitudes; service environments and structures; ability to navigate the health system; youth participation; and technology opportunities. Marginalized young people experience barriers in addition to those common to all young people. Future studies should consider the role of technology in access, engagement, and health system navigation, and the impact of intersectionality between marginalized groups. Copyright © 2017 The Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Accuracy of the hypothetical sky-polarimetric Viking navigation versus sky conditions: revealing solar elevations and cloudinesses favourable for this navigation method.

Science.gov (United States)

Száz, Dénes; Farkas, Alexandra; Barta, András; Kretzer, Balázs; Blahó, Miklós; Egri, Ádám; Szabó, Gyula; Horváth, Gábor

2017-09-01

According to Thorkild Ramskou's theory proposed in 1967, under overcast and foggy skies, Viking seafarers might have used skylight polarization analysed with special crystals called sunstones to determine the position of the invisible Sun. After finding the occluded Sun with sunstones, its elevation angle had to be measured and its shadow had to be projected onto the horizontal surface of a sun compass. According to Ramskou's theory, these sunstones might have been birefringent calcite or dichroic cordierite or tourmaline crystals working as polarizers. It has frequently been claimed that this method might have been suitable for navigation even in cloudy weather. This hypothesis has been accepted and frequently cited for decades without any experimental support. In this work, we determined the accuracy of this hypothetical sky-polarimetric Viking navigation for 1080 different sky situations characterized by solar elevation θ and cloudiness ρ , the sky polarization patterns of which were measured by full-sky imaging polarimetry. We used the earlier measured uncertainty functions of the navigation steps 1, 2 and 3 for calcite, cordierite and tourmaline sunstone crystals, respectively, and the newly measured uncertainty function of step 4 presented here. As a result, we revealed the meteorological conditions under which Vikings could have used this hypothetical navigation method. We determined the solar elevations at which the navigation uncertainties are minimal at summer solstice and spring equinox for all three sunstone types. On average, calcite sunstone ensures a more accurate sky-polarimetric navigation than tourmaline and cordierite. However, in some special cases (generally at 35° ≤  θ  ≤ 40°, 1 okta ≤  ρ  ≤ 6 oktas for summer solstice, and at 20° ≤  θ  ≤ 25°, 0 okta ≤  ρ  ≤ 4 oktas for spring equinox), the use of tourmaline and cordierite results in smaller navigation uncertainties than that of calcite

Navigational efficiency in a biased and correlated random walk model of individual animal movement.

Science.gov (United States)

Bailey, Joseph D; Wallis, Jamie; Codling, Edward A

2018-01-01

Understanding how an individual animal is able to navigate through its environment is a key question in movement ecology that can give insight into observed movement patterns and the mechanisms behind them. Efficiency of navigation is important for behavioral processes at a range of different spatio-temporal scales, including foraging and migration. Random walk models provide a standard framework for modeling individual animal movement and navigation. Here we consider a vector-weighted biased and correlated random walk (BCRW) model for directed movement (taxis), where external navigation cues are balanced with forward persistence. We derive a mathematical approximation of the expected navigational efficiency for any BCRW of this form and confirm the model predictions using simulations. We demonstrate how the navigational efficiency is related to the weighting given to forward persistence and external navigation cues, and highlight the counter-intuitive result that for low (but realistic) levels of error on forward persistence, a higher navigational efficiency is achieved by giving more weighting to this indirect navigation cue rather than direct navigational cues. We discuss and interpret the relevance of these results for understanding animal movement and navigation strategies. © 2017 by the Ecological Society of America.

A new visual navigation system for exploring biomedical Open Educational Resource (OER) videos.

Science.gov (United States)

Zhao, Baoquan; Xu, Songhua; Lin, Shujin; Luo, Xiaonan; Duan, Lian

2016-04-01

Biomedical videos as open educational resources (OERs) are increasingly proliferating on the Internet. Unfortunately, seeking personally valuable content from among the vast corpus of quality yet diverse OER videos is nontrivial due to limitations of today's keyword- and content-based video retrieval techniques. To address this need, this study introduces a novel visual navigation system that facilitates users' information seeking from biomedical OER videos in mass quantity by interactively offering visual and textual navigational clues that are both semantically revealing and user-friendly. The authors collected and processed around 25 000 YouTube videos, which collectively last for a total length of about 4000 h, in the broad field of biomedical sciences for our experiment. For each video, its semantic clues are first extracted automatically through computationally analyzing audio and visual signals, as well as text either accompanying or embedded in the video. These extracted clues are subsequently stored in a metadata database and indexed by a high-performance text search engine. During the online retrieval stage, the system renders video search results as dynamic web pages using a JavaScript library that allows users to interactively and intuitively explore video content both efficiently and effectively.ResultsThe authors produced a prototype implementation of the proposed system, which is publicly accessible athttps://patentq.njit.edu/oer To examine the overall advantage of the proposed system for exploring biomedical OER videos, the authors further conducted a user study of a modest scale. The study results encouragingly demonstrate the functional effectiveness and user-friendliness of the new system for facilitating information seeking from and content exploration among massive biomedical OER videos. Using the proposed tool, users can efficiently and effectively find videos of interest, precisely locate video segments delivering personally valuable

Overcoming urban GPS navigation challenges through the use of MEMS inertial sensors and proper verification of navigation system performance

Science.gov (United States)

Vinande, Eric T.

This research proposes several means to overcome challenges in the urban environment to ground vehicle global positioning system (GPS) receiver navigation performance through the integration of external sensor information. The effects of narrowband radio frequency interference and signal attenuation, both common in the urban environment, are examined with respect to receiver signal tracking processes. Low-cost microelectromechanical systems (MEMS) inertial sensors, suitable for the consumer market, are the focus of receiver augmentation as they provide an independent measure of motion and are independent of vehicle systems. A method for estimating the mounting angles of an inertial sensor cluster utilizing typical urban driving maneuvers is developed and is able to provide angular measurements within two degrees of truth. The integration of GPS and MEMS inertial sensors is developed utilizing a full state navigation filter. Appropriate statistical methods are developed to evaluate the urban environment navigation improvement due to the addition of MEMS inertial sensors. A receiver evaluation metric that combines accuracy, availability, and maximum error measurements is presented and evaluated over several drive tests. Following a description of proper drive test techniques, record and playback systems are evaluated as the optimal way of testing multiple receivers and/or integrated navigation systems in the urban environment as they simplify vehicle testing requirements.

75 FR 51473 - Houston/Galveston Navigation Safety Advisory Committee

Science.gov (United States)

2010-08-20

... DEPARTMENT OF HOMELAND SECURITY Coast Guard [Docket No. USCG-2010-0656] Houston/Galveston... Houston/Galveston Navigation Safety Advisory Committee (HOGANSAC) and its working groups will meet in Houston, Texas, to discuss waterway improvements, aids to navigation, area projects impacting safety on...

75 FR 23793 - Houston/Galveston Navigation Safety Advisory Committee

Science.gov (United States)

2010-05-04

... DEPARTMENT OF HOMELAND SECURITY Coast Guard [Docket No. USCG-2010-0032] Houston/Galveston... Houston/Galveston Navigation Safety Advisory Committee (``HOGANSAC'' or ``the Committee'') and its working groups will meet in Houston, Texas to discuss waterway improvements, aids to navigation, area projects...

FPGA-based real-time embedded system for RISS/GPS integrated navigation.

Science.gov (United States)

Abdelfatah, Walid Farid; Georgy, Jacques; Iqbal, Umar; Noureldin, Aboelmagd

2012-01-01

Navigation algorithms integrating measurements from multi-sensor systems overcome the problems that arise from using GPS navigation systems in standalone mode. Algorithms which integrate the data from 2D low-cost reduced inertial sensor system (RISS), consisting of a gyroscope and an odometer or wheel encoders, along with a GPS receiver via a Kalman filter has proved to be worthy in providing a consistent and more reliable navigation solution compared to standalone GPS receivers. It has been also shown to be beneficial, especially in GPS-denied environments such as urban canyons and tunnels. The main objective of this paper is to narrow the idea-to-implementation gap that follows the algorithm development by realizing a low-cost real-time embedded navigation system capable of computing the data-fused positioning solution. The role of the developed system is to synchronize the measurements from the three sensors, relative to the pulse per second signal generated from the GPS, after which the navigation algorithm is applied to the synchronized measurements to compute the navigation solution in real-time. Employing a customizable soft-core processor on an FPGA in the kernel of the navigation system, provided the flexibility for communicating with the various sensors and the computation capability required by the Kalman filter integration algorithm.

Hybrid Transverse Polar Navigation for High-Precision and Long-Term INSs.

Science.gov (United States)

Wu, Ruonan; Wu, Qiuping; Han, Fengtian; Zhang, Rong; Hu, Peida; Li, Haixia

2018-05-12

Transverse navigation has been proposed to help inertial navigation systems (INSs) fill the gap of polar navigation ability. However, as the transverse system does not have the ability of navigate globally, a complicated switch between the transverse and the traditional algorithms is necessary when the system moves across the polar circles. To maintain the inner continuity and consistency of the core algorithm, a hybrid transverse polar navigation is proposed in this research based on a combination of Earth-fixed-frame mechanization and transverse-frame outputs. Furthermore, a thorough analysis of kinematic error characteristics, proper damping technology and corresponding long-term contributions of main error sources is conducted for the high-precision INSs. According to the analytical expressions of the long-term navigation errors in polar areas, the 24-h period symmetrical oscillation with a slowly divergent amplitude dominates the transverse horizontal position errors, and the first-order drift dominates the transverse azimuth error, which results from the gyro drift coefficients that occur in corresponding directions. Simulations are conducted to validate the theoretical analysis and the deduced analytical expressions. The results show that the proposed hybrid transverse navigation can ensure the same accuracy and oscillation characteristics in polar areas as the traditional algorithm in low and mid latitude regions.

33 CFR 165.1704 - Prince William Sound, Alaska-regulated navigation area.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Prince William Sound, Alaska... District § 165.1704 Prince William Sound, Alaska-regulated navigation area. (a) The following is a... Hinchinbrook Light to Schooner Rock Light, comprising that portion of Prince William Sound between 146°30′ W...

Close but no cigar: Spatial precision deficits following medial temporal lobe lesions provide novel insight into theoretical models of navigation and memory.

Science.gov (United States)

Kolarik, Branden S; Baer, Trevor; Shahlaie, Kiarash; Yonelinas, Andrew P; Ekstrom, Arne D

2018-01-01

Increasing evidence suggests that the human hippocampus contributes to a range of different behaviors, including episodic memory, language, short-term memory, and navigation. A novel theoretical framework, the Precision and Binding Model, accounts for these phenomenon by describing a role for the hippocampus in high-resolution, complex binding. Other theories like Cognitive Map Theory, in contrast, predict a specific role for the hippocampus in allocentric navigation, while Declarative Memory Theory predicts a specific role in delay-dependent conscious memory. Navigation provides a unique venue for testing these predictions, with past results from research with humans providing inconsistent findings regarding the role of the human hippocampus in spatial navigation. Here, we tested five patients with lesions primarily restricted to the hippocampus and those extending out into the surrounding medial temporal lobe cortex on a virtual water maze task. Consistent with the Precision and Binding Model, we found partially intact allocentric memory in all patients, with impairments in the spatial precision of their searches for a hidden target. We found similar impairments at both immediate and delayed testing. Our findings are consistent with the Precision and Binding Model of hippocampal function, arguing for its role across domains in high-resolution, complex binding. Remembering goal locations in one's environment is a critical skill for survival. How this information is represented in the brain is still not fully understood, but is believed to rely in some capacity on structures in the medial temporal lobe. Contradictory findings from studies of both humans and animals have been difficult to reconcile with regard to the role of the MTL, specifically the hippocampus. By assessing impairments observed during navigation to a goal in patients with medial temporal lobe damage we can better understand the role these structures play in such behavior. Utilizing virtual reality

Navigating ECA-Zones

DEFF Research Database (Denmark)

Hansen, Carsten Ørts; Grønsedt, Peter; Hendriksen, Christian

This report examines the effect that ECA-zone regulation has on the optimal vessel fuel strategies for compliance. The findings of this report are trifold, and this report is coupled with a calculation tool which is released to assist ship-owners in the ECA decision making. The first key insight...... much time their operated vessels navigate the ECA in the future....

A Depth-Based Head-Mounted Visual Display to Aid Navigation in Partially Sighted Individuals

Science.gov (United States)

Hicks, Stephen L.; Wilson, Iain; Muhammed, Louwai; Worsfold, John; Downes, Susan M.; Kennard, Christopher

2013-01-01

Independent navigation for blind individuals can be extremely difficult due to the inability to recognise and avoid obstacles. Assistive techniques such as white canes, guide dogs, and sensory substitution provide a degree of situational awareness by relying on touch or hearing but as yet there are no techniques that attempt to make use of any residual vision that the individual is likely to retain. Residual vision can restricted to the awareness of the orientation of a light source, and hence any information presented on a wearable display would have to limited and unambiguous. For improved situational awareness, i.e. for the detection of obstacles, displaying the size and position of nearby objects, rather than including finer surface details may be sufficient. To test whether a depth-based display could be used to navigate a small obstacle course, we built a real-time head-mounted display with a depth camera and software to detect the distance to nearby objects. Distance was represented as brightness on a low-resolution display positioned close to the eyes without the benefit focussing optics. A set of sighted participants were monitored as they learned to use this display to navigate the course. All were able to do so, and time and velocity rapidly improved with practise with no increase in the number of collisions. In a second experiment a cohort of severely sight-impaired individuals of varying aetiologies performed a search task using a similar low-resolution head-mounted display. The majority of participants were able to use the display to respond to objects in their central and peripheral fields at a similar rate to sighted controls. We conclude that the skill to use a depth-based display for obstacle avoidance can be rapidly acquired and the simplified nature of the display may appropriate for the development of an aid for sight-impaired individuals. PMID:23844067

33 CFR 165.1171 - Copper Canyon, Lake Havasu, Colorado River-Regulated Navigation Area.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Copper Canyon, Lake Havasu... Guard District § 165.1171 Copper Canyon, Lake Havasu, Colorado River—Regulated Navigation Area. (a) Location. The following is a regulated navigation area: (1) In the water area of Copper Canyon, Lake Havasu...

Bilateral human-robot control for semi-autonomous UAV navigation

NARCIS (Netherlands)

Wopereis, Han Willem; Fumagalli, Matteo; Stramigioli, Stefano; Carloni, Raffaella

2015-01-01

This paper proposes a semi-autonomous bilateral control architecture for unmanned aerial vehicles. During autonomous navigation, a human operator is allowed to assist the autonomous controller of the vehicle by actively changing its navigation parameters to assist it in critical situations, such as

Information content in reflected global navigation satellite system signals

DEFF Research Database (Denmark)

Høeg, Per; Carlstrom, Anders

2011-01-01

The direct signals from satellites in global satellite navigation satellites systems (GNSS) as, GPS, GLONASS and GALILEO, constitute the primary source for positioning, navigation and timing from space. But also the reflected GNSS signals contain an important information content of signal travel...

Pilot perception and confidence of location during a simulated helicopter navigation task.

Science.gov (United States)

Yang, Ji Hyun; Cowden, Bradley T; Kennedy, Quinn; Schramm, Harrison; Sullivan, Joseph

2013-09-01

This paper aims to provide insights into human perception, navigation performance, and confidence in helicopter overland navigation. Helicopter overland navigation is a challenging mission area because it is a complex cognitive task, and failing to recognize when the aircraft is off-course can lead to operational failures and mishaps. A human-in-the-loop experiment to investigate pilot perception during simulated overland navigation by analyzing actual navigation trajectory, pilots' perceived location, and corresponding confidence levels was designed. There were 15 military officers with prior overland navigation experience who completed 4 simulated low-level navigation routes, 2 of which entailed auto-navigation. This route was paused roughly every 30 s for the subject to mark their perceived location on the map and their confidence level using a customized program. Analysis shows that there is no correlation between perceived and actual location of the aircraft, nor between confidence level and actual location. There is, however, some evidence that there is a correlation (rho = -0.60 to approximately 0.65) between perceived location and intended route of flight, suggesting that there is a bias toward believing one is on the intended flight route. If aviation personnel can proactively identify the circumstances in which usual misperceptions occur in navigation, they may reduce mission failure and accident rate. Fleet squadrons and instructional commands can benefit from this study to improve operations that require low-level flight while also improving crew resource management.

Navigation Strategies for Primitive Solar System Body Rendezvous and Proximity Operations

Science.gov (United States)

Getzandanner, Kenneth M.

2011-01-01

A wealth of scientific knowledge regarding the composition and evolution of the solar system can be gained through reconnaissance missions to primitive solar system bodies. This paper presents analysis of a baseline navigation strategy designed to address the unique challenges of primitive body navigation. Linear covariance and Monte Carlo error analysis was performed on a baseline navigation strategy using simulated data from a· design reference mission (DRM). The objective of the DRM is to approach, rendezvous, and maintain a stable orbit about the near-Earth asteroid 4660 Nereus. The outlined navigation strategy and resulting analyses, however, are not necessarily limited to this specific target asteroid as they may he applicable to a diverse range of mission scenarios. The baseline navigation strategy included simulated data from Deep Space Network (DSN) radiometric tracking and optical image processing (OpNav). Results from the linear covariance and Monte Carlo analyses suggest the DRM navigation strategy is sufficient to approach and perform proximity operations in the vicinity of the target asteroid with meter-level accuracy.

Next-Generation Navigational Infrastructure and the ATLAS Event Store

CERN Document Server

van Gemmeren, P; The ATLAS collaboration; Nowak, M

2014-01-01

The ATLAS event store employs a persistence framework with extensive navigational capabilities. These include real-time back navigation to upstream processing stages, externalizable data object references, navigation from any data object to any other both within a single file and across files, and more. The 2013-2014 shutdown of the Large Hadron Collider provides an opportunity to enhance this infrastructure in several ways that both extend these capabilities and allow the collaboration to better exploit emerging computing platforms. Enhancements include redesign with efficient file merging in mind, content-based indices in optimized reference types, and support for forward references. The latter provide the potential to construct valid references to data before those data are written, a capability that is useful in a variety of multithreading, multiprocessing, distributed processing, and deferred processing scenarios. This paper describes the architecture and design of the next generation of ATLAS navigation...

Next-Generation Navigational Infrastructure and the ATLAS Event Store

CERN Document Server

van Gemmeren, P; The ATLAS collaboration; Nowak, M

2013-01-01

The ATLAS event store employs a persistence framework with extensive navigational capabilities. These include real-time back navigation to upstream processing stages, externalizable data object references, navigation from any data object to any other both within a single file and across files, and more. The 2013-2014 shutdown of the Large Hadron Collider provides an opportunity to enhance this infrastructure in several ways that both extend these capabilities and allow the collaboration to better exploit emerging computing platforms. Enhancements include redesign with efficient file merging in mind, content-based indices in optimized reference types, and support for forward references. The latter provide the potential to construct valid references to data before those data are written, a capability that is useful in a variety of multithreading, multiprocessing, distributed processing, and deferred processing scenarios. This paper describes the architecture and design of the next generation of ATLAS navigation...

Next-generation navigational infrastructure and the ATLAS event store

International Nuclear Information System (INIS)

Gemmeren, P van; Malon, D; Nowak, M

2014-01-01

The ATLAS event store employs a persistence framework with extensive navigational capabilities. These include real-time back navigation to upstream processing stages, externalizable data object references, navigation from any data object to any other both within a single file and across files, and more. The 2013-2014 shutdown of the Large Hadron Collider provides an opportunity to enhance this infrastructure in several ways that both extend these capabilities and allow the collaboration to better exploit emerging computing platforms. Enhancements include redesign with efficient file merging in mind, content-based indices in optimized reference types, and support for forward references. The latter provide the potential to construct valid references to data before those data are written, a capability that is useful in a variety of multithreading, multiprocessing, distributed processing, and deferred processing scenarios. This paper describes the architecture and design of the next generation of ATLAS navigational infrastructure.

IMPLEMENTATION OF INTERTIAL NAVIGATION SYSTEM MODEL DURING AIRCRAFT TESTING

Directory of Open Access Journals (Sweden)

2016-01-01

Full Text Available The flight subset control is required during the aviation equipment test flights. In order to achieve this objective the complex consisting of strap down inertial navigation system (SINS and user equipment of satellite navigation systems (SNS can be used. Such combination needs to be used for error correction in positioning which is accumulated in SINS with time. This article shows the research results of the inertial navigation system (INS model. The results of the position- ing error calculation for various INS classes are given. Each of the examined INS has a different accumulated error for the same time lag. The methods of combining information of INS and SRNS are covered. The results obtained can be applied for upgrading the aircraft flight and navigation complexes. In particular, they can allow to continuously determine speed, coordinates, angular situation and repositioning rate of change of axes of the instrument frame.

Mars Atmospheric Entry Integrated Navigation with Partial Intermittent Measurements

Directory of Open Access Journals (Sweden)

Tai-shan Lou

2017-01-01

Full Text Available Signal degradation suffered by the vehicle is a combination brownout and blackout during Mars atmospheric entry. The communications brownout means that signal fades and blackout means that the signal is lost completely. The communications brownout and blackout periods are analyzed and predicted with an altitude and velocity profiles. In the brownout period, the range measurements between the vehicle and the orbiters are modeled as intermittent measurements with the radio signal arrival probabilities, which are distributed as a Rayleigh distribution of the electron number density around the entry vehicle. A new integrated navigation strategy during the Mars atmospheric entry phase is proposed to consider the probabilities of the radio measurements in the communications brownout and blackout periods under the IMU/beacon scenario based on the information filter with intermittent measurements. Numerical navigation simulations are designed to show the performance of the proposed navigation strategy under the integrated navigation scenario.

Multi-focal Vision and Gaze Control Improve Navigation Performance

Directory of Open Access Journals (Sweden)

Kolja Kuehnlenz

2008-11-01

Full Text Available Multi-focal vision systems comprise cameras with various fields of view and measurement accuracies. This article presents a multi-focal approach to localization and mapping of mobile robots with active vision. An implementation of the novel concept is done considering a humanoid robot navigation scenario where the robot is visually guided through a structured environment with several landmarks. Various embodiments of multi-focal vision systems are investigated and the impact on navigation performance is evaluated in comparison to a conventional mono-focal stereo set-up. The comparative studies clearly show the benefits of multi-focal vision for mobile robot navigation: flexibility to assign the different available sensors optimally in each situation, enhancement of the visible field, higher localization accuracy, and, thus, better task performance, i.e. path following behavior of the mobile robot. It is shown that multi-focal vision may strongly improve navigation performance.

Lucy: Navigating a Jupiter Trojan Tour

Science.gov (United States)

Stanbridge, Dale; Williams, Ken; Williams, Bobby; Jackman, Coralie; Weaver, Hal; Berry, Kevin; Sutter, Brian; Englander, Jacob

2017-01-01

In January 2017, NASA selected the Lucy mission to explore six Jupiter Trojan asteroids. These six bodies, remnants of the primordial material that formed the outer planets, were captured in the Sun-Jupiter L4 and L5 Lagrangian regions early in the solar system formation. These particular bodies were chosen because of their diverse spectral properties and the chance to observe up close for the first time two orbiting approximately equal mass binaries, Patroclus and Menoetius. KinetX, Inc. is the primary navigation supplier for the Lucy mission. This paper describes preliminary navigation analyses of the approach phase for each Trojan encounter.

Ontology-centric integration and navigation of the dengue literature.

Science.gov (United States)

Rajapakse, Menaka; Kanagasabai, Rajaraman; Ang, Wee Tiong; Veeramani, Anitha; Schreiber, Mark J; Baker, Christopher J O

2008-10-01

Uninhibited access to the unstructured information distributed across the web and in scientific literature databases continues to be beyond the reach of scientists and health professionals. To address this challenge we have developed a literature driven, ontology-centric navigation infrastructure consisting of a content acquisition engine, a domain-specific ontology (in OWL-DL) and an ontology instantiation pipeline delivering sentences derived by domain-specific text mining. A visual query tool for reasoning over A-box instances in the populated ontology is presented and used to build conceptual queries that can be issued to the knowledgebase. We have deployed this generic infrastructure to facilitate data integration and knowledge sharing in the domain of dengue, which is one of the most prevalent viral diseases that continue to infect millions of people in the tropical and subtropical regions annually. Using our unique methodology we illustrate simplified search and discovery on dengue information derived from distributed resources and aggregated according to dengue ontology. Furthermore we apply data mining to the instantiated ontology to elucidate trends in the mentions of dengue serotypes in scientific abstracts since 1974.

Iconic memory-based omnidirectional route panorama navigation.

Science.gov (United States)

Yagi, Yasushi; Imai, Kousuke; Tsuji, Kentaro; Yachida, Masahiko

2005-01-01

A route navigation method for a mobile robot with an omnidirectional image sensor is described. The route is memorized from a series of consecutive omnidirectional images of the horizon when the robot moves to its goal. While the robot is navigating to the goal point, input is matched against the memorized spatio-temporal route pattern by using dual active contour models and the exact robot position and orientation is estimated from the converged shape of the active contour models.

Eye tracking, strategies, and sex differences in virtual navigation.

Science.gov (United States)

Andersen, Nicolas E; Dahmani, Louisa; Konishi, Kyoko; Bohbot, Véronique D

2012-01-01

Reports of sex differences in wayfinding have typically used paradigms sensitive to the female advantage (navigation by landmarks) or sensitive to the male advantage (navigation by cardinal directions, Euclidian coordinates, environmental geometry, and absolute distances). The current virtual navigation paradigm allowed both men and women an equal advantage. We studied sex differences by systematically varying the number of landmarks. Eye tracking was used to quantify sex differences in landmark utilisation as participants solved an eight-arm radial maze task within different virtual environments. To solve the task, participants were required to remember the locations of target objects within environments containing 0, 2, 4, 6, or 8 landmarks. We found that, as the number of landmarks available in the environment increases, the proportion of time men and women spend looking at landmarks and the number of landmarks they use to find their way increases. Eye tracking confirmed that women rely more on landmarks to navigate, although landmark fixations were also associated with an increase in task completion time. Sex differences in navigational behaviour occurred only in environments devoid of landmarks and disappeared in environments containing multiple landmarks. Moreover, women showed sustained landmark-oriented gaze, while men's decreased over time. Finally, we found that men and women use spatial and response strategies to the same extent. Together, these results shed new light on the discrepancy in landmark utilisation between men and women and help explain the differences in navigational behaviour previously reported. Copyright © 2011 Elsevier Inc. All rights reserved.

Does intraoperative navigation improve the accuracy of mandibular angle osteotomy: Comparison between augmented reality navigation, individualised templates and free-hand techniques.

Science.gov (United States)

Zhu, Ming; Liu, Fei; Zhou, Chaozheng; Lin, Li; Zhang, Yan; Chai, Gang; Xie, Le; Qi, Fazhi; Li, Qingfeng

2018-04-11

Augmented reality (AR)-based navigation surgery has evolved to be an advanced assisted technology. The aim of this study is to manifest the accuracy of AR navigation for the intraoperative mandibular angle osteotomy by comparing the navigation with other interventional techniques. A retrospective study was conducted with 93 post-surgical patients with mandibular angle hypertrophy admitted at our plastic and reconstructive surgery department between September 2011 and June 2016. Thirty-one patients received osteotomy conducted using a navigation system based on augmented reality (AR group), 28 patients received osteotomy conducted using individualised templates (IT group) and the remaining 34 patients received osteotomy performed by free hand (free-hand group). The post-operative computed tomography (CT) images were reviewed and analysed by comparing with pre-surgical planning generated by three-dimensional (3D) software. The preparation time, cutting time, whole operating time and discrepancy in osteotomy lines were measured. The preparation time was much shorter for the free-hand group than that for the AR group and the IT group (P  0.05). In addition, the discrepancy in osteotomy lines was lower for the AR group and in the IT group than for the free-hand group (P < 0.01). The navigation system based on AR has a higher accuracy, more reliability and better user friendliness for some particular clinical procedures than for other techniques, which has a promising clinical prospect. Copyright © 2018. Published by Elsevier Ltd.

Representing User Navigation in XML Retrieval with Structural Summaries

DEFF Research Database (Denmark)

Ali, M. S.; Consens, Mariano P.; Larsen, Birger

This poster presents a novel way to represent user navigation in XML retrieval using collection statistics from XML summaries. Currently, developing user navigation models in XML retrieval is costly and the models are specific to collected user assessments. We address this problem by proposing...

Towards support for collaborative navigation in complex indoor environments

NARCIS (Netherlands)

Bouwer, A.; Nack, F.; Evers, V.

2011-01-01

In this paper we present first results of an observation study on indoor navigation behaviour of visitors at a large public fair. As an outcome we present a number of requirements for mobile indoor navigation systems that support collaborative destination and path finding tasks.

Remarks on the observability of single beacon underwater navigation

DEFF Research Database (Denmark)

Jouffroy, Jerome; Ross, Andrew

This paper contributes a simple and intuitive result in the analysis of underwater navigation using a single ranging beacon. This analysis should help with the design of small and lightweight underwater vehicles by reducing the amount of instrumentation required for accurate navigation. The concept...

Simulation-based camera navigation training in laparoscopy-a randomized trial

DEFF Research Database (Denmark)

Nilsson, Cecilia; Sørensen, Jette Led; Konge, Lars

2017-01-01

patient safety. The objectives of this trial were to examine how to train laparoscopic camera navigation and to explore the transfer of skills to the operating room. MATERIALS AND METHODS: A randomized, single-center superiority trial with three groups: The first group practiced simulation-based camera...... navigation tasks (camera group), the second group practiced performing a simulation-based cholecystectomy (procedure group), and the third group received no training (control group). Participants were surgical novices without prior laparoscopic experience. The primary outcome was assessment of camera.......033), had a higher score. CONCLUSIONS: Simulation-based training improves the technical skills required for camera navigation, regardless of practicing camera navigation or the procedure itself. Transfer to the clinical setting could, however, not be demonstrated. The control group demonstrated higher...

Minimally Invasive Spinal Surgery with Intraoperative Image-Guided Navigation

Directory of Open Access Journals (Sweden)

Terrence T. Kim

2016-01-01

Full Text Available We present our perioperative minimally invasive spine surgery technique using intraoperative computed tomography image-guided navigation for the treatment of various lumbar spine pathologies. We present an illustrative case of a patient undergoing minimally invasive percutaneous posterior spinal fusion assisted by the O-arm system with navigation. We discuss the literature and the advantages of the technique over fluoroscopic imaging methods: lower occupational radiation exposure for operative room personnel, reduced need for postoperative imaging, and decreased revision rates. Most importantly, we demonstrate that use of intraoperative cone beam CT image-guided navigation has been reported to increase accuracy.

Large-Scale Context-Aware Volume Navigation using Dynamic Insets

KAUST Repository

Al-Awami, Ali

2012-07-01

Latest developments in electron microscopy (EM) technology produce high resolution images that enable neuro-scientists to identify and put together the complex neural connections in a nervous system. However, because of the massive size and underlying complexity of this kind of data, processing, navigation and analysis suffer drastically in terms of time and effort. In this work, we propose the use of state-of- the-art navigation techniques, such as dynamic insets, built on a peta-scale volume visualization framework to provide focus and context-awareness to help neuro-scientists in their mission to analyze, reconstruct, navigate and explore EM neuroscience data.

Enhancing the care navigation model: potential roles for health sciences librarians

Science.gov (United States)

Huber, Jeffrey T.; Shapiro, Robert M.; Burke, Heather J.; Palmer, Aaron

2014-01-01

This study analyzed the overlap between roles and activities that health care navigators perform and competencies identified by the Medical Library Association's (MLA's) educational policy statement. Roles and activities that health care navigators perform were gleaned from published literature. Once common roles and activities that health care navigators perform were identified, MLA competencies were mapped against those roles and activities to identify areas of overlap. The greatest extent of correspondence occurred in patient empowerment and support. Further research is warranted to determine the extent to which health sciences librarians might assume responsibility for roles and activities that health care navigators perform. PMID:24415921

Effects of Visual, Auditory, and Tactile Navigation Cues on Navigation Performance, Situation Awareness, and Mental Workload

National Research Council Canada - National Science Library

Davis, Bradley M

2007-01-01

.... Results from both experiments indicate that augmented visual displays reduced time to complete navigation, maintained situation awareness, and drastically reduced mental workload in comparison...

Radio/FADS/IMU integrated navigation for Mars entry

Science.gov (United States)

Jiang, Xiuqiang; Li, Shuang; Huang, Xiangyu

2018-03-01

Supposing future orbiting and landing collaborative exploration mission as the potential project background, this paper addresses the issue of Mars entry integrated navigation using radio beacon, flush air data sensing system (FADS), and inertial measurement unit (IMU). The range and Doppler information sensed from an orbiting radio beacon, the dynamic pressure and heating data sensed from flush air data sensing system, and acceleration and attitude angular rate outputs from an inertial measurement unit are integrated in an unscented Kalman filter to perform state estimation and suppress the system and measurement noise. Computer simulations show that the proposed integrated navigation scheme can enhance the navigation accuracy, which enables precise entry guidance for the given Mars orbiting and landing collaborative exploration mission.

Spatial navigation – a unique window into physiological and pathological aging

Directory of Open Access Journals (Sweden)

Ivana eGazova

2012-06-01

Full Text Available Spatial navigation is a skill of determining and maintaining a trajectory from one place to another. Mild progressive decline of spatial navigation develops gradually during the course of physiological ageing. Nevertheless, severe spatial navigation deficit can be the first sign of incipient Alzheimer’s disease (AD, occurring in the stage of mild cognitive impairment (MCI, preceding the development of a full blown dementia. Patients with amnestic MCI, especially those with the hippocampal type of amnestic syndrome, are at very high risk of AD. These patients present with the same pattern of spatial navigation impairment as do the patients with mild AD. Spatial navigation testing of elderly as well as computer tests developed for routine clinical use thus represent a possibility for further investigation of this cognitive domain, but most of all, an opportunity for making early diagnosis of AD.

Monitoring Completed Navigation Projects Program

National Research Council Canada - National Science Library

Bottin, Jr., Robert R

2001-01-01

... (MCNP) Program. The program was formerly known as the Monitoring Completed Coastal Projects Program, but was modified in the late 1990s to include all navigation projects, inland as well as coastal...

Visual map and instruction-based bicycle navigation: a comparison of effects on behaviour.

Science.gov (United States)

de Waard, Dick; Westerhuis, Frank; Joling, Danielle; Weiland, Stella; Stadtbäumer, Ronja; Kaltofen, Leonie

2017-09-01

Cycling with a classic paper map was compared with navigating with a moving map displayed on a smartphone, and with auditory, and visual turn-by-turn route guidance. Spatial skills were found to be related to navigation performance, however only when navigating from a paper or electronic map, not with turn-by-turn (instruction based) navigation. While navigating, 25% of the time cyclists fixated at the devices that present visual information. Navigating from a paper map required most mental effort and both young and older cyclists preferred electronic over paper map navigation. In particular a turn-by-turn dedicated guidance device was favoured. Visual maps are in particular useful for cyclists with higher spatial skills. Turn-by-turn information is used by all cyclists, and it is useful to make these directions available in all devices. Practitioner Summary: Electronic navigation devices are preferred over a paper map. People with lower spatial skills benefit most from turn-by-turn guidance information, presented either auditory or on a dedicated device. People with higher spatial skills perform well with all devices. It is advised to keep in mind that all users benefit from turn-by-turn information when developing a navigation device for cyclists.

AUTOMATIC RECOGNITION OF INDOOR NAVIGATION ELEMENTS FROM KINECT POINT CLOUDS

Directory of Open Access Journals (Sweden)

L. Zeng

2017-09-01

Full Text Available This paper realizes automatically the navigating elements defined by indoorGML data standard – door, stairway and wall. The data used is indoor 3D point cloud collected by Kinect v2 launched in 2011 through the means of ORB-SLAM. By contrast, it is cheaper and more convenient than lidar, but the point clouds also have the problem of noise, registration error and large data volume. Hence, we adopt a shape descriptor – histogram of distances between two randomly chosen points, proposed by Osada and merges with other descriptor – in conjunction with random forest classifier to recognize the navigation elements (door, stairway and wall from Kinect point clouds. This research acquires navigation elements and their 3-d location information from each single data frame through segmentation of point clouds, boundary extraction, feature calculation and classification. Finally, this paper utilizes the acquired navigation elements and their information to generate the state data of the indoor navigation module automatically. The experimental results demonstrate a high recognition accuracy of the proposed method.

Automatic Recognition of Indoor Navigation Elements from Kinect Point Clouds

Science.gov (United States)

Zeng, L.; Kang, Z.

2017-09-01

This paper realizes automatically the navigating elements defined by indoorGML data standard - door, stairway and wall. The data used is indoor 3D point cloud collected by Kinect v2 launched in 2011 through the means of ORB-SLAM. By contrast, it is cheaper and more convenient than lidar, but the point clouds also have the problem of noise, registration error and large data volume. Hence, we adopt a shape descriptor - histogram of distances between two randomly chosen points, proposed by Osada and merges with other descriptor - in conjunction with random forest classifier to recognize the navigation elements (door, stairway and wall) from Kinect point clouds. This research acquires navigation elements and their 3-d location information from each single data frame through segmentation of point clouds, boundary extraction, feature calculation and classification. Finally, this paper utilizes the acquired navigation elements and their information to generate the state data of the indoor navigation module automatically. The experimental results demonstrate a high recognition accuracy of the proposed method.

Awake craniotomy using electromagnetic navigation technology without rigid pin fixation.

Science.gov (United States)

Morsy, Ahmed A; Ng, Wai Hoe

2015-11-01

We report our institutional experience using an electromagnetic navigation system, without rigid head fixation, for awake craniotomy patients. The StealthStation® S7 AxiEM™ navigation system (Medtronic, Inc.) was used for this technique. Detailed preoperative clinical and neuropsychological evaluations, patient education and contrast-enhanced MRI (thickness 1.5mm) were performed for each patient. The AxiEM Mobile Emitter was typically placed in a holder, which was mounted to the operating room table, and a non-invasive patient tracker was used as the patient reference device. A monitored conscious sedation technique was used in all awake craniotomy patients, and the AxiEM Navigation Pointer was used for navigation during the procedure. This offers the same accuracy as optical navigation, but without head pin fixation or interference with intraoperative neurophysiological techniques and surgical instruments. The application of the electromagnetic neuronavigation technology without rigid head fixation during an awake craniotomy is accurate, and offers superior patient comfort. It is recommended as an effective adjunctive technique for the conduct of awake surgery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Three-dimensional navigation is more accurate than two-dimensional navigation or conventional fluoroscopy for percutaneous sacroiliac screw fixation in the dysmorphic sacrum: a randomized multicenter study.

Science.gov (United States)

Matityahu, Amir; Kahler, David; Krettek, Christian; Stöckle, Ulrich; Grutzner, Paul Alfred; Messmer, Peter; Ljungqvist, Jan; Gebhard, Florian

2014-12-01

To evaluate the accuracy of computer-assisted sacral screw fixation compared with conventional techniques in the dysmorphic versus normal sacrum. Review of a previous study database. Database of a multinational study with 9 participating trauma centers. The reviewed group included 130 patients, 72 from the navigated group and 58 from the conventional group. Of these, 109 were in the nondysmorphic group and 21 in the dysmorphic group. Placement of sacroiliac (SI) screws was performed using standard fluoroscopy for the conventional group and BrainLAB navigation software with either 2-dimensional or 3-dimensional (3D) navigation for the navigated group. Accuracy of SI screw placement by 2-dimensional and 3D navigation versus conventional fluoroscopy in dysmorphic and nondysmorphic patients, as evaluated by 6 observers using postoperative computerized tomography imaging at least 1 year after initial surgery. Intraobserver agreement was also evaluated. There were 11.9% (13/109) of patients with misplaced screws in the nondysmorphic group and 28.6% (6/21) of patients with misplaced screws in the dysmorphic group, none of which were in the 3D navigation group. Raw agreement between the 6 observers regarding misplaced screws was 32%. However, the percent overall agreement was 69.0% (kappa = 0.38, P dysmorphic proximal sacral segment. We recommend the use of 3D navigation, where available, for insertion of SI screws in patients with normal and dysmorphic proximal sacral segments. Therapeutic level I.

GPM Ground Validation Navigation Data ER-2 OLYMPEX V1

Data.gov (United States)

National Aeronautics and Space Administration — The GPM Ground Validation NASA ER-2 Navigation Data OLYMPEX dataset supplies navigation data collected by the NASA ER-2 aircraft for flights that occurred during...

GNSS-based receiver autonomous integrity monitoring for aircraft navigation

NARCIS (Netherlands)

Imparato, D.

2016-01-01

Nowadays, GNSS-based navigation is moving more and more to critical applications. Global Navigation Satellite Systems (GNSS), which in the past used to be represented by the American GPS and the Russian GLONASS are now growing in number and performance. The European systemGalileo and the Chinese

Magnetic navigation and tracking of underwater vehicles

Digital Repository Service at National Institute of Oceanography (India)

Teixeira, F.C.; Pascoal, A.M.

for the navigation of AUVs has been proposed many years ago but the concept still requires practical demonstration. Implementation issues One of the advantages of mag- netic navigation consists in being passive and economical in terms of energy. Magnetic sensors do... like the present one, that require magnetic measurements with very high precision. A typical solution to this problem consists in the placement of magnetic sensors as far away as possible from the sources of noise but this may not be practical...

Integrating Communication and Navigation: Next Generation Broadcast Service (NGBS)

Science.gov (United States)

Donaldson, Jennifer

2017-01-01

NASA Goddard has been investing in technology demonstrations of a beacon service, now called Next Generation Broadcast Services (NGBS). NGBS is a global, space-based, communications and navigation service for users of Global Navigation Satellite Systems (GNSS) and the Tracking and Data Relay Satellite System (TDRSS). NGBS will provide an S-band beacon messaging source and radio navigation available to users at orbital altitudes 1400 km and below, increasing the autonomy and resiliency of onboard communication and navigation. NGBS will deliver both one-way radiometric (Doppler and pseudorange) and fast forward data transport services to users. Portions of the overall forward data volume will be allocated for fixed message types while the remaining data volume will be left for user forward command data. The NGBS signal will reside within the 2106.43 MHz spectrum currently allocated for the Space Networks multiple access forward (MAF) service and a live service demonstration is currently being planned via the 2nd and 3rd generation TDRS satellites.

PandaEPL: a library for programming spatial navigation experiments.

Science.gov (United States)

Solway, Alec; Miller, Jonathan F; Kahana, Michael J

2013-12-01

Recent advances in neuroimaging and neural recording techniques have enabled researchers to make significant progress in understanding the neural mechanisms underlying human spatial navigation. Because these techniques generally require participants to remain stationary, computer-generated virtual environments are used. We introduce PandaEPL, a programming library for the Python language designed to simplify the creation of computer-controlled spatial-navigation experiments. PandaEPL is built on top of Panda3D, a modern open-source game engine. It allows users to construct three-dimensional environments that participants can navigate from a first-person perspective. Sound playback and recording and also joystick support are provided through the use of additional optional libraries. PandaEPL also handles many tasks common to all cognitive experiments, including managing configuration files, logging all internal and participant-generated events, and keeping track of the experiment state. We describe how PandaEPL compares with other software for building spatial-navigation experiments and walk the reader through the process of creating a fully functional experiment.

Software engineering of a navigation and guidance system for commercial aircraft

Science.gov (United States)

Lachmann, S. G.; Mckinstry, R. G.

1975-01-01

The avionics experimental configuration of the considered system is briefly reviewed, taking into account the concept of an advanced air traffic management system, flight critical and noncritical functions, and display system characteristics. Cockpit displays and the navigation computer are examined. Attention is given to the functions performed in the navigation computer, major programs in the navigation computer, and questions of software development.

Mobile Robot Navigation Based on Q-Learning Technique

Directory of Open Access Journals (Sweden)

Lazhar Khriji

2011-03-01

Full Text Available This paper shows how Q-learning approach can be used in a successful way to deal with the problem of mobile robot navigation. In real situations where a large number of obstacles are involved, normal Q-learning approach would encounter two major problems due to excessively large state space. First, learning the Q-values in tabular form may be infeasible because of the excessive amount of memory needed to store the table. Second, rewards in the state space may be so sparse that with random exploration they will only be discovered extremely slowly. In this paper, we propose a navigation approach for mobile robot, in which the prior knowledge is used within Q-learning. We address the issue of individual behavior design using fuzzy logic. The strategy of behaviors based navigation reduces the complexity of the navigation problem by dividing them in small actions easier for design and implementation. The Q-Learning algorithm is applied to coordinate between these behaviors, which make a great reduction in learning convergence times. Simulation and experimental results confirm the convergence to the desired results in terms of saved time and computational resources.

33 CFR 150.705 - What are the requirements for maintaining and inspecting aids to navigation?

Science.gov (United States)

2010-07-01

... maintaining and inspecting aids to navigation? 150.705 Section 150.705 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DEEPWATER PORTS DEEPWATER PORTS: OPERATIONS Aids to Navigation § 150.705 What are the requirements for maintaining and inspecting aids to navigation? (a) All...

The contribution of virtual reality to the diagnosis of spatial navigation disorders and to the study of the role of navigational aids: A systematic literature review.

Science.gov (United States)

Cogné, M; Taillade, M; N'Kaoua, B; Tarruella, A; Klinger, E; Larrue, F; Sauzéon, H; Joseph, P-A; Sorita, E

2017-06-01

Spatial navigation, which involves higher cognitive functions, is frequently implemented in daily activities, and is critical to the participation of human beings in mainstream environments. Virtual reality is an expanding tool, which enables on one hand the assessment of the cognitive functions involved in spatial navigation, and on the other the rehabilitation of patients with spatial navigation difficulties. Topographical disorientation is a frequent deficit among patients suffering from neurological diseases. The use of virtual environments enables the information incorporated into the virtual environment to be manipulated empirically. But the impact of manipulations seems differ according to their nature (quantity, occurrence, and characteristics of the stimuli) and the target population. We performed a systematic review of research on virtual spatial navigation covering the period from 2005 to 2015. We focused first on the contribution of virtual spatial navigation for patients with brain injury or schizophrenia, or in the context of ageing and dementia, and then on the impact of visual or auditory stimuli on virtual spatial navigation. On the basis of 6521 abstracts identified in 2 databases (Pubmed and Scopus) with the keywords « navigation » and « virtual », 1103 abstracts were selected by adding the keywords "ageing", "dementia", "brain injury", "stroke", "schizophrenia", "aid", "help", "stimulus" and "cue"; Among these, 63 articles were included in the present qualitative analysis. Unlike pencil-and-paper tests, virtual reality is useful to assess large-scale navigation strategies in patients with brain injury or schizophrenia, or in the context of ageing and dementia. Better knowledge about both the impact of the different aids and the cognitive processes involved is essential for the use of aids in neurorehabilitation. Copyright © 2016. Published by Elsevier Masson SAS.

Monitoring of zebra mussels in the Shannon-Boyle navigation, other

OpenAIRE

Minchin, D.; Lucy, F.; Sullivan, M.

2002-01-01

The zebra mussel (Dreissena polymorpha) population has been closely monitored in Ireland following its discovery in 1997. The species has spread from lower Lough Derg, where it was first introduced, to most of the navigable areas of the Shannon and other interconnected navigable waters. This study took place in the summers of 2000 and 2001 and investigated the relative abundance and biomass of zebra mussels found in the main navigations of the Shannon and elsewhere in rivers, canals and lakes...

The Navigation Guide—Evidence-Based Medicine Meets Environmental Health: Systematic Review of Human Evidence for PFOA Effects on Fetal Growth

Science.gov (United States)

Sutton, Patrice; Atchley, Dylan S.; Koustas, Erica; Lam, Juleen; Sen, Saunak; Robinson, Karen A.; Axelrad, Daniel A.; Woodruff, Tracey J.

2014-01-01

Background: The Navigation Guide methodology was developed to meet the need for a robust method of systematic and transparent research synthesis in environmental health science. We conducted a case study systematic review to support proof of concept of the method. Objective: We applied the Navigation Guide systematic review methodology to determine whether developmental exposure to perfluorooctanoic acid (PFOA) affects fetal growth in humans. Methods: We applied the first 3 steps of the Navigation Guide methodology to human epidemiological data: 1) specify the study question, 2) select the evidence, and 3) rate the quality and strength of the evidence. We developed a protocol, conducted a comprehensive search of the literature, and identified relevant studies using prespecified criteria. We evaluated each study for risk of bias and conducted meta-analyses on a subset of studies. We rated quality and strength of the entire body of human evidence. Results: We identified 18 human studies that met our inclusion criteria, and 9 of these were combined through meta-analysis. Through meta-analysis, we estimated that a 1-ng/mL increase in serum or plasma PFOA was associated with a –18.9 g (95% CI: –29.8, –7.9) difference in birth weight. We concluded that the risk of bias across studies was low, and we assigned a “moderate” quality rating to the overall body of human evidence. Conclusion: On the basis of this first application of the Navigation Guide systematic review methodology, we concluded that there is “sufficient” human evidence that developmental exposure to PFOA reduces fetal growth. Citation: Johnson PI, Sutton P, Atchley DS, Koustas E, Lam J, Sen S, Robinson KA, Axelrad DA, Woodruff TJ. 2014. The Navigation Guide—evidence-based medicine meets environmental health: systematic review of human evidence for PFOA effects on fetal growth. Environ Health Perspect 122:1028–1039; http://dx.doi.org/10.1289/ehp.1307893 PMID:24968388

Implementation of a vector-based tracking loop receiver in a pseudolite navigation system.

Science.gov (United States)

So, Hyoungmin; Lee, Taikjin; Jeon, Sanghoon; Kim, Chongwon; Kee, Changdon; Kim, Taehee; Lee, Sanguk

2010-01-01

We propose a vector tracking loop (VTL) algorithm for an asynchronous pseudolite navigation system. It was implemented in a software receiver and experiments in an indoor navigation system were conducted. Test results show that the VTL successfully tracks signals against the near-far problem, one of the major limitations in pseudolite navigation systems, and could improve positioning availability by extending pseudolite navigation coverage.

GPS navigation algorithms for Autonomous Airborne Refueling of Unmanned Air Vehicles

Science.gov (United States)

Khanafseh, Samer Mahmoud

Unmanned Air Vehicles (UAVs) have recently generated great interest because of their potential to perform hazardous missions without risking loss of life. If autonomous airborne refueling is possible for UAVs, mission range and endurance will be greatly enhanced. However, concerns about UAV-tanker proximity, dynamic mobility and safety demand that the relative navigation system meets stringent requirements on accuracy, integrity, and continuity. In response, this research focuses on developing high-performance GPS-based navigation architectures for Autonomous Airborne Refueling (AAR) of UAVs. The AAR mission is unique because of the potentially severe sky blockage introduced by the tanker. To address this issue, a high-fidelity dynamic sky blockage model was developed and experimentally validated. In addition, robust carrier phase differential GPS navigation algorithms were derived, including a new method for high-integrity reacquisition of carrier cycle ambiguities for recently-blocked satellites. In order to evaluate navigation performance, world-wide global availability and sensitivity covariance analyses were conducted. The new navigation algorithms were shown to be sufficient for turn-free scenarios, but improvement in performance was necessary to meet the difficult requirements for a general refueling mission with banked turns. Therefore, several innovative methods were pursued to enhance navigation performance. First, a new theoretical approach was developed to quantify the position-domain integrity risk in cycle ambiguity resolution problems. A mechanism to implement this method with partially-fixed cycle ambiguity vectors was derived, and it was used to define tight upper bounds on AAR navigation integrity risk. A second method, where a new algorithm for optimal fusion of measurements from multiple antennas was developed, was used to improve satellite coverage in poor visibility environments such as in AAR. Finally, methods for using data-link extracted

PROBLEMS OF SEA-GOING NAVIGATION IN KERCI STRAIT

Directory of Open Access Journals (Sweden)

M. ŞTEFAN

2011-03-01

Full Text Available Kerch Strait was the main passage between the Azov Sea and the Black Sea.The passage of ships through the strait is hampered by several physical and geographical factors: emerged and submerged morphology, the climatic and hydrological parameters. As a result of the extremely low depths of the strait, for the safety of navigation, authorities have been forced to dredge a canal for passage of the vessels with a medium draft, to make a properly hydrographical develop¬ment of the fairway and of the shores, and to establish a favorable anchoring area etc. Ice, which occurs in winter, makes the navigation very difficult, which takes place in convoys, preceded by ice breakers. Fog, frequent in the transitional seasons, hampered navigation; many accidents happened because of this inconvenience. Most accidents due to weather conditions (fog, wind are specific to smaller vessels, sea-river type, which are sailing in the area and which, due to their construction, are not able to deal with exceptional weather conditions at sea. The existence of surface currents, with the dominant direction north-south, from the Sea of Azov to the Black Sea, affects navigation only around the heads where cau¬ses circular currents. In this case are affected only pleasure boats and low powered vessel. With all these impediments to navigation, the Kerch Strait is an important waterway, especially for the countries bordering the Sea of Azov: Ukraine and the Russian Federation, and also for the countries from the Black Sea basin.

Distributed Cognition in Ship Navigation and Prevention of Collision

DEFF Research Database (Denmark)

Koester, Thomas; Hyll, Nikolaj; Stage, Jan

2009-01-01

In this paper we investigate how technology can help the navigator to a better performance. We use three examples based on observations onboard three ships to show, how technology can support the work of the navigator and thereby enhance the performance. Our analysis is based on the paradigm...

Prefrontal-hippocampal interactions for spatial navigation.

Science.gov (United States)

Ito, Hiroshi T

2018-04-01

Animals have the ability to navigate to a desired location by making use of information about environmental landmarks and their own movements. While decades of neuroscience research have identified neurons in the hippocampus and parahippocampal structures that represent an animal's position in space, it is still largely unclear how an animal can choose the next movement direction to reach a desired goal. As the goal destination is typically located somewhere outside of the range of sensory perception, the animal is required to rely on the internal metric of space to estimate the direction and distance of the destination to plan a next action. Therefore, the hippocampal spatial map should interact with action-planning systems in other cortical regions. In accordance with this idea, several recent studies have indicated the importance of functional interactions between the hippocampus and the prefrontal cortex for goal-directed navigation. In this paper, I will review these studies and discuss how an animal can estimate its future positions correspond to a next movement. Investigation of the navigation problem may further provide general insights into internal models of the brain for action planning. Copyright © 2017 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

Unmanned Ground Vehicle Navigation and Coverage Hole Patching in Wireless Sensor Networks

Science.gov (United States)

Zhang, Guyu

2013-01-01

This dissertation presents a study of an Unmanned Ground Vehicle (UGV) navigation and coverage hole patching in coordinate-free and localization-free Wireless Sensor Networks (WSNs). Navigation and coverage maintenance are related problems since coverage hole patching requires effective navigation in the sensor network environment. A…

METHODOLOGY FOR ANALYSIS OF DECISION MAKING IN AIR NAVIGATION SYSTEM

Directory of Open Access Journals (Sweden)

Volodymyr Kharchenko

2011-03-01

Full Text Available Abstract. In the research of Air Navigation System as a complex socio-technical system the methodologyof analysis of human-operator's decision-making has been developed. The significance of individualpsychologicalfactors as well as the impact of socio-psychological factors on the professional activities of ahuman-operator during the flight situation development from normal to catastrophic were analyzed. On thebasis of the reflexive theory of bipolar choice the expected risks of decision-making by the Air NavigationSystem's operator influenced by external environment, previous experience and intentions were identified.The methods for analysis of decision-making by the human-operator of Air Navigation System usingstochastic networks have been developed.Keywords: Air Navigation System, bipolar choice, human operator, decision-making, expected risk, individualpsychologicalfactors, methodology of analysis, reflexive model, socio-psychological factors, stochastic network.

Observability during planetary approach navigation

Science.gov (United States)

Bishop, Robert H.; Burkhart, P. Daniel; Thurman, Sam W.

1993-01-01

The objective of the research is to develop an analytic technique to predict the relative navigation capability of different Earth-based radio navigation measurements. In particular, the problem is to determine the relative ability of geocentric range and Doppler measurements to detect the effects of the target planet gravitational attraction on the spacecraft during the planetary approach and near-encounter mission phases. A complete solution to the two-dimensional problem has been developed. Relatively simple analytic formulas are obtained for range and Doppler measurements which describe the observability content of the measurement data along the approach trajectories. An observability measure is defined which is based on the observability matrix for nonlinear systems. The results show good agreement between the analytic observability analysis and the computational batch processing method.

33 CFR 162.260 - Channel leading to San Juan Harbor, P.R.; use, administration, and navigation.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Channel leading to San Juan Harbor, P.R.; use, administration, and navigation. 162.260 Section 162.260 Navigation and Navigable... WATERWAYS NAVIGATION REGULATIONS § 162.260 Channel leading to San Juan Harbor, P.R.; use, administration...

Navigating the MESSENGER Spacecraft through End of Mission

Science.gov (United States)

Bryan, C. G.; Williams, B. G.; Williams, K. E.; Taylor, A. H.; Carranza, E.; Page, B. R.; Stanbridge, D. R.; Mazarico, E.; Neumann, G. A.; O'Shaughnessy, D. J.; McAdams, J. V.; Calloway, A. B.

2015-12-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft orbited the planet Mercury from March 2011 until the end of April 2015, when it impacted the planetary surface after propellant reserves used to maintain the orbit were depleted. This highly successful mission was led by the principal investigator, Sean C. Solomon, of Columbia University. The Johns Hopkins University Applied Physics Laboratory (JHU/APL) designed and assembled the spacecraft and served as the home for spacecraft operations. Spacecraft navigation for the entirety of the mission was provided by the Space Navigation and Flight Dynamics Practice (SNAFD) of KinetX Aerospace. Orbit determination (OD) solutions were generated through processing of radiometric tracking data provided by NASA's Deep Space Network (DSN) using the MIRAGE suite of orbital analysis tools. The MESSENGER orbit was highly eccentric, with periapsis at a high northern latitude and periapsis altitude in the range 200-500 km for most of the orbital mission phase. In a low-altitude "hover campaign" during the final two months of the mission, periapsis altitudes were maintained within a narrow range between about 35 km and 5 km. Navigating a spacecraft so near a planetary surface presented special challenges. Tasks required to meet those challenges included the modeling and estimation of Mercury's gravity field and of solar and planetary radiation pressure, and the design of frequent orbit-correction maneuvers. Superior solar conjunction also presented observational modeling issues. One key to the overall success of the low-altitude hover campaign was a strategy to utilize data from an onboard laser altimeter as a cross-check on the navigation team's reconstructed and predicted estimates of periapsis altitude. Data obtained from the Mercury Laser Altimeter (MLA) on a daily basis provided near-real-time feedback that proved invaluable in evaluating alternative orbit estimation strategies, and

Unified Approach of Unmanned Surface Vehicle Navigation in Presence of Waves

Directory of Open Access Journals (Sweden)

Oren Gal

2011-01-01

Full Text Available Most of the present work for unmanned surface vehicle (USV navigation does not take into account environmental disturbances such as ocean waves, winds, and currents. In some scenarios, waves should be treated as special case of dynamic obstacle and can be critical to USV’s safety. For the first time, this paper presents unique concept facing this challenge by combining ocean waves' formulation with the probabilistic velocity obstacle (PVO method for autonomous navigation. A simple navigation algorithm is presented in order to apply the method of USV’s navigation in presence of waves. A planner simulation dealing with waves and obstacles avoidance is introduced.

Lunar Navigator - A Miniature, Fully Autonomous, Lunar Navigation, Surveyor, and Range Finder System, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Microcosm will use existing hardware and software from related programs to create a prototype Lunar Navigation Sensor (LNS) early in Phase II, such that most of the...

New Navigation Post-Processing Tools for Oceanographic Submersibles

Science.gov (United States)

Kinsey, J. C.; Whitcomb, L. L.; Yoerger, D. R.; Howland, J. C.; Ferrini, V. L.; Hegrenas, O.

2006-12-01

We report the development of Navproc, a new set of software tools for post-processing oceanographic submersible navigation data that exploits previously reported improvements in navigation sensing and estimation (e.g. Eos Trans. AGU, 84(46), Fall Meet. Suppl., Abstract OS32A- 0225, 2003). The development of these tools is motivated by the need to have post-processing software that allows users to compensate for errors in vehicle navigation, recompute the vehicle position, and then save the results for use with quantitative science data (e.g. bathymetric sonar data) obtained during the mission. Navproc does not provide real-time navigation or display of data nor is it capable of high-resolution, three dimensional (3D) data display. Navproc supports the ASCII data formats employed by the vehicles of the National Deep Submergence Facility (NDSF) operated by the Woods Hole Oceanographic Institution (WHOI). Post-processing of navigation data with Navproc is comprised of three tasks. First, data is converted from the logged ASCII file to a binary Matlab file. When loaded into Matlab, each sensor has a data structure containing the time stamped data sampled at the native update rate of the sensor. An additional structure contains the real-time vehicle navigation data. Second, the data can be displayed using a Graphical User Interface (GUI), allowing users to visually inspect the quality of the data and graphically extract portions of the data. Third, users can compensate for errors in the real-time vehicle navigation. Corrections include: (i) manual filtering and median filtering of long baseline (LBL) ranges; (ii) estimation of the Doppler/gyro alignment using previously reported methodologies; and (iii) sound velocity, tide, and LBL transponder corrections. Using these corrections, the Doppler and LBL positions can be recomputed to provide improved estimates of the vehicle position compared to those computed in real-time. The data can be saved in either binary or ASCII

NOAA Electronic Navigational Charts (ENC)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Office of Coast Survey (OCS) has been involved in the development of a NOAA Electronic Navigational Chart (NOAA ENC) suite to support the marine transportation...

Jig-Time and Navigational Support in the Control of Road Transport

Directory of Open Access Journals (Sweden)

Nataliya Grigorievna Kuftinova

2015-05-01

Full Text Available In this article the question of the direction of use of jig-time and navigation providing the motor transport in the field of steering of transportation process is considered. The solution of transport tasks demand existence of jig-time and navigation providing (JTNP based on use of the global navigation satellite systems (GNSS, geographical information systems (GIS, means and technologies of telematics.

33 CFR 66.05-10 - State waters for private aids to navigation; designations; revisions, and revocations.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false State waters for private aids to... Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-10 State waters for private aids to navigation; designations; revisions, and...

A goggle navigation system for cancer resection surgery

Science.gov (United States)

Xu, Junbin; Shao, Pengfei; Yue, Ting; Zhang, Shiwu; Ding, Houzhu; Wang, Jinkun; Xu, Ronald

2014-02-01

We describe a portable fluorescence goggle navigation system for cancer margin assessment during oncologic surgeries. The system consists of a computer, a head mount display (HMD) device, a near infrared (NIR) CCD camera, a miniature CMOS camera, and a 780 nm laser diode excitation light source. The fluorescence and the background images of the surgical scene are acquired by the CCD camera and the CMOS camera respectively, co-registered, and displayed on the HMD device in real-time. The spatial resolution and the co-registration deviation of the goggle navigation system are evaluated quantitatively. The technical feasibility of the proposed goggle system is tested in an ex vivo tumor model. Our experiments demonstrate the feasibility of using a goggle navigation system for intraoperative margin detection and surgical guidance.

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

Navigation: bat orientation using Earth's magnetic field.

Science.gov (United States)

Holland, Richard A; Thorup, Kasper; Vonhof, Maarten J; Cochran, William W; Wikelski, Martin

2006-12-07

Bats famously orientate at night by echolocation, but this works over only a short range, and little is known about how they navigate over longer distances. Here we show that the homing behaviour of Eptesicus fuscus, known as the big brown bat, can be altered by artificially shifting the Earth's magnetic field, indicating that these bats rely on a magnetic compass to return to their home roost. This finding adds to the impressive array of sensory abilities possessed by this animal for navigation in the dark.

33 CFR 164.78 - Navigation under way: Towing vessels.

Science.gov (United States)

2010-07-01

...) Evaluates the danger of each closing visual or radar contact; (5) Knows and applies the variation and... type of correction; (6) Knows the speed and direction of the current, and the set, drift, and tidal... vessels. 164.78 Section 164.78 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND...

Issues in symbol design for electronic displays of navigation information

Science.gov (United States)

2004-10-24

An increasing number of electronic displays, ranging from small hand-held displays for general aviation to installed displays for air transport, are showing navigation information, such as symbols representing navigational aids. The wide range of dis...

A Neural Path Integration Mechanism for Adaptive Vector Navigation in Autonomous Agents

DEFF Research Database (Denmark)

Goldschmidt, Dennis; Dasgupta, Sakyasingha; Wörgötter, Florentin

2015-01-01

Animals show remarkable capabilities in navigating their habitat in a fully autonomous and energy-efficient way. In many species, these capabilities rely on a process called path integration, which enables them to estimate their current location and to find their way back home after long-distance...... of autonomous agent navigation, but it also reproduces various aspects of animal navigation. Finally, we discuss how the proposed path integration mechanism may be used as a scaffold for spatial learning in terms of vector navigation.......Animals show remarkable capabilities in navigating their habitat in a fully autonomous and energy-efficient way. In many species, these capabilities rely on a process called path integration, which enables them to estimate their current location and to find their way back home after long...

Age-Specific Patient Navigation Preferences Among Adolescents and Young Adults with Cancer.

Science.gov (United States)

Pannier, Samantha T; Warner, Echo L; Fowler, Brynn; Fair, Douglas; Salmon, Sara K; Kirchhoff, Anne C

2017-11-23

Patient navigation is increasingly being directed at adolescent and young adult (AYA) patients. This study provides a novel description of differences in AYA cancer patients' preferences for navigation services by developmental age at diagnosis. Eligible patients were diagnosed with cancer between ages 15 and 39 and had completed at least 1 month of treatment. Between October 2015 and January 2016, patients completed semi-structured interviews about navigation preferences. Summary statistics of demographic and cancer characteristics were generated. Differences in patient navigation preferences were examined through qualitative analyses by developmental age at diagnosis. AYAs were interviewed (adolescents 15-18 years N = 8; emerging adults 19-25 years N = 8; young adults 26-39 years N = 23). On average, participants were 4.5 years from diagnosis. All age groups were interested in face-to-face connection with a navigator and using multiple communication platforms (phone, text, email) to follow-up. Three of the most frequently cited needs were insurance, finances, and information. AYAs differed in support, healthcare, and resource preferences by developmental age; only adolescents preferred educational support. While all groups preferred financial and family support, the specific type of assistance (medical versus living expenses, partner/spouse, child, or parental assistance) varied by age group. AYAs with cancer have different preferences for patient navigation by developmental age at diagnosis. AYAs are not a one-size-fits-all population, and navigation programs can better assist AYAs when services are targeted to appropriate developmental ages. Future research should examine fertility and navigation preferences by time since diagnosis. While some navigation needs to span the AYA age range, other needs are specific to developmental age.

Lunar Navigator - A Miniature, Fully Autonomous, Lunar Navigation, Surveyor, and Range Finder System, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Microcosm proposes to design and develop a fully autonomous Lunar Navigator based on our MicroMak miniature star sensor and a gravity gradiometer similar to one on a...

Evaluation of a Hospital-Based Pneumonia Nurse Navigator Program.

Science.gov (United States)

Seldon, Lisa E; McDonough, Kelly; Turner, Barbara; Simmons, Leigh Ann

2016-12-01

The aim of this study is to evaluate the effectiveness of a hospital-based pneumonia nurse navigator program. This study used a retrospective, formative evaluation. Data of patients admitted from January 2012 through December 2014 to a large community hospital with a primary or secondary diagnosis of pneumonia, excluding aspiration pneumonia, were used. Data included patient demographics, diagnoses, insurance coverage, core measures, average length of stay (ALOS), disposition, readmission rate, financial outcomes, and patient barriers to care were collected. Descriptive statistics and parametric testing were used to analyze data. Core measure performance was sustained at the 90th percentile 2 years after the implementation of the navigator program. The ALOS did not decrease to established benchmarks; however, the SD for ALOS decreased by nearly half after implementation of the navigator program, suggesting the program decreased the number and length of extended stays. Charges per case decreased by 21% from 2012 to 2014. Variable costs decreased by 4% over a 2-year period, which increased net profit per case by 5%. Average readmission payments increased by 8% from 2012 to 2014, and the net revenue per case increased by 8.3%. The pneumonia nurse navigator program may improve core measures, reduce ALOS, and increase net revenue. Future evaluations are necessary to substantiate these findings and optimize the cost and quality performance of navigator programs.

Ultrasound-based tumor movement compensation during navigated laparoscopic liver interventions.

Science.gov (United States)

Shahin, Osama; Beširević, Armin; Kleemann, Markus; Schlaefer, Alexander

2014-05-01

Image-guided navigation aims to provide better orientation and accuracy in laparoscopic interventions. However, the ability of the navigation system to reflect anatomical changes and maintain high accuracy during the procedure is crucial. This is particularly challenging in soft organs such as the liver, where surgical manipulation causes significant tumor movements. We propose a fast approach to obtain an accurate estimation of the tumor position throughout the procedure. Initially, a three-dimensional (3D) ultrasound image is reconstructed and the tumor is segmented. During surgery, the position of the tumor is updated based on newly acquired tracked ultrasound images. The initial segmentation of the tumor is used to automatically detect the tumor and update its position in the navigation system. Two experiments were conducted. First, a controlled phantom motion using a robot was performed to validate the tracking accuracy. Second, a needle navigation scenario based on pseudotumors injected into ex vivo porcine liver was studied. In the robot-based evaluation, the approach estimated the target location with an accuracy of 0.4 ± 0.3 mm. The mean navigation error in the needle experiment was 1.2 ± 0.6 mm, and the algorithm compensated for tumor shifts up to 38 mm in an average time of 1 s. We demonstrated a navigation approach based on tracked laparoscopic ultrasound (LUS), and focused on the neighborhood of the tumor. Our experimental results indicate that this approach can be used to quickly and accurately compensate for tumor movements caused by surgical manipulation during laparoscopic interventions. The proposed approach has the advantage of being based on the routinely used LUS; however, it upgrades its functionality to estimate the tumor position in 3D. Hence, the approach is repeatable throughout surgery, and enables high navigation accuracy to be maintained.

Juvenile Osprey Navigation during Trans-Oceanic Migration.

Directory of Open Access Journals (Sweden)

Travis W Horton

Full Text Available To compensate for drift, an animal migrating through air or sea must be able to navigate. Although some species of bird, fish, insect, mammal, and reptile are capable of drift compensation, our understanding of the spatial reference frame, and associated coordinate space, in which these navigational behaviors occur remains limited. Using high resolution satellite-monitored GPS track data, we show that juvenile ospreys (Pandion haliaetus are capable of non-stop constant course movements over open ocean spanning distances in excess of 1500 km despite the perturbing effects of winds and the lack of obvious landmarks. These results are best explained by extreme navigational precision in an exogenous spatio-temporal reference frame, such as positional orientation relative to Earth's magnetic field and pacing relative to an exogenous mechanism of keeping time. Given the age (<1 year-old of these birds and knowledge of their hatching site locations, we were able to transform Enhanced Magnetic Model coordinate locations such that the origin of the magnetic coordinate space corresponded with each bird's nest. Our analyses show that trans-oceanic juvenile osprey movements are consistent with bicoordinate positional orientation in transformed magnetic coordinate or geographic space. Through integration of movement and meteorological data, we propose a new theoretical framework, chord and clock navigation, capable of explaining the precise spatial orientation and temporal pacing performed by juvenile ospreys during their long-distance migrations over open ocean.

Indoor Navigation from Point Clouds: 3d Modelling and Obstacle Detection

Science.gov (United States)

Díaz-Vilariño, L.; Boguslawski, P.; Khoshelham, K.; Lorenzo, H.; Mahdjoubi, L.

2016-06-01

In the recent years, indoor modelling and navigation has become a research of interest because many stakeholders require navigation assistance in various application scenarios. The navigational assistance for blind or wheelchair people, building crisis management such as fire protection, augmented reality for gaming, tourism or training emergency assistance units are just some of the direct applications of indoor modelling and navigation. Navigational information is traditionally extracted from 2D drawings or layouts. Real state of indoors, including opening position and geometry for both windows and doors, and the presence of obstacles is commonly ignored. In this work, a real indoor-path planning methodology based on 3D point clouds is developed. The value and originality of the approach consist on considering point clouds not only for reconstructing semantically-rich 3D indoor models, but also for detecting potential obstacles in the route planning and using these for readapting the routes according to the real state of the indoor depictured by the laser scanner.

INDOOR NAVIGATION FROM POINT CLOUDS: 3D MODELLING AND OBSTACLE DETECTION

Directory of Open Access Journals (Sweden)

L. Díaz-Vilariño

2016-06-01

Full Text Available In the recent years, indoor modelling and navigation has become a research of interest because many stakeholders require navigation assistance in various application scenarios. The navigational assistance for blind or wheelchair people, building crisis management such as fire protection, augmented reality for gaming, tourism or training emergency assistance units are just some of the direct applications of indoor modelling and navigation. Navigational information is traditionally extracted from 2D drawings or layouts. Real state of indoors, including opening position and geometry for both windows and doors, and the presence of obstacles is commonly ignored. In this work, a real indoor-path planning methodology based on 3D point clouds is developed. The value and originality of the approach consist on considering point clouds not only for reconstructing semantically-rich 3D indoor models, but also for detecting potential obstacles in the route planning and using these for readapting the routes according to the real state of the indoor depictured by the laser scanner.

Integrated navigation of aerial robot for GPS and GPS-denied environment

International Nuclear Information System (INIS)

Suzuki, Satoshi; Min, Hongkyu; Nonami, Kenzo; Wada, Tetsuya

2016-01-01

In this study, novel robust navigation system for aerial robot in GPS and GPS- denied environments is proposed. Generally, the aerial robot uses position and velocity information from Global Positioning System (GPS) for guidance and control. However, GPS could not be used in several environments, for example, GPS has huge error near buildings and trees, indoor, and so on. In such GPS-denied environment, Laser Detection and Ranging (LIDER) sensor based navigation system have generally been used. However, LIDER sensor also has an weakness, and it could not be used in the open outdoor environment where GPS could be used. Therefore, it is desired to develop the integrated navigation system which is seamlessly applied to GPS and GPS-denied environments. In this paper, the integrated navigation system for aerial robot using GPS and LIDER is developed. The navigation system is designed based on Extended Kalman Filter, and the effectiveness of the developed system is verified by numerical simulation and experiment. (paper)

Instrument-mounted displays for reducing cognitive load during surgical navigation.

Science.gov (United States)

Herrlich, Marc; Tavakol, Parnian; Black, David; Wenig, Dirk; Rieder, Christian; Malaka, Rainer; Kikinis, Ron

2017-09-01

Surgical navigation systems rely on a monitor placed in the operating room to relay information. Optimal monitor placement can be challenging in crowded rooms, and it is often not possible to place the monitor directly beside the situs. The operator must split attention between the navigation system and the situs. We present an approach for needle-based interventions to provide navigational feedback directly on the instrument and close to the situs by mounting a small display onto the needle. By mounting a small and lightweight smartwatch display directly onto the instrument, we are able to provide navigational guidance close to the situs and directly in the operator's field of view, thereby reducing the need to switch the focus of view between the situs and the navigation system. We devise a specific variant of the established crosshair metaphor suitable for the very limited screen space. We conduct an empirical user study comparing our approach to using a monitor and a combination of both. Results from the empirical user study show significant benefits for cognitive load, user preference, and general usability for the instrument-mounted display, while achieving the same level of performance in terms of time and accuracy compared to using a monitor. We successfully demonstrate the feasibility of our approach and potential benefits. With ongoing technological advancements, instrument-mounted displays might complement standard monitor setups for surgical navigation in order to lower cognitive demands and for improved usability of such systems.

Space Launch Systems Block 1B Preliminary Navigation System Design

Science.gov (United States)

Oliver, T. Emerson; Park, Thomas; Anzalone, Evan; Smith, Austin; Strickland, Dennis; Patrick, Sean

2018-01-01

NASA is currently building the Space Launch Systems (SLS) Block 1 launch vehicle for the Exploration Mission 1 (EM-1) test flight. In parallel, NASA is also designing the Block 1B launch vehicle. The Block 1B vehicle is an evolution of the Block 1 vehicle and extends the capability of the NASA launch vehicle. This evolution replaces the Interim Cryogenic Propulsive Stage (ICPS) with the Exploration Upper Stage (EUS). As the vehicle evolves to provide greater lift capability, increased robustness for manned missions, and the capability to execute more demanding missions so must the SLS Integrated Navigation System evolved to support those missions. This paper describes the preliminary navigation systems design for the SLS Block 1B vehicle. The evolution of the navigation hard-ware and algorithms from an inertial-only navigation system for Block 1 ascent flight to a tightly coupled GPS-aided inertial navigation system for Block 1B is described. The Block 1 GN&C system has been designed to meet a LEO insertion target with a specified accuracy. The Block 1B vehicle navigation system is de-signed to support the Block 1 LEO target accuracy as well as trans-lunar or trans-planetary injection accuracy. Additionally, the Block 1B vehicle is designed to support human exploration and thus is designed to minimize the probability of Loss of Crew (LOC) through high-quality inertial instruments and robust algorithm design, including Fault Detection, Isolation, and Recovery (FDIR) logic.

Navigation through unknown and dynamic open spaces using topological notions

Science.gov (United States)

Miguel-Tomé, Sergio

2018-04-01

Until now, most algorithms used for navigation have had the purpose of directing system towards one point in space. However, humans communicate tasks by specifying spatial relations among elements or places. In addition, the environments in which humans develop their activities are extremely dynamic. The only option that allows for successful navigation in dynamic and unknown environments is making real-time decisions. Therefore, robots capable of collaborating closely with human beings must be able to make decisions based on the local information registered by the sensors and interpret and express spatial relations. Furthermore, when one person is asked to perform a task in an environment, this task is communicated given a category of goals so the person does not need to be supervised. Thus, two problems appear when one wants to create multifunctional robots: how to navigate in dynamic and unknown environments using spatial relations and how to accomplish this without supervision. In this article, a new architecture to address the two cited problems is presented, called the topological qualitative navigation architecture. In previous works, a qualitative heuristic called the heuristic of topological qualitative semantics (HTQS) has been developed to establish and identify spatial relations. However, that heuristic only allows for establishing one spatial relation with a specific object. In contrast, navigation requires a temporal sequence of goals with different objects. The new architecture attains continuous generation of goals and resolves them using HTQS. Thus, the new architecture achieves autonomous navigation in dynamic or unknown open environments.

Error Analysis System for Spacecraft Navigation Using the Global Positioning System (GPS)

Science.gov (United States)

Truong, S. H.; Hart, R. C.; Hartman, K. R.; Tomcsik, T. L.; Searl, J. E.; Bernstein, A.

1997-01-01

The Flight Dynamics Division (FDD) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) is currently developing improved space-navigation filtering algorithms to use the Global Positioning System (GPS) for autonomous real-time onboard orbit determination. In connection with a GPS technology demonstration on the Small Satellite Technology Initiative (SSTI)/Lewis spacecraft, FDD analysts and programmers have teamed with the GSFC Guidance, Navigation, and Control Branch to develop the GPS Enhanced Orbit Determination Experiment (GEODE) system. The GEODE system consists of a Kalman filter operating as a navigation tool for estimating the position, velocity, and additional states required to accurately navigate the orbiting Lewis spacecraft by using astrodynamic modeling and GPS measurements from the receiver. A parallel effort at the FDD is the development of a GPS Error Analysis System (GEAS) that will be used to analyze and improve navigation filtering algorithms during development phases and during in-flight calibration. For GEAS, the Kalman filter theory is extended to estimate the errors in position, velocity, and other error states of interest. The estimation of errors in physical variables at regular intervals will allow the time, cause, and effect of navigation system weaknesses to be identified. In addition, by modeling a sufficient set of navigation system errors, a system failure that causes an observed error anomaly can be traced and accounted for. The GEAS software is formulated using Object Oriented Design (OOD) techniques implemented in the C++ programming language on a Sun SPARC workstation. The Phase 1 of this effort is the development of a basic system to be used to evaluate navigation algorithms implemented in the GEODE system. This paper presents the GEAS mathematical methodology, systems and operations concepts, and software design and implementation. Results from the use of the basic system to evaluate

Autonomous GPS/INS navigation experiment for Space Transfer Vehicle (STV)

Science.gov (United States)

Upadhyay, Triveni N.; Cotterill, Stephen; Deaton, A. Wayne

1991-01-01

An experiment to validate the concept of developing an autonomous integrated spacecraft navigation system using on board Global Positioning System (GPS) and Inertial Navigation System (INS) measurements is described. The feasibility of integrating GPS measurements with INS measurements to provide a total improvement in spacecraft navigation performance, i.e. improvement in position, velocity and attitude information, was previously demonstrated. An important aspect of this research is the automatic real time reconfiguration capability of the system designed to respond to changes in a spacecraft mission under the control of an expert system.

Modular Software for Spacecraft Navigation Using the Global Positioning System (GPS)

Science.gov (United States)

Truong, S. H.; Hartman, K. R.; Weidow, D. A.; Berry, D. L.; Oza, D. H.; Long, A. C.; Joyce, E.; Steger, W. L.

1996-01-01

The Goddard Space Flight Center Flight Dynamics and Mission Operations Divisions have jointly investigated the feasibility of engineering modular Global Positioning SYSTEM (GPS) navigation software to support both real time flight and ground postprocessing configurations. The goals of this effort are to define standard GPS data interfaces and to engineer standard, reusable navigation software components that can be used to build a broad range of GPS navigation support applications. The paper discusses the GPS modular software (GMOD) system and operations concepts, major requirements, candidate software architecture, feasibility assessment and recommended software interface standards. In additon, ongoing efforts to broaden the scope of the initial study and to develop modular software to support autonomous navigation using GPS are addressed,

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.

BOREAS Level-0 ER-2 Navigation Data

Science.gov (United States)

Strub, Richard; Dominguez, Roseanne; Newcomer, Jeffrey A.; Hall, Forrest G. (Editor)

2000-01-01

The BOREAS Staff Science effort covered those activities that were BOREAS community-level activities or required uniform data collection procedures across sites and time. These activities included the acquisition, processing, and archiving of aircraft navigation/attitude data to complement the digital image data. The level-0 ER-2 navigation data files contain aircraft attitude and position information acquired during the digital image and photographic data collection missions. Temporally, the data were acquired from April to September 1994. Data were recorded at intervals of 5 seconds. The data are stored in tabular ASCII files.

Navigation: Bat orientation using Earth's magnetic field

DEFF Research Database (Denmark)

Holland, Richard A.; Thorup, Kasper; Vonhof, Maarten J.

2006-01-01

Bats famously orientate at night by echolocation 1 , but this works over only a short range, and little is known about how they navigate over longer distances 2 . Here we show that the homing behaviour of Eptesicus fuscus, known as the big brown bat, can be altered by artificially shifting the Ea...... the Earth's magnetic field, indicating that these bats rely on a magnetic compass to return to their home roost. This finding adds to the impressive array of sensory abilities possessed by this animal for navigation in the dark....