14 CFR 63.55 - Experience requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... satisfactory flight navigation including celestial and radio navigation and dead reckoning. A pilot who has... exclusively for practicing long-range navigation methods, with emphasis on celestial navigation and dead...

14 CFR 63.55 - Experience requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... satisfactory flight navigation including celestial and radio navigation and dead reckoning. A pilot who has... exclusively for practicing long-range navigation methods, with emphasis on celestial navigation and dead...

Statistical Sensor Fusion of a 9-DOF Mems Imu for Indoor Navigation

NASA Astrophysics Data System (ADS)

Chow, J. C. K.

2017-09-01

Sensor fusion of a MEMS IMU with a magnetometer is a popular system design, because such 9-DoF (degrees of freedom) systems are capable of achieving drift-free 3D orientation tracking. However, these systems are often vulnerable to ambient magnetic distortions and lack useful position information; in the absence of external position aiding (e.g. satellite/ultra-wideband positioning systems) the dead-reckoned position accuracy from a 9-DoF MEMS IMU deteriorates rapidly due to unmodelled errors. Positioning information is valuable in many satellite-denied geomatics applications (e.g. indoor navigation, location-based services, etc.). This paper proposes an improved 9-DoF IMU indoor pose tracking method using batch optimization. By adopting a robust in-situ user self-calibration approach to model the systematic errors of the accelerometer, gyroscope, and magnetometer simultaneously in a tightly-coupled post-processed least-squares framework, the accuracy of the estimated trajectory from a 9-DoF MEMS IMU can be improved. Through a combination of relative magnetic measurement updates and a robust weight function, the method is able to tolerate a high level of magnetic distortions. The proposed auto-calibration method was tested in-use under various heterogeneous magnetic field conditions to mimic a person walking with the sensor in their pocket, a person checking their phone, and a person walking with a smartwatch. In these experiments, the presented algorithm improved the in-situ dead-reckoning orientation accuracy by 79.8-89.5 % and the dead-reckoned positioning accuracy by 72.9-92.8 %, thus reducing the relative positioning error from metre-level to decimetre-level after ten seconds of integration, without making assumptions about the user's dynamics.

FLEXnav: a fuzzy logic expert dead-reckoning system for the Segway RMP

NASA Astrophysics Data System (ADS)

Ojeda, Lauro; Raju, Mukunda; Borenstein, Johann

2004-09-01

Most mobile robots use a combination of absolute and relative sensing techniques for position estimation. Relative positioning techniques are generally known as dead-reckoning. Many systems use odometry as their only dead-reckoning means. However, in recent years fiber optic gyroscopes have become more affordable and are being used on many platforms to supplement odometry, especially in indoor applications. Still, if the terrain is not level (i.e., rugged or rolling terrain), the tilt of the vehicle introduces errors into the conversion of gyro readings to vehicle heading. In order to overcome this problem vehicle tilt must be measured and factored into the heading computation. A unique new mobile robot is the Segway Robotics Mobility Platform (RMP). This functionally close relative of the innovative Segway Human Transporter (HT) stabilizes a statically unstable single-axle robot dynamically, based on the principle of the inverted pendulum. While this approach works very well for human transportation, it introduces as unique set of challenges to navigation equipment using an onboard gyro. This is due to the fact that in operation the Segway RMP constantly changes its forward tilt, to prevent dynamically falling over. This paper introduces our new Fuzzy Logic Expert rule-based navigation (FLEXnav) method for fusing data from multiple gyroscopes and accelerometers in order to estimate accurately the attitude (i.e., heading and tilt) of a mobile robot. The attitude information is then further fused with wheel encoder data to estimate the three-dimensional position of the mobile robot. We have further extended this approach to include the special conditions of operation on the Segway RMP. The paper presents experimental results of a Segway RMP equipped with our system and running over moderately rugged terrain.

An Improved BLE Indoor Localization with Kalman-Based Fusion: An Experimental Study

PubMed Central

Röbesaat, Jenny; Zhang, Peilin; Abdelaal, Mohamed; Theel, Oliver

2017-01-01

Indoor positioning has grasped great attention in recent years. A number of efforts have been exerted to achieve high positioning accuracy. However, there exists no technology that proves its efficacy in various situations. In this paper, we propose a novel positioning method based on fusing trilateration and dead reckoning. We employ Kalman filtering as a position fusion algorithm. Moreover, we adopt an Android device with Bluetooth Low Energy modules as the communication platform to avoid excessive energy consumption and to improve the stability of the received signal strength. To further improve the positioning accuracy, we take the environmental context information into account while generating the position fixes. Extensive experiments in a testbed are conducted to examine the performance of three approaches: trilateration, dead reckoning and the fusion method. Additionally, the influence of the knowledge of the environmental context is also examined. Finally, our proposed fusion method outperforms both trilateration and dead reckoning in terms of accuracy: experimental results show that the Kalman-based fusion, for our settings, achieves a positioning accuracy of less than one meter. PMID:28445421

Dead reckoning pedometer

DOEpatents

Eakle, Jr., Robert F.; Hofstetter, Kenneth J.

2003-04-15

A system to determine the location of a person within a structure utilizes a magnetometer, magnets, pressure sensors and a CPU to calculate the length and direction of each step. The data may be displayed to the wearer, preferably on a map or floorplan and may be broadcast to persons outside the structure.

Integration of the B-52G Offensive Avionics System (OAS) with the Global Positioning System (GPS)

NASA Astrophysics Data System (ADS)

Foote, A. L.; Pluntze, S. C.

Integration of the B-52G OAS with the GPS has been accomplished by modification of existing OAS software. GPS derived position and velocity data are used to enhance the quality of the OAS inertial and dead reckoning navigation systems. The engineering design and the software development process used to implement this design are presented.

Fractionating dead reckoning: role of the compass, odometer, logbook, and home base establishment in spatial orientation

NASA Astrophysics Data System (ADS)

Wallace, Douglas G.; Martin, Megan M.; Winter, Shawn S.

2008-06-01

Rats use multiple sources of information to maintain spatial orientation. Although previous work has focused on rats’ use of environmental cues, a growing number of studies have demonstrated that rats also use self-movement cues to organize navigation. This review examines the extent that kinematic analysis of naturally occurring behavior has provided insight into processes that mediate dead-reckoning-based navigation. This work supports a role for separate systems in processing self-movement cues that converge on the hippocampus. The compass system is involved in deriving directional information from self-movement cues; whereas, the odometer system is involved in deriving distance information from self-movement cues. The hippocampus functions similar to a logbook in that outward path unique information from the compass and odometer is used to derive the direction and distance of a path to the point at which movement was initiated. Finally, home base establishment may function to reset this system after each excursion and anchor environmental cues to self-movement cues. The combination of natural behaviors and kinematic analysis has proven to be a robust paradigm to investigate the neural basis of spatial orientation.

Fractionating dead reckoning: role of the compass, odometer, logbook, and home base establishment in spatial orientation

PubMed Central

Martin, Megan M.; Winter, Shawn S.

2008-01-01

Rats use multiple sources of information to maintain spatial orientation. Although previous work has focused on rats' use of environmental cues, a growing number of studies have demonstrated that rats also use self-movement cues to organize navigation. This review examines the extent that kinematic analysis of naturally occurring behavior has provided insight into processes that mediate dead-reckoning-based navigation. This work supports a role for separate systems in processing self-movement cues that converge on the hippocampus. The compass system is involved in deriving directional information from self-movement cues; whereas, the odometer system is involved in deriving distance information from self-movement cues. The hippocampus functions similar to a logbook in that outward path unique information from the compass and odometer is used to derive the direction and distance of a path to the point at which movement was initiated. Finally, home base establishment may function to reset this system after each excursion and anchor environmental cues to self-movement cues. The combination of natural behaviors and kinematic analysis has proven to be a robust paradigm to investigate the neural basis of spatial orientation. PMID:18553065

Optimal sensor fusion for land vehicle navigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morrow, J.D.

1990-10-01

Position location is a fundamental requirement in autonomous mobile robots which record and subsequently follow x,y paths. The Dept. of Energy, Office of Safeguards and Security, Robotic Security Vehicle (RSV) program involves the development of an autonomous mobile robot for patrolling a structured exterior environment. A straight-forward method for autonomous path-following has been adopted and requires digitizing'' the desired road network by storing x,y coordinates every 2m along the roads. The position location system used to define the locations consists of a radio beacon system which triangulates position off two known transponders, and dead reckoning with compass and odometer. Thismore » paper addresses the problem of combining these two measurements to arrive at a best estimate of position. Two algorithms are proposed: the optimal'' algorithm treats the measurements as random variables and minimizes the estimate variance, while the average error'' algorithm considers the bias in dead reckoning and attempts to guarantee an average error. Data collected on the algorithms indicate that both work well in practice. 2 refs., 7 figs.« less

Cerebellum Augmented Rover Development

NASA Technical Reports Server (NTRS)

King, Matthew

2005-01-01

Bio-Inspired Technologies and Systems (BITS) are a very natural result of thinking about Nature's way of solving problems. Knowledge of animal behaviors an be used in developing robotic behaviors intended for planetary exploration. This is the expertise of the JFL BITS Group and has served as a philosophical model for NMSU RioRobolab. Navigation is a vital function for any autonomous system. Systems must have the ability to determine a safe path between their current location and some target location. The MER mission, as well as other JPL rover missions, uses a method known as dead-reckoning to determine position information. Dead-reckoning uses wheel encoders to sense the wheel's rotation. In a sandy environment such as Mars, this method is highly inaccurate because the wheels will slip in the sand. Improving positioning error will allow the speed of an autonomous navigating rover to be greatly increased. Therefore, local navigation based upon landmark tracking is desirable in planetary exploration. The BITS Group is developing navigation technology based upon landmark tracking. Integration of the current rover architecture with a cerebellar neural network tracking algorithm will demonstrate that this approach to navigation is feasible and should be implemented in future rover and spacecraft missions.

The Coast Guard Proceedings of the Marine Safety and Security Council: Spring 2016

DTIC Science & Technology

2016-04-01

PROCEEDINGS Spring 2016 Vol. 73, Number 1 Safety Management System Objectives 6 Safety Management Facilitates Safe Vessel Operation Vessel systems...crew, and operations. by LCDR Aaron W. Demo 9 Safety Management Systems to Prevent Pollution from Ships Standard procedures protect the environment...by LCDR Michael Lendvay 11 Dead Reckoning by Safety Management ? Check your course. by LCDR Corydon F. Heard IV Safety Management Systems and the Outer

A Final Approach Trajectory Model for Current Operations

NASA Technical Reports Server (NTRS)

Gong, Chester; Sadovsky, Alexander

2010-01-01

Predicting accurate trajectories with limited intent information is a challenge faced by air traffic management decision support tools in operation today. One such tool is the FAA's Terminal Proximity Alert system which is intended to assist controllers in maintaining safe separation of arrival aircraft during final approach. In an effort to improve the performance of such tools, two final approach trajectory models are proposed; one based on polynomial interpolation, the other on the Fourier transform. These models were tested against actual traffic data and used to study effects of the key final approach trajectory modeling parameters of wind, aircraft type, and weight class, on trajectory prediction accuracy. Using only the limited intent data available to today's ATM system, both the polynomial interpolation and Fourier transform models showed improved trajectory prediction accuracy over a baseline dead reckoning model. Analysis of actual arrival traffic showed that this improved trajectory prediction accuracy leads to improved inter-arrival separation prediction accuracy for longer look ahead times. The difference in mean inter-arrival separation prediction error between the Fourier transform and dead reckoning models was 0.2 nmi for a look ahead time of 120 sec, a 33 percent improvement, with a corresponding 32 percent improvement in standard deviation.

Inertial Pocket Navigation System: Unaided 3D Positioning

PubMed Central

Munoz Diaz, Estefania

2015-01-01

Inertial navigation systems use dead-reckoning to estimate the pedestrian's position. There are two types of pedestrian dead-reckoning, the strapdown algorithm and the step-and-heading approach. Unlike the strapdown algorithm, which consists of the double integration of the three orthogonal accelerometer readings, the step-and-heading approach lacks the vertical displacement estimation. We propose the first step-and-heading approach based on unaided inertial data solving 3D positioning. We present a step detector for steps up and down and a novel vertical displacement estimator. Our navigation system uses the sensor introduced in the front pocket of the trousers, a likely location of a smartphone. The proposed algorithms are based on the opening angle of the leg or pitch angle. We analyzed our step detector and compared it with the state-of-the-art, as well as our already proposed step length estimator. Lastly, we assessed our vertical displacement estimator in a real-world scenario. We found that our algorithms outperform the literature step and heading algorithms and solve 3D positioning using unaided inertial data. Additionally, we found that with the pitch angle, five activities are distinguishable: standing, sitting, walking, walking up stairs and walking down stairs. This information complements the pedestrian location and is of interest for applications, such as elderly care. PMID:25897501

Precision Positioning and Inertial Guidance Sensors. Technology and Operational Aspects

DTIC Science & Technology

1981-03-01

Ueberlingen, GE EVALUATION D’UN SYSTEME EUROPEEN DE NAVIGATION HYBRIDE A - - GYROLASER POUR HELICOPTERE: "SEXTAN" by D Regnault, Centre d’Essais en Vol de...NAVIGATION SYSTEM AND STANDARD STATE ELEMENT DEVIATIONMEASUREMENT SOURCES( Dead-reckoning with position fxP fy 5000 En ]TAS, heading and wind scale...Reproduction Ltd ilarford House. 7-9 Charlotte St. London. WIP JIHD [i Ii THEME A new class of precision positioning systems , including GPS (Global

AQUILA Remotely Piloted Vehicle System Technology Demonstrator (RPV-STD) Program. Volume I. System Description and Capabilities

DTIC Science & Technology

1979-04-01

tools, simplification of equipment interfaces involved in manual operations to provide simple system preparation, closing flight control inner loops ...alti- tude, and heading rate. The closed loops operate in three primary modes: cruise, dead reckoning, and approach. The aircraft is stabilized by...onboard closed loops , so the operator is not required to maintain hands-on operation to keep it in the air. The operator is able to command airspeed

Improving IMES Localization Accuracy by Integrating Dead Reckoning Information

PubMed Central

Fujii, Kenjiro; Arie, Hiroaki; Wang, Wei; Kaneko, Yuto; Sakamoto, Yoshihiro; Schmitz, Alexander; Sugano, Shigeki

2016-01-01

Indoor positioning remains an open problem, because it is difficult to achieve satisfactory accuracy within an indoor environment using current radio-based localization technology. In this study, we investigate the use of Indoor Messaging System (IMES) radio for high-accuracy indoor positioning. A hybrid positioning method combining IMES radio strength information and pedestrian dead reckoning information is proposed in order to improve IMES localization accuracy. For understanding the carrier noise ratio versus distance relation for IMES radio, the signal propagation of IMES radio is modeled and identified. Then, trilateration and extended Kalman filtering methods using the radio propagation model are developed for position estimation. These methods are evaluated through robot localization and pedestrian localization experiments. The experimental results show that the proposed hybrid positioning method achieved average estimation errors of 217 and 1846 mm in robot localization and pedestrian localization, respectively. In addition, in order to examine the reason for the positioning accuracy of pedestrian localization being much lower than that of robot localization, the influence of the human body on the radio propagation is experimentally evaluated. The result suggests that the influence of the human body can be modeled. PMID:26828492

Heading Estimation for Pedestrian Dead Reckoning Based on Robust Adaptive Kalman Filtering.

PubMed

Wu, Dongjin; Xia, Linyuan; Geng, Jijun

2018-06-19

Pedestrian dead reckoning (PDR) using smart phone-embedded micro-electro-mechanical system (MEMS) sensors plays a key role in ubiquitous localization indoors and outdoors. However, as a relative localization method, it suffers from the problem of error accumulation which prevents it from long term independent running. Heading estimation error is one of the main location error sources, and therefore, in order to improve the location tracking performance of the PDR method in complex environments, an approach based on robust adaptive Kalman filtering (RAKF) for estimating accurate headings is proposed. In our approach, outputs from gyroscope, accelerometer, and magnetometer sensors are fused using the solution of Kalman filtering (KF) that the heading measurements derived from accelerations and magnetic field data are used to correct the states integrated from angular rates. In order to identify and control measurement outliers, a maximum likelihood-type estimator (M-estimator)-based model is used. Moreover, an adaptive factor is applied to resist the negative effects of state model disturbances. Extensive experiments under static and dynamic conditions were conducted in indoor environments. The experimental results demonstrate the proposed approach provides more accurate heading estimates and supports more robust and dynamic adaptive location tracking, compared with methods based on conventional KF.

The Performance Analysis of the Map-Aided Fuzzy Decision Tree Based on the Pedestrian Dead Reckoning Algorithm in an Indoor Environment

PubMed Central

Chiang, Kai-Wei; Liao, Jhen-Kai; Tsai, Guang-Je; Chang, Hsiu-Wen

2015-01-01

Hardware sensors embedded in a smartphone allow the device to become an excellent mobile navigator. A smartphone is ideal for this task because its great international popularity has led to increased phone power and since most of the necessary infrastructure is already in place. However, using a smartphone for indoor pedestrian navigation can be problematic due to the low accuracy of sensors, imprecise predictability of pedestrian motion, and inaccessibility of the Global Navigation Satellite System (GNSS) in some indoor environments. Pedestrian Dead Reckoning (PDR) is one of the most common technologies used for pedestrian navigation, but in its present form, various errors tend to accumulate. This study introduces a fuzzy decision tree (FDT) aided by map information to improve the accuracy and stability of PDR with less dependency on infrastructure. First, the map is quickly surveyed by the Indoor Mobile Mapping System (IMMS). Next, Bluetooth beacons are implemented to enable the initializing of any position. Finally, map-aided FDT can estimate navigation solutions in real time. The experiments were conducted in different fields using a variety of smartphones and users in order to verify stability. The contrast PDR system demonstrates low stability for each case without pre-calibration and post-processing, but the proposed low-complexity FDT algorithm shows good stability and accuracy under the same conditions. PMID:26729114

Distributed Tactical Decision Support by Using Real-Time Database System

DTIC Science & Technology

1987-11-01

appendix A and detailed in depth in the Advanced Combat Direction System Specification (reference 5). The assumption is that ’ ime 0 (TO) of any contact...CONSTELLATION LAUNCH I F14A CAPM 330 350 10000 STOP At simulated engagement minute 30. the following orders are next submitted to the event generator...time of contact (ETC). There is the assumption in the ETC calculation that COURSE will change such that the new report would be on a dead- reckoning

Automated Support for Rapid Coordination of Joint UUV Operation

DTIC Science & Technology

2015-03-01

automata , dead-reckoning, static plan, nmtime plan, rapid deployment, GPS 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY...STATE MACHINES, MOORE AUTOMATA ..........................................9 A. MOORE AUTOMATA ...9 B. UUV PLANS AS MOORE AUTOMATA ...................................................11 C. SAMPLING RATE

Large-Area Visually Augmented Navigation for Autonomous Underwater Vehicles

DTIC Science & Technology

2005-06-01

constrain position drift . Correction of errors in position and orientation are made each time the mosaic is updated, which occurs every Lth video frame. They...are the greatest strength of a VAN methodology. It is these measurements which help to correct dead-reckoned drift error and enforce recovery of a...systems. [INSTRUMENT [VARIABLE I INTENAL? I UPDATE RATE PRECISION FRANGE J DRIFT Acoustic Altimeter Z - Altitude yes varies: 0.1-10 Hz 0.01-1.0 m varies

Human Factors Evaluation of Conflict Detection Tool for Terminal Area

NASA Technical Reports Server (NTRS)

Verma, Savita Arora; Tang, Huabin; Ballinger, Deborah; Chinn, Fay Cherie; Kozon, Thomas E.

2013-01-01

A conflict detection and resolution tool, Terminal-area Tactical Separation-Assured Flight Environment (T-TSAFE), is being developed to improve the timeliness and accuracy of alerts and reduce the false alert rate observed with the currently deployed technology. The legacy system in use today, Conflict Alert, relies primarily on a dead reckoning algorithm, whereas T-TSAFE uses intent information to augment dead reckoning. In previous experiments, T-TSAFE was found to reduce the rate of false alerts and increase time between the alert to the controller and a loss of separation over the legacy system. In the present study, T-TSAFE was tested under two meteorological conditions, 1) all aircraft operated under instrument flight regimen, and 2) some aircraft operated under mixed operating conditions. The tool was used to visually alert controllers to predicted Losses of separation throughout the terminal airspace, and show compression errors, on final approach. The performance of T-TSAFE on final approach was compared with Automated Terminal Proximity Alert (ATPA), a tool recently deployed by the FAA. Results show that controllers did not report differences in workload or situational awareness between the T-TSAFE and ATPA cones but did prefer T-TSAFE features over ATPA functionality. T-TSAFE will provide one tool that shows alerts in the data blocks and compression errors via cones on the final approach, implementing all tactical conflict detection and alerting via one tool in TRACON airspace.

Technologies Old and New: Teaching Ancient Navigation.

ERIC Educational Resources Information Center

Spalding, Simon

1995-01-01

One educator presents maritime history to students using technologies available to ancient seafarers. Techniques include dead reckoning, the sandglass, the magnetic compass, celestial navigation, and various navigation techniques of precontact Polynesia that depended upon oral transmission of knowledge. The paper notes differences between…

Navigation in a Virtual Environment Using a Walking Interface

DTIC Science & Technology

2000-11-01

Fukusima, 1993; Mittelstaedt & Glasauer, 1991; Schmuckler, 1995). Thus, only visual information is available for navigation by dead reckoning ( Gallistel ...Washington DC: National Academy Press. Gallistel , C.R. (1990). The Organization of Learning. Cambridge, MA: MIT Press. lwata, H. & Matsuda, K. (1992). Haptic

14 CFR 61.125 - Aeronautical knowledge.

Code of Federal Regulations, 2013 CFR

2013-01-01

... magnetic compass for pilotage and dead reckoning; (10) Use of air navigation facilities; (11) Aeronautical... aeronautical knowledge areas of paragraph (b) of this section that apply to the aircraft category and class... operation of aircraft; (6) Weight and balance computations; (7) Use of performance charts; (8) Significance...

Quartermaster 1 and C, Rate Training Manual.

ERIC Educational Resources Information Center

Naval Personnel Program Support Activity, Washington, DC.

The subject matter of this training manual is prepared for regular navy and naval reserve personnel. Operations of gyrocompasses and magnetic and magnesyn compasses are discussed with a background of error determination, compass adjustments, and degaussing applications. Navigation techniques are analyzed in terms of piloting, dead reckoning,…

Fast Light Optical Gyroscopes

NASA Technical Reports Server (NTRS)

Smith, David D.

2015-01-01

Next-generation space missions are currently constrained by existing spacecraft navigation systems which are not fully autonomous. These systems suffer from accumulated dead-reckoning errors and must therefore rely on periodic corrections provided by supplementary technologies that depend on line-of-sight signals from Earth, satellites, or other celestial bodies for absolute attitude and position determination, which can be spoofed, incorrectly identified, occluded, obscured, attenuated, or insufficiently available. These dead-reckoning errors originate in the ring laser gyros themselves, which constitute inertial measurement units. Increasing the time for standalone spacecraft navigation therefore requires fundamental improvements in gyroscope technologies. One promising solution to enhance gyro sensitivity is to place an anomalous dispersion or fast light material inside the gyro cavity. The fast light essentially provides a positive feedback to the gyro response, resulting in a larger measured beat frequency for a given rotation rate as shown in figure 1. Game Changing Development has been investing in this idea through the Fast Light Optical Gyros (FLOG) project, a collaborative effort which began in FY 2013 between NASA Marshall Space Flight Center (MSFC), the U.S. Army Aviation and Missile Research, Development, and Engineering Center (AMRDEC), and Northwestern University. MSFC and AMRDEC are working on the development of a passive FLOG (PFLOG), while Northwestern is developing an active FLOG (AFLOG). The project has demonstrated new benchmarks in the state of the art for scale factor sensitivity enhancement. Recent results show cavity scale factor enhancements of approx.100 for passive cavities.

In the Wake of Our Ancestors.

ERIC Educational Resources Information Center

Low, Sam

2003-01-01

To understand and revive the ancient Hawaiian culture, the crew of a traditional Polynesian double-hulled voyaging canoe sails among the Pacific Islands without charts or instruments. Trained by Western science, elders, and experience, the navigator guides the craft by the stars and dead reckoning. Each voyage is linked to Hawaiian classroom…

Coastal Piloting & Charting: Navigation 101.

ERIC Educational Resources Information Center

Osinski, Alison

This curriculum guide for a beginning course on marine navigation describes marine navigation (the art of and science of determining position of a ship and its movement from one position to another in order to keep track of where the ship is and where it is going) and defines dead reckoning, piloting, electronic navigation, and celestial…

Extinction from a Rationalist Perspective

PubMed Central

Gallistel, C. R.

2012-01-01

The merging of the computational theory of mind and evolutionary thinking leads to a kind of rationalism, in which enduring truths about the world have become implicit in the computations that enable the brain to cope with the experienced world. The dead reckoning computation, for example, is implemented within the brains of animals as one of the mechanisms that enables them to learn where they are (Gallistel, 1990, 1995). It integrates a velocity signal with respect to a time signal. Thus, the manner in which position and velocity relate to one another in the world is reflected in the manner in which signals representing those variables are processed in the brain. I use principles of information theory and Bayesian inference to derive from other simple principles explanations for: 1) the failure of partial reinforcement to increase reinforcements to acquisition; 2) the partial reinforcement extinction effect; 3) spontaneous recovery; 4) renewal; 5) reinstatement; 6) resurgence (aka facilitated reacquisition). Like the principle underlying dead-reckoning, these principles are grounded in analytic considerations. They are the kind of enduring truths about the world that are likely to have shaped the brain's computations. PMID:22391153

Fimbria-Fornix Lesions Disrupt the Dead Reckoning (Homing) Component of Exploratory Behavior in Mice

PubMed Central

Gorny, Joanna H.; Gorny, Bogdan; Wallace, Douglas G.; Whishaw, Ian Q.

2002-01-01

Exploration is the primary way in which rodents gather information about their spatial surroundings. Thus, spatial theories propose that damage to the hippocampus, a structure thought to play a fundamental role in spatial behavior, should disrupt exploration. Exploration in rats is organized. The animals create home bases that are central to exploratory excursions and returns, and hippocampal formation damage alters the organization of exploration by disrupting returns. Mice do not appear to readily establish home bases in novel environments, thus, for this species, it is more difficult to establish the contribution of the hippocampus to exploration. The purpose of the present study was threefold: develop a task in which mice center their exploration from a home base, determine whether the exploratory behavior is organized, and evaluate the role of fimbria-fornix lesions on exploration. Mice were given a novel exploratory task in which their nesting material was placed on a large circular table. Video records of control and fimbria-fornix mice were made in both light and dark (infrared light) conditions. Exploration patterns (outward trips, stops, and homeward trips) were reconstructed from the video records. Control mice centered their activity on their bedding, from which they made circuitous outward trips marked by many stops, and periodic direct returns. The bedding-centered behavior and outward trips of the fimbria-fornix mice were similar to those of the control mice, but significantly fewer direct return trips occurred. The direct homeward trips observed under light and dark conditions were consistent with a dead-reckoning strategy, in which an animal computes its present position and homeward trajectory from self-movement cues generated on the outward trip. Because the fimbria-fornix lesions disrupted the homeward component of exploratory trips, we conclude that the fimbria-fornix may contribute to dead reckoning in mice. The results also show that the home-bedding methodology facilitates the establishment of a home base by mice, thus providing a useful methodology for studies with mice. PMID:12464698

Role of Dentate Gyrus in Aligning Internal Spatial Map to External Landmark

ERIC Educational Resources Information Center

Lee, Jong Won; Kim, Woon Ryoung; Sun, Woong; Jung, Min Whan

2009-01-01

Humans and animals form internal representations of external space based on their own body movement (dead reckoning) as well as external landmarks. It is poorly understood, however, how different types of information are integrated to form a unified representation of external space. To examine the role of dentate gyrus (DG) in this process, we…

Amelia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, R.; Thrun, S.; Armstrong, G.

1996-12-31

Amelia was built by Real World Interface (RWI) using Xavier-a mobile robot platform developed at CMU on a B24 base from RWI-as a prototype. Amelia has substantial engineering improvements over Xavier. Amelia is built on a B21 base. It has a top speed of 32 inches per second, while improved integral dead-reckoning insures extremely accurate drive and position controls.

Vector Graph Assisted Pedestrian Dead Reckoning Using an Unconstrained Smartphone

PubMed Central

Qian, Jiuchao; Pei, Ling; Ma, Jiabin; Ying, Rendong; Liu, Peilin

2015-01-01

The paper presents a hybrid indoor positioning solution based on a pedestrian dead reckoning (PDR) approach using built-in sensors on a smartphone. To address the challenges of flexible and complex contexts of carrying a phone while walking, a robust step detection algorithm based on motion-awareness has been proposed. Given the fact that step length is influenced by different motion states, an adaptive step length estimation algorithm based on motion recognition is developed. Heading estimation is carried out by an attitude acquisition algorithm, which contains a two-phase filter to mitigate the distortion of magnetic anomalies. In order to estimate the heading for an unconstrained smartphone, principal component analysis (PCA) of acceleration is applied to determine the offset between the orientation of smartphone and the actual heading of a pedestrian. Moreover, a particle filter with vector graph assisted particle weighting is introduced to correct the deviation in step length and heading estimation. Extensive field tests, including four contexts of carrying a phone, have been conducted in an office building to verify the performance of the proposed algorithm. Test results show that the proposed algorithm can achieve sub-meter mean error in all contexts. PMID:25738763

Extinction from a rationalist perspective.

PubMed

Gallistel, C R

2012-05-01

The merging of the computational theory of mind and evolutionary thinking leads to a kind of rationalism, in which enduring truths about the world have become implicit in the computations that enable the brain to cope with the experienced world. The dead reckoning computation, for example, is implemented within the brains of animals as one of the mechanisms that enables them to learn where they are (Gallistel, 1990, 1995). It integrates a velocity signal with respect to a time signal. Thus, the manner in which position and velocity relate to one another in the world is reflected in the manner in which signals representing those variables are processed in the brain. I use principles of information theory and Bayesian inference to derive from other simple principles explanations for: (1) the failure of partial reinforcement to increase reinforcements to acquisition; (2) the partial reinforcement extinction effect; (3) spontaneous recovery; (4) renewal; (5) reinstatement; (6) resurgence (aka facilitated reacquisition). Like the principle underlying dead-reckoning, these principles are grounded in analytic considerations. They are the kind of enduring truths about the world that are likely to have shaped the brain's computations. Copyright © 2012 Elsevier B.V. All rights reserved.

U.S. Army Aviator Job Analysis

DTIC Science & Technology

2006-08-01

Differences by Airframe AH-64D CH-47 OH-58 UH-60 Task M SD M SD M SD M SD Plan IFR flight 3.56 1.25 3.41 1.15 2.00 1.43 4.07 .84 Perform aircraft...1.64 3.13 1.36 night systems Perform flight navigation by dead 3.91 .98 3.86 1.03 3.29 1.07 4.06 .87 reckoning Perform appropriate IFR approach 3.67...2. Check status of aircraft @ (D () T 3. Plan VFR flight T (Z 3 e 4. Plan IFR flight @ T 0 3 e 5. Perform tactical flight mission planning using the

Cross-coherent vector sensor processing for spatially distributed glider networks.

PubMed

Nichols, Brendan; Sabra, Karim G

2015-09-01

Autonomous underwater gliders fitted with vector sensors can be used as a spatially distributed sensor array to passively locate underwater sources. However, to date, the positional accuracy required for robust array processing (especially coherent processing) is not achievable using dead-reckoning while the gliders remain submerged. To obtain such accuracy, the gliders can be temporarily surfaced to allow for global positioning system contact, but the acoustically active sea surface introduces locally additional sensor noise. This letter demonstrates that cross-coherent array processing, which inherently mitigates the effects of local noise, outperforms traditional incoherent processing source localization methods for this spatially distributed vector sensor network.

A Short Tutorial on Inertial Navigation System and Global Positioning System Integration

NASA Technical Reports Server (NTRS)

Smalling, Kyle M.; Eure, Kenneth W.

2015-01-01

The purpose of this document is to describe a simple method of integrating Inertial Navigation System (INS) information with Global Positioning System (GPS) information for an improved estimate of vehicle attitude and position. A simple two dimensional (2D) case is considered. The attitude estimates are derived from sensor data and used in the estimation of vehicle position and velocity through dead reckoning within the INS. The INS estimates are updated with GPS estimates using a Kalman filter. This tutorial is intended for the novice user with a focus on bringing the reader from raw sensor measurements to an integrated position and attitude estimate. An application is given using a remotely controlled ground vehicle operating in assumed 2D environment. The theory is developed first followed by an illustrative example.

Ambler: Performance of a six-legged planetary rover

NASA Astrophysics Data System (ADS)

Krotkov, E. P.; Simmons, R. G.; Whittaker, W. L.

1995-01-01

In this paper we quantify several performance metrics for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. We present power consumption measures for walking on sandy terrain and for vertical lifts at different velocities. We document the performance of a novel dead-reckoning approach, and analyze its accuracy. We describe the results of autonomous walking experiments in terms of terrain traversed, walking speed and endurance.

Ambler - Performance of a six-legged planetary rover

NASA Astrophysics Data System (ADS)

Krotkov, E. P.; Simmons, R. G.; Whittaker, W. L.

1992-08-01

In this paper, several performance metrics are quantified for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. Power consumption measures are presented for walking on sandy terrain and for vertical lifts at different velocities. The performance of a novel dead reckoning approach is documented, and its accuracy is analyzed. The results of autonomous walking experiments are described in terms of terrain traversed, walking speed, and endurance.

Ambler - Performance of a six-legged planetary rover

NASA Technical Reports Server (NTRS)

Krotkov, E. P.; Simmons, R. G.; Whittaker, W. L.

1992-01-01

In this paper, several performance metrics are quantified for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. Power consumption measures are presented for walking on sandy terrain and for vertical lifts at different velocities. The performance of a novel dead reckoning approach is documented, and its accuracy is analyzed. The results of autonomous walking experiments are described in terms of terrain traversed, walking speed, and endurance.

Accurate path integration in continuous attractor network models of grid cells.

PubMed

Burak, Yoram; Fiete, Ila R

2009-02-01

Grid cells in the rat entorhinal cortex display strikingly regular firing responses to the animal's position in 2-D space and have been hypothesized to form the neural substrate for dead-reckoning. However, errors accumulate rapidly when velocity inputs are integrated in existing models of grid cell activity. To produce grid-cell-like responses, these models would require frequent resets triggered by external sensory cues. Such inadequacies, shared by various models, cast doubt on the dead-reckoning potential of the grid cell system. Here we focus on the question of accurate path integration, specifically in continuous attractor models of grid cell activity. We show, in contrast to previous models, that continuous attractor models can generate regular triangular grid responses, based on inputs that encode only the rat's velocity and heading direction. We consider the role of the network boundary in the integration performance of the network and show that both periodic and aperiodic networks are capable of accurate path integration, despite important differences in their attractor manifolds. We quantify the rate at which errors in the velocity integration accumulate as a function of network size and intrinsic noise within the network. With a plausible range of parameters and the inclusion of spike variability, our model networks can accurately integrate velocity inputs over a maximum of approximately 10-100 meters and approximately 1-10 minutes. These findings form a proof-of-concept that continuous attractor dynamics may underlie velocity integration in the dorsolateral medial entorhinal cortex. The simulations also generate pertinent upper bounds on the accuracy of integration that may be achieved by continuous attractor dynamics in the grid cell network. We suggest experiments to test the continuous attractor model and differentiate it from models in which single cells establish their responses independently of each other.

The NavTrax fleet management system

NASA Astrophysics Data System (ADS)

McLellan, James F.; Krakiwsky, Edward J.; Schleppe, John B.; Knapp, Paul L.

The NavTrax System, a dispatch-type automatic vehicle location and navigation system, is discussed. Attention is given to its positioning, communication, digital mapping, and dispatch center components. The positioning module is a robust GPS (Global Positioning System)-based system integrated with dead reckoning devices by a decentralized-federated filter, making the module fault tolerant. The error behavior and characteristics of GPS, rate gyro, compass, and odometer sensors are discussed. The communications module, as presently configured, utilizes UHF radio technology, and plans are being made to employ a digital cellular telephone system. Polling and automatic smart vehicle reporting are also discussed. The digital mapping component is an intelligent digital single line road network database stored in vector form with full connectivity and address ranges. A limited form of map matching is performed for the purposes of positioning, but its main purpose is to define location once position is determined.

An IBeacon-Based Location System for Smart Home Control.

PubMed

Liu, Qinghe; Yang, Xinshuang; Deng, Lizhen

2018-06-11

Indoor location and intelligent control system can bring convenience to people’s daily life. In this paper, an indoor control system is designed to achieve equipment remote control by using low-energy Bluetooth (BLE) beacon and Internet of Things (IoT) technology. The proposed system consists of five parts: web server, home gateway, smart terminal, smartphone app and BLE beacons. In the web server, fingerprint matching based on RSSI stochastic characteristic and posture recognition model based on geomagnetic sensing are used to establish a more efficient equipment control system, combined with Pedestrian Dead Reckoning (PDR) technology to improve the accuracy of location. A personalized menu of remote “one-click” control is finally offered to users in a smartphone app. This smart home control system has been implemented by hardware, and precision and stability tests have been conducted, which proved the practicability and good user experience of this solution.

Cellular-based preemption system

NASA Technical Reports Server (NTRS)

Bachelder, Aaron D. (Inventor)

2011-01-01

A cellular-based preemption system that uses existing cellular infrastructure to transmit preemption related data to allow safe passage of emergency vehicles through one or more intersections. A cellular unit in an emergency vehicle is used to generate position reports that are transmitted to the one or more intersections during an emergency response. Based on this position data, the one or more intersections calculate an estimated time of arrival (ETA) of the emergency vehicle, and transmit preemption commands to traffic signals at the intersections based on the calculated ETA. Additional techniques may be used for refining the position reports, ETA calculations, and the like. Such techniques include, without limitation, statistical preemption, map-matching, dead-reckoning, augmented navigation, and/or preemption optimization techniques, all of which are described in further detail in the above-referenced patent applications.

Application of artificial intelligence in Geodesy - A review of theoretical foundations and practical examples

NASA Astrophysics Data System (ADS)

Reiterer, Alexander; Egly, Uwe; Vicovac, Tanja; Mai, Enrico; Moafipoor, Shahram; Grejner-Brzezinska, Dorota A.; Toth, Charles K.

2010-12-01

Artificial Intelligence (AI) is one of the key technologies in many of today's novel applications. It is used to add knowledge and reasoning to systems. This paper illustrates a review of AI methods including examples of their practical application in Geodesy like data analysis, deformation analysis, navigation, network adjustment, and optimization of complex measurement procedures. We focus on three examples, namely, a geo-risk assessment system supported by a knowledge-base, an intelligent dead reckoning personal navigator, and evolutionary strategies for the determination of Earth gravity field parameters. Some of the authors are members of IAG Sub-Commission 4.2 - Working Group 4.2.3, which has the main goal to study and report on the application of AI in Engineering Geodesy.

Indoor Pedestrian Localization Using iBeacon and Improved Kalman Filter.

PubMed

Sung, Kwangjae; Lee, Dong Kyu 'Roy'; Kim, Hwangnam

2018-05-26

The reliable and accurate indoor pedestrian positioning is one of the biggest challenges for location-based systems and applications. Most pedestrian positioning systems have drift error and large bias due to low-cost inertial sensors and random motions of human being, as well as unpredictable and time-varying radio-frequency (RF) signals used for position determination. To solve this problem, many indoor positioning approaches that integrate the user's motion estimated by dead reckoning (DR) method and the location data obtained by RSS fingerprinting through Bayesian filter, such as the Kalman filter (KF), unscented Kalman filter (UKF), and particle filter (PF), have recently been proposed to achieve higher positioning accuracy in indoor environments. Among Bayesian filtering methods, PF is the most popular integrating approach and can provide the best localization performance. However, since PF uses a large number of particles for the high performance, it can lead to considerable computational cost. This paper presents an indoor positioning system implemented on a smartphone, which uses simple dead reckoning (DR), RSS fingerprinting using iBeacon and machine learning scheme, and improved KF. The core of the system is the enhanced KF called a sigma-point Kalman particle filter (SKPF), which localize the user leveraging both the unscented transform of UKF and the weighting method of PF. The SKPF algorithm proposed in this study is used to provide the enhanced positioning accuracy by fusing positional data obtained from both DR and fingerprinting with uncertainty. The SKPF algorithm can achieve better positioning accuracy than KF and UKF and comparable performance compared to PF, and it can provide higher computational efficiency compared with PF. iBeacon in our positioning system is used for energy-efficient localization and RSS fingerprinting. We aim to design the localization scheme that can realize the high positioning accuracy, computational efficiency, and energy efficiency through the SKPF and iBeacon indoors. Empirical experiments in real environments show that the use of the SKPF algorithm and iBeacon in our indoor localization scheme can achieve very satisfactory performance in terms of localization accuracy, computational cost, and energy efficiency.

Performance of a six-legged planetary rover - Power, positioning, and autonomous walking

NASA Technical Reports Server (NTRS)

Krotkov, Eric; Simmons, Reid

1992-01-01

The authors quantify several performance metrics for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. They present power consumption measures for walking on sandy terrain and for vertical lifts at different velocities. They document the accuracy of a novel dead reckoning approach, and analyze the accuracy. They describe the results of autonomous walking experiments in terms of terrain traversed, walking speed, number of instructions executed and endurance.

Performance of a six-legged planetary rover - Power, positioning, and autonomous walking

NASA Astrophysics Data System (ADS)

Krotkov, Eric; Simmons, Reid

The authors quantify several performance metrics for the Ambler, a six-legged robot configured for autonomous traversal of Mars-like terrain. They present power consumption measures for walking on sandy terrain and for vertical lifts at different velocities. They document the accuracy of a novel dead reckoning approach, and analyze the accuracy. They describe the results of autonomous walking experiments in terms of terrain traversed, walking speed, number of instructions executed and endurance.

Computations on metric maps in mammals: getting oriented and choosing a multi-destination route.

PubMed

Gallistel, C R; Cramer, A E

1996-01-01

The capacity to construct a cognitive map is hypothesized to rest on two foundations: (1) dead reckoning (path integration); (2) the perception of the direction and distance of terrain features relative to the animal. A map may be constructed by combining these two sources of positional information, with the result that the positions of all terrain features are represented in the coordinate framework used for dead reckoning. When animals need to become reoriented in a mapped space, results from rats and human toddlers indicate that they focus exclusively on the shape of the perceived environment, ignoring non-geometric features such as surface colors. As a result, in a rectangular space, they are misoriented half the time even when the two ends of the space differ strikingly in their appearance. In searching for a hidden object after becoming reoriented, both kinds of subjects search on the basis of the object's mapped position in the space rather than on the basis of its relationship to a goal sign (e.g. a distinctive container or nearby marker), even though they have demonstrably noted the relationship between the goal and the goal sign. When choosing a multidestination foraging route, vervet monkeys look at least three destinations ahead, even though they are only capable of keeping a maximum of six destinations in mind at once.

Visual navigation in insects: coupling of egocentric and geocentric information

PubMed

Wehner; Michel; Antonsen

1996-01-01

Social hymenopterans such as bees and ants are central-place foragers; they regularly depart from and return to fixed positions in their environment. In returning to the starting point of their foraging excursion or to any other point, they could resort to two fundamentally different ways of navigation by using either egocentric or geocentric systems of reference. In the first case, they would rely on information continuously collected en route (path integration, dead reckoning), i.e. integrate all angles steered and all distances covered into a mean home vector. In the second case, they are expected, at least by some authors, to use a map-based system of navigation, i.e. to obtain positional information by virtue of the spatial position they occupy within a larger environmental framework. In bees and ants, path integration employing a skylight compass is the predominant mechanism of navigation, but geocentred landmark-based information is used as well. This information is obtained while the animal is dead-reckoning and, hence, added to the vector course. For example, the image of the horizon skyline surrounding the nest entrance is retinotopically stored while the animal approaches the goal along its vector course. As shown in desert ants (genus Cataglyphis), there is neither interocular nor intraocular transfer of landmark information. Furthermore, this retinotopically fixed, and hence egocentred, neural snapshot is linked to an external (geocentred) system of reference. In this way, geocentred information might more and more complement and potentially even supersede the egocentred information provided by the path-integration system. In competition experiments, however, Cataglyphis never frees itself of its homeward-bound vector - its safety-line, so to speak - by which it is always linked to home. Vector information can also be transferred to a longer-lasting (higher-order) memory. There is no need to invoke the concept of the mental analogue of a topographic map - a metric map - assembled by the insect navigator. The flexible use of vectors, snapshots and landmark-based routes suffices to interpret the insect's behaviour. The cognitive-map approach in particular, and the representational paradigm in general, are discussed.

AUV Underwater Positioning Algorithm Based on Interactive Assistance of SINS and LBL.

PubMed

Zhang, Tao; Chen, Liping; Li, Yao

2015-12-30

This paper studies an underwater positioning algorithm based on the interactive assistance of a strapdown inertial navigation system (SINS) and LBL, and this algorithm mainly includes an optimal correlation algorithm with aided tracking of an SINS/Doppler velocity log (DVL)/magnetic compass pilot (MCP), a three-dimensional TDOA positioning algorithm of Taylor series expansion and a multi-sensor information fusion algorithm. The final simulation results show that compared to traditional underwater positioning algorithms, this scheme can not only directly correct accumulative errors caused by a dead reckoning algorithm, but also solves the problem of ambiguous correlation peaks caused by multipath transmission of underwater acoustic signals. The proposed method can calibrate the accumulative error of the AUV position more directly and effectively, which prolongs the underwater operating duration of the AUV.

Improving Inertial Pedestrian Dead-Reckoning by Detecting Unmodified Switched-on Lamps in Buildings

PubMed Central

Jiménez, Antonio R.; Zampella, Francisco; Seco, Fernando

2014-01-01

This paper explores how inertial Pedestrian Dead-Reckoning (PDR) location systems can be improved with the use of a light sensor to measure the illumination gradients created when a person walks under ceiling-mounted unmodified indoor lights. The process of updating the inertial PDR estimates with the information provided by light detections is a new concept that we have named Light-matching (LM). The displacement and orientation change of a person obtained by inertial PDR is used by the LM method to accurately propagate the location hypothesis, and vice versa; the LM approach benefits the PDR approach by obtaining an absolute localization and reducing the PDR-alone drift. Even from an initially unknown location and orientation, whenever the person passes below a switched-on light spot, the location likelihood is iteratively updated until it potentially converges to a unimodal probability density function. The time to converge to a unimodal position hypothesis depends on the number of lights detected and the asymmetries/irregularities of the spatial distribution of lights. The proposed LM method does not require any intensity illumination calibration, just the pre-storage of the position and size of all lights in a building, irrespective of their current on/off state. This paper presents a detailed description of the light-matching concept, the implementation details of the LM-assisted PDR fusion scheme using a particle filter, and several simulated and experimental tests, using a light sensor-equipped Galaxy S3 smartphone and an external foot-mounted inertial sensor. The evaluation includes the LM-assisted PDR approach as well as the fusion with other signals of opportunity (WiFi, RFID, Magnetometers or Map-matching) in order to compare their contribution in obtaining high accuracy indoor localization. The integrated solution achieves a localization error lower than 1 m in most of the cases. PMID:24394599

Flight Validation of the Thermal Propellant Gauging Method used at EADS Astrium

NASA Astrophysics Data System (ADS)

Dandaleix, L.; Ounougha, L.; Jallade, S.

2004-10-01

EADS Astrium recently met a major milestone in the field of propellant gauging with the first reorbitation of an Eurostar tanks equipped satellite. It proved successful determining the remaining available propellant mass for spacecraft displacement beyond the customer specified graveyard orbit; thus demonstrating its expertness in Propellant Gauging in correlation with tank residual mass minimization. A critical parameter in satellite operational planning is indeed the accurate knowledge of the on-board remaining propellant mass; basically for the commercial telecommunication missions, where it is the major criterion for lifetime maximization. To provide an accurate and reliable process for measurement of this propellant mass throughout lifetime, EADS Astrium uses a Combination of two independent techniques: The Dead Reckoning Method (maximum accuracy at BOL), based on thrusters flow rate prediction &the Thermal Propellant Gauging Technique, deriving the propellant mass from the tank thermal capacity (Absolute gauging method, with increasing accuracy along lifetime). Then, the present article shows the recent flight validation of the Gauging method obtained for Eurostar E2000 propellant tanks including the validation of the different thermodynamic models. ABBREVIATIONS &ACRONYMS BOL, MOL, EOL: Beginning, Middle &End of Life Cempty: Empty tank thermal inertia [J/K] Chelium: Helium thermal inertia [J/K] Cpropellant: Propellant thermal inertia [J/K] Ct = C1+C2: Total tank thermal inertia (Subscript for upper node and for lower node) [J/K] CPS: Combined Propulsion System DR: Dead Reckoning FM: Flight Model LAE: Liquid Apogee Engine lsb: Least significant byte M0: TPGS Uncertainty component linked to Cempty mox, mfuel: Propellant mass of oxidiser &fuel [kg] Pox, Pfuel: Pressure of oxidiser &fuel [bar] PTA: Propellant Tank Assembly Q: Heater power [W] Qox, Qfuel: Mass flow rate of oxidiser &fuel [kg/s] RCT: Reaction Control Thrusters T0: Spacecraft platform equilibrium temperature TPGS: Thermal Propellant Gauging Software TPGT: Thermal Propellant Gauging Technique T1i: Internal thermal gradients [K] T2i: External thermal gradients [K] Ï 1: Internal thermal characteristic time [s] 2: External thermal characteristic time [s

The MITy micro-rover: Sensing, control, and operation

NASA Technical Reports Server (NTRS)

Malafeew, Eric; Kaliardos, William

1994-01-01

The sensory, control, and operation systems of the 'MITy' Mars micro-rover are discussed. It is shown that the customized sun tracker and laser rangefinder provide internal, autonomous dead reckoning and hazard detection in unstructured environments. The micro-rover consists of three articulated platforms with sensing, processing and payload subsystems connected by a dual spring suspension system. A reactive obstacle avoidance routine makes intelligent use of robot-centered laser information to maneuver through cluttered environments. The hazard sensors include a rangefinder, inclinometers, proximity sensors and collision sensors. A 486/66 laptop computer runs the graphical user interface and programming environment. A graphical window displays robot telemetry in real time and a small TV/VCR is used for real time supervisory control. Guidance, navigation, and control routines work in conjunction with the mapping and obstacle avoidance functions to provide heading and speed commands that maneuver the robot around obstacles and towards the target.

Odometry and Laser Scanner Fusion Based on a Discrete Extended Kalman Filter for Robotic Platooning Guidance

PubMed Central

Espinosa, Felipe; Santos, Carlos; Marrón-Romera, Marta; Pizarro, Daniel; Valdés, Fernando; Dongil, Javier

2011-01-01

This paper describes a relative localization system used to achieve the navigation of a convoy of robotic units in indoor environments. This positioning system is carried out fusing two sensorial sources: (a) an odometric system and (b) a laser scanner together with artificial landmarks located on top of the units. The laser source allows one to compensate the cumulative error inherent to dead-reckoning; whereas the odometry source provides less pose uncertainty in short trajectories. A discrete Extended Kalman Filter, customized for this application, is used in order to accomplish this aim under real time constraints. Different experimental results with a convoy of Pioneer P3-DX units tracking non-linear trajectories are shown. The paper shows that a simple setup based on low cost laser range systems and robot built-in odometry sensors is able to give a high degree of robustness and accuracy to the relative localization problem of convoy units for indoor applications. PMID:22164079

Odometry and laser scanner fusion based on a discrete extended Kalman Filter for robotic platooning guidance.

PubMed

Espinosa, Felipe; Santos, Carlos; Marrón-Romera, Marta; Pizarro, Daniel; Valdés, Fernando; Dongil, Javier

2011-01-01

This paper describes a relative localization system used to achieve the navigation of a convoy of robotic units in indoor environments. This positioning system is carried out fusing two sensorial sources: (a) an odometric system and (b) a laser scanner together with artificial landmarks located on top of the units. The laser source allows one to compensate the cumulative error inherent to dead-reckoning; whereas the odometry source provides less pose uncertainty in short trajectories. A discrete Extended Kalman Filter, customized for this application, is used in order to accomplish this aim under real time constraints. Different experimental results with a convoy of Pioneer P3-DX units tracking non-linear trajectories are shown. The paper shows that a simple setup based on low cost laser range systems and robot built-in odometry sensors is able to give a high degree of robustness and accuracy to the relative localization problem of convoy units for indoor applications.

Wi-Fi/MARG Integration for Indoor Pedestrian Localization.

PubMed

Tian, Zengshan; Jin, Yue; Zhou, Mu; Wu, Zipeng; Li, Ze

2016-12-10

With the wide deployment of Wi-Fi networks, Wi-Fi based indoor localization systems that are deployed without any special hardware have caught significant attention and have become a currently practical technology. At the same time, the Magnetic, Angular Rate, and Gravity (MARG) sensors installed in commercial mobile devices can achieve highly-accurate localization in short time. Based on this, we design a novel indoor localization system by using built-in MARG sensors and a Wi-Fi module. The innovative contributions of this paper include the enhanced Pedestrian Dead Reckoning (PDR) and Wi-Fi localization approaches, and an Extended Kalman Particle Filter (EKPF) based fusion algorithm. A new Wi-Fi/MARG indoor localization system, including an Android based mobile client, a Web page for remote control, and a location server, is developed for real-time indoor pedestrian localization. The extensive experimental results show that the proposed system is featured with better localization performance, with the average error 0.85 m, than the one achieved by using the Wi-Fi module or MARG sensors solely.

AUV Underwater Positioning Algorithm Based on Interactive Assistance of SINS and LBL

PubMed Central

Zhang, Tao; Chen, Liping; Li, Yao

2015-01-01

This paper studies an underwater positioning algorithm based on the interactive assistance of a strapdown inertial navigation system (SINS) and LBL, and this algorithm mainly includes an optimal correlation algorithm with aided tracking of an SINS/Doppler velocity log (DVL)/magnetic compass pilot (MCP), a three-dimensional TDOA positioning algorithm of Taylor series expansion and a multi-sensor information fusion algorithm. The final simulation results show that compared to traditional underwater positioning algorithms, this scheme can not only directly correct accumulative errors caused by a dead reckoning algorithm, but also solves the problem of ambiguous correlation peaks caused by multipath transmission of underwater acoustic signals. The proposed method can calibrate the accumulative error of the AUV position more directly and effectively, which prolongs the underwater operating duration of the AUV. PMID:26729120

Single-camera visual odometry to track a surgical X-ray C-arm base.

PubMed

Esfandiari, Hooman; Lichti, Derek; Anglin, Carolyn

2017-12-01

This study provides a framework for a single-camera odometry system for localizing a surgical C-arm base. An application-specific monocular visual odometry system (a downward-looking consumer-grade camera rigidly attached to the C-arm base) is proposed in this research. The cumulative dead-reckoning estimation of the base is extracted based on frame-to-frame homography estimation. Optical-flow results are utilized to feed the odometry. Online positional and orientation parameters are then reported. Positional accuracy of better than 2% (of the total traveled distance) for most of the cases and 4% for all the cases studied and angular accuracy of better than 2% (of absolute cumulative changes in orientation) were achieved with this method. This study provides a robust and accurate tracking framework that not only can be integrated with the current C-arm joint-tracking system (i.e. TC-arm) but also is capable of being employed for similar applications in other fields (e.g. robotics).

NA-241_Quarterly Report_SBLibby - 12.31.2017_v2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, Stephen B.

This is an evaluation of candidate navigation solutions for GPS free inspection tools that can be used in tours of large building interiors. In principle, COTS portable inertial motion unit (IMU) sensors with satisfactory accuracy, SWAP (size, weight, power), low error, and bias drift can provide sufficiently accurate dead reckoning navigation in a large building in the absence of GPS. To explore this assumption, the capabilities of representative IMU navigation sensors to meet these requirements will be evaluated, starting with a market survey, and then carrying out a basic analysis of these sensors using LLNL’s navigation codes.

Aeronautic Instruments. Section VI : Aerial Navigation and Navigating Instruments

NASA Technical Reports Server (NTRS)

Eaton, H N

1923-01-01

This report outlines briefly the methods of aerial navigation which have been developed during the past few years, with a description of the different instruments used. Dead reckoning, the most universal method of aerial navigation, is first discussed. Then follows an outline of the principles of navigation by astronomical observation; a discussion of the practical use of natural horizons, such as sea, land, and cloud, in making extant observations; the use of artificial horizons, including the bubble, pendulum, and gyroscopic types. A description is given of the recent development of the radio direction finder and its application to navigation.

Inertial Pointing and Positioning System

NASA Technical Reports Server (NTRS)

Yee, Robert (Inventor); Robbins, Fred (Inventor)

1998-01-01

An inertial pointing and control system and method for pointing to a designated target with known coordinates from a platform to provide accurate position, steering, and command information. The system continuously receives GPS signals and corrects Inertial Navigation System (INS) dead reckoning or drift errors. An INS is mounted directly on a pointing instrument rather than in a remote location on the platform for-monitoring the terrestrial position and instrument attitude. and for pointing the instrument at designated celestial targets or ground based landmarks. As a result. the pointing instrument and die INS move independently in inertial space from the platform since the INS is decoupled from the platform. Another important characteristic of the present system is that selected INS measurements are combined with predefined coordinate transformation equations and control logic algorithms under computer control in order to generate inertial pointing commands to the pointing instrument. More specifically. the computer calculates the desired instrument angles (Phi, Theta. Psi). which are then compared to the Euler angles measured by the instrument- mounted INS. and forms the pointing command error angles as a result of the compared difference.

Kinematic Model-Based Pedestrian Dead Reckoning for Heading Correction and Lower Body Motion Tracking.

PubMed

Lee, Min Su; Ju, Hojin; Song, Jin Woo; Park, Chan Gook

2015-11-06

In this paper, we present a method for finding the enhanced heading and position of pedestrians by fusing the Zero velocity UPdaTe (ZUPT)-based pedestrian dead reckoning (PDR) and the kinematic constraints of the lower human body. ZUPT is a well known algorithm for PDR, and provides a sufficiently accurate position solution for short term periods, but it cannot guarantee a stable and reliable heading because it suffers from magnetic disturbance in determining heading angles, which degrades the overall position accuracy as time passes. The basic idea of the proposed algorithm is integrating the left and right foot positions obtained by ZUPTs with the heading and position information from an IMU mounted on the waist. To integrate this information, a kinematic model of the lower human body, which is calculated by using orientation sensors mounted on both thighs and calves, is adopted. We note that the position of the left and right feet cannot be apart because of the kinematic constraints of the body, so the kinematic model generates new measurements for the waist position. The Extended Kalman Filter (EKF) on the waist data that estimates and corrects error states uses these measurements and magnetic heading measurements, which enhances the heading accuracy. The updated position information is fed into the foot mounted sensors, and reupdate processes are performed to correct the position error of each foot. The proposed update-reupdate technique consequently ensures improved observability of error states and position accuracy. Moreover, the proposed method provides all the information about the lower human body, so that it can be applied more effectively to motion tracking. The effectiveness of the proposed algorithm is verified via experimental results, which show that a 1.25% Return Position Error (RPE) with respect to walking distance is achieved.

An Outdoor Navigation Platform with a 3D Scanner and Gyro-assisted Odometry

NASA Astrophysics Data System (ADS)

Yoshida, Tomoaki; Irie, Kiyoshi; Koyanagi, Eiji; Tomono, Masahiro

This paper proposes a light-weight navigation platform that consists of gyro-assisted odometry, a 3D laser scanner and map-based localization for human-scale robots. The gyro-assisted odometry provides highly accurate positioning only by dead-reckoning. The 3D laser scanner has a wide field of view and uniform measuring-point distribution. The map-based localization is robust and computationally inexpensive by utilizing a particle filter on a 2D grid map generated by projecting 3D points on to the ground. The system uses small and low-cost sensors, and can be applied to a variety of mobile robots in human-scale environments. Outdoor navigation experiments were conducted at the Tsukuba Challenge held in 2009 and 2010, which is an open proving ground for human-scale robots. Our robot successfully navigated the assigned 1-km courses in a fully autonomous mode multiple times.

Unsupervised Indoor Localization Based on Smartphone Sensors, iBeacon and Wi-Fi.

PubMed

Chen, Jing; Zhang, Yi; Xue, Wei

2018-04-28

In this paper, we propose UILoc, an unsupervised indoor localization scheme that uses a combination of smartphone sensors, iBeacons and Wi-Fi fingerprints for reliable and accurate indoor localization with zero labor cost. Firstly, compared with the fingerprint-based method, the UILoc system can build a fingerprint database automatically without any site survey and the database will be applied in the fingerprint localization algorithm. Secondly, since the initial position is vital to the system, UILoc will provide the basic location estimation through the pedestrian dead reckoning (PDR) method. To provide accurate initial localization, this paper proposes an initial localization module, a weighted fusion algorithm combined with a k-nearest neighbors (KNN) algorithm and a least squares algorithm. In UILoc, we have also designed a reliable model to reduce the landmark correction error. Experimental results show that the UILoc can provide accurate positioning, the average localization error is about 1.1 m in the steady state, and the maximum error is 2.77 m.

Wi-Fi/MARG Integration for Indoor Pedestrian Localization

PubMed Central

Tian, Zengshan; Jin, Yue; Zhou, Mu; Wu, Zipeng; Li, Ze

2016-01-01

With the wide deployment of Wi-Fi networks, Wi-Fi based indoor localization systems that are deployed without any special hardware have caught significant attention and have become a currently practical technology. At the same time, the Magnetic, Angular Rate, and Gravity (MARG) sensors installed in commercial mobile devices can achieve highly-accurate localization in short time. Based on this, we design a novel indoor localization system by using built-in MARG sensors and a Wi-Fi module. The innovative contributions of this paper include the enhanced Pedestrian Dead Reckoning (PDR) and Wi-Fi localization approaches, and an Extended Kalman Particle Filter (EKPF) based fusion algorithm. A new Wi-Fi/MARG indoor localization system, including an Android based mobile client, a Web page for remote control, and a location server, is developed for real-time indoor pedestrian localization. The extensive experimental results show that the proposed system is featured with better localization performance, with the average error 0.85 m, than the one achieved by using the Wi-Fi module or MARG sensors solely. PMID:27973412

Advanced Pedestrian Positioning System to Smartphones and Smartwatches.

PubMed

Correa, Alejandro; Munoz Diaz, Estefania; Bousdar Ahmed, Dina; Morell, Antoni; Lopez Vicario, Jose

2016-11-11

In recent years, there has been an increasing interest in the development of pedestrian navigation systems for satellite-denied scenarios. The popularization of smartphones and smartwatches is an interesting opportunity for reducing the infrastructure cost of the positioning systems. Nowadays, smartphones include inertial sensors that can be used in pedestrian dead-reckoning (PDR) algorithms for the estimation of the user's position. Both smartphones and smartwatches include WiFi capabilities allowing the computation of the received signal strength (RSS). We develop a new method for the combination of RSS measurements from two different receivers using a Gaussian mixture model. We also analyze the implication of using a WiFi network designed for communication purposes in an indoor positioning system when the designer cannot control the network configuration. In this work, we design a hybrid positioning system that combines inertial measurements, from low-cost inertial sensors embedded in a smartphone, with RSS measurements through an extended Kalman filter. The system has been validated in a real scenario, and results show that our system improves the positioning accuracy of the PDR system thanks to the use of two WiFi receivers. The designed system obtains an accuracy up to 1.4 m in a scenario of 6000 m 2 .

Integrated WiFi/PDR/Smartphone Using an Unscented Kalman Filter Algorithm for 3D Indoor Localization.

PubMed

Chen, Guoliang; Meng, Xiaolin; Wang, Yunjia; Zhang, Yanzhe; Tian, Peng; Yang, Huachao

2015-09-23

Because of the high calculation cost and poor performance of a traditional planar map when dealing with complicated indoor geographic information, a WiFi fingerprint indoor positioning system cannot be widely employed on a smartphone platform. By making full use of the hardware sensors embedded in the smartphone, this study proposes an integrated approach to a three-dimensional (3D) indoor positioning system. First, an improved K-means clustering method is adopted to reduce the fingerprint database retrieval time and enhance positioning efficiency. Next, with the mobile phone's acceleration sensor, a new step counting method based on auto-correlation analysis is proposed to achieve cell phone inertial navigation positioning. Furthermore, the integration of WiFi positioning with Pedestrian Dead Reckoning (PDR) obtains higher positional accuracy with the help of the Unscented Kalman Filter algorithm. Finally, a hybrid 3D positioning system based on Unity 3D, which can carry out real-time positioning for targets in 3D scenes, is designed for the fluent operation of mobile terminals.

Integrated WiFi/PDR/Smartphone Using an Unscented Kalman Filter Algorithm for 3D Indoor Localization

PubMed Central

Chen, Guoliang; Meng, Xiaolin; Wang, Yunjia; Zhang, Yanzhe; Tian, Peng; Yang, Huachao

2015-01-01

Because of the high calculation cost and poor performance of a traditional planar map when dealing with complicated indoor geographic information, a WiFi fingerprint indoor positioning system cannot be widely employed on a smartphone platform. By making full use of the hardware sensors embedded in the smartphone, this study proposes an integrated approach to a three-dimensional (3D) indoor positioning system. First, an improved K-means clustering method is adopted to reduce the fingerprint database retrieval time and enhance positioning efficiency. Next, with the mobile phone’s acceleration sensor, a new step counting method based on auto-correlation analysis is proposed to achieve cell phone inertial navigation positioning. Furthermore, the integration of WiFi positioning with Pedestrian Dead Reckoning (PDR) obtains higher positional accuracy with the help of the Unscented Kalman Filter algorithm. Finally, a hybrid 3D positioning system based on Unity 3D, which can carry out real-time positioning for targets in 3D scenes, is designed for the fluent operation of mobile terminals. PMID:26404314

RGB-D SLAM Combining Visual Odometry and Extended Information Filter

PubMed Central

Zhang, Heng; Liu, Yanli; Tan, Jindong; Xiong, Naixue

2015-01-01

In this paper, we present a novel RGB-D SLAM system based on visual odometry and an extended information filter, which does not require any other sensors or odometry. In contrast to the graph optimization approaches, this is more suitable for online applications. A visual dead reckoning algorithm based on visual residuals is devised, which is used to estimate motion control input. In addition, we use a novel descriptor called binary robust appearance and normals descriptor (BRAND) to extract features from the RGB-D frame and use them as landmarks. Furthermore, considering both the 3D positions and the BRAND descriptors of the landmarks, our observation model avoids explicit data association between the observations and the map by marginalizing the observation likelihood over all possible associations. Experimental validation is provided, which compares the proposed RGB-D SLAM algorithm with just RGB-D visual odometry and a graph-based RGB-D SLAM algorithm using the publicly-available RGB-D dataset. The results of the experiments demonstrate that our system is quicker than the graph-based RGB-D SLAM algorithm. PMID:26263990

Stereotaxy, navigation and the temporal concatenation.

PubMed

Apuzzo, M L; Chen, J C

1999-01-01

Nautical and cerebral navigation share similar elements of functional need and similar developmental pathways. The need for orientation necessitates the development of appropriate concepts, and such concepts are dependent on technology for practical realization. Occasionally, a concept precedes technology in time and requires periods of delay for appropriate development. A temporal concatenation exists where time allows the additive as need, concept and technology ultimately provide an endpoint of elegant solution. Nautical navigation has proceeded through periods of dead reckoning and celestial navigation to satellite orientation with associated refinements of instrumentation and charts for guidance. Cerebral navigation has progressed from craniometric orientation and burr hole mounted guidance systems to simple rectolinear and arc-centered devices based on radiographs to guidance by complex anatomical and functional maps provided as an amalgam of modern imaging modes. These maps are now augmented by complex frame and frameless systems which allow not only precise orientation, but also point and volumetric action. These complex technical modalities required and developed in part from elements of maritime navigation that have been translated to cerebral navigation in a temporal concatenation. Copyright 2000 S. Karger AG, Basel

Robotic Lunar Rover Technologies and SEI Supporting Technologies at Sandia National Laboratories

NASA Technical Reports Server (NTRS)

Klarer, Paul R.

1992-01-01

Existing robotic rover technologies at Sandia National Laboratories (SNL) can be applied toward the realization of a robotic lunar rover mission in the near term. Recent activities at the SNL-RVR have demonstrated the utility of existing rover technologies for performing remote field geology tasks similar to those envisioned on a robotic lunar rover mission. Specific technologies demonstrated include low-data-rate teleoperation, multivehicle control, remote site and sample inspection, standard bandwidth stereo vision, and autonomous path following based on both internal dead reckoning and an external position location update system. These activities serve to support the use of robotic rovers for an early return to the lunar surface by demonstrating capabilities that are attainable with off-the-shelf technology and existing control techniques. The breadth of technical activities at SNL provides many supporting technology areas for robotic rover development. These range from core competency areas and microsensor fabrication facilities, to actual space qualification of flight components that are designed and fabricated in-house.

A Low Cost Sensors Approach for Accurate Vehicle Localization and Autonomous Driving Application.

PubMed

Vivacqua, Rafael; Vassallo, Raquel; Martins, Felipe

2017-10-16

Autonomous driving in public roads requires precise localization within the range of few centimeters. Even the best current precise localization system based on the Global Navigation Satellite System (GNSS) can not always reach this level of precision, especially in an urban environment, where the signal is disturbed by surrounding buildings and artifacts. Laser range finder and stereo vision have been successfully used for obstacle detection, mapping and localization to solve the autonomous driving problem. Unfortunately, Light Detection and Ranging (LIDARs) are very expensive sensors and stereo vision requires powerful dedicated hardware to process the cameras information. In this context, this article presents a low-cost architecture of sensors and data fusion algorithm capable of autonomous driving in narrow two-way roads. Our approach exploits a combination of a short-range visual lane marking detector and a dead reckoning system to build a long and precise perception of the lane markings in the vehicle's backwards. This information is used to localize the vehicle in a map, that also contains the reference trajectory for autonomous driving. Experimental results show the successful application of the proposed system on a real autonomous driving situation.

A Low Cost Sensors Approach for Accurate Vehicle Localization and Autonomous Driving Application

PubMed Central

Vassallo, Raquel

2017-01-01

Autonomous driving in public roads requires precise localization within the range of few centimeters. Even the best current precise localization system based on the Global Navigation Satellite System (GNSS) can not always reach this level of precision, especially in an urban environment, where the signal is disturbed by surrounding buildings and artifacts. Laser range finder and stereo vision have been successfully used for obstacle detection, mapping and localization to solve the autonomous driving problem. Unfortunately, Light Detection and Ranging (LIDARs) are very expensive sensors and stereo vision requires powerful dedicated hardware to process the cameras information. In this context, this article presents a low-cost architecture of sensors and data fusion algorithm capable of autonomous driving in narrow two-way roads. Our approach exploits a combination of a short-range visual lane marking detector and a dead reckoning system to build a long and precise perception of the lane markings in the vehicle’s backwards. This information is used to localize the vehicle in a map, that also contains the reference trajectory for autonomous driving. Experimental results show the successful application of the proposed system on a real autonomous driving situation. PMID:29035334

Analysis of UAS DAA Alerting in Fast-Time Simulations without DAA Mitigation

NASA Technical Reports Server (NTRS)

Thipphavong, David P.; Santiago, Confesor; Isaacson, Douglas R.; Lee, Seung Man; Park, Chunki; Refai, Mohamad Said; Snow, James

2015-01-01

Realization of the expected proliferation of Unmanned Aircraft System (UAS) operations in the National Airspace System (NAS) depends on the development and validation of performance standards for UAS Detect and Avoid (DAA) Systems. The RTCA Special Committee 228 is charged with leading the development of draft Minimum Operational Performance Standards (MOPS) for UAS DAA Systems. NASA, as a participating member of RTCA SC-228 is committed to supporting the development and validation of draft requirements for DAA alerting system performance. A recent study conducted using NASA's ACES (Airspace Concept Evaluation System) simulation capability begins to address questions surrounding the development of draft MOPS for DAA alerting systems. ACES simulations were conducted to study the performance of alerting systems proposed by the SC-228 DAA Alerting sub-group. Analysis included but was not limited to: 1) correct alert (and timeliness), 2) false alert (and severity and duration), 3) missed alert, and 4) probability of an alert type at the time of loss of well clear. The performance of DAA alerting systems when using intent vs. dead-reckoning for UAS ownship trajectories was also compared. The results will be used by SC-228 to inform decisions about the surveillance standards of UAS DAA systems and future requirements development and validation efforts.

Flow Mapping Based on the Motion-Integration Errors of Autonomous Underwater Vehicles

NASA Astrophysics Data System (ADS)

Chang, D.; Edwards, C. R.; Zhang, F.

2016-02-01

Knowledge of a flow field is crucial in the navigation of autonomous underwater vehicles (AUVs) since the motion of AUVs is affected by ambient flow. Due to the imperfect knowledge of the flow field, it is typical to observe a difference between the actual and predicted trajectories of an AUV, which is referred to as a motion-integration error (also known as a dead-reckoning error if an AUV navigates via dead-reckoning). The motion-integration error has been essential for an underwater glider to compute its flow estimate from the travel information of the last leg and to improve navigation performance by using the estimate for the next leg. However, the estimate by nature exhibits a phase difference compared to ambient flow experienced by gliders, prohibiting its application in a flow field with strong temporal and spatial gradients. In our study, to mitigate the phase problem, we have developed a local ocean model by combining the flow estimate based on the motion-integration error with flow predictions from a tidal ocean model. Our model has been used to create desired trajectories of gliders for guidance. Our method is validated by Long Bay experiments in 2012 and 2013 in which we deployed multiple gliders on the shelf of South Atlantic Bight and near the edge of Gulf Stream. In our recent study, the application of the motion-integration error is further extended to create a spatial flow map. Considering that the motion-integration errors of AUVs accumulate along their trajectories, the motion-integration error is formulated as a line integral of ambient flow which is then reformulated into algebraic equations. By solving an inverse problem for these algebraic equations, we obtain the knowledge of such flow in near real time, allowing more effective and precise guidance of AUVs in a dynamic environment. This method is referred to as motion tomography. We provide the results of non-parametric and parametric flow mapping from both simulated and experimental data.

Advanced Pedestrian Positioning System to Smartphones and Smartwatches

PubMed Central

Correa, Alejandro; Munoz Diaz, Estefania; Bousdar Ahmed, Dina; Morell, Antoni; Lopez Vicario, Jose

2016-01-01

In recent years, there has been an increasing interest in the development of pedestrian navigation systems for satellite-denied scenarios. The popularization of smartphones and smartwatches is an interesting opportunity for reducing the infrastructure cost of the positioning systems. Nowadays, smartphones include inertial sensors that can be used in pedestrian dead-reckoning (PDR) algorithms for the estimation of the user’s position. Both smartphones and smartwatches include WiFi capabilities allowing the computation of the received signal strength (RSS). We develop a new method for the combination of RSS measurements from two different receivers using a Gaussian mixture model. We also analyze the implication of using a WiFi network designed for communication purposes in an indoor positioning system when the designer cannot control the network configuration. In this work, we design a hybrid positioning system that combines inertial measurements, from low-cost inertial sensors embedded in a smartphone, with RSS measurements through an extended Kalman filter. The system has been validated in a real scenario, and results show that our system improves the positioning accuracy of the PDR system thanks to the use of two WiFi receivers. The designed system obtains an accuracy up to 1.4 m in a scenario of 6000 m2. PMID:27845715

LiDAR Scan Matching Aided Inertial Navigation System in GNSS-Denied Environments

PubMed Central

Tang, Jian; Chen, Yuwei; Niu, Xiaoji; Wang, Li; Chen, Liang; Liu, Jingbin; Shi, Chuang; Hyyppä, Juha

2015-01-01

A new scan that matches an aided Inertial Navigation System (INS) with a low-cost LiDAR is proposed as an alternative to GNSS-based navigation systems in GNSS-degraded or -denied environments such as indoor areas, dense forests, or urban canyons. In these areas, INS-based Dead Reckoning (DR) and Simultaneous Localization and Mapping (SLAM) technologies are normally used to estimate positions as separate tools. However, there are critical implementation problems with each standalone system. The drift errors of velocity, position, and heading angles in an INS will accumulate over time, and on-line calibration is a must for sustaining positioning accuracy. SLAM performance is poor in featureless environments where the matching errors can significantly increase. Each standalone positioning method cannot offer a sustainable navigation solution with acceptable accuracy. This paper integrates two complementary technologies—INS and LiDAR SLAM—into one navigation frame with a loosely coupled Extended Kalman Filter (EKF) to use the advantages and overcome the drawbacks of each system to establish a stable long-term navigation process. Static and dynamic field tests were carried out with a self-developed Unmanned Ground Vehicle (UGV) platform—NAVIS. The results prove that the proposed approach can provide positioning accuracy at the centimetre level for long-term operations, even in a featureless indoor environment. PMID:26184206

LiDAR Scan Matching Aided Inertial Navigation System in GNSS-Denied Environments.

PubMed

Tang, Jian; Chen, Yuwei; Niu, Xiaoji; Wang, Li; Chen, Liang; Liu, Jingbin; Shi, Chuang; Hyyppä, Juha

2015-07-10

A new scan that matches an aided Inertial Navigation System (INS) with a low-cost LiDAR is proposed as an alternative to GNSS-based navigation systems in GNSS-degraded or -denied environments such as indoor areas, dense forests, or urban canyons. In these areas, INS-based Dead Reckoning (DR) and Simultaneous Localization and Mapping (SLAM) technologies are normally used to estimate positions as separate tools. However, there are critical implementation problems with each standalone system. The drift errors of velocity, position, and heading angles in an INS will accumulate over time, and on-line calibration is a must for sustaining positioning accuracy. SLAM performance is poor in featureless environments where the matching errors can significantly increase. Each standalone positioning method cannot offer a sustainable navigation solution with acceptable accuracy. This paper integrates two complementary technologies-INS and LiDAR SLAM-into one navigation frame with a loosely coupled Extended Kalman Filter (EKF) to use the advantages and overcome the drawbacks of each system to establish a stable long-term navigation process. Static and dynamic field tests were carried out with a self-developed Unmanned Ground Vehicle (UGV) platform-NAVIS. The results prove that the proposed approach can provide positioning accuracy at the centimetre level for long-term operations, even in a featureless indoor environment.

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

NASA Astrophysics Data System (ADS)

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 two-stage Kalman Filter approach. The performance comparison of the algorithm based on different field and simulated datasets, with varying levels of sensor errors, showed that 90 per cent success rate was achieved in detection of outliers for SL and 80 per cent for SD. The SL is predicted for both KBS-based ANN and FL approaches with an average accumulated error of 2 per cent, observed for the total distance traveled, which is generally an improvement over most of the existing pedometry systems. The target accuracy of the system is +/-(3-5)m CEP50 (circular error, probable 50%). This dissertation provides a performance analysis in the outdoor and indoor environments for different operators. Another objective of this dissertation is to test the system's navigation limitation in DR mode in terms of time and trajectory length in order to determine the upper limit of indoor operations. It was determined that for more than four indoor loops, where the user walked 261m in about 6.5 minutes, the DR performance met the required accuracy specifications. However, these results are only relevant to the existing data. Future studies should consider more comprehensive performance analysis for longer trajectories in challenging environments and possible extension to image-based navigation to expand the indoor capability of the system.

ULTRA: Underwater Localization for Transit and Reconnaissance Autonomy

NASA Technical Reports Server (NTRS)

Huntsberger, Terrance L.

2013-01-01

This software addresses the issue of underwater localization of unmanned vehicles and the inherent drift in their onboard sensors. The software gives a 2 to 3 factor of improvement over the state-of-the-art underwater localization algorithms. The software determines the localization (position, heading) of an AUV (autonomous underwater vehicle) in environments where there is no GPS signal. It accomplishes this using only the commanded position, onboard gyros/accelerometers, and the bathymetry of the bottom provided by an onboard sonar system. The software does not rely on an onboard bathymetry dataset, but instead incrementally determines the position of the AUV while mapping the bottom. In order to enable long-distance underwater navigation by AUVs, a localization method called ULTRA uses registration of the bathymetry data products produced by the onboard forward-looking sonar system for hazard avoidance during a transit to derive the motion and pose of the AUV in order to correct the DR (dead reckoning) estimates. The registration algorithm uses iterative point matching (IPM) combined with surface interpolation of the Iterative Closest Point (ICP) algorithm. This method was used previously at JPL for onboard unmanned ground vehicle localization, and has been optimized for efficient computational and memory use.

Autonomous vehicle navigation utilizing fuzzy controls concepts for a next generation wheelchair.

PubMed

Hansen, J D; Barrett, S F; Wright, C H G; Wilcox, M

2008-01-01

Three different positioning techniques were investigated to create an autonomous vehicle that could accurately navigate towards a goal: Global Positioning System (GPS), compass dead reckoning, and Ackerman steering. Each technique utilized a fuzzy logic controller that maneuvered a four-wheel car towards a target. The reliability and the accuracy of the navigation methods were investigated by modeling the algorithms in software and implementing them in hardware. To implement the techniques in hardware, positioning sensors were interfaced to a remote control car and a microprocessor. The microprocessor utilized the sensor measurements to orient the car with respect to the target. Next, a fuzzy logic control algorithm adjusted the front wheel steering angle to minimize the difference between the heading and bearing. After minimizing the heading error, the car maintained a straight steering angle along its path to the final destination. The results of this research can be used to develop applications that require precise navigation. The design techniques can also be implemented on alternate platforms such as a wheelchair to assist with autonomous navigation.

Initial Evaluation of a Conflict Detection Tool in the Terminal Area

NASA Technical Reports Server (NTRS)

Verma Savita Arora; Tang, Huabin; Ballinger, Deborah S.; Kozon, Thomas E.; Farrahi, Amir Hossein

2012-01-01

Despite the recent economic recession and its adverse impact on air travel, the Federal Aviation Administration (FAA) continues to forecast an increase in air traffic demand that may see traffic double or triple by the year 2025. Increases in air traffic will burden the air traffic management system, and higher levels of safety and efficiency will be required. The air traffic controllers primary task is to ensure separation between aircraft in their airspace and keep the skies safe. As air traffic is forecasted to increase in volume and complexity [1], there is an increased likelihood of conflicts between aircraft, which adds risk and inefficiency to air traffic management and increases controller workload. To attenuate these factors, recent ATM research has shown that air and ground-based automation tools could reduce controller workload, especially if the automation is focused on conflict detection and resolution. Conflict Alert is a short time horizon conflict detection tool deployed in the Terminal Radar Approach Control (TRACON), which has limited utility due to the high number of false alerts generated and its use of dead reckoning to predict loss of separation between aircraft. Terminal Tactical Separation Assurance Flight Environment (T-TSAFE) is a short time horizon conflict detection tool that uses both flight intent and dead reckoning to detect conflicts. Results of a fast time simulation experiment indicated that TTSAFE provided a more effective alert lead-time and generated less false alerts than Conflict Alert [2]. TSAFE was previously tested in a Human-In-The-Loop (HITL) simulation study that focused on the en route phase of flight [3]. The current study tested the T-TSAFE tool in an HITL simulation study, focusing on the terminal environment with current day operations. The study identified procedures, roles, responsibilities, information requirements and usability, with the help of TRACON controllers who participated in the experiment. Metrics such as lead alert time, alert response time, workload, situation awareness and other measures were statistically analyzed. These metrics were examined from an overall perspective and comparisons between conditions (altitude resolutions via keyboard entry vs. ADS-B entry) and controller positions (two final approach sectors and two feeder sectors) were also examined. Results of these analyses and controller feedback provided evidence of T-TSAFE s potential promise as a useful air traffic controller tool. Heuristic analysis also provided information on ways in which the T-TSAFE tool can be improved. Details of analyses results will be presented in the full paper.

Constructing an Indoor Floor Plan Using Crowdsourcing Based on Magnetic Fingerprinting

PubMed Central

Zhao, Fang; Jiang, Mengling; Ma, Hao; Zhang, Yuexia

2017-01-01

A large number of indoor positioning systems have recently been developed to cater for various location-based services. Indoor maps are a prerequisite of such indoor positioning systems; however, indoor maps are currently non-existent for most indoor environments. Construction of an indoor map by external experts excludes quick deployment and prevents widespread utilization of indoor localization systems. Here, we propose an algorithm for the automatic construction of an indoor floor plan, together with a magnetic fingerprint map of unmapped buildings using crowdsourced smartphone data. For floor plan construction, our system combines the use of dead reckoning technology, an observation model with geomagnetic signals, and trajectory fusion based on an affinity propagation algorithm. To obtain the indoor paths, the magnetic trajectory data obtained through crowdsourcing were first clustered using dynamic time warping similarity criteria. The trajectories were inferred from odometry tracing, and those belonging to the same cluster in the magnetic trajectory domain were then fused. Fusing these data effectively eliminates the inherent tracking errors originating from noisy sensors; as a result, we obtained highly accurate indoor paths. One advantage of our system is that no additional hardware such as a laser rangefinder or wheel encoder is required. Experimental results demonstrate that our proposed algorithm successfully constructs indoor floor plans with 0.48 m accuracy, which could benefit location-based services which lack indoor maps. PMID:29156639

Kalman filter with a linear state model for PDR+WLAN positioning and its application to assisting a particle filter

NASA Astrophysics Data System (ADS)

Raitoharju, Matti; Nurminen, Henri; Piché, Robert

2015-12-01

Indoor positioning based on wireless local area network (WLAN) signals is often enhanced using pedestrian dead reckoning (PDR) based on an inertial measurement unit. The state evolution model in PDR is usually nonlinear. We present a new linear state evolution model for PDR. In simulated-data and real-data tests of tightly coupled WLAN-PDR positioning, the positioning accuracy with this linear model is better than with the traditional models when the initial heading is not known, which is a common situation. The proposed method is computationally light and is also suitable for smoothing. Furthermore, we present modifications to WLAN positioning based on Gaussian coverage areas and show how a Kalman filter using the proposed model can be used for integrity monitoring and (re)initialization of a particle filter.

A miniature shoe-mounted orientation determination system for accurate indoor heading and trajectory tracking.

PubMed

Zhang, Shengzhi; Yu, Shuai; Liu, Chaojun; Liu, Sheng

2016-06-01

Tracking the position of pedestrian is urgently demanded when the most commonly used GPS (Global Position System) is unavailable. Benefited from the small size, low-power consumption, and relatively high reliability, micro-electro-mechanical system sensors are well suited for GPS-denied indoor pedestrian heading estimation. In this paper, a real-time miniature orientation determination system (MODS) was developed for indoor heading and trajectory tracking based on a novel dual-linear Kalman filter. The proposed filter precludes the impact of geomagnetic distortions on pitch and roll that the heading is subjected to. A robust calibration approach was designed to improve the accuracy of sensors measurements based on a unified sensor model. Online tests were performed on the MODS with an improved turntable. The results demonstrate that the average RMSE (root-mean-square error) of heading estimation is less than 1°. Indoor heading experiments were carried out with the MODS mounted on the shoe of pedestrian. Besides, we integrated the existing MODS into an indoor pedestrian dead reckoning application as an example of its utility in realistic actions. A human attitude-based walking model was developed to calculate the walking distance. Test results indicate that mean percentage error of indoor trajectory tracking achieves 2% of the total walking distance. This paper provides a feasible alternative for accurate indoor heading and trajectory tracking.

A low-cost test-bed for real-time landmark tracking

NASA Astrophysics Data System (ADS)

Csaszar, Ambrus; Hanan, Jay C.; Moreels, Pierre; Assad, Christopher

2007-04-01

A low-cost vehicle test-bed system was developed to iteratively test, refine and demonstrate navigation algorithms before attempting to transfer the algorithms to more advanced rover prototypes. The platform used here was a modified radio controlled (RC) car. A microcontroller board and onboard laptop computer allow for either autonomous or remote operation via a computer workstation. The sensors onboard the vehicle represent the types currently used on NASA-JPL rover prototypes. For dead-reckoning navigation, optical wheel encoders, a single axis gyroscope, and 2-axis accelerometer were used. An ultrasound ranger is available to calculate distance as a substitute for the stereo vision systems presently used on rovers. The prototype also carries a small laptop computer with a USB camera and wireless transmitter to send real time video to an off-board computer. A real-time user interface was implemented that combines an automatic image feature selector, tracking parameter controls, streaming video viewer, and user generated or autonomous driving commands. Using the test-bed, real-time landmark tracking was demonstrated by autonomously driving the vehicle through the JPL Mars yard. The algorithms tracked rocks as waypoints. This generated coordinates calculating relative motion and visually servoing to science targets. A limitation for the current system is serial computing-each additional landmark is tracked in order-but since each landmark is tracked independently, if transferred to appropriate parallel hardware, adding targets would not significantly diminish system speed.

Fusion of WiFi, smartphone sensors and landmarks using the Kalman filter for indoor localization.

PubMed

Chen, Zhenghua; Zou, Han; Jiang, Hao; Zhu, Qingchang; Soh, Yeng Chai; Xie, Lihua

2015-01-05

Location-based services (LBS) have attracted a great deal of attention recently. Outdoor localization can be solved by the GPS technique, but how to accurately and efficiently localize pedestrians in indoor environments is still a challenging problem. Recent techniques based on WiFi or pedestrian dead reckoning (PDR) have several limiting problems, such as the variation of WiFi signals and the drift of PDR. An auxiliary tool for indoor localization is landmarks, which can be easily identified based on specific sensor patterns in the environment, and this will be exploited in our proposed approach. In this work, we propose a sensor fusion framework for combining WiFi, PDR and landmarks. Since the whole system is running on a smartphone, which is resource limited, we formulate the sensor fusion problem in a linear perspective, then a Kalman filter is applied instead of a particle filter, which is widely used in the literature. Furthermore, novel techniques to enhance the accuracy of individual approaches are adopted. In the experiments, an Android app is developed for real-time indoor localization and navigation. A comparison has been made between our proposed approach and individual approaches. The results show significant improvement using our proposed framework. Our proposed system can provide an average localization accuracy of 1 m.

Fusion of WiFi, Smartphone Sensors and Landmarks Using the Kalman Filter for Indoor Localization

PubMed Central

Chen, Zhenghua; Zou, Han; Jiang, Hao; Zhu, Qingchang; Soh, Yeng Chai; Xie, Lihua

2015-01-01

Location-based services (LBS) have attracted a great deal of attention recently. Outdoor localization can be solved by the GPS technique, but how to accurately and efficiently localize pedestrians in indoor environments is still a challenging problem. Recent techniques based on WiFi or pedestrian dead reckoning (PDR) have several limiting problems, such as the variation of WiFi signals and the drift of PDR. An auxiliary tool for indoor localization is landmarks, which can be easily identified based on specific sensor patterns in the environment, and this will be exploited in our proposed approach. In this work, we propose a sensor fusion framework for combining WiFi, PDR and landmarks. Since the whole system is running on a smartphone, which is resource limited, we formulate the sensor fusion problem in a linear perspective, then a Kalman filter is applied instead of a particle filter, which is widely used in the literature. Furthermore, novel techniques to enhance the accuracy of individual approaches are adopted. In the experiments, an Android app is developed for real-time indoor localization and navigation. A comparison has been made between our proposed approach and individual approaches. The results show significant improvement using our proposed framework. Our proposed system can provide an average localization accuracy of 1 m. PMID:25569750

A Robust Crowdsourcing-Based Indoor Localization System.

PubMed

Zhou, Baoding; Li, Qingquan; Mao, Qingzhou; Tu, Wei

2017-04-14

WiFi fingerprinting-based indoor localization has been widely used due to its simplicity and can be implemented on the smartphones. The major drawback of WiFi fingerprinting is that the radio map construction is very labor-intensive and time-consuming. Another drawback of WiFi fingerprinting is the Received Signal Strength (RSS) variance problem, caused by environmental changes and device diversity. RSS variance severely degrades the localization accuracy. In this paper, we propose a robust crowdsourcing-based indoor localization system (RCILS). RCILS can automatically construct the radio map using crowdsourcing data collected by smartphones. RCILS abstracts the indoor map as the semantics graph in which the edges are the possible user paths and the vertexes are the location where users may take special activities. RCILS extracts the activity sequence contained in the trajectories by activity detection and pedestrian dead-reckoning. Based on the semantics graph and activity sequence, crowdsourcing trajectories can be located and a radio map is constructed based on the localization results. For the RSS variance problem, RCILS uses the trajectory fingerprint model for indoor localization. During online localization, RCILS obtains an RSS sequence and realizes localization by matching the RSS sequence with the radio map. To evaluate RCILS, we apply RCILS in an office building. Experiment results demonstrate the efficiency and robustness of RCILS.

A Robust Crowdsourcing-Based Indoor Localization System

PubMed Central

Zhou, Baoding; Li, Qingquan; Mao, Qingzhou; Tu, Wei

2017-01-01

WiFi fingerprinting-based indoor localization has been widely used due to its simplicity and can be implemented on the smartphones. The major drawback of WiFi fingerprinting is that the radio map construction is very labor-intensive and time-consuming. Another drawback of WiFi fingerprinting is the Received Signal Strength (RSS) variance problem, caused by environmental changes and device diversity. RSS variance severely degrades the localization accuracy. In this paper, we propose a robust crowdsourcing-based indoor localization system (RCILS). RCILS can automatically construct the radio map using crowdsourcing data collected by smartphones. RCILS abstracts the indoor map as the semantics graph in which the edges are the possible user paths and the vertexes are the location where users may take special activities. RCILS extracts the activity sequence contained in the trajectories by activity detection and pedestrian dead-reckoning. Based on the semantics graph and activity sequence, crowdsourcing trajectories can be located and a radio map is constructed based on the localization results. For the RSS variance problem, RCILS uses the trajectory fingerprint model for indoor localization. During online localization, RCILS obtains an RSS sequence and realizes localization by matching the RSS sequence with the radio map. To evaluate RCILS, we apply RCILS in an office building. Experiment results demonstrate the efficiency and robustness of RCILS. PMID:28420108

Hack-proof Synchronization Protocol for Multi-player Online Games

NASA Astrophysics Data System (ADS)

Fung, Yeung Siu; Lui, John C. S.

Modern multi-player online games are popular and attractive because they provide a sense of virtual world experience to users: players can interact with each other on the Internet but perceive a local area network responsiveness. To make this possible, most modern multi-player online games use similar networking architecture that aims to hide the effects of network latency, packet loss, and high variance of delay from players. Because real-time interactivity is a crucial feature from a player's point of view, any delay perceived by a player can affect his/her performance [16]. Therefore, the game client must be able to run and accept new user commands continuously regardless of the condition of the underlying communication channel, and that it will not stop responding because of waiting for update packets from other players. To make this possible, multi-player online games typically use protocols based on "dead-reckoning" [5, 6, 9] which allows loose synchronization between players.

Numerical bias in bounded and unbounded number line tasks.

PubMed

Cohen, Dale J; Blanc-Goldhammer, Daryn

2011-04-01

The number line task is often used to assess children's and adults' underlying representations of integers. Traditional bounded number line tasks, however, have limitations that can lead to misinterpretation. Here we present a new task, an unbounded number line task, that overcomes these limitations. In Experiment 1, we show that adults use a biased proportion estimation strategy to complete the traditional bounded number line task. In Experiment 2, we show that adults use a dead-reckoning integer estimation strategy in our unbounded number line task. Participants revealed a positively accelerating numerical bias in both tasks, but showed scalar variance only in the unbounded number line task. We conclude that the unbounded number line task is a more pure measure of integer representation than the bounded number line task, and using these results, we present a preliminary description of adults' underlying representation of integers.

High-resolution seismic-reflection data collected on R/V S.P. LEE: L9-84-CP, Marshall Islands to Hawaii

USGS Publications Warehouse

Schwab, William C.; Bailey, Norman G.

1984-01-01

The U.S. Geological Survey (USGS) R/V S.P. LEE (cruise L9-84-CP) left Majuro, Radak chain of the Marshall Islands on July 28, 1984, cruised over the Mid-Pacific Mountains, and reached Hawaii on August 15, 1984. The main objectives of the cruise were to study the distribution and composition of ferromanganese-oxide crusts in the Marshall Islands and to retrieve a current meter/sediment trap mooring deployed in October 1983 on Horizon Guyot, Mid-Pacific Mountains (USGS LS-83-HW cruise). The quality of the geophysical data collected is generally good. However, the declivity of some seamount, atoll, and guyot flanks are too large to allow high-quality resolution from the surface-towed systems that were used.The navigation system used was an integrated satellite-navigation/LORAN-C (in Mid-Pacific Mountains)/dead-reckoning system that was updated by radar when possible. A total of 5410 km of 12-kHz and 3.5-kHz seismic-reflection data and 730 km of 80-in3 to 148-in3 airgun seismic-reflection data were collected. The original records can be seen and studied at the USGS offices at Woods Hole, MA 02543. Microfilm copies of the seismic-reflection data can be purchased only from the National Geophysical Data Center, NOAA/EDIS/NGDC, 325 Broadway, Boulder, CO 80303.

The Design of WORKER'S Behavior Analysis Method in Workplace Using Indoor Positioning Technology

NASA Astrophysics Data System (ADS)

Tabata, K.; Konno, H.; Nakajima, M.

2016-06-01

This study presents a method for analyzing workers' behavior using indoor positioning technology and field test in the workplace. Recently, various indoor positioning methods, such as Wi-Fi, Bluetooth low energy (BLE), visible light communication, Japan's indoor messaging system, ultra-wide band (UWB), and pedestrian dead reckoning (PDR), have been investigated. The development of these technologies allows tracking of movement of both people and/or goods in indoor spaces, people and/or goods behavior analysis is expected as one of the key technologies for operation optimization. However, when we use these technologies for human tracking, there are some problem as follows. 1) Many cases need to use dedicated facilities (e.g. UWB). 2) When we use smartphone as sensing device, battery depletion is one of the big problem (especially using PDR). 3) the accuracy is instability for tracking (e.g. Wi-Fi). Based on these matters, in this study we designed and developed an indoor positioning system using BLE positioning. And, we adopted smartphone for business use as sensing device, developed a smartphone application runs on android OS. Moreover, we conducted the field test of developed system at Itoki Corporation's ITOKI Tokyo Innovation Center, SYNQA, office (Tokyo, Japan). Over 40 workers participated in this field test, and worker tracking log data were collected for 6 weeks. We analyzed the characteristics of the workers' behavior using this log data as a prototyping.

On calibrating the sensor errors of a PDR-based indoor localization system.

PubMed

Lan, Kun-Chan; Shih, Wen-Yuah

2013-04-10

Many studies utilize the signal strength of short-range radio systems (such as WiFi, ultrasound and infrared) to build a radio map for indoor localization, by deploying a large number of beacon nodes within a building. The drawback of such an infrastructure-based approach is that the deployment and calibration of the system are costly and labor-intensive. Some prior studies proposed the use of Pedestrian Dead Reckoning (PDR) for indoor localization, which does not require the deployment of beacon nodes. In a PDR system, a small number of sensors are put on the pedestrian. These sensors (such as a G-sensor and gyroscope) are used to estimate the distance and direction that a user travels. The effectiveness of a PDR system lies in its success in accurately estimating the user's moving distance and direction. In this work, we propose a novel waist-mounted based PDR that can measure the user's step lengths with a high accuracy. We utilize vertical acceleration of the body to calculate the user's change in height during walking. Based on the Pythagorean Theorem, we can then estimate each step length using this data. Furthermore, we design a map matching algorithm to calibrate the direction errors from the gyro using building floor plans. The results of our experiment show that we can achieve about 98.26% accuracy in estimating the user's walking distance, with an overall location error of about 0.48 m.

On Calibrating the Sensor Errors of a PDR-Based Indoor Localization System

PubMed Central

Lan, Kun-Chan; Shih, Wen-Yuah

2013-01-01

Many studies utilize the signal strength of short-range radio systems (such as WiFi, ultrasound and infrared) to build a radio map for indoor localization, by deploying a large number of beacon nodes within a building. The drawback of such an infrastructure-based approach is that the deployment and calibration of the system are costly and labor-intensive. Some prior studies proposed the use of Pedestrian Dead Reckoning (PDR) for indoor localization, which does not require the deployment of beacon nodes. In a PDR system, a small number of sensors are put on the pedestrian. These sensors (such as a G-sensor and gyroscope) are used to estimate the distance and direction that a user travels. The effectiveness of a PDR system lies in its success in accurately estimating the user's moving distance and direction. In this work, we propose a novel waist-mounted based PDR that can measure the user's step lengths with a high accuracy. We utilize vertical acceleration of the body to calculate the user's change in height during walking. Based on the Pythagorean Theorem, we can then estimate each step length using this data. Furthermore, we design a map matching algorithm to calibrate the direction errors from the gyro using building floor plans. The results of our experiment show that we can achieve about 98.26% accuracy in estimating the user's walking distance, with an overall location error of about 0.48 m. PMID:23575036

The Standardization of Time: A Sociohistorical Perspective.

ERIC Educational Resources Information Center

Zerubavel, Eviatar

1982-01-01

Explores the social process of establishing a standard time-reckoning framework. The paper examines the introduction of Greenwich Mean Time in Britain, the establishment of the American railway time-zone system, and the almost universal enforcement of the international standard time-zone system. (AM)

Soldier systems sensor fusion

NASA Astrophysics Data System (ADS)

Brubaker, Kathryne M.

1998-08-01

This paper addresses sensor fusion and its applications in emerging Soldier Systems integration and the unique challenges associated with the human platform. Technology that,provides the highest operational payoff in a lightweight warrior system must not only have enhanced capabilities, but have low power components resulting in order of magnitude reductions coupled with significant cost reductions. These reductions in power and cost will be achieved through partnership with industry and leveraging of commercial state of the art advancements in microelectronics and power sources. As new generation of full solution fire control systems (to include temperature, wind and range sensors) and target acquisition systems will accompany a new generation of individual combat weapons and upgrade existing weapon systems. Advanced lightweight thermal, IR, laser and video senors will be used for surveillance, target acquisition, imaging and combat identification applications. Multifunctional sensors will provide embedded training features in combat configurations allowing the soldier to 'train as he fights' without the traditional cost and weight penalties associated with separate systems. Personal status monitors (detecting pulse, respiration rate, muscle fatigue, core temperature, etc.) will provide commanders and highest echelons instantaneous medical data. Seamless integration of GPS and dead reckoning (compass and pedometer) and/or inertial sensors will aid navigation and increase position accuracy. Improved sensors and processing capability will provide earlier detection of battlefield hazards such as mines, enemy lasers and NBC (nuclear, biological, chemical) agents. Via the digitized network the situational awareness database will automatically be updated with weapon, medical, position and battlefield hazard data. Soldier Systems Sensor Fusion will ultimately establish each individual soldier as an individual sensor on the battlefield.

Integrating GPS, GYRO, vehicle speed sensor, and digital map to provide accurate and real-time position in an intelligent navigation system

NASA Astrophysics Data System (ADS)

Li, Qingquan; Fang, Zhixiang; Li, Hanwu; Xiao, Hui

2005-10-01

The global positioning system (GPS) has become the most extensively used positioning and navigation tool in the world. Applications of GPS abound in surveying, mapping, transportation, agriculture, military planning, GIS, and the geosciences. However, the positional and elevation accuracy of any given GPS location is prone to error, due to a number of factors. The applications of Global Positioning System (GPS) positioning is more and more popular, especially the intelligent navigation system which relies on GPS and Dead Reckoning technology is developing quickly for future huge market in China. In this paper a practical combined positioning model of GPS/DR/MM is put forward, which integrates GPS, Gyro, Vehicle Speed Sensor (VSS) and digital navigation maps to provide accurate and real-time position for intelligent navigation system. This model is designed for automotive navigation system making use of Kalman filter to improve position and map matching veracity by means of filtering raw GPS and DR signals, and then map-matching technology is used to provide map coordinates for map displaying. In practical examples, for illustrating the validity of the model, several experiments and their results of integrated GPS/DR positioning in intelligent navigation system will be shown for the conclusion that Kalman Filter based GPS/DR integrating position approach is necessary, feasible and efficient for intelligent navigation application. Certainly, this combined positioning model, similar to other model, can not resolve all situation issues. Finally, some suggestions are given for further improving integrated GPS/DR/MM application.

Real-Time Multi-Target Localization from Unmanned Aerial Vehicles

PubMed Central

Wang, Xuan; Liu, Jinghong; Zhou, Qianfei

2016-01-01

In order to improve the reconnaissance efficiency of unmanned aerial vehicle (UAV) electro-optical stabilized imaging systems, a real-time multi-target localization scheme based on an UAV electro-optical stabilized imaging system is proposed. First, a target location model is studied. Then, the geodetic coordinates of multi-targets are calculated using the homogeneous coordinate transformation. On the basis of this, two methods which can improve the accuracy of the multi-target localization are proposed: (1) the real-time zoom lens distortion correction method; (2) a recursive least squares (RLS) filtering method based on UAV dead reckoning. The multi-target localization error model is established using Monte Carlo theory. In an actual flight, the UAV flight altitude is 1140 m. The multi-target localization results are within the range of allowable error. After we use a lens distortion correction method in a single image, the circular error probability (CEP) of the multi-target localization is reduced by 7%, and 50 targets can be located at the same time. The RLS algorithm can adaptively estimate the location data based on multiple images. Compared with multi-target localization based on a single image, CEP of the multi-target localization using RLS is reduced by 25%. The proposed method can be implemented on a small circuit board to operate in real time. This research is expected to significantly benefit small UAVs which need multi-target geo-location functions. PMID:28029145

Real-Time Multi-Target Localization from Unmanned Aerial Vehicles.

PubMed

Wang, Xuan; Liu, Jinghong; Zhou, Qianfei

2016-12-25

In order to improve the reconnaissance efficiency of unmanned aerial vehicle (UAV) electro-optical stabilized imaging systems, a real-time multi-target localization scheme based on an UAV electro-optical stabilized imaging system is proposed. First, a target location model is studied. Then, the geodetic coordinates of multi-targets are calculated using the homogeneous coordinate transformation. On the basis of this, two methods which can improve the accuracy of the multi-target localization are proposed: (1) the real-time zoom lens distortion correction method; (2) a recursive least squares (RLS) filtering method based on UAV dead reckoning. The multi-target localization error model is established using Monte Carlo theory. In an actual flight, the UAV flight altitude is 1140 m. The multi-target localization results are within the range of allowable error. After we use a lens distortion correction method in a single image, the circular error probability (CEP) of the multi-target localization is reduced by 7%, and 50 targets can be located at the same time. The RLS algorithm can adaptively estimate the location data based on multiple images. Compared with multi-target localization based on a single image, CEP of the multi-target localization using RLS is reduced by 25%. The proposed method can be implemented on a small circuit board to operate in real time. This research is expected to significantly benefit small UAVs which need multi-target geo-location functions.

Correlated-Data Fusion and Cooperative Aiding in GNSS-Stressed or Denied Environments

NASA Astrophysics Data System (ADS)

Mokhtarzadeh, Hamid

A growing number of applications require continuous and reliable estimates of position, velocity, and orientation. Price requirements alone disqualify most traditional navigation or tactical-grade sensors and thus navigation systems based on automotive or consumer-grade sensors aided by Global Navigation Satellite Systems (GNSS), like the Global Positioning System (GPS), have gained popularity. The heavy reliance on GPS in these navigation systems is a point of concern and has created interest in alternative or back-up navigation systems to enable robust navigation through GPS-denied or stressed environments. This work takes advantage of current trends for increased sensing capabilities coupled with multilayer connectivity to propose a cooperative navigation-based aiding system as a means to limit dead reckoning error growth in the absence of absolute measurements like GPS. Each vehicle carries a dead reckoning navigation system which is aided by relative measurements, like range, to neighboring vehicles together with information sharing. Detailed architectures and concepts of operation are described for three specific applications: commercial aviation, Unmanned Aerial Vehicles (UAVs), and automotive applications. Both centralized and decentralized implementations of cooperative navigation-based aiding systems are described. The centralized system is based on a single Extended Kalman Filter (EKF). A decentralized implementation suited for applications with very limited communication bandwidth is discussed in detail. The presence of unknown correlation between the a priori state and measurement errors makes the standard Kalman filter unsuitable. Two existing estimators for handling this unknown correlation are Covariance Intersection (CI) and Bounded Covariance Inflation (BCInf) filters. A CI-based decentralized estimator suitable for decentralized cooperative navigation implementation is proposed. A unified derivation is presented for the Kalman filter, CI filter, and BCInf filter measurement update equations. Furthermore, characteristics important to the proper implementation of CI and BCInf in practice are discussed. A new covariance normalization step is proposed as necessary to properly apply CI or BCInf. Lastly, both centralized and decentralized implementations of cooperative aiding are analyzed and evaluated using experimental data in the three applications. In the commercial aviation study aircraft are simulated to use their Automatic Dependent Surveillance - Broadcast (ADS-B) and Traffic Collision Avoidance System (TCAS) systems to cooperatively aid their on board INS during a 60 min GPS outage in the national airspace. An availability study of cooperative navigation as proposed in this work around representative United States airports is performed. Availabilities between 70-100% were common at major airports like LGA and MSP in a 30 nmi radius around the airport during morning to evening hours. A GPS-denied navigation system for small UAVs based on cooperative information sharing is described. Experimentally collected flight data from 7 small UAV flights are played-back to evaluate the performance of the navigation system. The results show that the most effective of the architectures can lead to 5+ minutes of navigation without GPS maintaining position errors less than 200 m (1-sigma). The automotive case study considers 15 minutes of automotive traffic (2,000 + vehicles) driving through a half-mile stretch of highway without access to GPS. Automotive radar coupled with Dedicated Short Range Communication (DSRC) protocol are used to implement cooperative aiding to a low-cost 2-D INS on board each vehicle. The centralized system achieves an order of magnitude reduction in uncertainty by aggressively aiding the INS on board each vehicle. The proposed CI-based decentralized estimator is demonstrated to be conservative and maintain consistency. A quantitative analysis of bandwidth requirements shows that the proposed decentralized estimator falls comfortably within modern connectivity capabilities. A naive implementation of the high-performance centralized estimator is also achievable, but it was demonstrated to be burdensome, nearing the bandwidth limits.

Use of Earth's magnetic field for mitigating gyroscope errors regardless of magnetic perturbation.

PubMed

Afzal, Muhammad Haris; Renaudin, Valérie; Lachapelle, Gérard

2011-01-01

Most portable systems like smart-phones are equipped with low cost consumer grade sensors, making them useful as Pedestrian Navigation Systems (PNS). Measurements of these sensors are severely contaminated by errors caused due to instrumentation and environmental issues rendering the unaided navigation solution with these sensors of limited use. The overall navigation error budget associated with pedestrian navigation can be categorized into position/displacement errors and attitude/orientation errors. Most of the research is conducted for tackling and reducing the displacement errors, which either utilize Pedestrian Dead Reckoning (PDR) or special constraints like Zero velocity UPdaTes (ZUPT) and Zero Angular Rate Updates (ZARU). This article targets the orientation/attitude errors encountered in pedestrian navigation and develops a novel sensor fusion technique to utilize the Earth's magnetic field, even perturbed, for attitude and rate gyroscope error estimation in pedestrian navigation environments where it is assumed that Global Navigation Satellite System (GNSS) navigation is denied. As the Earth's magnetic field undergoes severe degradations in pedestrian navigation environments, a novel Quasi-Static magnetic Field (QSF) based attitude and angular rate error estimation technique is developed to effectively use magnetic measurements in highly perturbed environments. The QSF scheme is then used for generating the desired measurements for the proposed Extended Kalman Filter (EKF) based attitude estimator. Results indicate that the QSF measurements are capable of effectively estimating attitude and gyroscope errors, reducing the overall navigation error budget by over 80% in urban canyon environment.

Use of Earth’s Magnetic Field for Mitigating Gyroscope Errors Regardless of Magnetic Perturbation

PubMed Central

Afzal, Muhammad Haris; Renaudin, Valérie; Lachapelle, Gérard

2011-01-01

Most portable systems like smart-phones are equipped with low cost consumer grade sensors, making them useful as Pedestrian Navigation Systems (PNS). Measurements of these sensors are severely contaminated by errors caused due to instrumentation and environmental issues rendering the unaided navigation solution with these sensors of limited use. The overall navigation error budget associated with pedestrian navigation can be categorized into position/displacement errors and attitude/orientation errors. Most of the research is conducted for tackling and reducing the displacement errors, which either utilize Pedestrian Dead Reckoning (PDR) or special constraints like Zero velocity UPdaTes (ZUPT) and Zero Angular Rate Updates (ZARU). This article targets the orientation/attitude errors encountered in pedestrian navigation and develops a novel sensor fusion technique to utilize the Earth’s magnetic field, even perturbed, for attitude and rate gyroscope error estimation in pedestrian navigation environments where it is assumed that Global Navigation Satellite System (GNSS) navigation is denied. As the Earth’s magnetic field undergoes severe degradations in pedestrian navigation environments, a novel Quasi-Static magnetic Field (QSF) based attitude and angular rate error estimation technique is developed to effectively use magnetic measurements in highly perturbed environments. The QSF scheme is then used for generating the desired measurements for the proposed Extended Kalman Filter (EKF) based attitude estimator. Results indicate that the QSF measurements are capable of effectively estimating attitude and gyroscope errors, reducing the overall navigation error budget by over 80% in urban canyon environment. PMID:22247672

A Context-Recognition-Aided PDR Localization Method Based on the Hidden Markov Model

PubMed Central

Lu, Yi; Wei, Dongyan; Lai, Qifeng; Li, Wen; Yuan, Hong

2016-01-01

Indoor positioning has recently become an important field of interest because global navigation satellite systems (GNSS) are usually unavailable in indoor environments. Pedestrian dead reckoning (PDR) is a promising localization technique for indoor environments since it can be implemented on widely used smartphones equipped with low cost inertial sensors. However, the PDR localization severely suffers from the accumulation of positioning errors, and other external calibration sources should be used. In this paper, a context-recognition-aided PDR localization model is proposed to calibrate PDR. The context is detected by employing particular human actions or characteristic objects and it is matched to the context pre-stored offline in the database to get the pedestrian’s location. The Hidden Markov Model (HMM) and Recursive Viterbi Algorithm are used to do the matching, which reduces the time complexity and saves the storage. In addition, the authors design the turn detection algorithm and take the context of corner as an example to illustrate and verify the proposed model. The experimental results show that the proposed localization method can fix the pedestrian’s starting point quickly and improves the positioning accuracy of PDR by 40.56% at most with perfect stability and robustness at the same time. PMID:27916922

A floor-map-aided WiFi/pseudo-odometry integration algorithm for an indoor positioning system.

PubMed

Wang, Jian; Hu, Andong; Liu, Chunyan; Li, Xin

2015-03-24

This paper proposes a scheme for indoor positioning by fusing floor map, WiFi and smartphone sensor data to provide meter-level positioning without additional infrastructure. A topology-constrained K nearest neighbor (KNN) algorithm based on a floor map layout provides the coordinates required to integrate WiFi data with pseudo-odometry (P-O) measurements simulated using a pedestrian dead reckoning (PDR) approach. One method of further improving the positioning accuracy is to use a more effective multi-threshold step detection algorithm, as proposed by the authors. The "go and back" phenomenon caused by incorrect matching of the reference points (RPs) of a WiFi algorithm is eliminated using an adaptive fading-factor-based extended Kalman filter (EKF), taking WiFi positioning coordinates, P-O measurements and fused heading angles as observations. The "cross-wall" problem is solved based on the development of a floor-map-aided particle filter algorithm by weighting the particles, thereby also eliminating the gross-error effects originating from WiFi or P-O measurements. The performance observed in a field experiment performed on the fourth floor of the School of Environmental Science and Spatial Informatics (SESSI) building on the China University of Mining and Technology (CUMT) campus confirms that the proposed scheme can reliably achieve meter-level positioning.

A Smartphone Step Counter Using IMU and Magnetometer for Navigation and Health Monitoring Applications

PubMed Central

Khedr, Maan; El-Sheimy, Nasser

2017-01-01

The growing market of smart devices make them appealing for various applications. Motion tracking can be achieved using such devices, and is important for various applications such as navigation, search and rescue, health monitoring, and quality of life-style assessment. Step detection is a crucial task that affects the accuracy and quality of such applications. In this paper, a new step detection technique is proposed, which can be used for step counting and activity monitoring for health applications as well as part of a Pedestrian Dead Reckoning (PDR) system. Inertial and Magnetic sensors measurements are analyzed and fused for detecting steps under varying step modes and device pose combinations using a free-moving handheld device (smartphone). Unlike most of the state of the art research in the field, the proposed technique does not require a classifier, and adaptively tunes the filters and thresholds used without the need for presets while accomplishing the task in a real-time operation manner. Testing shows that the proposed technique successfully detects steps under varying motion speeds and device use cases with an average performance of 99.6%, and outperforms some of the state of the art techniques that rely on classifiers and commercial wristband products. PMID:29117143

Improved Conflict Detection for Reducing Operational Errors in Air Traffic Control

NASA Technical Reports Server (NTRS)

Paielli, Russell A.; Erzberger, Hainz

2003-01-01

An operational error is an incident in which an air traffic controller allows the separation between two aircraft to fall below the minimum separation standard. The rates of such errors in the US have increased significantly over the past few years. This paper proposes new detection methods that can help correct this trend by improving on the performance of Conflict Alert, the existing software in the Host Computer System that is intended to detect and warn controllers of imminent conflicts. In addition to the usual trajectory based on the flight plan, a "dead-reckoning" trajectory (current velocity projection) is also generated for each aircraft and checked for conflicts. Filters for reducing common types of false alerts were implemented. The new detection methods were tested in three different ways. First, a simple flightpath command language was developed t o generate precisely controlled encounters for the purpose of testing the detection software. Second, written reports and tracking data were obtained for actual operational errors that occurred in the field, and these were "replayed" to test the new detection algorithms. Finally, the detection methods were used to shadow live traffic, and performance was analysed, particularly with regard to the false-alert rate. The results indicate that the new detection methods can provide timely warnings of imminent conflicts more consistently than Conflict Alert.

Magnetometer-enhanced personal locator for tunnels and GPS-denied outdoor environments

NASA Astrophysics Data System (ADS)

Kwanmuang, Surat; Ojeda, Lauro; Borenstein, Johann

2011-06-01

This paper describes recent advances with our earlier developed Personal Dead-reckoning (PDR) system for GPS-denied environments. The PDR system uses a foot-mounted Inertial Measurement Unit (IMU) that also houses a three axismagnetometer. In earlier work we developed methods for correcting the drift errors in the accelerometers, thereby allowing very accurate measurements of distance traveled. In addition, we developed a powerful heuristic method for correcting heading errors caused by gyro drift. The heuristics exploit the rectilinear features found in almost all manmade structures and therefore limit this technology to indoor use only. Most recently we integrated a three-axis magnetometer with the IMU, using a Kalman Filter. While it is well known that the ubiquitous magnetic disturbances found in most modern buildings render magnetometers almost completely useless indoors, these sensors are nonetheless very effective in pristine outdoor environments as well as in some tunnels and caves. The present paper describes the integrated magnetometer/IMU system and presents detailed experimental results. Specifically, the paper reports results of an objective test conducted by Firefighters of California's CAL-FIRE. In this particular test, two firefighters in full operational gear and one civilian hiked up a two-mile long mountain trail over rocky, sometimes steeply inclined terrain, each wearing one of our magnetometer-enhanced PDR systems but not using any GPS. During the hour-long hike the average position error was about 20 meters and the maximum error was less than 45 meters, which is about 1.4% of distance traveled for all three PDR systems.

Continuous Indoor Positioning Fusing WiFi, Smartphone Sensors and Landmarks

PubMed Central

Deng, Zhi-An; Wang, Guofeng; Qin, Danyang; Na, Zhenyu; Cui, Yang; Chen, Juan

2016-01-01

To exploit the complementary strengths of WiFi positioning, pedestrian dead reckoning (PDR), and landmarks, we propose a novel fusion approach based on an extended Kalman filter (EKF). For WiFi positioning, unlike previous fusion approaches setting measurement noise parameters empirically, we deploy a kernel density estimation-based model to adaptively measure the related measurement noise statistics. Furthermore, a trusted area of WiFi positioning defined by fusion results of previous step and WiFi signal outlier detection are exploited to reduce computational cost and improve WiFi positioning accuracy. For PDR, we integrate a gyroscope, an accelerometer, and a magnetometer to determine the user heading based on another EKF model. To reduce accumulation error of PDR and enable continuous indoor positioning, not only the positioning results but also the heading estimations are recalibrated by indoor landmarks. Experimental results in a realistic indoor environment show that the proposed fusion approach achieves substantial positioning accuracy improvement than individual positioning approaches including PDR and WiFi positioning. PMID:27608019

An Indoor Positioning Method for Smartphones Using Landmarks and PDR.

PubMed

Wang, Xi; Jiang, Mingxing; Guo, Zhongwen; Hu, Naijun; Sun, Zhongwei; Liu, Jing

2016-12-15

Recently location based services (LBS) have become increasingly popular in indoor environments. Among these indoor positioning techniques providing LBS, a fusion approach combining WiFi-based and pedestrian dead reckoning (PDR) techniques is drawing more and more attention of researchers. Although this fusion method performs well in some cases, it still has some limitations, such as heavy computation and inconvenience for real-time use. In this work, we study map information of a given indoor environment, analyze variations of WiFi received signal strength (RSS), define several kinds of indoor landmarks, and then utilize these landmarks to correct accumulated errors derived from PDR. This fusion scheme, called Landmark-aided PDR (LaP), is proved to be light-weight and suitable for real-time implementation by running an Android application designed for the experiment. We compared LaP with other PDR-based fusion approaches. Experimental results show that the proposed scheme can achieve a significant improvement with an average accuracy of 2.17 m.

Continuous Indoor Positioning Fusing WiFi, Smartphone Sensors and Landmarks.

PubMed

Deng, Zhi-An; Wang, Guofeng; Qin, Danyang; Na, Zhenyu; Cui, Yang; Chen, Juan

2016-09-05

To exploit the complementary strengths of WiFi positioning, pedestrian dead reckoning (PDR), and landmarks, we propose a novel fusion approach based on an extended Kalman filter (EKF). For WiFi positioning, unlike previous fusion approaches setting measurement noise parameters empirically, we deploy a kernel density estimation-based model to adaptively measure the related measurement noise statistics. Furthermore, a trusted area of WiFi positioning defined by fusion results of previous step and WiFi signal outlier detection are exploited to reduce computational cost and improve WiFi positioning accuracy. For PDR, we integrate a gyroscope, an accelerometer, and a magnetometer to determine the user heading based on another EKF model. To reduce accumulation error of PDR and enable continuous indoor positioning, not only the positioning results but also the heading estimations are recalibrated by indoor landmarks. Experimental results in a realistic indoor environment show that the proposed fusion approach achieves substantial positioning accuracy improvement than individual positioning approaches including PDR and WiFi positioning.

An Indoor Positioning Method for Smartphones Using Landmarks and PDR †

PubMed Central

Wang, Xi; Jiang, Mingxing; Guo, Zhongwen; Hu, Naijun; Sun, Zhongwei; Liu, Jing

2016-01-01

Recently location based services (LBS) have become increasingly popular in indoor environments. Among these indoor positioning techniques providing LBS, a fusion approach combining WiFi-based and pedestrian dead reckoning (PDR) techniques is drawing more and more attention of researchers. Although this fusion method performs well in some cases, it still has some limitations, such as heavy computation and inconvenience for real-time use. In this work, we study map information of a given indoor environment, analyze variations of WiFi received signal strength (RSS), define several kinds of indoor landmarks, and then utilize these landmarks to correct accumulated errors derived from PDR. This fusion scheme, called Landmark-aided PDR (LaP), is proved to be light-weight and suitable for real-time implementation by running an Android application designed for the experiment. We compared LaP with other PDR-based fusion approaches. Experimental results show that the proposed scheme can achieve a significant improvement with an average accuracy of 2.17 m. PMID:27983670

Informed peg-in-hole insertion using optical sensors

NASA Astrophysics Data System (ADS)

Paulos, Eric; Canny, John F.

1993-08-01

Peg-in-hole insertion is not only a longstanding problem in robotics but the most common automated mechanical assembly task. In this paper we present a high precision, self-calibrating peg-in-hole insertion strategy using several very simple, inexpensive, and accurate optical sensors. The self-calibrating feature allows us to achieve successful dead-reckoning insertions with tolerances of 25 microns without any accurate initial position information for the robot, pegs, or holes. The program we implemented works for any cylindrical peg, and the sensing steps do not depend on the peg diameter, which the program does not know. The key to the strategy is the use of a fixed sensor to localize both a mobile sensor and the peg, while the mobile sensor localizes the hole. Our strategy is extremely fast, localizing pegs as they are in route to their insertion location without pausing. The result is that insertion times are dominated by the transport time between pick and place operations.

Parachute Testing for the NASA X-38 Crew Return Vehicle

NASA Technical Reports Server (NTRS)

Stein, Jenny M.

2005-01-01

NASA's X-38 program was an in-house technology demonstration program to develop a Crew Return Vehicle (CRV) for the International Space Station capable of returning seven crewmembers to Earth when the Space Shuttle was not present at the station. The program, managed out of NASA's Johnson Space Center, was started in 1995 and was cancelled in 2003. Eight flights with a prototype atmospheric vehicle were successfully flown at Edwards Air Force Base, demonstrating the feasibility of a parachute landing system for spacecraft. The intensive testing conducted by the program included testing of large ram-air parafoils. The flight test techniques, instrumentation, and simulation models developed during the parachute test program culminated in the successful demonstration of a guided parafoil system to land a 25,000 Ib spacecraft. The test program utilized parafoils of sizes ranging from 750 to 7500 p. The guidance, navigation, and control system (GN&C) consisted of winches, laser or radar altimeter, global positioning system (GPS), magnetic compass, barometric altimeter, flight computer, and modems for uplink commands and downlink data. The winches were used to steer the parafoil and to perform the dynamic flare maneuver for a soft landing. The laser or radar altimeter was used to initiate the flare. In the event of a GPS failure, the software navigated by dead reckoning using the compass and barometric altimeter data. The GN&C test beds included platforms dropped from cargo aircraft, atmospheric vehicles released from a 8-52, and a Buckeye powered parachute. This paper will describe the test program and significant results.

Teaching "The Reckoning": Understanding the International Criminal Court. A Facing History and Ourselves Study Guide

ERIC Educational Resources Information Center

Kanner, Elisabeth Fieldstone

2010-01-01

Facing History and Ourselves has developed "Teaching The Reckoning" to help classrooms explore essential questions about judgment by studying the creation of the International Criminal Court. Ever since the Nuremberg Trials, individuals around the world have imagined how an international judicial body could be used to prevent genocide,…

Innere Fuehrung - A Superior Concept of Leadership

DTIC Science & Technology

2008-06-01

Large, “Reckoning without the Past: The HIAG of the Waffen -SS and the Politics of Rehabilitation in the Bonn Republic, 1950–1961.” The Journal of...1992): S173-S186. 108 ———. “Reckoning without the Past: The HIAG of the Waffen -SS and the Politics of Rehabilitation in the Bonn Republic, 1950-1961

Accurate Orientation Estimation Using AHRS under Conditions of Magnetic Distortion

PubMed Central

Yadav, Nagesh; Bleakley, Chris

2014-01-01

Low cost, compact attitude heading reference systems (AHRS) are now being used to track human body movements in indoor environments by estimation of the 3D orientation of body segments. In many of these systems, heading estimation is achieved by monitoring the strength of the Earth's magnetic field. However, the Earth's magnetic field can be locally distorted due to the proximity of ferrous and/or magnetic objects. Herein, we propose a novel method for accurate 3D orientation estimation using an AHRS, comprised of an accelerometer, gyroscope and magnetometer, under conditions of magnetic field distortion. The system performs online detection and compensation for magnetic disturbances, due to, for example, the presence of ferrous objects. The magnetic distortions are detected by exploiting variations in magnetic dip angle, relative to the gravity vector, and in magnetic strength. We investigate and show the advantages of using both magnetic strength and magnetic dip angle for detecting the presence of magnetic distortions. The correction method is based on a particle filter, which performs the correction using an adaptive cost function and by adapting the variance during particle resampling, so as to place more emphasis on the results of dead reckoning of the gyroscope measurements and less on the magnetometer readings. The proposed method was tested in an indoor environment in the presence of various magnetic distortions and under various accelerations (up to 3 g). In the experiments, the proposed algorithm achieves <2° static peak-to-peak error and <5° dynamic peak-to-peak error, significantly outperforming previous methods. PMID:25347584

A Floor-Map-Aided WiFi/Pseudo-Odometry Integration Algorithm for an Indoor Positioning System

PubMed Central

Wang, Jian; Hu, Andong; Liu, Chunyan; Li, Xin

2015-01-01

This paper proposes a scheme for indoor positioning by fusing floor map, WiFi and smartphone sensor data to provide meter-level positioning without additional infrastructure. A topology-constrained K nearest neighbor (KNN) algorithm based on a floor map layout provides the coordinates required to integrate WiFi data with pseudo-odometry (P-O) measurements simulated using a pedestrian dead reckoning (PDR) approach. One method of further improving the positioning accuracy is to use a more effective multi-threshold step detection algorithm, as proposed by the authors. The “go and back” phenomenon caused by incorrect matching of the reference points (RPs) of a WiFi algorithm is eliminated using an adaptive fading-factor-based extended Kalman filter (EKF), taking WiFi positioning coordinates, P-O measurements and fused heading angles as observations. The “cross-wall” problem is solved based on the development of a floor-map-aided particle filter algorithm by weighting the particles, thereby also eliminating the gross-error effects originating from WiFi or P-O measurements. The performance observed in a field experiment performed on the fourth floor of the School of Environmental Science and Spatial Informatics (SESSI) building on the China University of Mining and Technology (CUMT) campus confirms that the proposed scheme can reliably achieve meter-level positioning. PMID:25811224

An Accurate GPS-IMU/DR Data Fusion Method for Driverless Car Based on a Set of Predictive Models and Grid Constraints

PubMed Central

Wang, Shiyao; Deng, Zhidong; Yin, Gang

2016-01-01

A high-performance differential global positioning system (GPS)  receiver with real time kinematics provides absolute localization for driverless cars. However, it is not only susceptible to multipath effect but also unable to effectively fulfill precise error correction in a wide range of driving areas. This paper proposes an accurate GPS–inertial measurement unit (IMU)/dead reckoning (DR) data fusion method based on a set of predictive models and occupancy grid constraints. First, we employ a set of autoregressive and moving average (ARMA) equations that have different structural parameters to build maximum likelihood models of raw navigation. Second, both grid constraints and spatial consensus checks on all predictive results and current measurements are required to have removal of outliers. Navigation data that satisfy stationary stochastic process are further fused to achieve accurate localization results. Third, the standard deviation of multimodal data fusion can be pre-specified by grid size. Finally, we perform a lot of field tests on a diversity of real urban scenarios. The experimental results demonstrate that the method can significantly smooth small jumps in bias and considerably reduce accumulated position errors due to DR. With low computational complexity, the position accuracy of our method surpasses existing state-of-the-arts on the same dataset and the new data fusion method is practically applied in our driverless car. PMID:26927108

An Accurate GPS-IMU/DR Data Fusion Method for Driverless Car Based on a Set of Predictive Models and Grid Constraints.

PubMed

Wang, Shiyao; Deng, Zhidong; Yin, Gang

2016-02-24

A high-performance differential global positioning system (GPS)  receiver with real time kinematics provides absolute localization for driverless cars. However, it is not only susceptible to multipath effect but also unable to effectively fulfill precise error correction in a wide range of driving areas. This paper proposes an accurate GPS-inertial measurement unit (IMU)/dead reckoning (DR) data fusion method based on a set of predictive models and occupancy grid constraints. First, we employ a set of autoregressive and moving average (ARMA) equations that have different structural parameters to build maximum likelihood models of raw navigation. Second, both grid constraints and spatial consensus checks on all predictive results and current measurements are required to have removal of outliers. Navigation data that satisfy stationary stochastic process are further fused to achieve accurate localization results. Third, the standard deviation of multimodal data fusion can be pre-specified by grid size. Finally, we perform a lot of field tests on a diversity of real urban scenarios. The experimental results demonstrate that the method can significantly smooth small jumps in bias and considerably reduce accumulated position errors due to DR. With low computational complexity, the position accuracy of our method surpasses existing state-of-the-arts on the same dataset and the new data fusion method is practically applied in our driverless car.

Underwater Multi-Vehicle Trajectory Alignment and Mapping Using Acoustic and Optical Constraints

PubMed Central

Campos, Ricard; Gracias, Nuno; Ridao, Pere

2016-01-01

Multi-robot formations are an important advance in recent robotic developments, as they allow a group of robots to merge their capacities and perform surveys in a more convenient way. With the aim of keeping the costs and acoustic communications to a minimum, cooperative navigation of multiple underwater vehicles is usually performed at the control level. In order to maintain the desired formation, individual robots just react to simple control directives extracted from range measurements or ultra-short baseline (USBL) systems. Thus, the robots are unaware of their global positioning, which presents a problem for the further processing of the collected data. The aim of this paper is two-fold. First, we present a global alignment method to correct the dead reckoning trajectories of multiple vehicles to resemble the paths followed during the mission using the acoustic messages passed between vehicles. Second, we focus on the optical mapping application of these types of formations and extend the optimization framework to allow for multi-vehicle geo-referenced optical 3D mapping using monocular cameras. The inclusion of optical constraints is not performed using the common bundle adjustment techniques, but in a form improving the computational efficiency of the resulting optimization problem and presenting a generic process to fuse optical reconstructions with navigation data. We show the performance of the proposed method on real datasets collected within the Morph EU-FP7 project. PMID:26999144

Reforming the Education System in Bangladesh: Reckoning a Knowledge-Based Society

ERIC Educational Resources Information Center

Khan, Md. Nasir Uddin; Rana, Ebney Ayaj; Haque, Md. Reazul

2014-01-01

Education renders people with certain capabilities that prepare them to contribute to the social and economic development of the nation. Such capabilities turn them into human capital which, according to development economists, raises productivity when increased. Following an exhaustive review of literature on education research, this paper,…

Teacher Pension Plans in Canada: A Force to Be Reckoned With.

ERIC Educational Resources Information Center

Lawton, Stephen B.

1999-01-01

Summarizes the status of teacher pension plans in Canada's 10 provinces and considers their current role in renewing and downsizing educational systems in some provinces. Discusses pensions' use as economic instruments for provincial and national development and questions assumptions underlying the rhetoric celebrating their contribution to the…

Architectural Considerations for Highly Scalable Computing to Support On-demand Video Analytics

DTIC Science & Technology

2017-04-19

enforcement . The system was tested in the wild using video files as well as a commercial Video Management System supporting more than 100 surveillance...research were used to implement a distributed on-demand video analytics system that was prototyped for the use of forensics investigators in law...cameras as video sources. The architectural considerations of this system are presented. Issues to be reckoned with in implementing a scalable

Learning to select useful landmarks.

PubMed

Greiner, R; Isukapalli, R

1996-01-01

To navigate effectively, an autonomous agent must be able to quickly and accurately determine its current location. Given an initial estimate of its position (perhaps based on dead-reckoning) and an image taken of a known environment, our agent first attempts to locate a set of landmarks (real-world objects at known locations), then uses their angular separation to obtain an improved estimate of its current position. Unfortunately, some landmarks may not be visible, or worse, may be confused with other landmarks, resulting in both time wasted in searching for the undetected landmarks, and in further errors in the agent's estimate of its position. To address these problems, we propose a method that uses previous experiences to learn a selection function that, given the set of landmarks that might be visible, returns the subset that can be used to reliably provide an accurate registration of the agent's position. We use statistical techniques to prove that the learned selection function is, with high probability, effectively at a local optimum in the space of such functions. This paper also presents empirical evidence, using real-world data, that demonstrate the effectiveness of our approach.

Africa Counts: Number and Pattern in African Culture.

ERIC Educational Resources Information Center

Zaslavsky, Claudia

This document describes the contributions of African peoples to the science of mathematics. The development of a number system is seen as related to need. Names of numbers, time reckoning, gesture counting, and counting materials are examined. Mystical beliefs about numbers and special meanings in pattern are presented. Reproductions of patterns,…

A Bluetooth/PDR Integration Algorithm for an Indoor Positioning System.

PubMed

Li, Xin; Wang, Jian; Liu, Chunyan

2015-09-25

This paper proposes two schemes for indoor positioning by fusing Bluetooth beacons and a pedestrian dead reckoning (PDR) technique to provide meter-level positioning without additional infrastructure. As to the PDR approach, a more effective multi-threshold step detection algorithm is used to improve the positioning accuracy. According to pedestrians' different walking patterns such as walking or running, this paper makes a comparative analysis of multiple step length calculation models to determine a linear computation model and the relevant parameters. In consideration of the deviation between the real heading and the value of the orientation sensor, a heading estimation method with real-time compensation is proposed, which is based on a Kalman filter with map geometry information. The corrected heading can inhibit the positioning error accumulation and improve the positioning accuracy of PDR. Moreover, this paper has implemented two positioning approaches integrated with Bluetooth and PDR. One is the PDR-based positioning method based on map matching and position correction through Bluetooth. There will not be too much calculation work or too high maintenance costs using this method. The other method is a fusion calculation method based on the pedestrians' moving status (direct movement or making a turn) to determine adaptively the noise parameters in an Extended Kalman Filter (EKF) system. This method has worked very well in the elimination of various phenomena, including the "go and back" phenomenon caused by the instability of the Bluetooth-based positioning system and the "cross-wall" phenomenon due to the accumulative errors caused by the PDR algorithm. Experiments performed on the fourth floor of the School of Environmental Science and Spatial Informatics (SESSI) building in the China University of Mining and Technology (CUMT) campus showed that the proposed scheme can reliably achieve a 2-meter precision.

A Bluetooth/PDR Integration Algorithm for an Indoor Positioning System

PubMed Central

Li, Xin; Wang, Jian; Liu, Chunyan

2015-01-01

This paper proposes two schemes for indoor positioning by fusing Bluetooth beacons and a pedestrian dead reckoning (PDR) technique to provide meter-level positioning without additional infrastructure. As to the PDR approach, a more effective multi-threshold step detection algorithm is used to improve the positioning accuracy. According to pedestrians’ different walking patterns such as walking or running, this paper makes a comparative analysis of multiple step length calculation models to determine a linear computation model and the relevant parameters. In consideration of the deviation between the real heading and the value of the orientation sensor, a heading estimation method with real-time compensation is proposed, which is based on a Kalman filter with map geometry information. The corrected heading can inhibit the positioning error accumulation and improve the positioning accuracy of PDR. Moreover, this paper has implemented two positioning approaches integrated with Bluetooth and PDR. One is the PDR-based positioning method based on map matching and position correction through Bluetooth. There will not be too much calculation work or too high maintenance costs using this method. The other method is a fusion calculation method based on the pedestrians’ moving status (direct movement or making a turn) to determine adaptively the noise parameters in an Extended Kalman Filter (EKF) system. This method has worked very well in the elimination of various phenomena, including the “go and back” phenomenon caused by the instability of the Bluetooth-based positioning system and the “cross-wall” phenomenon due to the accumulative errors caused by the PDR algorithm. Experiments performed on the fourth floor of the School of Environmental Science and Spatial Informatics (SESSI) building in the China University of Mining and Technology (CUMT) campus showed that the proposed scheme can reliably achieve a 2-meter precision. PMID:26404277

PDR with a Foot-Mounted IMU and Ramp Detection

PubMed Central

Jiménez, Antonio R.; Seco, Fernando; Zampella, Francisco; Prieto, José C.; Guevara, Jorge

2011-01-01

The localization of persons in indoor environments is nowadays an open problem. There are partial solutions based on the deployment of a network of sensors (Local Positioning Systems or LPS). Other solutions only require the installation of an inertial sensor on the person’s body (Pedestrian Dead-Reckoning or PDR). PDR solutions integrate the signals coming from an Inertial Measurement Unit (IMU), which usually contains 3 accelerometers and 3 gyroscopes. The main problem of PDR is the accumulation of positioning errors due to the drift caused by the noise in the sensors. This paper presents a PDR solution that incorporates a drift correction method based on detecting the access ramps usually found in buildings. The ramp correction method is implemented over a PDR framework that uses an Inertial Navigation algorithm (INS) and an IMU attached to the person’s foot. Unlike other approaches that use external sensors to correct the drift error, we only use one IMU on the foot. To detect a ramp, the slope of the terrain on which the user is walking, and the change in height sensed when moving forward, are estimated from the IMU. After detection, the ramp is checked for association with one of the existing in a database. For each associated ramp, a position correction is fed into the Kalman Filter in order to refine the INS-PDR solution. Drift-free localization is achieved with positioning errors below 2 meters for 1,000-meter-long routes in a building with a few ramps. PMID:22163701

Up, down, and across the Land: Landscape Terms, Place Names, and Spatial Language in Tzeltal

ERIC Educational Resources Information Center

Brown, Penelope

2008-01-01

The Tzeltal language is spoken in a mountainous region of southern Mexico by some 280,000 Mayan corn farmers. This paper focuses on landscape and place vocabulary in the Tzeltal municipio of Tenejapa, where speakers use an absolute system of spatial reckoning based on the overall uphill (southward)/downhill (northward) slope of the land. The paper…

Multibeam 3D Underwater SLAM with Probabilistic Registration.

PubMed

Palomer, Albert; Ridao, Pere; Ribas, David

2016-04-20

This paper describes a pose-based underwater 3D Simultaneous Localization and Mapping (SLAM) using a multibeam echosounder to produce high consistency underwater maps. The proposed algorithm compounds swath profiles of the seafloor with dead reckoning localization to build surface patches (i.e., point clouds). An Iterative Closest Point (ICP) with a probabilistic implementation is then used to register the point clouds, taking into account their uncertainties. The registration process is divided in two steps: (1) point-to-point association for coarse registration and (2) point-to-plane association for fine registration. The point clouds of the surfaces to be registered are sub-sampled in order to decrease both the computation time and also the potential of falling into local minima during the registration. In addition, a heuristic is used to decrease the complexity of the association step of the ICP from O(n2) to O(n) . The performance of the SLAM framework is tested using two real world datasets: First, a 2.5D bathymetric dataset obtained with the usual down-looking multibeam sonar configuration, and second, a full 3D underwater dataset acquired with a multibeam sonar mounted on a pan and tilt unit.

Pose and motion recovery from feature correspondences and a digital terrain map.

PubMed

Lerner, Ronen; Rivlin, Ehud; Rotstein, Héctor P

2006-09-01

A novel algorithm for pose and motion estimation using corresponding features and a Digital Terrain Map is proposed. Using a Digital Terrain (or Digital Elevation) Map (DTM/DEM) as a global reference enables the elimination of the ambiguity present in vision-based algorithms for motion recovery. As a consequence, the absolute position and orientation of a camera can be recovered with respect to the external reference frame. In order to do this, the DTM is used to formulate a constraint between corresponding features in two consecutive frames. Explicit reconstruction of the 3D world is not required. When considering a number of feature points, the resulting constraints can be solved using nonlinear optimization in terms of position, orientation, and motion. Such a procedure requires an initial guess of these parameters, which can be obtained from dead-reckoning or any other source. The feasibility of the algorithm is established through extensive experimentation. Performance is compared with a state-of-the-art alternative algorithm, which intermediately reconstructs the 3D structure and then registers it to the DTM. A clear advantage for the novel algorithm is demonstrated in variety of scenarios.

Estimating Uncertainties of Ship Course and Speed in Early Navigations using ICOADS3.0

NASA Astrophysics Data System (ADS)

Chan, D.; Huybers, P. J.

2017-12-01

Information on ship position and its uncertainty is potentially important for mapping out climatologists and changes in SSTs. Using the 2-hourly ship reports from the International Comprehensive Ocean Atmosphere Dataset 3.0 (ICOADS 3.0), we estimate the uncertainties of ship course, ship speed, and latitude/longitude corrections during 1870-1900. After reviewing the techniques used in early navigations, we build forward navigation model that uses dead reckoning technique, celestial latitude corrections, and chronometer longitude corrections. The modeled ship tracks exhibit jumps in longitude and latitude, when a position correction is applied. These jumps are also seen in ICOADS3.0 observations. In this model, position error at the end of each day increases following a 2D random walk; the latitudinal/longitude errors are reset when a latitude/longitude correction is applied.We fit the variance of the magnitude of latitude/longitude corrections in the observation against model outputs, and estimate that the standard deviation of uncertainty is 5.5 degree for ship course, 32% for ship speed, 22km for latitude correction, and 27km for longitude correction. The estimates here are informative priors for Bayesian methods that quantify position errors of individual tracks.

All at sea without a clock - Longitude from lunar distances.

NASA Astrophysics Data System (ADS)

Floyd, D. J. E.

2005-12-01

I present a brief history of the ``Lunar Distance" technique for determining Longitude at sea, as developed by Astronomer Royal Neville Maskelyne (1732-1811) and others. I illustrate this history using images and results from a recent (2001) BBC History project to re-enact part of Captain James Cook's first voyage, from near-shipwreck on the east coast Australia, back to the relative safety of Batavia (modern-day Djakarta). I demonstrate the practical use of Lunars to determine longitude at sea, illustrated through comparison to GPS coordinates obtained along the voyage. During windows of lunar visibility, using new tables drawn up at HMNAO, we were able to match or exceed Maskelyne's stated accuracy of 30 nautical miles (0.5 degrees). Close to New Moon, dependent on our own skills of dead-reckoning, we prove far less able navigators than Cook and his cohort! I acknowledge the enormous assistance of Catherine Hohenkerk of the HMNAO, Tanya Batchelor of the BBC, George Huxtable, John Jeffrey, and John Selwyn-Gilbert in researching this subject. I gratefully acknowledge funding from the BBC, and HM Bark Endeavour Foundation for the use of their glorious ship, the Endeavour.

An Indoor Continuous Positioning Algorithm on the Move by Fusing Sensors and Wi-Fi on Smartphones.

PubMed

Li, Huaiyu; Chen, Xiuwan; Jing, Guifei; Wang, Yuan; Cao, Yanfeng; Li, Fei; Zhang, Xinlong; Xiao, Han

2015-12-11

Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative points include an improved Wi-Fi positioning algorithm and a novel positioning fusion algorithm named the Trust Chain Positioning Fusion (TCPF) algorithm. The improved Wi-Fi positioning algorithm was designed based on the properties of Wi-Fi signals on the move, which are found in a novel "quasi-dynamic" Wi-Fi signal experiment. The TCPF algorithm is proposed to realize the "process-level" fusion of Wi-Fi and Pedestrians Dead Reckoning (PDR) positioning, including three parts: trusted point determination, trust state and positioning fusion algorithm. An experiment is carried out for verification in a typical indoor environment, and the average positioning error on the move is 1.36 m, a decrease of 28.8% compared to an existing algorithm. The results show that the proposed algorithm can effectively reduce the influence caused by the unstable Wi-Fi signals, and improve the accuracy and stability of indoor continuous positioning on the move.

High accuracy navigation information estimation for inertial system using the multi-model EKF fusing adams explicit formula applied to underwater gliders.

PubMed

Huang, Haoqian; Chen, Xiyuan; Zhang, Bo; Wang, Jian

2017-01-01

The underwater navigation system, mainly consisting of MEMS inertial sensors, is a key technology for the wide application of underwater gliders and plays an important role in achieving high accuracy navigation and positioning for a long time of period. However, the navigation errors will accumulate over time because of the inherent errors of inertial sensors, especially for MEMS grade IMU (Inertial Measurement Unit) generally used in gliders. The dead reckoning module is added to compensate the errors. In the complicated underwater environment, the performance of MEMS sensors is degraded sharply and the errors will become much larger. It is difficult to establish the accurate and fixed error model for the inertial sensor. Therefore, it is very hard to improve the accuracy of navigation information calculated by sensors. In order to solve the problem mentioned, the more suitable filter which integrates the multi-model method with an EKF approach can be designed according to different error models to give the optimal estimation for the state. The key parameters of error models can be used to determine the corresponding filter. The Adams explicit formula which has an advantage of high precision prediction is simultaneously fused into the above filter to achieve the much more improvement in attitudes estimation accuracy. The proposed algorithm has been proved through theory analyses and has been tested by both vehicle experiments and lake trials. Results show that the proposed method has better accuracy and effectiveness in terms of attitudes estimation compared with other methods mentioned in the paper for inertial navigation applied to underwater gliders. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

From Columbus to Columbia

NASA Astrophysics Data System (ADS)

Morain, Stanley A.

On the eve of Christopher Columbus's historic voyage to the New World, the international community of remote sensing and mapping sciences is poised to lead a new, environmentally conscious world into the 21st century. Developments in remote sensing and GIS technology during the past 25 years have paved the way for a modern round of earth exploration that could well equal in lasting importance the geographic achievement of Columbus, 500 years ago. Human experience has evolved from land-lubbing to sea-faring, air-faring and now space-faring so that in future all four modes will be used to enhacce our understanding of earth systems. Columbus "dead reckoned" his place into history by sailing the southern arm of the Atlantic Gyre westward to the Bahamas. For reasons beyond his knowledge, he was "lost" almost from the moment he departed; and to this day, his landfall is placed at several islands between Grand Turk at latitude 21.5°N and San Salvador at 24°N. His headings, nautical speeds, and drift are all subjects of controversy. Today, with global positioning systems, scientists and entrepreneurs can triangulate with considerable accuracy almost any point on the earth's surface, day or night; and, with a fourth satellite, can determine elevation. The same satellite constellation can monitor the speeds and headings of land, sea, and air transportation carriers for the benefit of all international commerce - a knowledge that would have been the envy of Spain's Admiral of the Ocean Seas throughout his search for spices, souls, and gold. We can only imagine what he and his captains might have given for a nightly satellite weather report, let alone images by which to navigate.

An Alternative for Emergency Preemption of Traffic Lights

NASA Technical Reports Server (NTRS)

Foster, Conrad; Bachelder, Aaron

2006-01-01

An electronic communication-and-control system has been developed as a prototype of advanced means of automatically modifying the switching of traffic lights to give priority to emergency vehicles. This system could be used alternatively or in addition to other emergency traffic-light-preemption systems, including a variety of systems now in use as well as two proposed systems described in "Systems Would Preempt Traffic Lights for Emergency Vehicles" (NPO-30573), NASA Tech Briefs, Vol. 28, No. 10 (October 2004), page 36. Unlike those prior systems that depend on detection of sounds and/or lights emitted by emergency vehicles, this system is not subject to severe range limitations. This system can be retrofitted into any pre-existing traffic-light-control system, without need to modify that system other than to make a minimal number of wire connections between the two systems. This system comprises several subsystems, including a transponder and interface circuitry on each emergency vehicle, a monitoring and control unit at each intersection equipped with traffic lights, and a wide-area two-way radio communication network that connects the emergency vehicles and intersection units. Computers in the various intersections and vehicle units run special-purpose software that implements the traffic- light-preemption scheme. The operations of the intersection and vehicle units are synchronized by use of Global Positioning System (GPS) timing signals. The transponder in each vehicle estimates its own position and velocity by use of GPS signals, deductive ("dead") reckoning, data from the onboard diagnostic (OBD) computer of the vehicle, and/or triangulation of beacon signals. When the operator of an emergency vehicle turns on its flashing lights and sirens in response to a request for an emergency response, the transponder unit goes into action, reading the OBD data to determine speed and acceleration, and reading and gathering further navigational data as described above. The position, velocity, and acceleration data are combined with vehicle-identification data in a prescribed format, and the resulting set of data is transmitted to the intersections within communication range of the transponder.

Gait Monitoring for Early Neurological Disorder Detection Using Sensors in a Smartphone: Validation and a Case Study of Parkinsonism.

PubMed

Raknim, Paweeya; Lan, Kun-Chan

2016-01-01

Diagnosing brain disorders, such as Parkinson's disease (PD) or Alzheimer's disease, is often difficult, especially in the early stages. Moreover, it has been estimated that nearly 40% of people with PD may not be diagnosed. Traditionally, the diagnosis of neurological disorders, such as PD, often required a doctor to observe the patient over time to recognize signs of rigidity in movement. The pedestrian dead reckoning (PDR) system is a self-contained technique that has been widely used for indoor localization. In this work we propose a PDR-based method to continuously monitor and record the patient's gait characteristics using a smartphone. Seventeen patients were studied over a period of 1 year. During the year it became apparent that 1 of the patients was actually developing PD. To the best of our knowledge, our work is the first attempt to use sensors in a smartphone to help identify patients in their early stages of neurological disease. On average, the accuracy of our step length estimation was about 98%. Using a binary classification method-namely, support vector machine-we carried out a case study and showed that it was feasible to identify changes in the walking patterns of a PD patient with an accuracy of 94%. Using 1 year of gait trace data obtained from the users' phones, our work provides a first step to experimentally show the possibility of applying smartphone sensor data to provide early warnings to potential PD patients to encourage them to seek medical assistance and thus help doctors diagnose this disease earlier.

Development of a Kalman Filter in the Gauss-Helmert Model for Reliability Analysis in Orientation Determination with Smartphone Sensors

PubMed Central

Ettlinger, Andreas; Neuner, Hans; Burgess, Thomas

2018-01-01

The topic of indoor positioning and indoor navigation by using observations from smartphone sensors is very challenging as the determined trajectories can be subject to significant deviations compared to the route travelled in reality. Especially the calculation of the direction of movement is the critical part of pedestrian positioning approaches such as Pedestrian Dead Reckoning (“PDR”). Due to distinct systematic effects in filtered trajectories, it can be assumed that there are systematic deviations present in the observations from smartphone sensors. This article has two aims: one is to enable the estimation of partial redundancies for each observation as well as for observation groups. Partial redundancies are a measure for the reliability indicating how well systematic deviations can be detected in single observations used in PDR. The second aim is to analyze the behavior of partial redundancy by modifying the stochastic and functional model of the Kalman filter. The equations relating the observations to the orientation are condition equations, which do not exhibit the typical structure of the Gauss-Markov model (“GMM”), wherein the observations are linear and can be formulated as functions of the states. To calculate and analyze the partial redundancy of the observations from smartphone-sensors used in PDR, the system equation and the measurement equation of a Kalman filter as well as the redundancy matrix need to be derived in the Gauss-Helmert model (“GHM”). These derivations are introduced in this article and lead to a novel Kalman filter structure based on condition equations, enabling reliability assessment of each observation. PMID:29385076

Development of a Kalman Filter in the Gauss-Helmert Model for Reliability Analysis in Orientation Determination with Smartphone Sensors.

PubMed

Ettlinger, Andreas; Neuner, Hans; Burgess, Thomas

2018-01-31

The topic of indoor positioning and indoor navigation by using observations from smartphone sensors is very challenging as the determined trajectories can be subject to significant deviations compared to the route travelled in reality. Especially the calculation of the direction of movement is the critical part of pedestrian positioning approaches such as Pedestrian Dead Reckoning ("PDR"). Due to distinct systematic effects in filtered trajectories, it can be assumed that there are systematic deviations present in the observations from smartphone sensors. This article has two aims: one is to enable the estimation of partial redundancies for each observation as well as for observation groups. Partial redundancies are a measure for the reliability indicating how well systematic deviations can be detected in single observations used in PDR. The second aim is to analyze the behavior of partial redundancy by modifying the stochastic and functional model of the Kalman filter. The equations relating the observations to the orientation are condition equations, which do not exhibit the typical structure of the Gauss-Markov model ("GMM"), wherein the observations are linear and can be formulated as functions of the states. To calculate and analyze the partial redundancy of the observations from smartphone-sensors used in PDR, the system equation and the measurement equation of a Kalman filter as well as the redundancy matrix need to be derived in the Gauss-Helmert model ("GHM"). These derivations are introduced in this article and lead to a novel Kalman filter structure based on condition equations, enabling reliability assessment of each observation.

RECKONER: read error corrector based on KMC.

PubMed

Dlugosz, Maciej; Deorowicz, Sebastian

2017-04-01

Presence of sequencing errors in data produced by next-generation sequencers affects quality of downstream analyzes. Accuracy of them can be improved by performing error correction of sequencing reads. We introduce a new correction algorithm capable of processing eukaryotic close to 500 Mbp-genome-size, high error-rated data using less than 4 GB of RAM in about 35 min on 16-core computer. Program is freely available at http://sun.aei.polsl.pl/REFRESH/reckoner . sebastian.deorowicz@polsl.pl. Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

An Observability Metric for Underwater Vehicle Localization Using Range Measurements

PubMed Central

Arrichiello, Filippo; Antonelli, Gianluca; Aguiar, Antonio Pedro; Pascoal, Antonio

2013-01-01

The paper addresses observability issues related to the general problem of single and multiple Autonomous Underwater Vehicle (AUV) localization using only range measurements. While an AUV is submerged, localization devices, such as Global Navigation Satellite Systems, are ineffective, due to the attenuation of electromagnetic waves. AUV localization based on dead reckoning techniques and the use of affordable motion sensor units is also not practical, due to divergence caused by sensor bias and drift. For these reasons, localization systems often build on trilateration algorithms that rely on the measurements of the ranges between an AUV and a set of fixed transponders using acoustic devices. Still, such solutions are often expensive, require cumbersome calibration procedures and only allow for AUV localization in an area that is defined by the geometrical arrangement of the transponders. A viable alternative for AUV localization that has recently come to the fore exploits the use of complementary information on the distance from the AUV to a single transponder, together with information provided by on-board resident motion sensors, such as, for example, depth, velocity and acceleration measurements. This concept can be extended to address the problem of relative localization between two AUVs equipped with acoustic sensors for inter-vehicle range measurements. Motivated by these developments, in this paper, we show that both the problems of absolute localization of a single vehicle and the relative localization of multiple vehicles can be treated using the same mathematical framework, and tailoring concepts of observability derived for nonlinear systems, we analyze how the performance in localization depends on the types of motion imparted to the AUVs. For this effect, we propose a well-defined observability metric and validate its usefulness, both in simulation and by carrying out experimental tests with a real marine vehicle during which the performance of an Extended Kalman Filter state observer is shown to depend on the types of motion imparted to the vehicle.

Automated coregistration of MTI spectral bands

NASA Astrophysics Data System (ADS)

Theiler, James P.; Galbraith, Amy E.; Pope, Paul A.; Ramsey, Keri A.; Szymanski, John J.

2002-08-01

In the focal plane of a pushbroom imager, a linear array of pixels is scanned across the scene, building up the image one row at a time. For the Multispectral Thermal Imager (MTI), each of fifteen different spectral bands has its own linear array. These arrays are pushed across the scene together, but since each band's array is at a different position on the focal plane, a separate image is produced for each band. The standard MTI data products (LEVEL1B_R_COREG and LEVEL1B_R_GEO) resample these separate images to a common grid and produce coregistered multispectral image cubes. The coregistration software employs a direct ``dead reckoning' approach. Every pixel in the calibrated image is mapped to an absolute position on the surface of the earth, and these are resampled to produce an undistorted coregistered image of the scene. To do this requires extensive information regarding the satellite position and pointing as a function of time, the precise configuration of the focal plane, and the distortion due to the optics. These must be combined with knowledge about the position and altitude of the target on the rotating ellipsoidal earth. We will discuss the direct approach to MTI coregistration, as well as more recent attempts to tweak the precision of the band-to-band registration using correlations in the imagery itself.

An Adaptive Method for Switching between Pedestrian/Car Indoor Positioning Algorithms based on Multilayer Time Sequences

PubMed Central

Gu, Zhining; Guo, Wei; Li, Chaoyang; Zhu, Xinyan; Guo, Tao

2018-01-01

Pedestrian dead reckoning (PDR) positioning algorithms can be used to obtain a target’s location only for movement with step features and not for driving, for which the trilateral Bluetooth indoor positioning method can be used. In this study, to obtain the precise locations of different states (pedestrian/car) using the corresponding positioning algorithms, we propose an adaptive method for switching between the PDR and car indoor positioning algorithms based on multilayer time sequences (MTSs). MTSs, which consider the behavior context, comprise two main aspects: filtering of noisy data in small-scale time sequences and using a state chain to reduce the time delay of algorithm switching in large-scale time sequences. The proposed method can be expected to realize the recognition of stationary, walking, driving, or other states; switch to the correct indoor positioning algorithm; and improve the accuracy of localization compared to using a single positioning algorithm. Our experiments show that the recognition of static, walking, driving, and other states improves by 5.5%, 45.47%, 26.23%, and 21% on average, respectively, compared with convolutional neural network (CNN) method. The time delay decreases by approximately 0.5–8.5 s for the transition between states and by approximately 24 s for the entire process. PMID:29495503

Compliant-linkage kinematic design for multi-degree-of-freedom mobile robots

NASA Astrophysics Data System (ADS)

Borenstein, Johann

1993-05-01

Multi-degree-of-freedom (MDOF) vehicles have many potential advantages over conventional (i.e., 2-DOF) vehicles. For example, MDOF vehicles can travel sideways and they can negotiate tight turns more easily. In addition, some MDOF designs provide better payload capability, better traction, and improved static and dynamic stability. However, MDOF vehicles with more than three degrees-of-freedom are difficult to control because of their overconstrained nature. These difficulties translate into severe wheel slippage or jerky motion under certain driving conditions. In the past, these problems limited the use of MDOF vehicles to applications where the vehicle would follow a guide-wire, which would correct wheel slippage and control errors. By contrast, autonomous or semi-autonomous mobile robots usually rely on dead-reckoning between periodic absolute position updates and their performance is diminished by excessive wheel slippage. This paper introduces a new concept in the kinematic design of MDOF vehicles. This concept is based on the provision of a compliant linkage between drive wheels or drive axles. Simulation results indicate that compliant linkage allows to overcome the control problems found in conventional MDOF vehicles and reduces the amount of wheel slippage to the same level (or less) than the amount of slippage found on a comparable 2-DOF vehicle.

An Indoor Continuous Positioning Algorithm on the Move by Fusing Sensors and Wi-Fi on Smartphones

PubMed Central

Li, Huaiyu; Chen, Xiuwan; Jing, Guifei; Wang, Yuan; Cao, Yanfeng; Li, Fei; Zhang, Xinlong; Xiao, Han

2015-01-01

Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative points include an improved Wi-Fi positioning algorithm and a novel positioning fusion algorithm named the Trust Chain Positioning Fusion (TCPF) algorithm. The improved Wi-Fi positioning algorithm was designed based on the properties of Wi-Fi signals on the move, which are found in a novel “quasi-dynamic” Wi-Fi signal experiment. The TCPF algorithm is proposed to realize the “process-level” fusion of Wi-Fi and Pedestrians Dead Reckoning (PDR) positioning, including three parts: trusted point determination, trust state and positioning fusion algorithm. An experiment is carried out for verification in a typical indoor environment, and the average positioning error on the move is 1.36 m, a decrease of 28.8% compared to an existing algorithm. The results show that the proposed algorithm can effectively reduce the influence caused by the unstable Wi-Fi signals, and improve the accuracy and stability of indoor continuous positioning on the move. PMID:26690447

Three Dimensional Computer Graphics Federates for the 2012 Smackdown Simulation

NASA Technical Reports Server (NTRS)

Fordyce, Crystal; Govindaiah, Swetha; Muratet, Sean; O'Neil, Daniel A.; Schricker, Bradley C.

2012-01-01

The Simulation Interoperability Standards Organization (SISO) Smackdown is a two-year old annual event held at the 2012 Spring Simulation Interoperability Workshop (SIW). A primary objective of the Smackdown event is to provide college students with hands-on experience in developing distributed simulations using High Level Architecture (HLA). Participating for the second time, the University of Alabama in Huntsville (UAHuntsville) deployed four federates, two federates simulated a communications server and a lunar communications satellite with a radio. The other two federates generated 3D computer graphics displays for the communication satellite constellation and for the surface based lunar resupply mission. Using the Light-Weight Java Graphics Library, the satellite display federate presented a lunar-texture mapped sphere of the moon and four Telemetry Data Relay Satellites (TDRS), which received object attributes from the lunar communications satellite federate to drive their motion. The surface mission display federate was an enhanced version of the federate developed by ForwardSim, Inc. for the 2011 Smackdown simulation. Enhancements included a dead-reckoning algorithm and a visual indication of which communication satellite was in line of sight of Hadley Rille. This paper concentrates on these two federates by describing the functions, algorithms, HLA object attributes received from other federates, development experiences and recommendations for future, participating Smackdown teams.

29 CFR 1915.162 - Ship's boilers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... dead boiler with the live system or systems shall be secured, blanked, and tagged indicating that... and shutoff valves connecting the dead boiler with the live system or systems shall be secured, locked, and tagged. (2) Drain connections to atmosphere on all of the dead interconnecting systems shall be...

29 CFR 1915.162 - Ship's boilers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... dead boiler with the live system or systems shall be secured, blanked, and tagged indicating that... and shutoff valves connecting the dead boiler with the live system or systems shall be secured, locked, and tagged. (2) Drain connections to atmosphere on all of the dead interconnecting systems shall be...

29 CFR 1915.162 - Ship's boilers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... dead boiler with the live system or systems shall be secured, blanked, and then locked or tagged, in... the dead boiler with the live system or systems shall be secured, and then locked or tagged, in accordance with § 1915.89. (2) Drain connections to atmosphere on all of the dead interconnecting systems...

29 CFR 1915.162 - Ship's boilers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... dead boiler with the live system or systems shall be secured, blanked, and then locked or tagged, in... the dead boiler with the live system or systems shall be secured, and then locked or tagged, in accordance with § 1915.89. (2) Drain connections to atmosphere on all of the dead interconnecting systems...

29 CFR 1915.163 - Ship's piping systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... are taken: (1) The isolation and shutoff valves connecting the dead system with the live system or... welded instead of bolted, at least two isolation and shutoff valves connecting the dead system with the...) Drain connections to the atmosphere on all of the dead interconnecting systems shall be opened for...

29 CFR 1915.163 - Ship's piping systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

... are taken: (1) The isolation and shutoff valves connecting the dead system with the live system or... welded instead of bolted, at least two isolation and shutoff valves connecting the dead system with the...) Drain connections to the atmosphere on all of the dead interconnecting systems shall be opened for...

29 CFR 1915.162 - Ship's boilers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... dead boiler with the live system or systems shall be secured, blanked, and then locked or tagged, in... the dead boiler with the live system or systems shall be secured, and then locked or tagged, in accordance with § 1915.89. (2) Drain connections to atmosphere on all of the dead interconnecting systems...

29 CFR 1915.163 - Ship's piping systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

... are taken: (1) The isolation and shutoff valves connecting the dead system with the live system or... welded instead of bolted, at least two isolation and shutoff valves connecting the dead system with the...) Drain connections to the atmosphere on all of the dead interconnecting systems shall be opened for...

Depth-averaged instantaneous currents in a tidally dominated shelf sea from glider observations

NASA Astrophysics Data System (ADS)

Merckelbach, Lucas

2016-12-01

Ocean gliders have become ubiquitous observation platforms in the ocean in recent years. They are also increasingly used in coastal environments. The coastal observatory system COSYNA has pioneered the use of gliders in the North Sea, a shallow tidally energetic shelf sea. For operational reasons, the gliders operated in the North Sea are programmed to resurface every 3-5 h. The glider's dead-reckoning algorithm yields depth-averaged currents, averaged in time over each subsurface interval. Under operational conditions these averaged currents are a poor approximation of the instantaneous tidal current. In this work an algorithm is developed that estimates the instantaneous current (tidal and residual) from glider observations only. The algorithm uses a first-order Butterworth low pass filter to estimate the residual current component, and a Kalman filter based on the linear shallow water equations for the tidal component. A comparison of data from a glider experiment with current data from an acoustic Doppler current profilers deployed nearby shows that the standard deviations for the east and north current components are better than 7 cm s-1 in near-real-time mode and improve to better than 6 cm s-1 in delayed mode, where the filters can be run forward and backward. In the near-real-time mode the algorithm provides estimates of the currents that the glider is expected to encounter during its next few dives. Combined with a behavioural and dynamic model of the glider, this yields predicted trajectories, the information of which is incorporated in warning messages issued to ships by the (German) authorities. In delayed mode the algorithm produces useful estimates of the depth-averaged currents, which can be used in (process-based) analyses in case no other source of measured current information is available.

Enhanced Pedestrian Navigation Based on Course Angle Error Estimation Using Cascaded Kalman Filters

PubMed Central

Park, Chan Gook

2018-01-01

An enhanced pedestrian dead reckoning (PDR) based navigation algorithm, which uses two cascaded Kalman filters (TCKF) for the estimation of course angle and navigation errors, is proposed. The proposed algorithm uses a foot-mounted inertial measurement unit (IMU), waist-mounted magnetic sensors, and a zero velocity update (ZUPT) based inertial navigation technique with TCKF. The first stage filter estimates the course angle error of a human, which is closely related to the heading error of the IMU. In order to obtain the course measurements, the filter uses magnetic sensors and a position-trace based course angle. For preventing magnetic disturbance from contaminating the estimation, the magnetic sensors are attached to the waistband. Because the course angle error is mainly due to the heading error of the IMU, and the characteristic error of the heading angle is highly dependent on that of the course angle, the estimated course angle error is used as a measurement for estimating the heading error in the second stage filter. At the second stage, an inertial navigation system-extended Kalman filter-ZUPT (INS-EKF-ZUPT) method is adopted. As the heading error is estimated directly by using course-angle error measurements, the estimation accuracy for the heading and yaw gyro bias can be enhanced, compared with the ZUPT-only case, which eventually enhances the position accuracy more efficiently. The performance enhancements are verified via experiments, and the way-point position error for the proposed method is compared with those for the ZUPT-only case and with other cases that use ZUPT and various types of magnetic heading measurements. The results show that the position errors are reduced by a maximum of 90% compared with the conventional ZUPT based PDR algorithms. PMID:29690539

Texture-based measurement of spatial frequency response using the dead leaves target: extensions, and application to real camera systems

NASA Astrophysics Data System (ADS)

McElvain, Jon; Campbell, Scott P.; Miller, Jonathan; Jin, Elaine W.

2010-01-01

The dead leaves model was recently introduced as a method for measuring the spatial frequency response (SFR) of camera systems. The target consists of a series of overlapping opaque circles with a uniform gray level distribution and radii distributed as r-3. Unlike the traditional knife-edge target, the SFR derived from the dead leaves target will be penalized for systems that employ aggressive noise reduction. Initial studies have shown that the dead leaves SFR correlates well with sharpness/texture blur preference, and thus the target can potentially be used as a surrogate for more expensive subjective image quality evaluations. In this paper, the dead leaves target is analyzed for measurement of camera system spatial frequency response. It was determined that the power spectral density (PSD) of the ideal dead leaves target does not exhibit simple power law dependence, and scale invariance is only loosely obeyed. An extension to the ideal dead leaves PSD model is proposed, including a correction term to account for system noise. With this extended model, the SFR of several camera systems with a variety of formats was measured, ranging from 3 to 10 megapixels; the effects of handshake motion blur are also analyzed via the dead leaves target.

29 CFR 1915.163 - Ship's piping systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... are taken: (1) The isolation and shutoff valves connecting the dead system with the live system or.... Where valves are welded instead of bolted at least two isolation and shutoff valves connecting the dead... atmosphere on all of the dead interconnecting systems shall be opened for visual observation of drainage. [47...

29 CFR 1915.163 - Ship's piping systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... are taken: (1) The isolation and shutoff valves connecting the dead system with the live system or.... Where valves are welded instead of bolted at least two isolation and shutoff valves connecting the dead... atmosphere on all of the dead interconnecting systems shall be opened for visual observation of drainage. [47...

Sensor-based animal tracking

NASA Astrophysics Data System (ADS)

Hunter, Andrew

The advent of Global Positioning System (GPS) technologies has provided wildlife researchers with new insights into the movement and habitat utilization patterns of wildlife species by being able to provide vast quantities of detailed location data. However, current wildlife tracking techniques have numerous limitations, as GPS locations can be biased to an unknown extent because animals move through habitats that are often denied GPS signals. This can result in some habitat types being under sampled or not sampled at all. Additionally, researchers using GPS tracking systems cannot understand what behaviour an animal is exhibiting at each GPS position without either relying on extensive field data or statistical techniques that may infer behaviour. Overall these issues, and others, limit the knowledge that can be derived from the data currently being collected by GPS collars alone. To address these limitations, a dead reckoning solution (called the NavAid) has been developed to augment GPS tracking collars, which enables both the acquisition of continuous movement trajectories for animals under study, and the collection of digital images on a user-defined schedule along travel routes. Analysis of an animal's velocity allows one to identify different types of movement behaviours that can be associated with foraging, searching for food, and locomotion between patches. In addition, the ability to capture continuous paths allows researchers to identify habitat that is important to a species, and habitat that is not---something that is not possible when relying solely on GPS. This new system weighs approximately 220 g and can be deployed on most conventional collar systems for a wide range of species. This thesis presents the research and development of this new system over the past four years, along with preliminary findings from field work carried out on grizzly bears (Ursus arctos) in the foothills of the Canadian Rocky Mountains. Analysis of tracking data suggests that animals select different types of habitat for different purposes, that foraging occurs at movement rates of less than 52m/minute, searching for food between movement rates of 52 m/minute and 223 m/minute and locomotion, or active walking between foraging sites at movement rates greater than 223 m/minute.

Seismic-reflection and sidescan-sonar data collected on the Potomac River, Maryland and Virginia, during May 1979

USGS Publications Warehouse

Knebel, Harley J.

1981-01-01

The U.S. Geological Survey collected 2,170 line kilometers of single-channel seismic-reflection profiles and sidescan sonar records on the Potomac River during R/V NEECHO cruise NE-3-79 in May 1979. The purposes of the survey were to define: (1) areas of sediment accumulation and erosion; (2) the thickness of Holocene sediments; (3) the internal structure of the near-surface sediments; (4) the types of bottom topography; and (5) the general geologic framework of the tidal river and estuary.The survey utilized a variety of acoustic systems. Bottom data were obtained by using a Raytheon _1/ model DE-719 fathometer (200 kHz) and an EDO Western model 606 sidescan-sonar system (100 kHz). Subbottom data were collected with a 7-kHz Raytheon model PTR-106 system and a small airgun system (170-645 Hz band pass; l in3 chamber). An EDO Western sidescan fish (model 604-150) coupled with a 2.5-kHz seismic-reflection system also was used during the longitudinal run up the river. The totals for the ,various kinds of data collected were 481 line kilometers each of fathometer, sidescan sonar, 7-kHz, and airgun records, and 246 line kilometers of 2.5-kHz records. Positional control for all tracklines was provided by frequent radar fixes, by dead reckoning, and by sightings on buoys, landmarks, and other navigational aids.The quality of the acoustic records varied with location in the river. Good fathometer and sidescan-sonar records were collected along all tracklines. However, because of the nature of the sediments within some sections of the river, the degree of subbottom penetration in many places was limited. In general, the subbottom penetration and resolution were poor in the upper and middle reaches of the river, whereas the subbottom records from the lower reach usually were quite good.The original records may be examined at the U.S. Geological Survey, Woods Hole, MA 02543. Microfilm copies of the data are available for purchase from the National Geophysical and Solar-Terrestrial Data Center (NGSDC), Boulder, CO 80303.

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

49 CFR 236.55 - Dead section; maximum length.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Dead section; maximum length. 236.55 Section 236... Instructions: All Systems Track Circuits § 236.55 Dead section; maximum length. Where dead section exceeds 35... over such dead section is less than 35 feet, the maximum length of the dead section shall not exceed...

Multi-dimensional Precision Livestock Farming: a potential toolbox for sustainable rangeland management.

PubMed

di Virgilio, Agustina; Morales, Juan M; Lambertucci, Sergio A; Shepard, Emily L C; Wilson, Rory P

2018-01-01

Precision Livestock Farming (PLF) is a promising approach to minimize the conflicts between socio-economic activities and landscape conservation. However, its application on extensive systems of livestock production can be challenging. The main difficulties arise because animals graze on large natural pastures where they are exposed to competition with wild herbivores for heterogeneous and scarce resources, predation risk, adverse weather, and complex topography. Considering that the 91% of the world's surface devoted to livestock production is composed of extensive systems (i.e., rangelands), our general aim was to develop a PLF methodology that quantifies: (i) detailed behavioural patterns, (ii) feeding rate, and (iii) costs associated with different behaviours and landscape traits. For this, we used Merino sheep in Patagonian rangelands as a case study. We combined data from an animal-attached multi-sensor tag (tri-axial acceleration, tri-axial magnetometry, temperature sensor and Global Positioning System) with landscape layers from a Geographical Information System to acquire data. Then, we used high accuracy decision trees, dead reckoning methods and spatial data processing techniques to show how this combination of tools could be used to assess energy balance, predation risk and competition experienced by livestock through time and space. The combination of methods proposed here are a useful tool to assess livestock behaviour and the different factors that influence extensive livestock production, such as topography, environmental temperature, predation risk and competition for heterogeneous resources. We were able to quantify feeding rate continuously through time and space with high accuracy and show how it could be used to estimate animal production and the intensity of grazing on the landscape. We also assessed the effects of resource heterogeneity (inferred through search times), and the potential costs associated with predation risk, competition, thermoregulation and movement on complex topography. The quantification of feeding rate and behavioural costs provided by our approach could be used to estimate energy balance and to predict individual growth, survival and reproduction. Finally, we discussed how the information provided by this combination of methods can be used to develop wildlife-friendly strategies that also maximize animal welfare, quality and environmental sustainability.

Pedestrian dead reckoning employing simultaneous activity recognition cues

NASA Astrophysics Data System (ADS)

Altun, Kerem; Barshan, Billur

2012-02-01

We consider the human localization problem using body-worn inertial/magnetic sensor units. Inertial sensors are characterized by a drift error caused by the integration of their rate output to obtain position information. Because of this drift, the position and orientation data obtained from inertial sensors are reliable over only short periods of time. Therefore, position updates from externally referenced sensors are essential. However, if the map of the environment is known, the activity context of the user can provide information about his position. In particular, the switches in the activity context correspond to discrete locations on the map. By performing localization simultaneously with activity recognition, we detect the activity context switches and use the corresponding position information as position updates in a localization filter. The localization filter also involves a smoother that combines the two estimates obtained by running the zero-velocity update algorithm both forward and backward in time. We performed experiments with eight subjects in indoor and outdoor environments involving walking, turning and standing activities. Using a spatial error criterion, we show that the position errors can be decreased by about 85% on the average. We also present the results of two 3D experiments performed in realistic indoor environments and demonstrate that it is possible to achieve over 90% error reduction in position by performing localization simultaneously with activity recognition.

A Robust Step Detection Algorithm and Walking Distance Estimation Based on Daily Wrist Activity Recognition Using a Smart Band.

PubMed

Trong Bui, Duong; Nguyen, Nhan Duc; Jeong, Gu-Min

2018-06-25

Human activity recognition and pedestrian dead reckoning are an interesting field because of their importance utilities in daily life healthcare. Currently, these fields are facing many challenges, one of which is the lack of a robust algorithm with high performance. This paper proposes a new method to implement a robust step detection and adaptive distance estimation algorithm based on the classification of five daily wrist activities during walking at various speeds using a smart band. The key idea is that the non-parametric adaptive distance estimator is performed after two activity classifiers and a robust step detector. In this study, two classifiers perform two phases of recognizing five wrist activities during walking. Then, a robust step detection algorithm, which is integrated with an adaptive threshold, peak and valley correction algorithm, is applied to the classified activities to detect the walking steps. In addition, the misclassification activities are fed back to the previous layer. Finally, three adaptive distance estimators, which are based on a non-parametric model of the average walking speed, calculate the length of each strike. The experimental results show that the average classification accuracy is about 99%, and the accuracy of the step detection is 98.7%. The error of the estimated distance is 2.2⁻4.2% depending on the type of wrist activities.

Way-finding in displaced clock-shifted bees proves bees use a cognitive map.

PubMed

Cheeseman, James F; Millar, Craig D; Greggers, Uwe; Lehmann, Konstantin; Pawley, Matthew D M; Gallistel, Charles R; Warman, Guy R; Menzel, Randolf

2014-06-17

Mammals navigate by means of a metric cognitive map. Insects, most notably bees and ants, are also impressive navigators. The question whether they, too, have a metric cognitive map is important to cognitive science and neuroscience. Experimentally captured and displaced bees often depart from the release site in the compass direction they were bent on before their capture, even though this no longer heads them toward their goal. When they discover their error, however, the bees set off more or less directly toward their goal. This ability to orient toward a goal from an arbitrary point in the familiar environment is evidence that they have an integrated metric map of the experienced environment. We report a test of an alternative hypothesis, which is that all the bees have in memory is a collection of snapshots that enable them to recognize different landmarks and, associated with each such snapshot, a sun-compass-referenced home vector derived from dead reckoning done before and after previous visits to the landmark. We show that a large shift in the sun-compass rapidly induced by general anesthesia does not alter the accuracy or speed of the homeward-oriented flight made after the bees discover the error in their initial postrelease flight. This result rules out the sun-referenced home-vector hypothesis, further strengthening the now extensive evidence for a metric cognitive map in bees.

Way-finding in displaced clock-shifted bees proves bees use a cognitive map

PubMed Central

Cheeseman, James F.; Millar, Craig D.; Greggers, Uwe; Lehmann, Konstantin; Pawley, Matthew D. M.; Gallistel, Charles R.; Warman, Guy R.; Menzel, Randolf

2014-01-01

Mammals navigate by means of a metric cognitive map. Insects, most notably bees and ants, are also impressive navigators. The question whether they, too, have a metric cognitive map is important to cognitive science and neuroscience. Experimentally captured and displaced bees often depart from the release site in the compass direction they were bent on before their capture, even though this no longer heads them toward their goal. When they discover their error, however, the bees set off more or less directly toward their goal. This ability to orient toward a goal from an arbitrary point in the familiar environment is evidence that they have an integrated metric map of the experienced environment. We report a test of an alternative hypothesis, which is that all the bees have in memory is a collection of snapshots that enable them to recognize different landmarks and, associated with each such snapshot, a sun-compass–referenced home vector derived from dead reckoning done before and after previous visits to the landmark. We show that a large shift in the sun-compass rapidly induced by general anesthesia does not alter the accuracy or speed of the homeward-oriented flight made after the bees discover the error in their initial postrelease flight. This result rules out the sun-referenced home-vector hypothesis, further strengthening the now extensive evidence for a metric cognitive map in bees. PMID:24889633

A Unified Approach to Adaptive Neural Control for Nonlinear Discrete-Time Systems With Nonlinear Dead-Zone Input.

PubMed

Liu, Yan-Jun; Gao, Ying; Tong, Shaocheng; Chen, C L Philip

2016-01-01

In this paper, an effective adaptive control approach is constructed to stabilize a class of nonlinear discrete-time systems, which contain unknown functions, unknown dead-zone input, and unknown control direction. Different from linear dead zone, the dead zone, in this paper, is a kind of nonlinear dead zone. To overcome the noncausal problem, which leads to the control scheme infeasible, the systems can be transformed into a m -step-ahead predictor. Due to nonlinear dead-zone appearance, the transformed predictor still contains the nonaffine function. In addition, it is assumed that the gain function of dead-zone input and the control direction are unknown. These conditions bring about the difficulties and the complicacy in the controller design. Thus, the implicit function theorem is applied to deal with nonaffine dead-zone appearance, the problem caused by the unknown control direction can be resolved through applying the discrete Nussbaum gain, and the neural networks are used to approximate the unknown function. Based on the Lyapunov theory, all the signals of the resulting closed-loop system are proved to be semiglobal uniformly ultimately bounded. Moreover, the tracking error is proved to be regulated to a small neighborhood around zero. The feasibility of the proposed approach is demonstrated by a simulation example.

SU-E-I-88: The Effect of System Dead Time On Real-Time Plastic and GOS Based Fiber-Optic Dosimetry Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoerner, M; Hintenlang, D

Purpose: A methodology is presented to correct for measurement inaccuracies at high detector count rates using a plastic and GOS scintillation fibers coupled to a photomultiplier tube with digital readout. This system allows temporal acquisition and manipulation of measured data. Methods: The detection system used was a plastic scintillator and a separate gadolinium scintillator, both (0.5 diameter) coupled to an optical fiber with a Hamamatsu photon counter with a built-in microcontroller and digital interface. Count rate performance of the system was evaluated using the nonparalzable detector model. Detector response was investigated across multiple radiation sources including: orthovoltage x-ray system, colbat-60more » gamma rays, proton therapy beam, and a diagnostic radiography x-ray tube. The dead time parameter was calculated by measuring the count rate of the system at different exposure rates using a reference detector. Results: The system dead time was evaluated for the following sources of radiation used clinically: diagnostic energy x-rays, cobalt-60 gamma rays, orthovoltage xrays, particle proton accelerator, and megavoltage x-rays. It was found that dead time increased significantly when exposing the detector to sources capable of generating Cerenkov radiation, all of the sources sans the diagnostic x-rays, with increasing prominence at higher photon energies. Percent depth dose curves generated by a dedicated ionization chamber and compared to the detection system demonstrated that correcting for dead time improves accuracy. On most sources, nonparalzable model fit provided an improved system response. Conclusion: Overall, the system dead time was variable across the investigated radiation particles and energies. It was demonstrated that the system response accuracy was greatly improved by correcting for dead time effects. Cerenkov radiation plays a significant role in the increase in the system dead time through transient absorption effects attributed to electron hole-pair creations within the optical waveguide.« less

Safety evaluation of traces of nickel and chrome in cosmetics: The case of Dead Sea mud.

PubMed

Ma'or, Ze'evi; Halicz, Ludwik; Portugal-Cohen, Meital; Russo, Matteo Zanotti; Robino, Federica; Vanhaecke, Tamara; Rogiers, Vera

2015-12-01

Metal impurities such as nickel and chrome are present in natural ingredients-containing cosmetic products. These traces are unavoidable due to the ubiquitous nature of these elements. Dead Sea mud is a popular natural ingredient of cosmetic products in which nickel and chrome residues are likely to occur. To analyze the potential systemic and local toxicity of Dead Sea mud taking into consideration Dead Sea muds' natural content of nickel and chrome. The following endpoints were evaluated: (Regulation No. 1223/20, 21/12/2009) systemic and (SCCS's Notes of Guidance) local toxicity of topical application of Dead Sea mud; health reports during the last five years of commercial marketing of Dead Sea mud. Following exposure to Dead Sea mud, MoS (margin of safety) calculations for nickel and chrome indicate no toxicological concern for systemic toxicity. Skin sensitization is also not to be expected by exposure of normal healthy skin to Dead Sea mud. Topical application, however, is not recommended for already nickel-or chrome-sensitized persons. As risk assessment of impurities present in cosmetics may be a difficult exercise, the case of Dead Sea mud is taken here as an example of a natural material that may contain traces of unavoidable metals. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Adaptive NN tracking control of uncertain nonlinear discrete-time systems with nonaffine dead-zone input.

PubMed

Liu, Yan-Jun; Tong, Shaocheng

2015-03-01

In the paper, an adaptive tracking control design is studied for a class of nonlinear discrete-time systems with dead-zone input. The considered systems are of the nonaffine pure-feedback form and the dead-zone input appears nonlinearly in the systems. The contributions of the paper are that: 1) it is for the first time to investigate the control problem for this class of discrete-time systems with dead-zone; 2) there are major difficulties for stabilizing such systems and in order to overcome the difficulties, the systems are transformed into an n-step-ahead predictor but nonaffine function is still existent; and 3) an adaptive compensative term is constructed to compensate for the parameters of the dead-zone. The neural networks are used to approximate the unknown functions in the transformed systems. Based on the Lyapunov theory, it is proven that all the signals in the closed-loop system are semi-globally uniformly ultimately bounded and the tracking error converges to a small neighborhood of zero. Two simulation examples are provided to verify the effectiveness of the control approach in the paper.

Dead time corrections using the backward extrapolation method

NASA Astrophysics Data System (ADS)

Gilad, E.; Dubi, C.; Geslot, B.; Blaise, P.; Kolin, A.

2017-05-01

Dead time losses in neutron detection, caused by both the detector and the electronics dead time, is a highly nonlinear effect, known to create high biasing in physical experiments as the power grows over a certain threshold, up to total saturation of the detector system. Analytic modeling of the dead time losses is a highly complicated task due to the different nature of the dead time in the different components of the monitoring system (e.g., paralyzing vs. non paralyzing), and the stochastic nature of the fission chains. In the present study, a new technique is introduced for dead time corrections on the sampled Count Per Second (CPS), based on backward extrapolation of the losses, created by increasingly growing artificially imposed dead time on the data, back to zero. The method has been implemented on actual neutron noise measurements carried out in the MINERVE zero power reactor, demonstrating high accuracy (of 1-2%) in restoring the corrected count rate.

Alaska Athabascan stellar astronomy

NASA Astrophysics Data System (ADS)

Cannon, Christopher M.

2014-01-01

Stellar astronomy is a fundamental component of Alaska Athabascan cultures that facilitates time-reckoning, navigation, weather forecasting, and cosmology. Evidence from the linguistic record suggests that a group of stars corresponding to the Big Dipper is the only widely attested constellation across the Northern Athabascan languages. However, instruction from expert Athabascan consultants shows that the correlation of these names with the Big Dipper is only partial. In Alaska Gwich'in, Ahtna, and Upper Tanana languages the Big Dipper is identified as one part of a much larger circumpolar humanoid constellation that spans more than 133 degrees across the sky. The Big Dipper is identified as a tail, while the other remaining asterisms within the humanoid constellation are named using other body part terms. The concept of a whole-sky humanoid constellation provides a single unifying system for mapping the night sky, and the reliance on body-part metaphors renders the system highly mnemonic. By recognizing one part of the constellation the stargazer is immediately able to identify the remaining parts based on an existing mental map of the human body. The circumpolar position of a whole-sky constellation yields a highly functional system that facilitates both navigation and time-reckoning in the subarctic. Northern Athabascan astronomy is not only much richer than previously described; it also provides evidence for a completely novel and previously undocumented way of conceptualizing the sky---one that is unique to the subarctic and uniquely adapted to northern cultures. The concept of a large humanoid constellation may be widespread across the entire subarctic and have great antiquity. In addition, the use of cognate body part terms describing asterisms within humanoid constellations is similarly found in Navajo, suggesting a common ancestor from which Northern and Southern Athabascan stellar naming strategies derived.

Analysis and experimental kinematics of a skid-steering wheeled robot based on a laser scanner sensor.

PubMed

Wang, Tianmiao; Wu, Yao; Liang, Jianhong; Han, Chenhao; Chen, Jiao; Zhao, Qiteng

2015-04-24

Skid-steering mobile robots are widely used because of their simple mechanism and robustness. However, due to the complex wheel-ground interactions and the kinematic constraints, it is a challenge to understand the kinematics and dynamics of such a robotic platform. In this paper, we develop an analysis and experimental kinematic scheme for a skid-steering wheeled vehicle based-on a laser scanner sensor. The kinematics model is established based on the boundedness of the instantaneous centers of rotation (ICR) of treads on the 2D motion plane. The kinematic parameters (the ICR coefficient , the path curvature variable and robot speed ), including the effect of vehicle dynamics, are introduced to describe the kinematics model. Then, an exact but costly dynamic model is used and the simulation of this model's stationary response for the vehicle shows a qualitative relationship for the specified parameters and . Moreover, the parameters of the kinematic model are determined based-on a laser scanner localization experimental analysis method with a skid-steering robotic platform, Pioneer P3-AT. The relationship between the ICR coefficient and two physical factors is studied, i.e., the radius of the path curvature and the robot speed . An empirical function-based relationship between the ICR coefficient of the robot and the path parameters is derived. To validate the obtained results, it is empirically demonstrated that the proposed kinematics model significantly improves the dead-reckoning performance of this skid-steering robot.

Genome-Wide Association Study in African-Americans with Systemic Lupus Erythematosus

DTIC Science & Technology

2013-09-01

Americans with Systemic Lupus Erythematosus PRINCIPAL INVESTIGATOR: John Harley, M.D., Ph.D...SUPPLEMENTARY NOTES 14. ABSTRACT Systemic lupus erythematosus ( lupus ) is a potentially deadly systemic autoimmune disease that disproportionately... Systemic lupus erythematosus ( lupus ) is a potentially deadly systemic autoimmune disease that disproportionately afflicts women and African

Control design based on dead-zone and leakage adaptive laws for artificial swarm mechanical systems

NASA Astrophysics Data System (ADS)

Zhao, Xiaomin; Chen, Y. H.; Zhao, Han

2017-05-01

We consider the control design of artificial swarm systems with emphasis on four characteristics. First, the agent is made of mechanical components. As a result, the motion of each agent is subject to physical laws that govern mechanical systems. Second, both nonlinearity and uncertainty of the mechanical system are taken into consideration. Third, the ideal agent kinematic performance is treated as a desired d'Alembert constraint. This in turn suggests a creative way of embedding the constraint into the control design. Fourth, two types of adaptive robust control schemes are designed. They both contain leakage and dead-zone. However, one design suggests a trade-off between the amount of leakage and the size of dead-zone, in exchange for a simplified dead-zone structure.

Tailoring Green Infrastructure Implementation Scenarios based on Stormwater Management Objectives

EPA Science Inventory

Green infrastructure (GI) refers to stormwater management practices that mimic nature by soaking up, storing, and controlling onsite. GI practices can contribute reckonable benefits towards meeting stormwater management objectives, such as runoff peak shaving, volume reduction, f...

Self-Interaction Chromatography of mAbs: Accurate Measurement of Dead Volumes.

PubMed

Hedberg, S H M; Heng, J Y Y; Williams, D R; Liddell, J M

2015-12-01

Measurement of the second virial coefficient B22 for proteins using self-interaction chromatography (SIC) is becoming an increasingly important technique for studying their solution behaviour. In common with all physicochemical chromatographic methods, measuring the dead volume of the SIC packed column is crucial for accurate retention data; this paper examines best practise for dead volume determination. SIC type experiments using catalase, BSA, lysozyme and a mAb as model systems are reported, as well as a number of dead column measurements. It was observed that lysozyme and mAb interacted specifically with Toyopearl AF-Formyl dead columns depending upon pH and [NaCl], invalidating their dead volume usage. Toyopearl AF-Amino packed dead columns showed no such problems and acted as suitable dead columns without any solution condition dependency. Dead volume determinations using dextran MW standards with protein immobilised SIC columns provided dead volume estimates close to those obtained using Toyopearl AF-Amino dead columns. It is concluded that specific interactions between proteins, including mAbs, and select SIC support phases can compromise the use of some standard approaches for estimating the dead volume of SIC columns. Two other methods were shown to provide good estimates for the dead volume.

High-rate dead-time corrections in a general purpose digital pulse processing system

PubMed Central

Abbene, Leonardo; Gerardi, Gaetano

2015-01-01

Dead-time losses are well recognized and studied drawbacks in counting and spectroscopic systems. In this work the abilities on dead-time correction of a real-time digital pulse processing (DPP) system for high-rate high-resolution radiation measurements are presented. The DPP system, through a fast and slow analysis of the output waveform from radiation detectors, is able to perform multi-parameter analysis (arrival time, pulse width, pulse height, pulse shape, etc.) at high input counting rates (ICRs), allowing accurate counting loss corrections even for variable or transient radiations. The fast analysis is used to obtain both the ICR and energy spectra with high throughput, while the slow analysis is used to obtain high-resolution energy spectra. A complete characterization of the counting capabilities, through both theoretical and experimental approaches, was performed. The dead-time modeling, the throughput curves, the experimental time-interval distributions (TIDs) and the counting uncertainty of the recorded events of both the fast and the slow channels, measured with a planar CdTe (cadmium telluride) detector, will be presented. The throughput formula of a series of two types of dead-times is also derived. The results of dead-time corrections, performed through different methods, will be reported and discussed, pointing out the error on ICR estimation and the simplicity of the procedure. Accurate ICR estimations (nonlinearity < 0.5%) were performed by using the time widths and the TIDs (using 10 ns time bin width) of the detected pulses up to 2.2 Mcps. The digital system allows, after a simple parameter setting, different and sophisticated procedures for dead-time correction, traditionally implemented in complex/dedicated systems and time-consuming set-ups. PMID:26289270

Simulation of Rate-Related (Dead-Time) Losses In Passive Neutron Multiplicity Counting Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, L.G.; Norman, P.I.; Leadbeater, T.W.

Passive Neutron Multiplicity Counting (PNMC) based on Multiplicity Shift Register (MSR) electronics (a form of time correlation analysis) is a widely used non-destructive assay technique for quantifying spontaneously fissile materials such as Pu. At high event rates, dead-time losses perturb the count rates with the Singles, Doubles and Triples being increasingly affected. Without correction these perturbations are a major source of inaccuracy in the measured count rates and assay values derived from them. This paper presents the simulation of dead-time losses and investigates the effect of applying different dead-time models on the observed MSR data. Monte Carlo methods have beenmore » used to simulate neutron pulse trains for a variety of source intensities and with ideal detection geometry, providing an event by event record of the time distribution of neutron captures within the detection system. The action of the MSR electronics was modelled in software to analyse these pulse trains. Stored pulse trains were perturbed in software to apply the effects of dead-time according to the chosen physical process; for example, the ideal paralysable (extending) and non-paralysable models with an arbitrary dead-time parameter. Results of the simulations demonstrate the change in the observed MSR data when the system dead-time parameter is varied. In addition, the paralysable and non-paralysable models of deadtime are compared. These results form part of a larger study to evaluate existing dead-time corrections and to extend their application to correlated sources. (authors)« less

Possible Astronomical Depictions in Franco-Cantabrian Paleolithic Rock Art

NASA Astrophysics Data System (ADS)

Rappenglück, Michael A.

In some cases there is evidence for astronomical depictions among the rock art of the Franco-Cantabrian Upper Paleolithic (40-12 ka BP). Phenological almanacs, some kind of lunar time reckoning, certain asterisms, and manifestations of cosmovisions are probably present.

Including Internet insurance as part of a hospital computer network security plan.

PubMed

Riccardi, Ken

2002-01-01

Cyber attacks on a hospital's computer network is a new crime to be reckoned with. Should your hospital consider internet insurance? The author explains this new phenomenon and presents a risk assessment for determining network vulnerabilities.

Navigation system for a mobile robot with a visual sensor using a fish-eye lens

NASA Astrophysics Data System (ADS)

Kurata, Junichi; Grattan, Kenneth T. V.; Uchiyama, Hironobu

1998-02-01

Various position sensing and navigation systems have been proposed for the autonomous control of mobile robots. Some of these systems have been installed with an omnidirectional visual sensor system that proved very useful in obtaining information on the environment around the mobile robot for position reckoning. In this article, this type of navigation system is discussed. The sensor is composed of one TV camera with a fish-eye lens, using a reference target on a ceiling and hybrid image processing circuits. The position of the robot, with respect to the floor, is calculated by integrating the information obtained from a visual sensor and a gyroscope mounted in the mobile robot, and the use of a simple algorithm based on PTP control for guidance is discussed. An experimental trial showed that the proposed system was both valid and useful for the navigation of an indoor vehicle.

Investigating Aquatic Dead Zones

ERIC Educational Resources Information Center

Testa, Jeremy; Gurbisz, Cassie; Murray, Laura; Gray, William; Bosch, Jennifer; Burrell, Chris; Kemp, Michael

2010-01-01

This article features two engaging high school activities that include current scientific information, data, and authentic case studies. The activities address the physical, biological, and chemical processes that are associated with oxygen-depleted areas, or "dead zones," in aquatic systems. Students can explore these dead zones through both…

Refractory pulse counting processes in stochastic neural computers.

PubMed

McNeill, Dean K; Card, Howard C

2005-03-01

This letter quantitiatively investigates the effect of a temporary refractory period or dead time in the ability of a stochastic Bernoulli processor to record subsequent pulse events, following the arrival of a pulse. These effects can arise in either the input detectors of a stochastic neural network or in subsequent processing. A transient period is observed, which increases with both the dead time and the Bernoulli probability of the dead-time free system, during which the system reaches equilibrium. Unless the Bernoulli probability is small compared to the inverse of the dead time, the mean and variance of the pulse count distributions are both appreciably reduced.

Note: An improved 3D imaging system for electron-electron coincidence measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Yun Fei; Lee, Suk Kyoung; Adhikari, Pradip

We demonstrate an improved imaging system that can achieve highly efficient 3D detection of two electrons in coincidence. The imaging system is based on a fast frame complementary metal-oxide semiconductor camera and a high-speed waveform digitizer. We have shown previously that this detection system is capable of 3D detection of ions and electrons with good temporal and spatial resolution. Here, we show that with a new timing analysis algorithm, this system can achieve an unprecedented dead-time (<0.7 ns) and dead-space (<1 mm) when detecting two electrons. A true zero dead-time detection is also demonstrated.

Note: An improved 3D imaging system for electron-electron coincidence measurements

NASA Astrophysics Data System (ADS)

Lin, Yun Fei; Lee, Suk Kyoung; Adhikari, Pradip; Herath, Thushani; Lingenfelter, Steven; Winney, Alexander H.; Li, Wen

2015-09-01

We demonstrate an improved imaging system that can achieve highly efficient 3D detection of two electrons in coincidence. The imaging system is based on a fast frame complementary metal-oxide semiconductor camera and a high-speed waveform digitizer. We have shown previously that this detection system is capable of 3D detection of ions and electrons with good temporal and spatial resolution. Here, we show that with a new timing analysis algorithm, this system can achieve an unprecedented dead-time (<0.7 ns) and dead-space (<1 mm) when detecting two electrons. A true zero dead-time detection is also demonstrated.

Labor History and Industrial Relations: A Symposium.

ERIC Educational Resources Information Center

Salvatore, Nick; And Others

1989-01-01

Includes "Labor History, Industrial Relations, and the Crisis of American Labor" (Brody); "Reckoning with Company Unions: The Case of Thompson Products, 1934-1964" (Jacoby); "Managers and Nonunion Workers in the Rubber Industry: Union Avoidance Strategies in the 1930s" (Nelson); and "'Light Manufacturing': The…

Absolute dose calibration of an X-ray system and dead time investigations of photon-counting techniques

NASA Astrophysics Data System (ADS)

Carpentieri, C.; Schwarz, C.; Ludwig, J.; Ashfaq, A.; Fiederle, M.

2002-07-01

High precision concerning the dose calibration of X-ray sources is required when counting and integrating methods are compared. The dose calibration for a dental X-ray tube was executed with special dose calibration equipment (dosimeter) as function of exposure time and rate. Results were compared with a benchmark spectrum and agree within ±1.5%. Dead time investigations with the Medipix1 photon-counting chip (PCC) have been performed by rate variations. Two different types of dead time, paralysable and non-paralysable will be discussed. The dead time depends on settings of the front-end electronics and is a function of signal height, which might lead to systematic defects of systems. Dead time losses in excess of 30% have been found for the PCC at 200 kHz absorbed photons per pixel.

Mortality, fertility, and the OY ratio in a model hunter-gatherer system.

PubMed

White, Andrew A

2014-06-01

An agent-based model (ABM) is used to explore how the ratio of old to young adults (the OY ratio) in a sample of dead individuals is related to aspects of mortality, fertility, and longevity experienced by the living population from which the sample was drawn. The ABM features representations of rules, behaviors, and constraints that affect person- and household-level decisions about marriage, reproduction, and infant mortality in hunter-gatherer systems. The demographic characteristics of the larger model system emerge through human-level interactions playing out in the context of "global" parameters that can be adjusted to produce a range of mortality and fertility conditions. Model data show a relationship between the OY ratios of living populations (the living OY ratio) and assemblages of dead individuals drawn from those populations (the dead OY ratio) that is consistent with that from empirically known ethnographic hunter-gatherer cases. The dead OY ratio is clearly related to the mean ages, mean adult mortality rates, and mean total fertility rates experienced by living populations in the model. Sample size exerts a strong effect on the accuracy with which the calculated dead OY ratio reflects the actual dead OY ratio of the complete assemblage. These results demonstrate that the dead OY ratio is a potentially useful metric for paleodemographic analysis of changes in mortality and mean age, and suggest that, in general, hunter-gatherer populations with higher mortality, higher fertility, and lower mean ages are characterized by lower dead OY ratios. Copyright © 2014 Wiley Periodicals, Inc.

The RNA Helicase DeaD Stimulates ExsA Translation To Promote Expression of the Pseudomonas aeruginosa Type III Secretion System

PubMed Central

Intile, Peter J.; Balzer, Grant J.; Wolfgang, Matthew C.

2015-01-01

ABSTRACT The Pseudomonas aeruginosa type III secretion system (T3SS) is a primary virulence factor important for phagocytic avoidance, disruption of host cell signaling, and host cell cytotoxicity. ExsA is the master regulator of T3SS transcription. The expression, synthesis, and activity of ExsA is tightly regulated by both intrinsic and extrinsic factors. Intrinsic regulation consists of the well-characterized ExsECDA partner-switching cascade, while extrinsic factors include global regulators that alter exsA transcription and/or translation. To identify novel extrinsic regulators of ExsA, we conducted a transposon mutagenesis screen in the absence of intrinsic control. Transposon disruptions within gene PA2840, which encodes a homolog of the Escherichia coli RNA-helicase DeaD, significantly reduced T3SS gene expression. Recent studies indicate that E. coli DeaD can promote translation by relieving inhibitory secondary structures within target mRNAs. We report here that PA2840, renamed DeaD, stimulates ExsA synthesis at the posttranscriptional level. Genetic experiments demonstrate that the activity of an exsA translational fusion is reduced in a deaD mutant. In addition, exsA expression in trans fails to restore T3SS gene expression in a deaD mutant. We hypothesized that DeaD relaxes mRNA secondary structure to promote exsA translation and found that altering the mRNA sequence of exsA or the native exsA Shine-Dalgarno sequence relieved the requirement for DeaD in vivo. Finally, we show that purified DeaD promotes ExsA synthesis using in vitro translation assays. Together, these data reveal a novel regulatory mechanism for P. aeruginosa DeaD and add to the complexity of global regulation of T3SS. IMPORTANCE Although members of the DEAD box family of RNA helicases are appreciated for their roles in mRNA degradation and ribosome biogenesis, an additional role in gene regulation is now emerging in bacteria. By relaxing secondary structures in mRNAs, DEAD box helicases are now thought to promote translation by enhancing ribosomal recruitment. We identify here an RNA helicase that plays a critical role in promoting ExsA synthesis, the central regulator of the Pseudomonas aeruginosa type III secretion system, and provide additional evidence that DEAD box helicases directly stimulate translation of target genes. The finding that DeaD stimulates exsA translation adds to a growing list of transcriptional and posttranscriptional regulatory mechanisms that control type III gene expression. PMID:26055113

Raising the Dead without a Red Sea-Dead Sea Canal? A hydro-economic-institutional analysis

NASA Astrophysics Data System (ADS)

Rosenberg, D. E.

2010-12-01

Presently, just 100 million cubic meters per year (MCM/year) of the 1,000+ MCM/year that historically flowed in the lower Jordan River reach the Dead Sea. Israeli, Jordanian, and Syrian dam and extraction projects built over seven decades have principally caused the reduced flow, associated falling Dead Sea level, shrinking surface area, sink holes, salinity, and other catastrophic problems. These problems will be magnified in the face of up to 20% reductions in precipitation expected with climate change. The fix proposed by Jordan, Israel, and Palestine—and now under study by the World Bank—envisions building a $US 5 billion multipurpose canal from the Red Sea to the Dead Sea that would also generate hydropower and desalinated water. Yet alternatives to raise the Dead Sea level that could take advantage of hydrologic variability remain unstudied. Here we show system-wide hydrologic and economic impacts of and discusses institutional management for alternatives to raise the Dead Sea level. Hydro-economic model results for the inter-tied Israel-Jordan-Palestinian water systems show the desalination component of the Red Sea-Dead Sea project is economically unviable. Further, many decentralized new supply, wastewater reuse, conveyance, conservation, and leak reduction projects and programs in each country together increase economic benefits and can reliably deliver up to 900 MCM/year to the Dead Sea. In all cases, results show that net benefits fall and water scarcity rises as the flow volume delivered to the Dead Sea increases. These findings suggest that (i) each country has little individual incentive to allow water to flow to the Dead Sea, and (ii) outside institutions—such as the World Bank—that seek to raise the Dead should instead offer the countries direct incentives to deliver water rather than build them new infrastructure. The work expands the set of viable options to raise the Dead Sea level and can help the World Bank and others recommend whether to move forward with the Red Sea-Dead Sea project.

The Begg's uprighting spring – Revisited

PubMed Central

Kumar, Vinay; Sundareswaran, Shobha

2015-01-01

Uprighting springs, an integral part of the Begg ligsht wire differential force technique is gaining more and more popularity, as a useful adjunct in contemporary preadjusted edgewise appliance systems as well. It can be used with brackets containing vertical slots for mesiodistal crown uprighting, or as braking auxiliaries providing additional anchorage while protracting posteriors. Here, we present a simple and quick chair side method of fabricating and customizing uprighting springs according to the required crown/root movement for correction. This communication would serve as a ready reckoner during fabrication of the springs, thus dispelling the confusion that usually arises regarding direction and position of the coil and active arm. PMID:25657990

Geologic time: The age of the Earth

USGS Publications Warehouse

Newman, William L.

1977-01-01

The Earth is very old 4 1/2 billion years or more according to recent estimates. This vast span of time, called geologic time by earth scientists and believed by some to reach back to the birth of the Solar System, is difficult if not impossible to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and man's centuries-old search for the key led to the beginning and nourished the growth of geologic science.

The Balanced Books

ERIC Educational Resources Information Center

Cords, Sarah Statz; Elsen, Carol; Geck, Caroline; Heckman, Lucy; Maxted, Lawrence R.; Turner, Stephen E.

2007-01-01

The year's business reading identified new trends, reckoned with old challenges, offered counteropinions on hot topics, reinforced some old lessons, highlighted gains over losses, celebrated innovations that have potential for all, and observed the failures of these innovations to keep their promise. In short, it was a year of balancing…

Adaptive Fault-Tolerant Control of Uncertain Nonlinear Large-Scale Systems With Unknown Dead Zone.

PubMed

Chen, Mou; Tao, Gang

2016-08-01

In this paper, an adaptive neural fault-tolerant control scheme is proposed and analyzed for a class of uncertain nonlinear large-scale systems with unknown dead zone and external disturbances. To tackle the unknown nonlinear interaction functions in the large-scale system, the radial basis function neural network (RBFNN) is employed to approximate them. To further handle the unknown approximation errors and the effects of the unknown dead zone and external disturbances, integrated as the compounded disturbances, the corresponding disturbance observers are developed for their estimations. Based on the outputs of the RBFNN and the disturbance observer, the adaptive neural fault-tolerant control scheme is designed for uncertain nonlinear large-scale systems by using a decentralized backstepping technique. The closed-loop stability of the adaptive control system is rigorously proved via Lyapunov analysis and the satisfactory tracking performance is achieved under the integrated effects of unknown dead zone, actuator fault, and unknown external disturbances. Simulation results of a mass-spring-damper system are given to illustrate the effectiveness of the proposed adaptive neural fault-tolerant control scheme for uncertain nonlinear large-scale systems.

An estimate of the percentage of non-predatory dead variability in coastal zooplankton of the southern Humboldt Current System.

PubMed

Krautz, M C; Hernández-Miranda, E; Veas, R; Bocaz, P; Riquelme, P; Quiñones, R A

2017-12-01

Non-predatory dead variability in zooplankton remains poorly quantified worldwide. Here, we make the first estimation of the percentage of dead organisms in coastal zooplankton communities in the Humboldt Current System (HCS) under in situ conditions. The study was conducted in four coastal sites of the southern HCS (between 36 and 37°S) over a period of one year. Percentages of dead organisms were based on the classification as live or dead of 158,220 holoplankton and 17,591 meroplankton individuals using neutral red staining technique. The percentage of dead organisms in total-zooplankton was between 4.3% in Coronel Bay (summer) and 76.9% in Llico (autumn). The percentage of dead total-holoplankton varied from 4.2% (Itata River Mouth; autumn) to 77.6% (Llico; autumn), while the percentage of dead total-meroplankton ranged from 1.5% to 56.8% in Coronel Bay and Coliumo Bay, respectively. The most abundant taxa analyzed were the copepods Acartia sp., Paracalanus sp., Calanoides sp., Cladocera, Polychaeta, and the eggs of anchoveta Engraulis ringens. Among these taxa, there was a high degree of interspecific variability in the estimation of the dead organisms. The Pearson correlation shows significant relationships between maximum temperature, and minimum salinity, with the percentage of dead individuals of Acartia sp. and Paracalanus sp. Environmental factors explaining those relationships were: the El Niño 2015-2016 event, and freshwater river runoff. The use of vital staining to estimate non-predatory death for total-zooplankton and selected sentinel species is a promising tool to establish baselines to evaluate natural perturbations (e.g. ENSO), and anthropogenic alterations in coastal pelagic ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Heartland Horticulture

ERIC Educational Resources Information Center

Poquette, Bonnie L.

2009-01-01

Midwestern gardeners are legendary for enduring and outwitting winter, with its heavy snowpack and recurring freezes and thaws. Most of them also reckon with a relatively short growing period. All of them find their horticultural plans complicated by hot, humid summers. In fact, the Midwest deals with four seasons dictating special considerations…

Estimating the Effective System Dead Time Parameter for Correlated Neutron Counting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Croft, Stephen; Cleveland, Steve; Favalli, Andrea

We present that neutron time correlation analysis is one of the main technical nuclear safeguards techniques used to verify declarations of, or to independently assay, special nuclear materials. Quantitative information is generally extracted from the neutron-event pulse train, collected from moderated assemblies of 3He proportional counters, in the form of correlated count rates that are derived from event-triggered coincidence gates. These count rates, most commonly referred to as singles, doubles and triples rates etc., when extracted using shift-register autocorrelation logic, are related to the reduced factorial moments of the time correlated clusters of neutrons emerging from the measurement items. Correctingmore » these various rates for dead time losses has received considerable attention recently. The dead time losses for the higher moments in particular, and especially for large mass (high rate and highly multiplying) items, can be significant. Consequently, even in thoughtfully designed systems, accurate dead time treatments are needed if biased mass determinations are to be avoided. In support of this effort, in this paper we discuss a new approach to experimentally estimate the effective system dead time of neutron coincidence counting systems. It involves counting a random neutron source (e.g. AmLi is a good approximation to a source without correlated emission) and relating the second and higher moments of the neutron number distribution recorded in random triggered interrogation coincidence gates to the effective value of dead time parameter. We develop the theoretical basis of the method and apply it to the Oak Ridge Large Volume Active Well Coincidence Counter using sealed AmLi radionuclide neutron sources and standard multiplicity shift register electronics. The method is simple to apply compared to the predominant present approach which involves using a set of 252Cf sources of wide emission rate, it gives excellent precision in a conveniently short time, and it yields consistent results as a function of the order of the moment used to extract the dead time parameter. In addition, this latter observation is reassuring in that it suggests the assumptions underpinning the theoretical analysis are fit for practical application purposes. However, we found that the effective dead time parameter obtained is not constant, as might be expected for a parameter that in the dead time model is characteristic of the detector system, but rather, varies systematically with gate width.« less

Estimating the Effective System Dead Time Parameter for Correlated Neutron Counting

DOE PAGES

Croft, Stephen; Cleveland, Steve; Favalli, Andrea; ...

2017-04-29

We present that neutron time correlation analysis is one of the main technical nuclear safeguards techniques used to verify declarations of, or to independently assay, special nuclear materials. Quantitative information is generally extracted from the neutron-event pulse train, collected from moderated assemblies of 3He proportional counters, in the form of correlated count rates that are derived from event-triggered coincidence gates. These count rates, most commonly referred to as singles, doubles and triples rates etc., when extracted using shift-register autocorrelation logic, are related to the reduced factorial moments of the time correlated clusters of neutrons emerging from the measurement items. Correctingmore » these various rates for dead time losses has received considerable attention recently. The dead time losses for the higher moments in particular, and especially for large mass (high rate and highly multiplying) items, can be significant. Consequently, even in thoughtfully designed systems, accurate dead time treatments are needed if biased mass determinations are to be avoided. In support of this effort, in this paper we discuss a new approach to experimentally estimate the effective system dead time of neutron coincidence counting systems. It involves counting a random neutron source (e.g. AmLi is a good approximation to a source without correlated emission) and relating the second and higher moments of the neutron number distribution recorded in random triggered interrogation coincidence gates to the effective value of dead time parameter. We develop the theoretical basis of the method and apply it to the Oak Ridge Large Volume Active Well Coincidence Counter using sealed AmLi radionuclide neutron sources and standard multiplicity shift register electronics. The method is simple to apply compared to the predominant present approach which involves using a set of 252Cf sources of wide emission rate, it gives excellent precision in a conveniently short time, and it yields consistent results as a function of the order of the moment used to extract the dead time parameter. In addition, this latter observation is reassuring in that it suggests the assumptions underpinning the theoretical analysis are fit for practical application purposes. However, we found that the effective dead time parameter obtained is not constant, as might be expected for a parameter that in the dead time model is characteristic of the detector system, but rather, varies systematically with gate width.« less

Estimating the effective system dead time parameter for correlated neutron counting

NASA Astrophysics Data System (ADS)

Croft, Stephen; Cleveland, Steve; Favalli, Andrea; McElroy, Robert D.; Simone, Angela T.

2017-11-01

Neutron time correlation analysis is one of the main technical nuclear safeguards techniques used to verify declarations of, or to independently assay, special nuclear materials. Quantitative information is generally extracted from the neutron-event pulse train, collected from moderated assemblies of 3He proportional counters, in the form of correlated count rates that are derived from event-triggered coincidence gates. These count rates, most commonly referred to as singles, doubles and triples rates etc., when extracted using shift-register autocorrelation logic, are related to the reduced factorial moments of the time correlated clusters of neutrons emerging from the measurement items. Correcting these various rates for dead time losses has received considerable attention recently. The dead time losses for the higher moments in particular, and especially for large mass (high rate and highly multiplying) items, can be significant. Consequently, even in thoughtfully designed systems, accurate dead time treatments are needed if biased mass determinations are to be avoided. In support of this effort, in this paper we discuss a new approach to experimentally estimate the effective system dead time of neutron coincidence counting systems. It involves counting a random neutron source (e.g. AmLi is a good approximation to a source without correlated emission) and relating the second and higher moments of the neutron number distribution recorded in random triggered interrogation coincidence gates to the effective value of dead time parameter. We develop the theoretical basis of the method and apply it to the Oak Ridge Large Volume Active Well Coincidence Counter using sealed AmLi radionuclide neutron sources and standard multiplicity shift register electronics. The method is simple to apply compared to the predominant present approach which involves using a set of 252Cf sources of wide emission rate, it gives excellent precision in a conveniently short time, and it yields consistent results as a function of the order of the moment used to extract the dead time parameter. This latter observation is reassuring in that it suggests the assumptions underpinning the theoretical analysis are fit for practical application purposes. However, we found that the effective dead time parameter obtained is not constant, as might be expected for a parameter that in the dead time model is characteristic of the detector system, but rather, varies systematically with gate width.

Analysis and Experimental Kinematics of a Skid-Steering Wheeled Robot Based on a Laser Scanner Sensor

PubMed Central

Wang, Tianmiao; Wu, Yao; Liang, Jianhong; Han, Chenhao; Chen, Jiao; Zhao, Qiteng

2015-01-01

Skid-steering mobile robots are widely used because of their simple mechanism and robustness. However, due to the complex wheel-ground interactions and the kinematic constraints, it is a challenge to understand the kinematics and dynamics of such a robotic platform. In this paper, we develop an analysis and experimental kinematic scheme for a skid-steering wheeled vehicle based-on a laser scanner sensor. The kinematics model is established based on the boundedness of the instantaneous centers of rotation (ICR) of treads on the 2D motion plane. The kinematic parameters (the ICR coefficient χ, the path curvature variable λ and robot speed v), including the effect of vehicle dynamics, are introduced to describe the kinematics model. Then, an exact but costly dynamic model is used and the simulation of this model’s stationary response for the vehicle shows a qualitative relationship for the specified parameters χ and λ. Moreover, the parameters of the kinematic model are determined based-on a laser scanner localization experimental analysis method with a skid-steering robotic platform, Pioneer P3-AT. The relationship between the ICR coefficient χ and two physical factors is studied, i.e., the radius of the path curvature λ and the robot speed v. An empirical function-based relationship between the ICR coefficient of the robot and the path parameters is derived. To validate the obtained results, it is empirically demonstrated that the proposed kinematics model significantly improves the dead-reckoning performance of this skid–steering robot. PMID:25919370

Image-Based Localization Aided Indoor Pedestrian Trajectory Estimation Using Smartphones

PubMed Central

Zhou, Yan; Zheng, Xianwei; Chen, Ruizhi; Xiong, Hanjiang; Guo, Sheng

2018-01-01

Accurately determining pedestrian location in indoor environments using consumer smartphones is a significant step in the development of ubiquitous localization services. Many different map-matching methods have been combined with pedestrian dead reckoning (PDR) to achieve low-cost and bias-free pedestrian tracking. However, this works only in areas with dense map constraints and the error accumulates in open areas. In order to achieve reliable localization without map constraints, an improved image-based localization aided pedestrian trajectory estimation method is proposed in this paper. The image-based localization recovers the pose of the camera from the 2D-3D correspondences between the 2D image positions and the 3D points of the scene model, previously reconstructed by a structure-from-motion (SfM) pipeline. This enables us to determine the initial location and eliminate the accumulative error of PDR when an image is successfully registered. However, the image is not always registered since the traditional 2D-to-3D matching rejects more and more correct matches when the scene becomes large. We thus adopt a robust image registration strategy that recovers initially unregistered images by integrating 3D-to-2D search. In the process, the visibility and co-visibility information is adopted to improve the efficiency when searching for the correspondences from both sides. The performance of the proposed method was evaluated through several experiments and the results demonstrate that it can offer highly acceptable pedestrian localization results in long-term tracking, with an error of only 0.56 m, without the need for dedicated infrastructures. PMID:29342123

CHLORINE DECAY AND BIOFILM STUDIES IN A PILOT SCALE DRINKING WATER DISTRIBUTION DEAD END PIPE SYSTEM

EPA Science Inventory

Chlorine decay experiments using a pilot-scale water distribution dead end pipe system were conducted to define relationships between chlorine decay and environmental factors. These included flow rate, biomass concentration and biofilm density, and initial chlorine concentrations...

Unified dead-time compensation structure for SISO processes with multiple dead times.

PubMed

Normey-Rico, Julio E; Flesch, Rodolfo C C; Santos, Tito L M

2014-11-01

This paper proposes a dead-time compensation structure for processes with multiple dead times. The controller is based on the filtered Smith predictor (FSP) dead-time compensator structure and it is able to control stable, integrating, and unstable processes with multiple input/output dead times. An equivalent model of the process is first computed in order to define the predictor structure. Using this equivalent model, the primary controller and the predictor filter are tuned to obtain an internally stable closed-loop system which also attempts some closed-loop specifications in terms of set-point tracking, disturbance rejection, and robustness. Some simulation case studies are used to illustrate the good properties of the proposed approach. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Challenges for Policy and Standards for Adult and Higher Education

ERIC Educational Resources Information Center

Wheelan, Belle S.

2016-01-01

This chapter addresses educational policy as a force that contemporary adult education would be required to reckon with from the point of view of an accreditor. It identifies the issues and projects shifts that are currently taking place in higher education policy at the national, state, and regional levels.

Emerging Scholars

ERIC Educational Resources Information Center

Anyaso, Hilary Hurd; Rolo, Mark Anthony; Roach, Ronald; Delos, Robin Chen; Branch-Brioso, Karen; Miranda, Maria Eugenia; Seymour, Add, Jr.; Grossman, Wendy; Nealy, Michelle J.; Lum, Lydia

2009-01-01

This year's group of "emerging scholars" is a force to be reckoned with. This diverse group of young (under-40) crusaders is pushing the boundaries of research, technology and public policy in ways never imagined and reaching new heights of accomplishments. The Class of 2009 includes a physiologist who devised an artificial pancreas to produce the…

Marketing Needed to Make Universities Globally Competitive

ERIC Educational Resources Information Center

Naik, B. M.

2016-01-01

The article aims at improving the quality of higher and technical education in India to world class standard. Institutions in knowledge economy are reckoned to be the drivers of development. Indian institutions are making efforts, investing money, appointing professors, students are studying hard but due to the lack of marketing strategy, their…

Days of Reckoning--Days of Opportunity: The 1981 Statesmen's Roundtable.

ERIC Educational Resources Information Center

Gallagher, James J.

Presented are the formal presentation and edited comments from the 1981 Statesmen's Roundtable focusing on professional accountability in special education. The author's presentation addresses some of the assumptions made about special education, and the role of The Council for Exceptional Children regarding evaluation and accountability. Among…

A Reckoning

ERIC Educational Resources Information Center

Novak, Michael

2002-01-01

In this article, the author states that because people are willing to kill us just for being Americans, we ought at least to know what being American is. Yet many of our students have been taught painfully little about our nation's history, purposes, or achievements. In America's original founding narrative, faith and reason work together. Both…

Effect of Detector Dead Time on the Performance of Optical Direct-Detection Communication Links

NASA Technical Reports Server (NTRS)

Chen, C.-C.

1988-01-01

Avalanche photodiodes (APDs) operating in the Geiger mode can provide a significantly improved single-photon detect ion sensitivity over conventional photodiodes. However, the quenching circuit required to remove the excess charge carriers after each photon event can introduce an undesirable dead time into the detection process. The effect of this detector dead time on the performance of a binary pulse-position-modulted (PPM) channel is studied by analyzing the error probability. It is shown that, when back- ground noise is negligible, the performance of the detector with dead time is similar to that o f a quantum-limited receiver. For systems with increasing background intensities, the error rate of the receiver starts to degrade rapidly with increasing dead time. The power penalty due to detector dead time is also evaluated and shown to depend critically on background intensity as well as dead time. Given the expected background strength in an optical channel, therefore, a constraint must be placed on the bandwidth of the receiver to limit the amount of power penalty due to detector dead time.

Effect of detector dead time on the performance of optical direct-detection communication links

NASA Astrophysics Data System (ADS)

Chen, C.-C.

1988-05-01

Avalanche photodiodes (APDs) operating in the Geiger mode can provide a significantly improved single-photon detection sensitivity over conventional photodiodes. However, the quenching circuit required to remove the excess charge carriers after each photon event can introduce an undesirable dead time into the detection process. The effect of this detector dead time on the performance of a binary pulse-position-modulated (PPM) channel is studied by analyzing the error probability. It is shown that, when background noise is negligible, the performance of the detector with dead time is similar to that of a quantum-limited receiver. For systems with increasing background intensities, the error rate of the receiver starts to degrade rapidly with increasing dead time. The power penalty due to detector dead time is also evaluated and shown to depend critically on badkground intensity as well as dead time. Given the expected background strength in an optical channel, therefore, a constraint must be placed on the bandwidth of the receiver to limit the amount of power penalty due to detector dead time.

Complex Adaptive Systems of Systems (CASoS) engineering and foundations for global design.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brodsky, Nancy S.; Finley, Patrick D.; Beyeler, Walter Eugene

2012-01-01

Complex Adaptive Systems of Systems, or CASoS, are vastly complex ecological, sociological, economic and/or technical systems which must be recognized and reckoned with to design a secure future for the nation and the world. Design within CASoS requires the fostering of a new discipline, CASoS Engineering, and the building of capability to support it. Towards this primary objective, we created the Phoenix Pilot as a crucible from which systemization of the new discipline could emerge. Using a wide range of applications, Phoenix has begun building both theoretical foundations and capability for: the integration of Applications to continuously build common understandingmore » and capability; a Framework for defining problems, designing and testing solutions, and actualizing these solutions within the CASoS of interest; and an engineering Environment required for 'the doing' of CASoS Engineering. In a secondary objective, we applied CASoS Engineering principles to begin to build a foundation for design in context of Global CASoS« less

Comprehensive Measurements of Wind Systems at the Dead Sea

NASA Astrophysics Data System (ADS)

Metzger, Jutta; Corsmeier, Ulrich; Kalthoff, Norbert; Wieser, Andreas; Alpert, Pinhas; Lati, Joseph

2016-04-01

The Dead Sea is a unique place on earth. It is located at the lowest point of the Jordan Rift valley and its water level is currently at -429 m above mean sea level (amsl). To the West the Judean Mountains (up to 1000 m amsl) and to the East the Moab mountains (up to 1300 m amsl) confine the north-south oriented valley. The whole region is located in a transition zone of semi-arid to arid climate conditions and together with the steep orography, this forms a quite complex and unique environment. The Virtual Institute DEad SEa Research Venue (DESERVE) is an international project funded by the German Helmholtz Association and was established to study coupled atmospheric, hydrological, and lithospheric processes in the changing environment of the Dead Sea. Previous studies showed that the valley's atmosphere is often governed by periodic wind systems (Bitan, 1974), but most of the studies were limited to ground measurements and could therefore not resolve the three dimensional development and evolution of these wind systems. Performed airborne measurements found three distinct layers above the Dead Sea (Levin, 2005). Two layers are directly affected by the Dead Sea and the third is the commonly observed marine boundary layer over Israel. In the framework of DESERVE a field campaign with the mobile observatory KITcube was conducted to study the three dimensional structure of atmospheric processes at the Dead Sea in 2014. The combination of several in-situ and remote sensing instruments allows temporally and spatially high-resolution measurements in an atmospheric volume of about 10x10x10 km3. With this data set, the development and evolution of typical local wind systems, as well as the impact of regional scale wind conditions on the valley's atmosphere could be analyzed. The frequent development of a nocturnal drainage flow with wind velocities of over 10 m s-1, the typical lake breeze during the day, its onset and vertical extension as well as strong downslope winds in the afternoon, which are often intensified by regional scale wind systems like the Mediterranean Sea Breeze and the coupling of the synoptic flow, will be presented. Bitan, A. (1974). The wind regime in the north-west section of the Dead-Sea. Archiv für Meteorologie, Geophysik und Bioklimatologie, Serie B, 22(4), 313-335. Levin, Z., Gershon, H., & Ganor, E. (2005). Vertical distribution of physical and chemical properties of haze particles in the Dead Sea valley. Atmospheric Environment, 39(27), 4937-4945.

Adaptive Fuzzy Control for Nonstrict Feedback Systems With Unmodeled Dynamics and Fuzzy Dead Zone via Output Feedback.

PubMed

Wang, Lijie; Li, Hongyi; Zhou, Qi; Lu, Renquan

2017-09-01

This paper investigates the problem of observer-based adaptive fuzzy control for a category of nonstrict feedback systems subject to both unmodeled dynamics and fuzzy dead zone. Through constructing a fuzzy state observer and introducing a center of gravity method, unmeasurable states are estimated and the fuzzy dead zone is defuzzified, respectively. By employing fuzzy logic systems to identify the unknown functions. And combining small-gain approach with adaptive backstepping control technique, a novel adaptive fuzzy output feedback control strategy is developed, which ensures that all signals involved are semi-globally uniformly bounded. Simulation results are given to demonstrate the effectiveness of the presented method.

Narratives on Longing, Being, and Knowing: Envisioning a Writing Epistemology

ERIC Educational Resources Information Center

Chawla, Devika; Rodriguez, Amardo

2008-01-01

In this paper, I problematize the inextricable relationship between how I constitute knowledge and how I articulate knowledge. Through various narrative reflections I explore my own reckoning with dominant ways of articulating knowledge that reinforce ways of constituting knowledge that are inherently strange to me. I also outline my sojourns and…

The Profit Prophets in Higher Education

ERIC Educational Resources Information Center

Halfond, Jay A.

2010-01-01

The nation seems to have suddenly awoken to the reality that for-profit academic institutions are a force to be reckoned with. For so long, they have been ignored as inconsequential, second-rate competition, and vilified for their greed and lack of quality. Two events have changed their image into something far more formidable: (1) the realization…

Cryptic speciation in the Acari: a function of species lifestyles or our ability to separate species?

USDA-ARS?s Scientific Manuscript database

There are approximately 55,000 described Acari species, accounting for almost half of all known Arachnida species, but total estimated Acari diversity is reckoned to be far greater. One important source of currently hidden Acari diversity is cryptic speciation, which poses challenges to taxonomists ...

Research of improved banker algorithm

NASA Astrophysics Data System (ADS)

Yuan, Xingde; Xu, Hong; Qiao, Shijiao

2013-03-01

In the multi-process operating system, resource management strategy of system is a critical global issue, especially when many processes implicating for the limited resources, since unreasonable scheduling will cause dead lock. The most classical solution for dead lock question is the banker algorithm; however, it has its own deficiency and only can avoid dead lock occurring in a certain extent. This article aims at reducing unnecessary safety checking, and then uses the new allocation strategy to improve the banker algorithm. Through full analysis and example verification of the new allocation strategy, the results show the improved banker algorithm obtains substantial increase in performance.

The organ transplantation act and recent trends in Korea.

PubMed

Joo, Ho No

2013-03-01

The Organ Transplantation Act, including transplantation of organs from brain-dead donors, entered into force in Korea on February 9, 2000. This article introduces the Organ Transplantation Act, focusing on scope of the Act, determination of brain death, removal of organs from brain-dead or deceased donors, removal from living donors, organ allocation, and prohibition of trade in human organs. Especially, some primary ethical dilemmas surrounding organ allocation arise from the shortage of available organs. The primary ethical problems surrounding organ allocation are as follows. A key purpose of the organ donation incentive system is to increase the number of organ transplants from brain-dead donors. In particular, the priority for kidney patient was allowed in consideration of doctor's strong desire to increase the brain-dead donors. Also, the organ allocation criteria based on the organ donation incentive system appear unfair, especially for the kidney patient, because the criteria do not fit the principles of distributive justice. In the future, the organ donation incentive system itself may need to be reexamined.

Microfluidics microFACS for Life Detection

NASA Technical Reports Server (NTRS)

Platt, Donald W.; Hoover, Richard B.

2010-01-01

A prototype micro-scale Fluorescent Activated Cell Sorter (microFACS) for life detection has been built and is undergoing testing. A functional miniature microfluidics instrument with the ability to remotely distinguish live or dead bacterial cells from abiotic particulates in ice or permafrost of icy bodies of the solar system would be of fundamental value to NASA. The use of molecular probes to obtain the bio-signature of living or dead cells could answer the most fundamental question of Astrobiology: Does life exist beyond Earth? The live-dead fluorescent stains to be used in the microFACS instrument function only with biological cell walls. The detection of the cell membranes of living or dead bacteria (unlike PAH's and many other Biomarkers) would provide convincing evidence of present or past life. This miniature device rapidly examine large numbers of particulates from a polar ice or permafrost sample and distinguish living from dead bacteria cells and biological cells from mineral grains and abiotic particulates and sort the cells and particulates based on a staining system. Any sample found to exhibit fluorescence consistent with living cells could then be used in conjunction with a chiral labeled release experiment or video microscopy system to seek addition evidence for cellular metabolism or motility. Results of preliminary testing and calibration of the microFACS prototype instrument system with pure cultures and enrichment assemblages of microbial extremophiles will be reported.

YALINA-booster subcritical assembly pulsed-neutron e xperiments: detector dead time and apatial corrections.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Y.; Gohar, Y.; Nuclear Engineering Division

In almost every detector counting system, a minimal dead time is required to record two successive events as two separated pulses. Due to the random nature of neutron interactions in the subcritical assembly, there is always some probability that a true neutron event will not be recorded because it occurs too close to the preceding event. These losses may become rather severe for counting systems with high counting rates, and should be corrected before any utilization of the experimental data. This report examines the dead time effects for the pulsed neutron experiments of the YALINA-Booster subcritical assembly. The nonparalyzable modelmore » is utilized to correct the experimental data due to dead time. Overall, the reactivity values are increased by 0.19$ and 0.32$ after the spatial corrections for the YALINA-Booster 36% and 21% configurations respectively. The differences of the reactivities obtained with He-3 long or short detectors at the same detector channel diminish after the dead time corrections of the experimental data for the 36% YALINA-Booster configuration. In addition, better agreements between reactivities obtained from different experimental data sets are also observed after the dead time corrections for the 21% YALINA-Booster configuration.« less

Dead time corrections for inbeam γ-spectroscopy measurements

NASA Astrophysics Data System (ADS)

Boromiza, M.; Borcea, C.; Negret, A.; Olacel, A.; Suliman, G.

2017-08-01

Relatively high counting rates were registered in a proton inelastic scattering experiment on 16O and 28Si using HPGe detectors which was performed at the Tandem facility of IFIN-HH, Bucharest. In consequence, dead time corrections were needed in order to determine the absolute γ-production cross sections. Considering that the real counting rate follows a Poisson distribution, the dead time correction procedure is reformulated in statistical terms. The arriving time interval between the incoming events (Δt) obeys an exponential distribution with a single parameter - the average of the associated Poisson distribution. We use this mathematical connection to calculate and implement the dead time corrections for the counting rates of the mentioned experiment. Also, exploiting an idea introduced by Pommé et al., we describe a consistent method for calculating the dead time correction which completely eludes the complicated problem of measuring the dead time of a given detection system. Several comparisons are made between the corrections implemented through this method and by using standard (phenomenological) dead time models and we show how these results were used for correcting our experimental cross sections.

Measuring Cycling Effort.

ERIC Educational Resources Information Center

Jahnke, Thomas; Hamson, Mike

1999-01-01

Investigates the basic mechanics of cycling with a simple reckoning of how much effort is needed from the cyclist. The work done by the cyclist is quantified when the ride is on the flat and also when pedaling uphill. Proves that by making use of the available gears on a mountain bike, cycling uphill can be accomplished without pain. (Author/ASK)

Debt Bomb Is Ticking Loudly on Campuses

ERIC Educational Resources Information Center

Blumenstyk, Goldie

2009-01-01

The end of the fiscal year usually isn't a momentous occasion for colleges. But this June 30 could be a day of reckoning many never expected. Colleges borrowed billions of dollars over the past decade to improve facilities and fulfill their ambitions. Now the consequences may be about to blow up in their finances. The author reports on how…

Teaching as Intervention: Saving the English Curriculum in a Time of Reckoning.

ERIC Educational Resources Information Center

Favat, F. Andre

Although English teachers have been blamed for the decreasing verbal ability of the nation's children, recent declines may be more accurately attributed to the general instructional climate of the day. The post-Sputnik era viewed education as a function of active intervention, where the teacher assumed a dominant role in shaping the students'…

A Force to Be Reckoned with

ERIC Educational Resources Information Center

Stanistreet, Paul

2011-01-01

In the second article in a series marking 90 years of NIACE support for adult learning, the author charts the changing shape of adult education in the decades following the Second World War, and the Institute's emergence as a "major non-governmental force" in the development of adult education. In 1983 the NIAE changed its name to the…

Countering Coloniality in Educational Research: From Ownership to Answerability

ERIC Educational Resources Information Center

Patel, Lisa

2014-01-01

In this theoretical article, I argue for a relational stance on learning as a way of reckoning with educational research as part of the settler colonial structure of the United States. Because of my geopolitical location to the United States as a settler colony, I begin by contrasting the stances of anticolonial and decolonial. I then analyze the…

Application of the Nelson model to four timelag fuel classes using Oklahoma field observations: Model evaluation and comparison with national Fire Danger Rating System algorithms

Treesearch

J. D. Carlson; Larry S. Bradshaw; Ralph M. Nelson; Randall R Bensch; Rafal Jabrzemski

2007-01-01

The application of a next-generation dead-fuel moisture model, the 'Nelson model', to four timelag fuel classes using an extensive 21-month dataset of dead-fuel moisture observations is described. Developed by Ralph Nelson in the 1990s, the Nelson model is a dead-fuel moisture model designed to take advantage of frequent automated weather observations....

Use of MEMs and optical sensors for closed loop heliostat control

NASA Astrophysics Data System (ADS)

Harper, Paul Julian; Dreijer, Janto; Malan, Karel; Larmuth, James; Gauche, Paul

2016-05-01

The Helio 100 project at STERG (Stellenbosch Solar Thermal Research Group) aims to help reduce the cost of Concentrated Solar Thermal plants by deploying large numbers of small (1x2 m) low cost heliostats. One of the methods employed to reduce the cost of the heliostat field is to have a field that requires no site preparation (grading, leveling, vegetation clearance) and no expensive foundations or concrete pouring for each individual heliostat base. This implies that the heliostat pod frames and vertical mounts might be slightly out of vertical, and the normal method of dead reckoning using accurately surveyed and aligned heliostat bases cannot be used. This paper describes a combination of MEMs and optical sensors on the back of the heliostat, that together with a simple machine learning approach, give accurate and reproducible azimuth and elevation information for the heliostat plane. Initial experiments were done with an android phone mounted on the back of a heliostat as it was a readily available platform combining accelerometers' and camera into one programmable package. It was found quite easy to determine the pointing angle of the heliostat to within 1 milliradian using the rear facing camera and correlating known heliostat angles with target image features on the ground. We also tested the accuracy at various image resolutions by halving the image size successively till the feature detection failed. This showed that even a VGA (640x480) resolution image could give mean errors of 1.5 milliradian. The optical technique is exceedingly simple and does not use any camera calibration, angular reconstruction or knowledge of heliostat drive geometry. We also tested the ability of the 3d accelerometers to determine angle, but this was coarser than the camera and only accurate to around 10 milliradians.

Evaluating Alerting and Guidance Performance of a UAS Detect-And-Avoid System

NASA Technical Reports Server (NTRS)

Lee, Seung Man; Park, Chunki; Thipphavong, David P.; Isaacson, Douglas R.; Santiago, Confesor

2016-01-01

A key challenge to the routine, safe operation of unmanned aircraft systems (UAS) is the development of detect-and-avoid (DAA) systems to aid the UAS pilot in remaining "well clear" of nearby aircraft. The goal of this study is to investigate the effect of alerting criteria and pilot response delay on the safety and performance of UAS DAA systems in the context of routine civil UAS operations in the National Airspace System (NAS). A NAS-wide fast-time simulation study was conducted to assess UAS DAA system performance with a large number of encounters and a broad set of DAA alerting and guidance system parameters. Three attributes of the DAA system were controlled as independent variables in the study to conduct trade-off analyses: UAS trajectory prediction method (dead-reckoning vs. intent-based), alerting time threshold (related to predicted time to LoWC), and alerting distance threshold (related to predicted Horizontal Miss Distance, or HMD). A set of metrics, such as the percentage of true positive, false positive, and missed alerts, based on signal detection theory and analysis methods utilizing the Receiver Operating Characteristic (ROC) curves were proposed to evaluate the safety and performance of DAA alerting and guidance systems and aid development of DAA system performance standards. The effect of pilot response delay on the performance of DAA systems was evaluated using a DAA alerting and guidance model and a pilot model developed to support this study. A total of 18 fast-time simulations were conducted with nine different DAA alerting threshold settings and two different trajectory prediction methods, using recorded radar traffic from current Visual Flight Rules (VFR) operations, and supplemented with DAA-equipped UAS traffic based on mission profiles modeling future UAS operations. Results indicate DAA alerting distance threshold has a greater effect on DAA system performance than DAA alerting time threshold or ownship trajectory prediction method. Further analysis on the alert lead time (time in advance of predicted loss of well clear at which a DAA alert is first issued) indicated a strong positive correlation between alert lead time and DAA system performance (i.e. the ability of the UAS pilot to maneuver the unmanned aircraft to remain well clear). While bigger distance thresholds had beneficial effects on alert lead time and missed alert rate, it also generated a higher rate of false alerts. In the design and development of DAA alerting and guidance systems, therefore, the positive and negative effects of false alerts and missed alerts should be carefully considered to achieve acceptable alerting system performance by balancing false and missed alerts. The results and methodology presented in this study are expected to help stakeholders, policymakers and standards committees define the appropriate setting of DAA system parameter thresholds for UAS that ensure safety while minimizing operational impacts to the NAS and equipage requirements for its users before DAA operational performance standards can be finalized.

SU-E-T-458: Determining Threshold-Of-Failure for Dead Pixel Rows in EPID-Based Dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gersh, J; Wiant, D

Purpose: A pixel correction map is applied to all EPID-based applications on the TrueBeam (Varian Medical Systems, Palo Alto, CA). When dead pixels are detected, an interpolative smoothing algorithm is applied using neighboring-pixel information to supplement missing-pixel information. The vendor suggests that when the number of dead pixels exceeds 70,000, the panel should be replaced. It is common for entire detector rows to be dead, as well as their neighboring rows. Approximately 70 rows can be dead before the panel reaches this threshold. This study determines the number of neighboring dead-pixel rows that would create a large enough deviation inmore » measured fluence to cause failures in portal dosimetry (PD). Methods: Four clinical two-arc VMAT plans were generated using Eclipse's AXB algorithm and PD plans were created using the PDIP algorithm. These plans were chosen to represent those commonly encountered in the clinic: prostate, lung, abdomen, and neck treatments. During each iteration of this study, an increasing number of dead-pixel rows are artificially applied to the correction map and a fluence QA is performed using the EPID (corrected with this map). To provide a worst-case-scenario, the dead-pixel rows are chosen so that they present artifacts in the highfluence region of the field. Results: For all eight arc-fields deemed acceptable via a 3%/3mm gamma analysis (pass rate greater than 99%), VMAT QA yielded identical results with a 5 pixel-width dead zone. When 10 dead lines were present, half of the fields had pass rates below the 99% pass rate. With increasing dead rows, the pass rates were reduced substantially. Conclusion: While the vendor still suggests to request service at the point where 70,000 dead rows are measured (as recommended by the vendor), the authors suggest that service should be requested when there are greater than 5 consecutive dead rows.« less

Robust model reference adaptive output feedback tracking for uncertain linear systems with actuator fault based on reinforced dead-zone modification.

PubMed

Bagherpoor, H M; Salmasi, Farzad R

2015-07-01

In this paper, robust model reference adaptive tracking controllers are considered for Single-Input Single-Output (SISO) and Multi-Input Multi-Output (MIMO) linear systems containing modeling uncertainties, unknown additive disturbances and actuator fault. Two new lemmas are proposed for both SISO and MIMO, under which dead-zone modification rule is improved such that the tracking error for any reference signal tends to zero in such systems. In the conventional approach, adaption of the controller parameters is ceased inside the dead-zone region which results tracking error, while preserving the system stability. In the proposed scheme, control signal is reinforced with an additive term based on tracking error inside the dead-zone which results in full reference tracking. In addition, no Fault Detection and Diagnosis (FDD) unit is needed in the proposed approach. Closed loop system stability and zero tracking error are proved by considering a suitable Lyapunov functions candidate. It is shown that the proposed control approach can assure that all the signals of the close loop system are bounded in faulty conditions. Finally, validity and performance of the new schemes have been illustrated through numerical simulations of SISO and MIMO systems in the presence of actuator faults, modeling uncertainty and output disturbance. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Stratigraphy, climate and downhole logging data - an example from the ICDP Dead Sea deep drilling project

NASA Astrophysics Data System (ADS)

Coianiz, Lisa; Ben-Avraham, Zvi; Lazar, Michael

2017-04-01

During the late Quaternary a series of lakes occupied the Dead Sea tectonic basin. The sediments that accumulated within these lakes preserved the environmental history (tectonic and climatic) of the basin and its vicinity. Most of the information on these lakes was deduced from exposures along the marginal terraces of the modern Dead Sea, e.g. the exposures of the last glacial Lake Lisan and Holocene Dead Sea. The International Continental Drilling Program (ICDP) project conducted in the Dead Sea during 2010-2011 recovered several cores that were drilled in the deep depocenter of the lake (water depth of 300 m) and at the margin (depth of 3 m offshore Ein Gedi spa). New high resolution logging data combined with a detailed lithological description and published age models for the deep 5017-1-A borehole were used to establish a sequence stratigraphic framework for the Lakes Amora, Samra, Lisan and Zeelim strata. This study presents a stratigraphic timescale for reconstructing the last ca 225 ka. It provides a context within which the timing of key sequence surfaces identified in the distal part of the basin can be mapped on a regional and stratigraphic time frame. In addition, it permitted the examination of depositional system tracts and related driving mechanisms controlling their formation. The sequence stratigraphic model developed for the Northern Dead Sea Basin is based on the identification of sequence bounding surfaces including: sequence boundary (SB), transgressive surface (TS) and maximum flooding surface (MFS). They enabled the division of depositional sequences into a Lowstand systems tracts (LST), Transgressive systems tracts (TST) and Highstand systems tracts (HST), which can be interpreted in terms of relative lake level changes. The analysis presented here show that system tract stacking patterns defined for the distal 5017-1-A borehole can be correlated to the proximal part of the basin, and widely support the claim that changes in relative lake levels were synchronous across the northern Dead Sea, although differences do exist. These discrepancies can possibly be explained in part by the tectonic nature of the basin. Within the 5017-1-A section, the interpreted changes in depositional environments derived primarily from the gamma ray log patterns show a good correlation in time with sequence-chronostratigraphic framework, extracted lake level curves and paleohydrological records of other areas worldwide. Sequence stratigraphic analysis presented here allows for a detailed, high resolution examination of the sedimentary sequences in the Northern Dead Sea Basin together with an independent proxy that is an indirect indicator of changes in relative lake level.

Simulation of the Aerosol-Atmosphere Interaction in the Dead Sea Area with COSMO-ART

NASA Astrophysics Data System (ADS)

Vogel, Bernhard; Bangert, Max; Kottmeier, Christoph; Rieger, Daniel; Schad, Tobias; Vogel, Heike

2014-05-01

The Dead Sea is a unique environment located in the Dead Sea Rift Valley. The fault system of the Dead Sea Rift Valley marks the political borders between Israel, Jordan, and Palestine. The Dead Sea region and the ambient Eastern Mediterranean coastal zone provide a natural laboratory for studying atmospheric processes ranging from the smallest scale of cloud processes to regional weather and climate. The virtual institute DESERVE is designed as a cross-disciplinary and cooperative international project of the Helmholtz Centers KIT, GFZ, and UFZ with well-established partners in Israel, Jordan and Palestine. One main focus of one of the work packages is the role of aerosols in modifying clouds and precipitation and in developing the Dead Sea haze layer as one of the most intriguing questions. The haze influences visibility, solar radiation, and evaporation and may even affect economy and health. We applied the online coupled model system COSMO-ART, which is able to treat the feedback processes between aerosol, radiation, and cloud formation, for a case study above the Dead Sea and adjacent regions. Natural aerosol like mineral dust and sea salt as well as anthropogenic primary and secondary aerosol is taken into account. Some of the observed features like the vertical double structure of the haze layer are already covered by the simulation. We found that absorbing aerosol like mineral dust causes a temperature increase in parts of the model domain. In other areas a decrease in temperature due to cirrus clouds modified by elevated dust layers is simulated.

PID tuning rules for SOPDT systems: review and some new results.

PubMed

Panda, Rames C; Yu, Cheng-Ching; Huang, Hsiao-Ping

2004-04-01

PID controllers are widely used in industries and so many tuning rules have been proposed over the past 50 years that users are often lost in the jungle of tuning formulas. Moreover, unlike PI control, different control laws and structures of implementation further complicate the use of the PID controller. In this work, five different tuning rules are taken for study to control second-order plus dead time systems with wide ranges of damping coefficients and dead time to time constant ratios (D/tau). Four of them are based on IMC design with different types of approximations on dead time and the other on desired closed-loop specifications (i.e., specified forward transfer function). The method of handling dead time in the IMC type of design is important especially for systems with large D/tau ratios. A systematic approach was followed to evaluate the performance of controllers. The regions of applicability of suitable tuning rules are highlighted and recommendations are also given. It turns out that IMC designed with the Maclaurin series expansion type PID is a better choice for both set point and load changes for systems with D/tau greater than 1. For systems with D/tau less than 1, the desired closed-loop specification approach is favored.

Robust adaptive precision motion control of hydraulic actuators with valve dead-zone compensation.

PubMed

Deng, Wenxiang; Yao, Jianyong; Ma, Dawei

2017-09-01

This paper addresses the high performance motion control of hydraulic actuators with parametric uncertainties, unmodeled disturbances and unknown valve dead-zone. By constructing a smooth dead-zone inverse, a robust adaptive controller is proposed via backstepping method, in which adaptive law is synthesized to deal with parametric uncertainties and a continuous nonlinear robust control law to suppress unmodeled disturbances. Since the unknown dead-zone parameters can be estimated by adaptive law and then the effect of dead-zone can be compensated effectively via inverse operation, improved tracking performance can be expected. In addition, the disturbance upper bounds can also be updated online by adaptive laws, which increases the controller operability in practice. The Lyapunov based stability analysis shows that excellent asymptotic output tracking with zero steady-state error can be achieved by the developed controller even in the presence of unmodeled disturbance and unknown valve dead-zone. Finally, the proposed control strategy is experimentally tested on a servovalve controlled hydraulic actuation system subjected to an artificial valve dead-zone. Comparative experimental results are obtained to illustrate the effectiveness of the proposed control scheme. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

A Sharper Focus on What Students Pay, and Whether They Graduate

ERIC Educational Resources Information Center

Lipka, Sara

2012-01-01

Efforts to keep higher education affordable for all students and to promote not only access, but success--all in a climate of dwindling state appropriations and lean budgets--made the past year one of reckoning for colleges. Total outstanding student-loan debt hit the $1-trillion mark as federal officials scrambled to ease the burden on borrowers,…

A Review of Major Obstacles to Women's Participation in Higher Education in Kenya

ERIC Educational Resources Information Center

Sifuna, Daniel N.

2006-01-01

The paper provides a comprehensive review of the major obstacles that hinder the participation of girls and women in higher education in Kenya. This is on the basis that their low participation in this level of education is a key constraint to the development of the country. While it is reckoned that girls' and women's education is inextricably…

On Progress of Mass Tertiary Education: Case of Lebanon, Kenya and Oman

ERIC Educational Resources Information Center

Liu, Zhimin; Mutinda, Gladys

2016-01-01

Mass higher education is a huge force to be reckoned with and its existence, already in the expansion of tertiary institutions is undeniable. This study will focus on three countries: Lebanon, Kenya and Oman. The purpose of this study is to evaluate mass tertiary education progress in these countries. It will synthesize data results of gross…

Global effects of the DEAD-box RNA helicase DeaD (CsdA) on gene expression over a broad range of temperatures

PubMed Central

Vakulskas, Christopher A.; Pannuri, Archana; Cortés-Selva, Diana; Zere, Tesfalem R.; Ahmer, Brian M.; Babitzke, Paul; Romeo, Tony

2014-01-01

Summary In Escherichia coli, activity of the global regulatory RNA binding protein CsrA is antagonized by two noncoding sRNAs, CsrB and CsrC, which sequester it away from its lower affinity mRNA targets. Transcription of csrB/C requires the BarA-UvrY two component signal transduction system, which responds to short chain carboxylates. We show that two DEAD-box RNA helicases, DeaD and SrmB, activate csrB/C expression by different pathways. DeaD facilitates uvrY translation by counteracting the inhibitory effect of long distance basepairing between the uvrY mRNA leader and coding region, while SrmB does not affect UvrY or UvrY-phosphate levels. Contrary to the prevailing notion that these helicases act primarily at low temperatures, DeaD and SrmB activated csrB expression over a wide temperature range. High-throughput sequencing of RNA isolated by crosslinking immunoprecipitation (HITS-CLIP) revealed in vivo interactions of DeaD with 39 mRNAs, including those of uvrY and 9 other regulatory genes. Studies on the expression of several of the identified genes revealed regulatory effects of DeaD in all cases and diverse temperature response patterns. Our findings uncover an expanded regulatory role for DeaD, which is mediated through novel mRNA targets, important global regulators and under physiological conditions that were considered to be incompatible with its function. PMID:24708042

Donation after circulatory death: burying the dead donor rule.

PubMed

Rodríguez-Arias, David; Smith, Maxwell J; Lazar, Neil M

2011-08-01

Despite continuing controversies regarding the vital status of both brain-dead donors and individuals who undergo donation after circulatory death (DCD), respecting the dead donor rule (DDR) remains the standard moral framework for organ procurement. The DDR increases organ supply without jeopardizing trust in transplantation systems, reassuring society that donors will not experience harm during organ procurement. While the assumption that individuals cannot be harmed once they are dead is reasonable in the case of brain-dead protocols, we argue that the DDR is not an acceptable strategy to protect donors from harm in DCD protocols. We propose a threefold alternative to justify organ procurement practices: (1) ensuring that donors are sufficiently protected from harm; (2) ensuring that they are respected through informed consent; and (3) ensuring that society is fully informed of the inherently debatable nature of any criterion to declare death.

EVAPORITE MICROBIAL FILMS, MATS, MICROBIALITES AND STROMATOLITES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brigmon, R; Penny Morris, P; Garriet Smith, G

2008-01-28

Evaporitic environments are found in a variety of depositional environments as early as the Archean. The depositional settings, microbial community and mineralogical composition vary significantly as no two settings are identical. The common thread linking all of the settings is that evaporation exceeds precipitation resulting in elevated concentrations of cations and anions that are higher than in oceanic systems. The Dead Sea and Storrs Lake are examples of two diverse modern evaporitic settings as the former is below sea level and the latter is a coastal lake on an island in the Caribbean. Each system varies in water chemistry asmore » the Dead Sea dissolved ions originate from surface weathered materials, springs, and aquifers while Storrs Lake dissolved ion concentration is primarily derived from sea water. Consequently some of the ions, i.e., Sr, Ba are found at significantly lower concentrations in Storrs Lake than in the Dead Sea. The origin of the dissolved ions are ultimately responsible for the pH of each system, alkaline versus mildly acidic. Each system exhibits unique biogeochemical properties as the extreme environments select certain microorganisms. Storrs Lake possesses significant biofilms and stromatolitic deposits and the alkalinity varies depending on rainfall and storm activity. The microbial community Storrs Lake is much more diverse and active than those observed in the Dead Sea. The Dead Sea waters are mildly acidic, lack stromatolites, and possess a lower density of microbial populations. The general absence of microbial and biofilm fossilization is due to the depletion of HCO{sub 3} and slightly acidic pH.« less

Changes in the organ procurement system in South Korea: effects on brain-dead donor numbers.

PubMed

Lee, S D; Kim, J H

2009-11-01

In Korea, the Organ Transplantation Act came into effect in 2000, establishing the Korean Network for Organ Sharing (KONOS) with centralized authority for organ procurement as well as for approval of donors and recipients to ensure fair organ allocation. However, the number of brain-dead donors decreased sharply, and the organ allocation system proved inefficient. The government revised the Organ Transplantation Act in August 2002, introducing an incentive system. If a transplantation hospital formed a Committee for Brain Death Evaluation and a Hospital Organ Procurement Organization, it could receive a kidney from a brain dead-donor as an incentive to foster organ procurement regardless of the KONOS wait list. The government also launched a pilot brain-dead donor registry program to strengthen Hospital Organ Procurement Organization activity. If local hospitals collaborated with specialized hospitals in organ procurement, local hospitals obtained financial incentives. But because the organ shortage problem has not been resolved, the government has proposed four initiatives: first, broadening the incentive system, which makes it possible to give each specialized hospital a choice of one of eight organs from each donor as an incentive; second, development of an Independent Organ Procurement Organization; third introduction of an opt-out system; and last, improvement of the Committee for Brain Death Evaluation system. It is uncertain which initiatives will be adopted, but changes in organ procurement systems are nonetheless considered a key to solve the organ shortage problem in Korea.

Two-degree-of-freedom fractional order-PID controllers design for fractional order processes with dead-time.

PubMed

Li, Mingjie; Zhou, Ping; Zhao, Zhicheng; Zhang, Jinggang

2016-03-01

Recently, fractional order (FO) processes with dead-time have attracted more and more attention of many researchers in control field, but FO-PID controllers design techniques available for the FO processes with dead-time suffer from lack of direct systematic approaches. In this paper, a simple design and parameters tuning approach of two-degree-of-freedom (2-DOF) FO-PID controller based on internal model control (IMC) is proposed for FO processes with dead-time, conventional one-degree-of-freedom control exhibited the shortcoming of coupling of robustness and dynamic response performance. 2-DOF control can overcome the above weakness which means it realizes decoupling of robustness and dynamic performance from each other. The adjustable parameter η2 of FO-PID controller is directly related to the robustness of closed-loop system, and the analytical expression is given between the maximum sensitivity specification Ms and parameters η2. In addition, according to the dynamic performance requirement of the practical system, the parameters η1 can also be selected easily. By approximating the dead-time term of the process model with the first-order Padé or Taylor series, the expressions for 2-DOF FO-PID controller parameters are derived for three classes of FO processes with dead-time. Moreover, compared with other methods, the proposed method is simple and easy to implement. Finally, the simulation results are given to illustrate the effectiveness of this method. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Sustainability and business: what is green corporate image?

NASA Astrophysics Data System (ADS)

Bathmanathan, Vathana; Hironaka, Chikako

2016-03-01

Green corporate image is reckon to be the driving factor in the current business setups. Stakeholder’s green perception of the firm encourages growth of businesses. Organisation is moving from conventional businesses to running businesses with sustainable agenda that creates values to their brand. This paper analyses several green corporate image initiatives and concepts by various researches and shares how this can be essential for business.

The Power of Technology to Transform Adult Learning: Expanding Access to Adult Education & Workforce Skills through Distance Learning

ERIC Educational Resources Information Center

McCain, Mary L.

2009-01-01

There is a highly compelling case for using technology on a large scale to increase access to and improve America's adult education and workforce skills enterprise. By the reckoning of the National Commission on Adult Literacy and others, the nation must reach many more millions of adults with effective college- and job-readiness skills programs…

Deal with It We Must: Education, Social Justice, and the Curriculum of Hip Hop Culture

ERIC Educational Resources Information Center

Baszile, Denise Taliaferro

2009-01-01

Although hip hop culture has been one of the most significant urban youth movements over the last three decades, it has only recently gained attention within the educational literature as a force to be reckoned with. And even then, much of the literature seeks to understand how hip hop can be used to engage students in the official school…

Don't Get Rode Hard and Put Away Wet

ERIC Educational Resources Information Center

Galloway, Robin

2012-01-01

Back in the old days, some folks reckoned an equine was just a disposable tool to get their jobs done. They might ride a horse hard, so it was sweaty, panting, and broken down. When done they would throw it out to pasture without proper grooming. This is probably the origin of the expression to "get rode hard and put away wet." As…

Concentrations of the UV filter ethylhexyl methoxycinnamate in the aquatic compartment: a comparison of modelled concentrations for Swiss surface waters with empirical monitoring data.

PubMed

Straub, Jürg Oliver

2002-05-10

UV filters in sunscreens and cosmetics protect the skin from damage through UV radiation. Many tonnes per year of UV filters are being used in Europe and will be present, at least seasonally, in detectable concentrations in surface waters similar to common pharmaceutically active substances. Predicted environmental concentrations (PECs) of ethylhexyl methoxycinnamate (EHMC; CAS 5466-77-3) were extrapolated for Switzerland, taking into consideration substance-specific environmental fate data and marketing estimates, by crude worst-case reckoning and by applying two environmental models (Mackay Level III; USES 3.0), both configured for Swiss hydrological and area data. By worst-case reckoning the summer PEC is 70.8-81.3 ng/l while for the remaining 8 months of the year the PEC is 13.1-15.1 ng/l. The Level III model results in concentrations of 2.4 ng/l during the summer and 0.44 ng/l during the rest of the year, while the USES 3.0 model gives an average PEC for the whole year of 7.6 ng/l. Pooling summer monitoring data (90 single analyses) from the River Rhine below Basel in the year 1997 (Water Protection Board of Basel) and from Lakes Zurich and Hüttner in 1998 (Poiger et al., in preparation) allowed a derivation of a probabilistic median concentration of 4.6 ng/l, a 95th-percentile concentration of 18.6 ng/l and a 99th-percentile concentration of 33.5 ng/l. The 6-fold range from the median value to the maximum calls for caution in interpreting published monitoring concentrations. Comparison of modelled PECs with realistic median concentrations shows that crude reckoning overestimates actual concentrations by a factor of about 10, probably through insufficient consideration of (further) degradation of EHMC in sewage works, surface waters, sediments or river banks. Both computer models, in contrast, are within the same order of magnitude as the actual summer concentrations. Based on the available data, both these environmental fate and distribution models give realistic PECs.

Distributed Adaptive Neural Network Output Tracking of Leader-Following High-Order Stochastic Nonlinear Multiagent Systems With Unknown Dead-Zone Input.

PubMed

Hua, Changchun; Zhang, Liuliu; Guan, Xinping

2017-01-01

This paper studies the problem of distributed output tracking consensus control for a class of high-order stochastic nonlinear multiagent systems with unknown nonlinear dead-zone under a directed graph topology. The adaptive neural networks are used to approximate the unknown nonlinear functions and a new inequality is used to deal with the completely unknown dead-zone input. Then, we design the controllers based on backstepping method and the dynamic surface control technique. It is strictly proved that the resulting closed-loop system is stable in probability in the sense of semiglobally uniform ultimate boundedness and the tracking errors between the leader and the followers approach to a small residual set based on Lyapunov stability theory. Finally, two simulation examples are presented to show the effectiveness and the advantages of the proposed techniques.

Adaptive neural network output feedback control for stochastic nonlinear systems with unknown dead-zone and unmodeled dynamics.

PubMed

Tong, Shaocheng; Wang, Tong; Li, Yongming; Zhang, Huaguang

2014-06-01

This paper discusses the problem of adaptive neural network output feedback control for a class of stochastic nonlinear strict-feedback systems. The concerned systems have certain characteristics, such as unknown nonlinear uncertainties, unknown dead-zones, unmodeled dynamics and without the direct measurements of state variables. In this paper, the neural networks (NNs) are employed to approximate the unknown nonlinear uncertainties, and then by representing the dead-zone as a time-varying system with a bounded disturbance. An NN state observer is designed to estimate the unmeasured states. Based on both backstepping design technique and a stochastic small-gain theorem, a robust adaptive NN output feedback control scheme is developed. It is proved that all the variables involved in the closed-loop system are input-state-practically stable in probability, and also have robustness to the unmodeled dynamics. Meanwhile, the observer errors and the output of the system can be regulated to a small neighborhood of the origin by selecting appropriate design parameters. Simulation examples are also provided to illustrate the effectiveness of the proposed approach.

Water input requirements of the rapidly shrinking Dead Sea

NASA Astrophysics Data System (ADS)

Abu Ghazleh, Shahrazad; Hartmann, Jens; Jansen, Nils; Kempe, Stephan

2009-05-01

The deepest point on Earth, the Dead Sea level, has been dropping alarmingly since 1978 by 0.7 m/a on average due to the accelerating water consumption in the Jordan catchment and stood in 2008 at 420 m below sea level. In this study, a terrain model of the surface area and water volume of the Dead Sea was developed from the Shuttle Radar Topography Mission data using ArcGIS. The model shows that the lake shrinks on average by 4 km2/a in area and by 0.47 km3/a in volume, amounting to a cumulative loss of 14 km3 in the last 30 years. The receding level leaves almost annually erosional terraces, recorded here for the first time by Differential Global Positioning System field surveys. The terrace altitudes were correlated among the different profiles and dated to specific years of the lake level regression, illustrating the tight correlation between the morphology of the terrace sequence and the receding lake level. Our volume-level model described here and previous work on groundwater inflow suggest that the projected Dead Sea-Red Sea channel or the Mediterranean-Dead Sea channel must have a carrying capacity of >0.9 km3/a in order to slowly re-fill the lake to its former level and to create a sustainable system of electricity generation and freshwater production by desalinization. Moreover, such a channel will maintain tourism and potash industry on both sides of the Dead Sea and reduce the natural hazard caused by the recession.

Near bottom temperature anomalies in the Dead Sea

NASA Astrophysics Data System (ADS)

Ben-Avraham, Zvi; Ballard, Robert D.

1984-12-01

A bottom photographic and temperature study was carried out in the Dead Sea using a miniature version of the unmanned camera system ANGUS (mini-ANGUS). Due to the low transparency of the Dead Sea water, the bottom photographs provide very poor results. Only in a very few locations was the floor visible and in those cases it was found to be a white undulating sedimentary surface. The bottom temperature measurements, which were made continuously along the ship track, indicate the presence of a large zone of temperature anomalies. This zone is located in the deep part of the north basin at a water depth of over 330 m. The anomalies occur above a portion of an east-west fault which cuts through the Dead Sea suggesting the presence of hydrothermal activity.

The Dead Sea, The Lake and Its Setting

NASA Astrophysics Data System (ADS)

Brink, Uri ten

I cannot think of a subject more befitting the description of interdisciplinary research with societal relevance than the study of the Dead Sea, a terminal lake of the Jordan River in Israel and Jordan. The scientific study of the Dead Sea is intimately connected with politics, religion, archeology, economic development, tourism, and environmental change.The Dead Sea is a relatively closed geologic and limnologic system with drastic physical changes often occurring on human timescales and with a long human history to observe these changes. Research in this unique area covers diverse aspects such as active subsidence and deformation along strike-slip faults; vertical stratification and stability of the water column; physical properties of extremely saline and dense (1234 kg/m3) water; spontaneous precipitation of minerals in an oversaturated environment; origin of the unusual chemical composition of the brine; existence of life in extreme environments; use of lake level fluctuations as a paleoclimatic indicator; and effects on the environment of human intervention versus natural climatic variability. Although the Dead Sea covers a small area on a global scale, it is nevertheless one of the largest natural laboratories for these types of research on Earth. These reasons make the Dead Sea a fascinating topic for the curious mind.

Persistence of bacterial DNA in orthopedic infections.

PubMed

Kaplan, Heidi B; Miranda, Justin A; Gogola, Gloria R; Gomez, Karen; Ambrose, Catherine G

2018-06-01

Polymerase chain reaction (PCR) has been proposed as a method to identify bacteria in clinical samples because it is more sensitive than culture techniques and can produce results rapidly. However, PCR can detect DNA from dead cells and thus cannot distinguish between live and dead cells in a tissue sample. Killed Staphylococcus aureus cells were implanted into the femurs and knee joints of rats to determine the length of time that DNA from dead cells is detectable in a living animal under conditions similar to common orthopedic infections. In the joint infection model studied here, the DNA from the dead planktonic bacteria was detected using PCR immediately after injection or 24 h later, but was undetectable 48 and 72 h after injection. In the biofilm implanted-device model studied, the DNA from these dead biofilm cells was detected by PCR immediately after implantation and at 24 h, but not at 48 or 72 h. Thus, our results indicate that DNA from dead cells does not persist in these animal model systems for more than 2 days, which should reduce concerns about possible false positive results using molecular DNA-based techniques for the detection of pathogens. Copyright © 2018. Published by Elsevier Inc.

Traffic-Light-Preemption Vehicle-Transponder Software Module

NASA Technical Reports Server (NTRS)

Bachelder, Aaron; Foster, Conrad

2005-01-01

A prototype wireless data-communication and control system automatically modifies the switching of traffic lights to give priority to emergency vehicles. The system, which was reported in several NASA Tech Briefs articles at earlier stages of development, includes a transponder on each emergency vehicle, a monitoring and control unit (an intersection controller) at each intersection equipped with traffic lights, and a central monitoring subsystem. An essential component of the system is a software module executed by a microcontroller in each transponder. This module integrates and broadcasts data on the position, velocity, acceleration, and emergency status of the vehicle. The position, velocity, and acceleration data are derived partly from the Global Positioning System, partly from deductive reckoning, and partly from a diagnostic computer aboard the vehicle. The software module also monitors similar broadcasts from other vehicles and from intersection controllers, informs the driver of which intersections it controls, and generates visible and audible alerts to inform the driver of any other emergency vehicles that are close enough to create a potential hazard. The execution of the software module can be monitored remotely and the module can be upgraded remotely and, hence, automatically

The day of reckoning: Does human ultrasociality continue?

PubMed

Ristau, Carolyn A

2016-01-01

To counter human ultrasociality, alternative communities can arise (ongoing), and, unlike insects, lower echelons can unite and rebel. Examples include movements such as: "Black Lives Matter," "Fight for $15," "Occupy," and the "Village Movement." To strengthen ultrasociality, a surplus bottom echelon can be reduced: for example, by means such as imprisoning Blacks, deporting immigrants, wars, and the Holocaust. Alternatively, a new structure could be created, for example, ISIL (even more ultrasocial?).

THE BRAIN (The Harvard Experimental Basic Reckoning and Instructional Network)

DTIC Science & Technology

1968-10-01

shown to be flexible enough to be serviceable, at least initially, for most users. As the user grows in experience and his programs in...and firmly established of the two. The advance of science has been marked by a progressive and rapidly accelerating separation of observable...impossible for them to distinguish incorrect reasoning or calculation from errors in graphing. " The bridge crossed, the instrument grows more

A Gadamerian Phenomenological Study Examining the Meaning of Having a Bachelor's Degree Expressed by Associate Degree Nurses (ADN) Who Educationally Transitioned to a Baccalaureate Degree in Nursing (BSN)

ERIC Educational Resources Information Center

Sauld, Jill Pierpont

2017-01-01

Since the inception of associate degree nursing programs, professional nursing conversations and debate have grappled with reckoning differences between the associate degree in nursing (ADN) and the bachelor's degree in nursing (BSN). Research reporting better patient outcomes with more baccalaureate prepared nurses has been a driving force for…

Uranium loans: Delaying the day of reckoning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-09-01

Spot market volume so far this year, by NUKEM's estimates, comes to just under 11 million lbs. It appears that existing loans are either being extended, or paid back with material borrowed from other sources. Therefore, there has been no significant amount of purchases on the spot market to pay back borrowed uranium. How do we know the loans have not been paid back with spot purchases For one thing, the amount of uranium loans outstanding has increased. According to our current survey, there may now be as much as 32 million lbs U3O8 equivalent in outstanding loans. At currentmore » prices, it's cheaper to borrow than to buy uranium. So borrowers are gambling that prices will remain low for some time, allowing them to delay repayment of the loans. Borrowers then, in essence, are delaying the day of reckoning on these loans. How long they can do so is anyone's guess. As long as uranium is in abundance and utilities remain willing to lend it out, loan activity will likely remain at or near current levels. But when supplies tighten and the market swings in a more positive direction, borrowers may get caught scrambling to repay their loans as quickly as possible.« less

The hunt for the perfect discounting function and a reckoning of time perception.

PubMed

Namboodiri, Vijay Mk; Hussain Shuler, Marshall G

2016-10-01

Making decisions that factor the cost of time is fundamental to survival. Yet, while it is readily appreciated that our perception of time is intimately involved in this process, theories regarding intertemporal decision-making and theories regarding time perception are treated, largely, independently. Even within these respective domains, models providing good fits to data fail to provide insight as to why, from a normative sense, those fits should take their apparent form. Conversely, normative models that proffer a rationalization for why an agent should weigh options in a particular way, or to perceive time in a particular way, fail to account for the full body of well-established experimental evidence. Here we review select, yet key advances in our understanding, identifying conceptual breakthroughs in the fields of intertemporal decision-making and in time perception, as well as their limits and failings in the face of hard-won experimental observation. On this background of accrued knowledge, a new conception unifying the domains of decision-making and time perception is put forward (Training-Integrated Maximization of Reinforcement Rate, TIMERR) to provide a better fit to observations and a more parsimonious reckoning of why we make choices, and thereby perceive time, the way we do. Copyright © 2016 Elsevier Ltd. All rights reserved.

The active structure of the Dead Sea depression

NASA Astrophysics Data System (ADS)

Shamir, G.

2003-04-01

The ~220km long gravitational and structural Dead Sea Depression (DSD), situated along the southern section of the Dead Sea Transform (DST), is centered by the Dead Sea basin sensu strictu (DSB), which has been described since the 1960?s as a pull-apart basin over a presumed left-hand fault step. However, several observations, or their lack thereof, question this scheme, e.g. (i) It is not supported by recent seismological and geomorphic data; (ii) It does not explain the fault pattern and mixed sinistral and dextral offset along the DSB western boundary; (iii) It does not simply explain the presence of intense deformation outside the presumed fault step zone; (iv) It is inconsistent with the orientation of seismically active faults within the Dead Sea and Jericho Valley; (v); It is apparently inconsistent with the symmetrical structure of the DSD; (vi) The length of the DSB exceeds the total offset along the Dead Sea Transform, while its subsidence is about the age of the DST. Integration of newly acquired and analyzed data (high resolution and petroleum seismic reflection data, earthquake relocation and fault plane solutions) with previously published data (structural mapping, fracture orientation distribution, Bouguer anomaly maps, sinkhole distribution, geomorphic lineaments) now shows that the active upper crustal manifestation of the DSD is a broad shear zone dominated by internal fault systems oriented NNE and NNW. These fault systems are identified by earthquake activity, seismic reflection observations, alignment of recent sinkholes, and distribution of Bouguer anomaly gradients. Motion on the NNE system is normal-dextral, suggesting that counterclockwise rotation may have taken place within the shear zone. The overall sinistral motion between the Arabian and Israel-Sinai plates along the DSD is thus accommodated by distributed shear across the N-S extending DSD. The three-dimensionality of this motion at the DSD may be related to the rate of convergence between the two plates.

Groundwater-saline lakes interaction - The contribution of saline groundwater circulation to solute budget of saline lakes: a lesson from the Dead Sea

NASA Astrophysics Data System (ADS)

Kiro, Yael; Weinstein, Yishai; Starinsky, Abraham; Yechieli, Yoseph

2013-04-01

Saline lakes act as base level for both surface water and groundwater. Thus, a change in lake levels is expected to result in changes in the hydrogeological system in its vicinity, exhibited in groundwater levels, location of the fresh-saline water interface, sub-lacustrine groundwater discharge (SGD) and saline water circulation. All these processes were observed in the declining Dead Sea system, whose water level dropped by ~35 meters in the last 50 years. This work focuses mainly on the effect of circulation of Dead Sea water in the aquifer, which continues even in this very rapid base level drop. In general, seawater circulation in coastal aquifers is now recognized as a major process affecting trace element mass balances in coastal areas. Estimates of submarine groundwater discharge (SGD) vary over several orders of magnitude (1-1000000 m3/yr per meter shoreline). These estimates are sensitive to fresh-saline SGD ratios and to the temporal and spatial scales of the circulation. The Dead Sea system is an excellent natural field lab for studying seawater-groundwater interaction and large-scale circulation due to the absence of tides and to the minor role played by waves. During Dead Sea water circulation in the aquifer several geochemical reactions occur, ranging from short-term adsorption-desorption reactions and up to long-term precipitation and dissolution reactions. These processes affect the trace element distribution in the saline groundwater. Barite and celestine, which are supersaturated in the lake water, precipitate during circulation in the aquifer, reducing barium (from 5 to 1.5 mg/L), strontium (from 350 to 300 mg/L) and the long-lived 226Ra (from 145 to 60 dpm/L) in the saline groundwater. Redox-controlled reactions cause a decrease in uranium from 2.4 to 0.1 μg/L, and an increase in iron from 1 to 13 mg/L. 228Ra (t1/2=5.75 yr) activity in the Dead Sea is ~1 dpm/L and increase gradually as the saline water flows further inland until reaching steady-state activities (~27 dpm/L) with the aquifer sediments. The decrease in 226Ra and increase in 228Ra in the circulation process provide a robust method for calculating the amount of Dead Sea water circulating in the aquifer. This process can affect trace element concentrations in the Dead Sea and emphasize the potential of long-term seawater circulation in mass balances of saline water bodies.

Crow deaths as a sentinel surveillance system for West Nile virus in the northeastern United States, 1999

USGS Publications Warehouse

Eidson, M.; Komar, N.; Sorhage, F.; Nelson, R.; Talbot, T.; Mostashari, F.; McLean, R.; ,

2001-01-01

In addition to human encephalitis and meningitis cases, the West Nile (WN) virus outbreak in the summer and fall of 1999 in New York State resulted in bird deaths in New York, New Jersey, and Connecticut. From August to December 1999, 295 dead birds were laboratory-confirmed with WN virus infection; 262 (89%) were American Crows (Corvus brachyrhynchos). The New York State Department of Health received reports of 17,339 dead birds, including 5,697 (33%) crows; in Connecticut 1,040 dead crows were reported. Bird deaths were critical in identifying WN virus as the cause of the human outbreak and defining its geographic and temporal limits. If established before a WN virus outbreak, a surveillance system based on bird deaths may provide a sensitive method of detecting WN virus.

DNase I and Proteinase K eliminate DNA from injured or dead bacteria but not from living bacteria in microbial reference systems and natural drinking water biofilms for subsequent molecular biology analyses.

PubMed

Villarreal, Jessica Varela; Jungfer, Christina; Obst, Ursula; Schwartz, Thomas

2013-09-01

Molecular techniques, such as polymerase chain reaction (PCR) and quantitative PCR (qPCR), are very sensitive, but may detect total DNA present in a sample, including extracellular DNA (eDNA) and DNA coming from live and dead cells. DNase I is an endonuclease that non-specifically cleaves single- and double-stranded DNA. This enzyme was tested in this study to analyze its capacity of digesting DNA coming from dead cells with damaged cell membranes, leaving DNA from living cells with intact cell membranes available for DNA-based methods. For this purpose, an optimized DNase I/Proteinase K (DNase/PK) protocol was developed. Intact Staphylococcus aureus cells, heat-killed Pseudomonas aeruginosa cells, free genomic DNA of Salmonella enterica, and a mixture of these targets were treated according to the developed DNase/PK protocol. In parallel, these samples were treated with propidium monoazide (PMA) as an already described assay for live-dead discrimination. Quantitative PCR and PCR-DGGE of the eubacterial 16S rDNA fragment were used to test the ability of the DNase/PK and PMA treatments to distinguish DNA coming from cells with intact cell membranes in the presence of DNA from dead cells and free genomic DNA. The methods were applied to three months old autochthonous drinking water biofilms from a pilot facility built at a German waterworks. Shifts in the DNA patterns observed after DGGE analysis demonstrated the applicability of DNase/PK as well as of the PMA treatment for natural biofilm investigation. However, the DNase/PK treatment demonstrated some practical advantages in comparison with the PMA treatment for live/dead discrimination of bacterial targets in drinking water systems. © 2013 Elsevier B.V. All rights reserved.

How is health-related "deservingness" reckoned? Perspectives from unauthorized im/migrants in Tel Aviv.

PubMed

Willen, Sarah S

2012-03-01

Do unauthorized im/migrants have a right to health? Do they deserve health care, or health protection, or access to the social determinants of good health? Are they party to prevailing social contracts, or does their exclusion from mainstream systems of health promotion, prevention, and care "make sense"? Questions like these, which generate considerable attention in multiple spheres of scholarship, policy, and public debate, revolve around an issue that merits substantially greater consideration among social scientists of health: health-related "deservingness." In addition to putting the issue of health-related deservingness squarely on the map as an object of analysis, this article further argues that we cannot focus solely on those with power, influence, and public voice. Rather, we also must investigate how deservingness is reckoned in relation to--and, furthermore, from the perspectives of-- unauthorized im/migrants and members of other groups commonly constructed in public and policy discourse as undeserving. Additionally, we must consider the complicated relationship between universalizing juridical arguments about formal entitlement to health rights, on one hand, and situationally specific, vernacular moral arguments about deservingness, on the other. The paper analyzes findings from a 29-month mixed-methods study conducted in Tel Aviv, Israel, that approached unauthorized im/migrants as subjects, rather than simply objects, of ethical deliberation. Participants' conceptions of health-related deservingness are investigated using two sources of data: (1) quantitative findings from a self-administered, closed-ended survey conducted with 170 im/migrant patients at an NGO-run Open Clinic (2002-2003), and (2) qualitative findings from the larger ethnographic study of which the survey was part (2000-2010). The study findings both (1) contradict commonly circulating assumptions that unauthorized im/migrants are "freeloaders," and (2) highlight the need for rigorous investigation of how unauthorized im/migrants, among other marginalized and vulnerable groups, conceptualize their own relative deservingness of health-related concern and investment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Registering Ground and Satellite Imagery for Visual Localization

DTIC Science & Technology

2012-08-01

reckoning, inertial, stereo, light detection and ranging ( LIDAR ), cellular radio, and visual. As no sensor or algorithm provides perfect localization in...by metric localization approaches to confine the region of a map that needs to be searched. Simultaneous Localization and Mapping ( SLAM ) (5, 6), using...estimate the metric location of the camera. Se et al. (7) use SIFT features for both appearance-based global localization and incremental 3D SLAM . Johns and

The Media’s Role in Combatting Terrorism

DTIC Science & Technology

1991-04-01

changed after the1972 Munich Olympics Massacre; from then on, the PLO was a force to be reckoned and negotiated with. For better or worse, Yasser Arafat...Coverage During Captivity," Political Communication and Persuation . Vol. 5, No. 4, 1988, p. 244. 12. Uri Ra’anan, Robert L. Pfaltzgraff, Jr., Richard H...Media: Problems, Solutions and Counterproblems." Political Communication and Persuation . Vol. 6, 4 November 1989, pp. 311-339. 12. Dilaura, Arnold E

A high-resolution and intelligent dead pixel detection scheme for an electrowetting display screen

NASA Astrophysics Data System (ADS)

Luo, ZhiJie; Luo, JianKun; Zhao, WenWen; Cao, Yang; Lin, WeiJie; Zhou, GuoFu

2018-02-01

Electrowetting display technology is realized by tuning the surface energy of a hydrophobic surface by applying a voltage based on electrowetting mechanism. With the rapid development of the electrowetting industry, how to analyze efficiently the quality of an electrowetting display screen has a very important significance. There are two kinds of dead pixels on the electrowetting display screen. One is that the oil of pixel cannot completely cover the display area. The other is that indium tin oxide semiconductor wire connecting pixel and foil was burned. In this paper, we propose a high-resolution and intelligent dead pixel detection scheme for an electrowetting display screen. First, we built an aperture ratio-capacitance model based on the electrical characteristics of electrowetting display. A field-programmable gate array is used as the integrated logic hub of the system for a highly reliable and efficient control of the circuit. Dead pixels can be detected and displayed on a PC-based 2D graphical interface in real time. The proposed dead pixel detection scheme reported in this work has promise in automating electrowetting display experiments.

Intra-specific competition (crowding) of giant sequoias (Sequoiadendron giganteum)

USGS Publications Warehouse

Stohlgren, Thomas J.

1993-01-01

Information on the size and location of 1916 giant sequoias (Sequoiadendron giganteum (Lindl.) Buchholz) in Muir Grove, Sequoia National Park, in the southern Sierra Nevada of California was used to assess intra-specific crowding. Study objectives were to: (1) determine which parameters associated with intra-specific competition (i.e. size and distance to nearest neighbor, crowding/root system area overlap, or number of neighbors) might be important in spatial pattern development, growth, and survivorship of established giant sequoias; (2) quantify the level of intra-specific crowding of different sized live sequoias based on a model of estimated overlapping root system areas (i.e. an index of relative crowding); (3) compare the level of intra-specific crowding of similarly sized live and dead giant sequoias (less than 30 cm diameter at breast height (dbh) at the time of inventory (1969). Mean distances to the nearest live giant sequoia neighbor were not significantly different (at α = 0.05) for live and dead sequoias in similar size classes. A zone of influence competition model (i.e. index of crowding) based on horizontal overlap of estimated root system areas was developed for 1753 live sequoias. The model, based only on the spatial arrangement of live sequoias, was then tested on dead sequoias of less than 30 cm dbh (n = 163 trees; also recorded in 1969). The dead sequoias had a significantly higher crowding index than 561 live trees of similar diameter. Results showed that dead sequoias of less than 16.6 cm dbh had a significantly greater mean number of live neighbors and mean crowding index than live sequoias of similar size. Intra-specific crowding may be an important mechanism in determining the spatial distribution of sequoias in old-growth forests.

Improving the counting efficiency in time-correlated single photon counting experiments by dead-time optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peronio, P.; Acconcia, G.; Rech, I.

Time-Correlated Single Photon Counting (TCSPC) has been long recognized as the most sensitive method for fluorescence lifetime measurements, but often requiring “long” data acquisition times. This drawback is related to the limited counting capability of the TCSPC technique, due to pile-up and counting loss effects. In recent years, multi-module TCSPC systems have been introduced to overcome this issue. Splitting the light into several detectors connected to independent TCSPC modules proportionally increases the counting capability. Of course, multi-module operation also increases the system cost and can cause space and power supply problems. In this paper, we propose an alternative approach basedmore » on a new detector and processing electronics designed to reduce the overall system dead time, thus enabling efficient photon collection at high excitation rate. We present a fast active quenching circuit for single-photon avalanche diodes which features a minimum dead time of 12.4 ns. We also introduce a new Time-to-Amplitude Converter (TAC) able to attain extra-short dead time thanks to the combination of a scalable array of monolithically integrated TACs and a sequential router. The fast TAC (F-TAC) makes it possible to operate the system towards the upper limit of detector count rate capability (∼80 Mcps) with reduced pile-up losses, addressing one of the historic criticisms of TCSPC. Preliminary measurements on the F-TAC are presented and discussed.« less

Signal to noise ratio of energy selective x-ray photon counting systems with pileup.

PubMed

Alvarez, Robert E

2014-11-01

To derive fundamental limits on the effect of pulse pileup and quantum noise in photon counting detectors on the signal to noise ratio (SNR) and noise variance of energy selective x-ray imaging systems. An idealized model of the response of counting detectors to pulse pileup is used. The model assumes a nonparalyzable response and delta function pulse shape. The model is used to derive analytical formulas for the noise and energy spectrum of the recorded photons with pulse pileup. These formulas are first verified with a Monte Carlo simulation. They are then used with a method introduced in a previous paper [R. E. Alvarez, "Near optimal energy selective x-ray imaging system performance with simple detectors," Med. Phys. 37, 822-841 (2010)] to compare the signal to noise ratio with pileup to the ideal SNR with perfect energy resolution. Detectors studied include photon counting detectors with pulse height analysis (PHA), detectors that simultaneously measure the number of photons and the integrated energy (NQ detector), and conventional energy integrating and photon counting detectors. The increase in the A-vector variance with dead time is also computed and compared to the Monte Carlo results. A formula for the covariance of the NQ detector is developed. The validity of the constant covariance approximation to the Cramèr-Rao lower bound (CRLB) for larger counts is tested. The SNR becomes smaller than the conventional energy integrating detector (Q) SNR for 0.52, 0.65, and 0.78 expected number photons per dead time for counting (N), two, and four bin PHA detectors, respectively. The NQ detector SNR is always larger than the N and Q SNR but only marginally so for larger dead times. Its noise variance increases by a factor of approximately 3 and 5 for the A1 and A2 components as the dead time parameter increases from 0 to 0.8 photons per dead time. With four bin PHA data, the increase in variance is approximately 2 and 4 times. The constant covariance approximation to the CRLB is valid for larger counts such as those used in medical imaging. The SNR decreases rapidly as dead time increases. This decrease places stringent limits on allowable dead times with the high count rates required for medical imaging systems. The probability distribution of the idealized data with pileup is shown to be accurately described as a multivariate normal for expected counts greater than those typically utilized in medical imaging systems. The constant covariance approximation to the CRLB is also shown to be valid in this case. A new formula for the covariance of the NQ detector with pileup is derived and validated.

Signal to noise ratio of energy selective x-ray photon counting systems with pileup

PubMed Central

Alvarez, Robert E.

2014-01-01

Purpose: To derive fundamental limits on the effect of pulse pileup and quantum noise in photon counting detectors on the signal to noise ratio (SNR) and noise variance of energy selective x-ray imaging systems. Methods: An idealized model of the response of counting detectors to pulse pileup is used. The model assumes a nonparalyzable response and delta function pulse shape. The model is used to derive analytical formulas for the noise and energy spectrum of the recorded photons with pulse pileup. These formulas are first verified with a Monte Carlo simulation. They are then used with a method introduced in a previous paper [R. E. Alvarez, “Near optimal energy selective x-ray imaging system performance with simple detectors,” Med. Phys. 37, 822–841 (2010)] to compare the signal to noise ratio with pileup to the ideal SNR with perfect energy resolution. Detectors studied include photon counting detectors with pulse height analysis (PHA), detectors that simultaneously measure the number of photons and the integrated energy (NQ detector), and conventional energy integrating and photon counting detectors. The increase in the A-vector variance with dead time is also computed and compared to the Monte Carlo results. A formula for the covariance of the NQ detector is developed. The validity of the constant covariance approximation to the Cramèr–Rao lower bound (CRLB) for larger counts is tested. Results: The SNR becomes smaller than the conventional energy integrating detector (Q) SNR for 0.52, 0.65, and 0.78 expected number photons per dead time for counting (N), two, and four bin PHA detectors, respectively. The NQ detector SNR is always larger than the N and Q SNR but only marginally so for larger dead times. Its noise variance increases by a factor of approximately 3 and 5 for the A1 and A2 components as the dead time parameter increases from 0 to 0.8 photons per dead time. With four bin PHA data, the increase in variance is approximately 2 and 4 times. The constant covariance approximation to the CRLB is valid for larger counts such as those used in medical imaging. Conclusions: The SNR decreases rapidly as dead time increases. This decrease places stringent limits on allowable dead times with the high count rates required for medical imaging systems. The probability distribution of the idealized data with pileup is shown to be accurately described as a multivariate normal for expected counts greater than those typically utilized in medical imaging systems. The constant covariance approximation to the CRLB is also shown to be valid in this case. A new formula for the covariance of the NQ detector with pileup is derived and validated. PMID:25370642

Effects of backlash and dead band on temperature control of the primary loop of a conceptual nuclear Brayton space powerplant

NASA Technical Reports Server (NTRS)

Petrick, E. J.

1973-01-01

An analytical study was made of the stability of a closed-loop liquid-lithium temperature control of the primary loop of a conceptual nuclear Brayton space powerplant. The operating point was varied from 20 to 120 percent of design. A describing-function technique was used to evaluate the effects of temperature dead band and control coupling backlash. From the system investigation, it was predicted that a limit cycle will not exist with a temperature dead band, but a limit cycle will not exist when backlash is present. The results compare favorably with a digital computer simulation.

"What a Long, Strange Trip It's Been": The Grateful Dead, the Deadheads, and the Refiguration of Subculture."

ERIC Educational Resources Information Center

Lane, Philip J.

The relationship between mass mediated symbol systems and the development of subculture were studied through an analysis of the "hardcore" followers of the rock group, the Grateful Dead, i.e., the "Deadheads." As a way of compiling a "thick description" of the kind proposed by Clifford Geertz (1973), several key areas…

Management of water repellency in Australia, and risks associated with preferential flow, pesticide concentration and leaching

NASA Astrophysics Data System (ADS)

Blackwell, P. S.

2000-05-01

The three most westerly states of southern Australia have the largest area of water repellent soils, which limit agricultural production, of any country in the world. Simplified principles of the problems caused by repellency and the principles of soil management solutions are considered and related to experimental evidence. The phenomena of diverted soil water flow and isolated dry soil can explain most of the problems caused by repellency. Plant adaptation, soil or hydrophobic removal, reduced soil drying, reduced surface tension, water harvesting, avoidance, masking and, perhaps, water movement along dead root systems are the main soil management principles. Dead roots may play a role in zero till cropping systems, allowing more uniform wetting of dry hydrophobic soil at the base of a dead plant and along the dendritic pattern of the dead root system. Application of these management principles, especially water harvesting, avoidance and masking (by the use of deep trenching, furrow sowing methods or claying), have made a considerable improvement to sustainability and productivity of farming systems on the water repellent soils of Australia. Evidence is selected to assess risks of preferential flow, pesticide concentration and leaching for different agricultural soil management methods. All management methods can have some risks, but claying seems to have the least risk and furrowing the highest risk of encouraging preferential flow, pesticide concentration and leaching. It is suggested we have insufficient information and understanding to quantify the risks of groundwater contamination for different environments, farming systems and soil management methods to control repellency. There is an urgent need to develop quantified guidelines to minimise any possible groundwater contamination hazard for the extensive areas using farming systems with furrows and increasing amounts of pesticide and fertiliser.

Solid Propulsion De-Orbiting and Re-Orbiting

NASA Astrophysics Data System (ADS)

Schonenborg, R. A. C.; Schoyer, H. F. R.

2009-03-01

With many "innovative" de-orbit systems (e.g. tethers, aero breaking, etc.) and with natural de-orbit, the place of impact of unburned spacecraft debris on Earth can not be determined accurately. The idea that satellites burn up completely upon re-entry is a common misunderstanding. To the best of our knowledge only rocket motors are capable of delivering an impulse that is high enough, to conduct a de-orbit procedure swiftly, hence to de-orbit at a specific moment that allows to predict the impact point of unburned spacecraft debris accurately in remote areas. In addition, swift de-orbiting will reduce the on-orbit time of the 'dead' satellite, which reduces the chance of the dead satellite being hit by other dead or active satellites, while spiralling down to Earth during a slow, 25 year, or more, natural de-orbit process. Furthermore the reduced on-orbit time reduces the chance that spacecraft batteries, propellant tanks or other components blow up and also reduces the time that the object requires tracking from Earth.The use of solid propellant for the de-orbiting of spacecraft is feasible. The main advantages of a solid propellant based system are the relatively high thrust and the facts that the system can be made autonomous quite easily and that the system can be very reliable. The latter is especially desirable when one wants to de-orbit old or 'dead' satellites that might not be able to rely anymore on their primary systems. The disadvantage however, is the addition of an extra system to the spacecraft as well as a (small) mass penalty. [1]This paper describes the above mentioned system and shows as well, why such a system can also be used to re-orbit spacecraft in GEO, at the end of their life to a graveyard orbit.Additionally the system is theoretically compared to an existing system, of which performance data is available.A swift market analysis is performed as well.

Predictive control strategies for wind turbine system based on permanent magnet synchronous generator.

PubMed

Maaoui-Ben Hassine, Ikram; Naouar, Mohamed Wissem; Mrabet-Bellaaj, Najiba

2016-05-01

In this paper, Model Predictive Control and Dead-beat predictive control strategies are proposed for the control of a PMSG based wind energy system. The proposed MPC considers the model of the converter-based system to forecast the possible future behavior of the controlled variables. It allows selecting the voltage vector to be applied that leads to a minimum error by minimizing a predefined cost function. The main features of the MPC are low current THD and robustness against parameters variations. The Dead-beat predictive control is based on the system model to compute the optimum voltage vector that ensures zero-steady state error. The optimum voltage vector is then applied through Space Vector Modulation (SVM) technique. The main advantages of the Dead-beat predictive control are low current THD and constant switching frequency. The proposed control techniques are presented and detailed for the control of back-to-back converter in a wind turbine system based on PMSG. Simulation results (under Matlab-Simulink software environment tool) and experimental results (under developed prototyping platform) are presented in order to show the performances of the considered control strategies. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Crustal Deformation across the Jericho Valley Section of the Dead Sea Fault as Resolved by Detailed Field and Geodetic Observations

NASA Astrophysics Data System (ADS)

Hamiel, Yariv; Piatibratova, Oksana; Mizrahi, Yaakov; Nahmias, Yoav; Sagy, Amir

2018-04-01

Detailed field and geodetic observations of crustal deformation across the Jericho Fault section of the Dead Sea Fault are presented. New field observations reveal several slip episodes that rupture the surface, consist with strike slip and extensional deformation along a fault zone width of about 200 m. Using dense Global Positioning System measurements, we obtain the velocities of new stations across the fault. We find that this section is locked for strike-slip motion with a locking depth of 16.6 ± 7.8 km and a slip rate of 4.8 ± 0.7 mm/year. The Global Positioning System measurements also indicate asymmetrical extension at shallow depths of the Jericho Fault section, between 0.3 and 3 km. Finally, our results suggest the vast majority of the sinistral slip along the Dead Sea Fault in southern Jorden Valley is accommodated by the Jericho Fault section.

Energy Balance, Evapo-transpiration and Dew deposition in the Dead Sea Valley

NASA Astrophysics Data System (ADS)

Metzger, Jutta; Corsmeier, Ulrich

2016-04-01

The Dead Sea is a unique place on earth. It is a terminal hypersaline lake, located at the lowest point on earth with a lake level of currently -429 m above mean sea level (amsl). It is located in a transition zone of semiarid to arid climate conditions, which makes it highly sensible to climate change (Alpert1997, Smiatek2011). The Virtual Institute DEad SEa Research Venue (DESERVE) is an international project funded by the German Helmholtz Association and was established to study coupled atmospheric hydrological, and lithospheric processes in the changing environment of the Dead Sea. At the moment the most prominent environmental change is the lake level decline of approximately 1 m / year due to anthropogenic interferences (Gertman, 2002). This leads to noticeable changes in the fractions of the existing terrestrial surfaces - water, bare soil and vegetated areas - in the valley. Thus, the partitioning of the net radiation in the valley changes as well. To thoroughly study the atmospheric and hydrological processes in the Dead Sea valley, which are driven by the energy balance components, sound data of the energy fluxes of the different surfaces are necessary. Before DESERVE no long-term monitoring network simultaneously measuring the energy balance components of the different surfaces in the Dead Sea valley was available. Therefore, three energy balance stations were installed at three characteristic sites at the coast-line, over bare soil, and within vegetation, measuring all energy balance components by using the eddy covariance method. The results show, that the partitioning of the energy into sensible and latent heat flux on a diurnal scale is totally different at the three sites. This results in gradients between the sites, which are e.g. responsible for the typical diurnal wind systems at the Dead Sea. Furthermore, driving forces of evapo-transpiration at the sites were identified and a detailed analysis of the daily evaporation and dew deposition rates for a whole annual cycle will be presented. Alpert, P., Shafir, H., & Issahary, D. (1997). Recent changes in the climate at the Dead Sea-a preliminary study. Climatic Change, 37(3), 513-537. Gertman, I., & Hecht, A. (2002). The Dead Sea hydrography from 1992 to 2000. Journal of marine systems, 35(3), 169-181. Smiatek, G., Kunstmann, H., & Heckl, A. (2011). High-resolution climate change simulations for the Jordan River area. Journal of Geophysical Research: Atmospheres (1984-2012), 116(D16).

Status of the University of Rochester tandem upgrade

NASA Astrophysics Data System (ADS)

Cross, Clinton; Miller, Thomas

1986-05-01

The status of the University of Rochester tandem Van de Graaff accelerator upgrade is reviewed. The accelerator upgrade to 18 MV consists of extended tubes, shielded resistors, dead-section ion pumping, two rotating insulating power shaft systems to provide power to the dead sections and terminal, and a pelletron charging system to replace the charging belt. Control of many of the accelerator operating systems will be done by two IBM personal computers. The negative ion injector diffusion pump, isolation transformer, preacceleration high-voltage power supply, and high-voltage corona enclosure will all be replaced. Finally, the SF6 gas handling system will be improved with the addition of a second set of gas dryers and a larger recirculating pump.

Prescribed performance distributed consensus control for nonlinear multi-agent systems with unknown dead-zone input

NASA Astrophysics Data System (ADS)

Cui, Guozeng; Xu, Shengyuan; Ma, Qian; Li, Yongmin; Zhang, Zhengqiang

2018-05-01

In this paper, the problem of prescribed performance distributed output consensus for higher-order non-affine nonlinear multi-agent systems with unknown dead-zone input is investigated. Fuzzy logical systems are utilised to identify the unknown nonlinearities. By introducing prescribed performance, the transient and steady performance of synchronisation errors are guaranteed. Based on Lyapunov stability theory and the dynamic surface control technique, a new distributed consensus algorithm for non-affine nonlinear multi-agent systems is proposed, which ensures cooperatively uniformly ultimately boundedness of all signals in the closed-loop systems and enables the output of each follower to synchronise with the leader within predefined bounded error. Finally, simulation examples are provided to demonstrate the effectiveness of the proposed control scheme.

Genome analysis of Listeria ivanovii strain G770 that caused a deadly aortic prosthesis infection

PubMed Central

Beye, M.; Gouriet, F.; Michelle, C.; Casalta, J.-P.; Habib, G.; Raoult, D.; Fournier, P.-E.

2016-01-01

We sequenced the genome of Listeria ivanovii strain G770, which caused a deadly infection of the thoracic aortic prosthesis of a 78-year-old man. The 2.9 Mb genome exhibited 21 specific genes among L. ivanovii strains, including five genes encoding a type I restriction modification system and one glycopeptide resistance gene. PMID:26933501

Special Operations Forces to the Twenty-First Century: What Threat, What Response

DTIC Science & Technology

1991-05-24

successful campaign plan against the German war machine had been the use of resistance forces, the Maquis in France, the Partisans in Yugoslavia, and...General Eisenhower reckoned the Maquis resistance had been worth 15 divisions./4 Some far-seeing planners realized that should the Soviets roll...Prime minister and others, less noted by western eyes . India has a sense of history and a sense of paranoia. She knows that in Africa from Kuwait to

Conceptual design studies for surface infrastructure

NASA Technical Reports Server (NTRS)

Bufkin, Ann L.; Jones, William R., II

1986-01-01

The utimate design of a manned Mars base will be the result of considerable engineering analysis and many trade studies to optimize the configuration. Many options and scenarios are available and all need to be considered at this time. Initial base elements, two base configuration concepts, internal space architectural concerns, and two base set-up scenarios are discussed. There are many variables as well as many unknowns to be reckoned with before people set foot on the red planet.

JPRS Report, Soviet Union, World Economy & International Relations, No. 9 September 1987

DTIC Science & Technology

1988-01-12

states have if in addition to the growing competition of beet sugar they are forced to reckon with the fact that today even corn sweeteners...policy of pressure. The reality today is such that (as graphically demon- strated at the Cancun meeting in 1981) the U.S. Admin- istration and, in ...markets of devel- oped capitalist countries no longer justify themselves as a means of competitive struggle and an increase in currency earnings. What

We Will Find A Way: Understanding the Legacy of Canadian Special Operations Forces

DTIC Science & Technology

2012-02-01

and numerous contemporary English accounts conceded that the Canadian raiders “are well known to be the most dangerous enemy of any... reckoned...of the 1st Canadian Parachute Bat- talion, at great cost and personal sacrifice, pioneered a new innovative form of warfare and demonstrated agility...The MND quickly realized the strategic impact at a relatively low cost , that even a small SOF task force could achieve. As such, he pushed for

Peak phosphorus - peak food? The need to close the phosphorus cycle.

PubMed

Rhodes, Christopher J

2013-01-01

The peak in the world production of phosphorus has been predicted to occur in 2033, based on world reserves of rock phosphate (URR) reckoned at around 24,000 million tonnes (Mt), with around 18,000 Mt remaining. This figure was reckoned-up to 71,000 Mt, by the USGS, in 2012, but a production maximum during the present century is still highly probable. There are complex issues over what the demand will be for phosphorus in the future, as measured against a rising population (from 7 billion to over 9 billion in 2050), and a greater per capita demand for fertiliser to grow more grain, in part to feed animals and meet a rising demand for meat by a human species that is not merely more populous but more affluent. As a counterweight to this, we may expect that greater efficiencies in the use of phosphorus - including recycling from farms and of human and animal waste - will reduce the per capita demand for phosphate rock. The unseen game changer is peak oil, since phosphate is mined and recovered using machinery powered by liquid fuels refined from crude oil. Hence, peak oil and peak phosphorus might appear as conjoined twins. There is no unequivocal case that we can afford to ignore the likelihood of a supply-demand gap for phosphorus occurring sometime this century, and it would be perilous to do so.

Ring Attractor Dynamics Emerge from a Spiking Model of the Entire Protocerebral Bridge.

PubMed

Kakaria, Kyobi S; de Bivort, Benjamin L

2017-01-01

Animal navigation is accomplished by a combination of landmark-following and dead reckoning based on estimates of self motion. Both of these approaches require the encoding of heading information, which can be represented as an allocentric or egocentric azimuthal angle. Recently, Ca 2+ correlates of landmark position and heading direction, in egocentric coordinates, were observed in the ellipsoid body (EB), a ring-shaped processing unit in the fly central complex (CX; Seelig and Jayaraman, 2015). These correlates displayed key dynamics of so-called ring attractors, namely: (1) responsiveness to the position of external stimuli; (2) persistence in the absence of external stimuli; (3) locking onto a single external stimulus when presented with two competitors; (4) stochastically switching between competitors with low probability; and (5) sliding or jumping between positions when an external stimulus moves. We hypothesized that ring attractor-like activity in the EB arises from reciprocal neuronal connections to a related structure, the protocerebral bridge (PB). Using recent light-microscopy resolution catalogs of neuronal cell types in the PB (Lin et al., 2013; Wolff et al., 2015), we determined a connectivity matrix for the PB-EB circuit. When activity in this network was simulated using a leaky-integrate-and-fire model, we observed patterns of activity that closely resemble the reported Ca 2+ phenomena. All qualitative ring attractor behaviors were recapitulated in our model, allowing us to predict failure modes of the putative PB-EB ring attractor and the circuit dynamics phenotypes of thermogenetic or optogenetic manipulations. Ring attractor dynamics emerged under a wide variety of parameter configurations, even including non-spiking leaky-integrator implementations. This suggests that the ring-attractor computation is a robust output of this circuit, apparently arising from its high-level network properties (topological configuration, local excitation and long-range inhibition) rather than fine-scale biological detail.

Astronomy, Illumination and Heritage: the Arles-Fontvieille megalithic monuments and their implications for archaeoastronomy and world heritage

NASA Astrophysics Data System (ADS)

Sterling Saletta, Morgan

2015-08-01

Recent archaeoastronomical research at the Arles-Fontvieille monuments has important implications for establishing potential Outstanding Universal Value of megalithic monuments and establishing the credibility of archaeoastronomical sites. My discovery of seasonal light and shadow hierophanies within the Arles-Fontvieille monuments has interpretive and heritage value implications not only for these sites but for late prehistoric European monuments more generally.While horizon astronomy was very likely used for time-reckoning in the Neolithic, I argue the ‘seasonal illumination hypothesis’ is more appropriate than the ‘celestial targeting paradigm’ not only for the interpretation of the role of astronomy and cosmological symbolism in the construction of the Arles-Fontvieille monuments but also for late prehistoric European tombs with chambers and passages more generally.Multiple lines of evidence suggest a cosmologically symbolic link between houses of the living and houses of the dead in late prehistoric Europe. I will suggest that this practice originated not only in symbolic aspects of domestic dwellings, but also in functional solar orientation.If seasonal illumination was a major impetus for the orientation signatures of late prehistoric European monuments, how best to establish this? Time-lapse photography or video, while not unproblematic, is a powerful method of establishing the credibility of archaeoastronomical sites- one which has been used to great effect at monuments such as Newgrange and Stonehenge. In the past, this method was limited by the cost of equipment and the time needed to visit sites and at specific periods of time. Both of these limitations have been significantly lessened in recent years. Digital cameras have become ubiquitous. More importantly, examples of “crowd-sourcing” research problems in science provide a strategy for field documentation of sites whose level of preservation is sufficient to reveal seasonal illumination by the sun and/or the moon by mobilizing volunteers in a collaborative research project.

Averaged Propulsive Body Acceleration (APBA) Can Be Calculated from Biologging Tags That Incorporate Gyroscopes and Accelerometers to Estimate Swimming Speed, Hydrodynamic Drag and Energy Expenditure for Steller Sea Lions

PubMed Central

Trites, Andrew W.; Rosen, David A. S.; Potvin, Jean

2016-01-01

Forces due to propulsion should approximate forces due to hydrodynamic drag for animals horizontally swimming at a constant speed with negligible buoyancy forces. Propulsive forces should also correlate with energy expenditures associated with locomotion—an important cost of foraging. As such, biologging tags containing accelerometers are being used to generate proxies for animal energy expenditures despite being unable to distinguish rotational movements from linear movements. However, recent miniaturizations of gyroscopes offer the possibility of resolving this shortcoming and obtaining better estimates of body accelerations of swimming animals. We derived accelerations using gyroscope data for swimming Steller sea lions (Eumetopias jubatus), and determined how well the measured accelerations correlated with actual swimming speeds and with theoretical drag. We also compared dive averaged dynamic body acceleration estimates that incorporate gyroscope data, with the widely used Overall Dynamic Body Acceleration (ODBA) metric, which does not use gyroscope data. Four Steller sea lions equipped with biologging tags were trained to swim alongside a boat cruising at steady speeds in the range of 4 to 10 kph. At each speed, and for each dive, we computed a measure called Gyro-Informed Dynamic Acceleration (GIDA) using a method incorporating gyroscope data with accelerometer data. We derived a new metric—Averaged Propulsive Body Acceleration (APBA), which is the average gain in speed per flipper stroke divided by mean stroke cycle duration. Our results show that the gyro-based measure (APBA) is a better predictor of speed than ODBA. We also found that APBA can estimate average thrust production during a single stroke-glide cycle, and can be used to estimate energy expended during swimming. The gyroscope-derived methods we describe should be generally applicable in swimming animals where propulsive accelerations can be clearly identified in the signal—and they should also prove useful for dead-reckoning and improving estimates of energy expenditures from locomotion. PMID:27285467

Wind systems the driving force of evaporation at the Dead Sea

NASA Astrophysics Data System (ADS)

Metzger, Jutta; Corsmeier, Ulrich; Alpert, Pinhas

2017-04-01

The Dead Sea is a unique place on earth. It is located in the Eastern Mediterranean at the lowest point of the Jordan Rift valley and its water level is currently at 429 m below mean sea level. The region is located in a transition zone of semi-arid to arid climate conditions and endangered by severe environmental problems, especially the rapid lake level decline (>1m/year), causing the shifting of fresh/saline groundwater interfaces and the drying up of the lake. Two key features are relevant for these environmental changes: the evaporation from the water surface and its driving mechanisms. The main driver of evaporation at the Dead Sea is the wind velocity and hence the governing wind systems with different scales in space and time. In the framework of the Virtual Institute DEad SEa Research Venue (DESERVE) an extensive field campaign was conducted to study the governing wind systems in the valley and the energy balance of the water and land surface simultaneously. The combination of several in-situ and remote sensing instruments allowed temporally and spatially high-resolution measurements to investigate the frequency of occurrence of the wind systems, their three-dimensional structure, associated wind velocities and their impact on evaporation. The characteristics of the three local wind systems governing the valley's wind field, as well as their impact on evaporation, will be presented. Mostly decoupled from the large scale flow a local lake breeze determines the conditions during the day. Strong downslope winds drive the evaporation in the afternoon, and down valley flows with wind velocities of over 10 m s-1 dominate during the night causing unusually high evaporation rates after sunset.

Dunbar's number: group size and brain physiology in humans reexamined.

PubMed

de Ruiter, Jan; Weston, Gavin; Lyon, Stephen M

2011-01-01

Popular academic ideas linking physiological adaptations to social behaviors are spreading disconcertingly into wider societal contexts. In this article, we note our skepticism with one particularly popular—in our view, problematic—supposed causal correlation between neocortex size and social group size. The resulting Dunbar's Number, as it has come to be called, has been statistically tested against observed group size in different primate species. Although there may be reason to doubt the Dunbar's Number hypothesis among nonhuman primate species, we restrict ourselves here to the application of such an explanatory hypothesis to human, culture-manipulating populations. Human information process management, we argue, cannot be understood as a simple product of brain physiology. Cross-cultural comparison of not only group size but also relationship-reckoning systems like kinship terminologies suggests that although neocortices are undoubtedly crucial to human behavior, they cannot be given such primacy in explaining complex group composition, formation, or management.

Reverse engineering of the homogeneous-entity product profiles based on CCD

NASA Astrophysics Data System (ADS)

Gan, Yong; Zhong, Jingru; Sun, Ning; Sun, Aoran

2011-08-01

This measurement system uses delaminated measurement principle, measures the three perpendicular direction values of the entities. When the measured entity is immerged in the liquid layer by layer, every layer's image are collected by CCD and digitally processed. It introduces the basic measuring principle and the working process of the measure method. According to Archimedes law, the related buoyancy and volume that soaked in different layer's depth are measured by electron balance and the mathematics models are established. Through calculating every layer's weight and centre of gravity by computer based on the method of Artificial Intelligence, we can reckon 3D coordinate values of every minute entity cell in different layers and its 3D contour picture is constructed. The experimental results show that for all the homogeneous entity insoluble in water, it can measure them. The measurement velocity is fast and non-destructive test, it can measure the entity with internal hole.

Behavior of micro-particles in monolith ceramic membrane filtration with pre-coagulation.

PubMed

Yonekawa, H; Tomita, Y; Watanabe, Y

2004-01-01

This paper is intended to clarify the characteristics unique to monolith ceramic membranes with pre-coagulation by referring to the behavior of micro-particles. Flow analysis and experiments have proved that monolith ceramic membranes show a unique flow pattern in the channels within the element, causing extremely rapid flocculation in the channel during dead-end filtration. It was assumed that charge-neutralized micro-particles concentrated near the membrane surface grow in size due to flocculation, and as a result, coarse micro-particles were taken up by the shearing force to flow out. As the dead end points of flow in all the channels are located near the end of the channels with higher filterability, most of the flocculated coarse particles are formed to a columnar cake intensively at the dead end point. Therefore cake layer forming on the membrane other than around the dead end point is alleviated. This behavior of particle flocculation and cake formation at the dead end point within the channels are unique characteristics of monolith ceramic membranes. This is why all monolith ceramic membrane water purification systems operating in Japan do not have pretreatment equipment for flocculation and sedimentation.

Design of push-pull system to control diesel particular matter inside a dead-end entry.

PubMed

Zheng, Yi; Thiruvengadam, Magesh; Lan, Hai; Tien, Jerry C

Diesel particulate matter (DPM) is considered to be carcinogenic after prolonged exposure. With more diesel-powered equipment used in underground mines, miners' exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push-pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push-pull systems considered include: long push and short pull tubing; short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.

Evolution of an accretion disc in binary black hole systems

NASA Astrophysics Data System (ADS)

Kimura, Shigeo S.; Takahashi, Sanemichi Z.; Toma, Kenji

2017-03-01

We investigate evolution of an accretion disc in binary black hole (BBH) systems and possible electromagnetic counterparts of the gravitational waves from mergers of BBHs. Perna et al. proposed a novel evolutionary scenario of an accretion disc in BBHs in which a disc eventually becomes 'dead', I.e. the magnetorotational instability (MRI) becomes inactive. In their scenario, the dead disc survives until a few seconds before the merger event. We improve the dead disc model and propose another scenario, taking account of effects of the tidal torque from the companion and the critical ionization degree for MRI activation more carefully. We find that the mass of the dead disc is much lower than that in the Perna's scenario. When the binary separation sufficiently becomes small, the mass inflow induced by the tidal torque reactivates MRI, restarting mass accretion on to the black hole. We also find that this disc 'revival' happens more than thousands of years before the merger. The mass accretion induced by the tidal torque increases as the separation decreases, and a relativistic jet could be launched before the merger. The emissions from these jets are too faint compared to gamma-ray bursts, but detectable if the merger events happen within ≲10 Mpc or if the masses of the black holes are as massive as ˜105 M⊙.

Neural-adaptive control of single-master-multiple-slaves teleoperation for coordinated multiple mobile manipulators with time-varying communication delays and input uncertainties.

PubMed

Li, Zhijun; Su, Chun-Yi

2013-09-01

In this paper, adaptive neural network control is investigated for single-master-multiple-slaves teleoperation in consideration of time delays and input dead-zone uncertainties for multiple mobile manipulators carrying a common object in a cooperative manner. Firstly, concise dynamics of teleoperation systems consisting of a single master robot, multiple coordinated slave robots, and the object are developed in the task space. To handle asymmetric time-varying delays in communication channels and unknown asymmetric input dead zones, the nonlinear dynamics of the teleoperation system are transformed into two subsystems through feedback linearization: local master or slave dynamics including the unknown input dead zones and delayed dynamics for the purpose of synchronization. Then, a model reference neural network control strategy based on linear matrix inequalities (LMI) and adaptive techniques is proposed. The developed control approach ensures that the defined tracking errors converge to zero whereas the coordination internal force errors remain bounded and can be made arbitrarily small. Throughout this paper, stability analysis is performed via explicit Lyapunov techniques under specific LMI conditions. The proposed adaptive neural network control scheme is robust against motion disturbances, parametric uncertainties, time-varying delays, and input dead zones, which is validated by simulation studies.

Is floral specialization an evolutionary dead-end? Pollination system transitions in Ruellia (Acanthaceae).

PubMed

Tripp, Erin A; Manos, Paul S

2008-07-01

Pollination systems frequently reflect adaptations to particular groups of pollinators. Such systems are indicative of evolutionary specialization and have been important in angiosperm diversification. We studied the evolution of pollination systems in the large genus Ruellia. Phylogenetic analyses, morphological ordinations, ancestral state reconstructions, and a character mapping simulation were conducted to reveal key patterns in the direction and lability of floral characters associated with pollination. We found significant floral morphological differences among species that were generally associated with different groups of floral visitors. Floral evolution has been highly labile and also directional. Some specialized systems such as hawkmoth or bat pollination are likely evolutionary dead-ends. In contrast, specialized pollination by hummingbirds is clearly not a dead-end. We found evidence for multiple reverse transitions from presumed ancestral hummingbird pollination to more derived bee or insect pollination. These repeated origins of insect pollination from hummingbird-pollinated ancestors have not evolved without historical baggage. Flowers of insect-pollinated species derived from hummingbird-pollinated ancestors are morphologically more similar to hummingbird flowers than they are to other more distantly related insect-pollinated flowers. Finally, some pollinator switches were concomitant with changes in floral morphology that are associated with those pollinators. These observations are consistent with the hypothesis that some transitions have been adaptive in the evolution of Ruellia.

Developing Army Leaders for 21st Century Missions: Teaching Army Leaders Behavioral Science Theories to Educate and Prepare for Full Spectrum Operations

DTIC Science & Technology

2002-07-01

reckoned with and one that is likely to succeed. Leaders who effectively motivate their soldiers inspire , encourage, and guide them toward mission...Virginia 22134-5068 MASTER OF MILITARY STUDIES Developing Army Leaders for 21st Century Missions: Teaching Army Leaders Behavioral Science Theories to...REPORT TYPE Student research paper 3. DATES COVERED (FROM - TO) xx-xx-2001 to xx-xx-2002 4. TITLE AND SUBTITLE Developing Army Leaders for 21st Century

Options for reducing HIV transmission related to the dead space in needles and syringes.

PubMed

Zule, William A; Pande, Poonam G; Otiashvili, David; Bobashev, Georgiy V; Friedman, Samuel R; Gyarmathy, V Anna; Des Jarlais, Don C

2018-01-15

When shared by people who inject drugs, needles and syringes with different dead space may affect the probability of HIV and hepatitis C virus (HCV) transmission differently. We measured dead space in 56 needle and syringe combinations obtained from needle and syringe programs across 17 countries in Europe and Asia. We also calculated the amounts of blood and HIV that would remain in different combinations following injection and rinsing. Syringe barrel capacities ranged from 0.5 to 20 mL. Needles ranged in length from 8 to 38 mm. The average dead space was 3 μL in low dead space syringes with permanently attached needles, 13 μL in high dead space syringes with low dead space needles, 45 μL in low dead space syringes with high dead space needles, and 99 μL in high dead space syringes with high dead space needles. Among low dead space designs, calculated volumes of blood and HIV viral burden were lowest for low dead space syringes with permanently attached needles and highest for low dead space syringes with high dead space needles. The dead space in different low dead space needle and syringe combinations varied substantially. To reduce HIV transmission related to syringe sharing, needle and syringe programs need to combine this knowledge with the needs of their clients.

Comparison of capnovolumetry-derived dead space parameters with pulmonary function test in normal adults using histamine provocation.

PubMed

Sun, Xiaoli; Zhang, Yan; Yang, Wenlan; Liu, Jinming

2015-04-01

This study in healthy adults was conducted to explore the clinical application of capnovolumetric indices as compared to lung function parameters using histamine provocation. Forty healthy subjects received aerosol histamine or salbutamol in an automatic stimulation system with escalating doses of histamine. Dead space volumes of capnovolumetry and lung function parameters were examined with increased concentrations of histamine at a fixed time interval. The doses of histamine were selected from 0.0562 mg-2.2 mg and 0.1 mg salbutamol was inhaled when a maximal dose of histamine was reached. Baseline values in each group were calculated prior to histamine inhalation. Fowler dead space (VDF), Wolff dead space (VDW), threshold dead space (VDT), Bohr dead space (VDB), forced expiratory volume in 1 s (FEV1 ) and peak expiratory flow (PEF) showed a dose-dependent reduction following histamine provocation, but there were no statistical differences in the measurements at baseline and post S6 provocation. The value of dC3/DV at the maximal dose was significantly increased over its baseline value (P < 0.05). VDF, VDT and VDW were significantly increased after bronchodilator use (P < 0.05 or <0.01). The changes in capnovolumetry did not correspond with the results of lung function test. The dC3/DV and airway dead spaces of capnovolumetry in healthy adults are significantly increased compared to lung function parameters before or after bronchodilator use, suggesting that capnovolumetry is feasible in diagnostic evaluation of airway reactivity, especially for persons who are unable to undertake lung function test. © 2014 John Wiley & Sons Ltd.

How big is the Ocean Dead Zone off the Coast of California?

NASA Astrophysics Data System (ADS)

Hofmann, A. F.; Peltzer, E. T.; Walz, P. M.; Brewer, P. G.

2010-12-01

The term “Ocean Dead Zone”, generally referring to a zone that is devoid of aerobic marine life of value to humans, is now widely used in the press and scientific literature but it appears to be not universally defined. The global assessment and monitoring of ocean dead zones, however, is of high public concern due to the considerable economic value associated with impacted fisheries and with questions over the growth of these zones forced by climate change. We report on the existence of a zone at ~850m depth off Santa Monica, California where dissolved oxygen (DO) levels are 1 μmol/kg; an order of magnitude below any existing definition of an “Ocean Dead Zone”. ROV dives show the region to be visually devoid of all aerobic marine life. But how large is this dead zone, and how may its boundaries be defined? Without an accepted definition we cannot report this nor can we compare it to other dead zones reported elsewhere in the world. “Dead zones” are now assessed solely by DO levels. A multitude of values in different units are used (Fig 1), which are clearly not universally applicable. This seriously hampers an integrated global monitoring and management effort and frustrates the development of valid connections with climate change and assessment of the consequences. Furthermore, input of anthropogenic CO2 can also stress marine life. Recent work supported by classical data suggests that higher pCO2 influences the thermodynamic energy efficiency of oxic respiration (CH2O + O2 -> CO2 + H2O). The ratio pO2/pCO2, called the respiration index (RI), emerges as the critical variable, combining the impacts of warming on DO and rising CO2 levels within a single, well defined quantity. We advocate that future monitoring efforts report pO2 and pCO2 concurrently, thus making it possible to classify, monitor and manage “dead zones” within a standard reference system that may include, as with e.g, hurricanes, differing categories of intensity. Fig.1. A DO profile off Southern California with overlay of commonly used DO thresholds (μmolO2/kg); “dead zones” may occur anywhere from 250 - 2,200 m depth. The widely reported “dead zone” off the Mississippi delta is defined by DO of < 2 mg/l (~ 64 μmol/kg).

Foehn-induced effects on dust pollution, frontal clouds and solar radiation in the Dead Sea valley

NASA Astrophysics Data System (ADS)

Kishcha, Pavel; Starobinets, Boris; Alpert, Pinhas; Kaplan, Michael

2017-04-01

The significant drying up of the Dead Sea over the past 40 years has led to an increase in an exposed area contributing to local dust pollution. Measurements show that, sometimes, in the Dead Sea valley, dust pollution can reach extreme concentrations up to several thousands of micrograms per cubic meters. Our analysis of a meteorological situation shows that a foehn phenomenon can be a causal factor for the aforementioned extreme local dust concentration. This foehn phenomenon creates strong warm and dry winds, which are accompanied by air turbulence and temperature inversion. In our study, foehn-induced effects on dust pollution, frontal clouds and solar radiation were analyzed over the Judean Mountains ( 1000 m) and over the Dead Sea valley (-420 m), using high-resolution numerical simulations and in-situ observations at meteorological stations located across the mountain ridge. An extreme dust episode occurring on March 22, 2013, was analyzed, which was characterized by measured surface dust concentrations of up to 7000 µg m-3 in the Dead Sea valley. We simulated this foehn phenomenon with the 3-km resolution COSMO-ART model. Our analysis has shown that the foehn phenomenon could be observed even over the relatively low Judean Mountains. This analysis was based on various meteorological, pyranometer, radar, and aerosol measurements together with high-resolution model data. In the Dead Sea valley, the maximum aerosol optical depth (AOD) did not coincide with the maximum surface dust concentration. This lack of coincidence indicates difficulties in using satellite-based AOD for initializing dust concentration within numerical forecast systems over this region with complex terrain. In the western Dead Sea valley, strong foehn winds of over 20 m/s were accompanied by maximal air turbulence leading to maximal local dust emissions. Thus, the model showed that, by creating significant turbulence, the foehn phenomenon intensified the saltation (bombardment) mechanism of local dust generation in the western Dead Sea valley. In addition, the foehn-induced pronounced temperature inversion trapped dust particles beneath this inversion. These two factors caused the measured extreme surface dust concentration in the Dead Sea valley on the specified day. Radar data on March 22 showed a passage of multi-layer frontal cloudiness through the area of the Dead Sea valley leading to a sharp drop in noon solar radiation. The strong descending airflow over the downwind side of the Judean Mountains significantly influenced the frontal cloudiness leading to the formation of a cloud-free band over the Dead Sea valley.

Complement component 4

MedlinePlus

... of a certain protein. This protein is part of the complement system. The complement system is a group of proteins ... system and play a role in the development of inflammation. The complement system protects the body from infections, dead cells and ...

Normal Grief and Complicated Bereavement among Traumatized Cambodian Refugees: Cultural Context and the Central Role of Dreams of the Dead

PubMed Central

Hinton, Devon E.; Peou, Sonith; Joshi, Siddharth; Nickerson, Angela; Simon, Naomi

2013-01-01

This article profiles bereavement among traumatized Cambodian refugees and explores the validity of a model of how grief and PTSD interact in this group to form a unique bereavement ontology, a model in which dreams of the dead play a crucial role. Several studies were conducted at a psychiatric clinic treating Cambodian refugees who survived the Pol Pot genocide. Key findings included that Pol Pot deaths were made even more deeply disturbing owing to cultural ideas about “bad death” and the consequences of not performing mortuary rites; that pained recall of the dead in the last month was common (76% of patients) and usually caused great emotional and somatic distress; that severity of pained recall of the dead was strongly associated with PTSD severity (r = .62); that pained recall was very often triggered by dreaming about the dead, usually of someone who died in the Pol Pot period; and that Cambodians have a complex system of interpretation of dreams of the deceased that frequently causes those dreams to give rise to great distress. Cases are provided that further illustrate the centrality of dreams of the dead in the Cambodian experiencing of grief and PTSD. The article shows that not assessing dreams and concerns about the spiritual status of the deceased in the evaluation of bereavement results in “category truncation,” i.e., a lack of content validity, a form of category fallacy. PMID:23868080

Normal grief and complicated bereavement among traumatized Cambodian refugees: cultural context and the central role of dreams of the dead.

PubMed

Hinton, Devon E; Peou, Sonith; Joshi, Siddharth; Nickerson, Angela; Simon, Naomi M

2013-09-01

This article profiles bereavement among traumatized Cambodian refugees and explores the validity of a model of how grief and post-traumatic stress disorder (PTSD) interact in this group to form a unique bereavement ontology, a model in which dreams of the dead play a crucial role. Several studies were conducted at a psychiatric clinic treating Cambodian refugees who survived the Pol Pot genocide. Key findings included that Pol Pot deaths were made even more deeply disturbing owing to cultural ideas about "bad death" and the consequences of not performing mortuary rites; that pained recall of the dead in the last month was common (76 % of patients) and usually caused great emotional and somatic distress; that severity of pained recall of the dead was strongly associated with PTSD severity (r = .62); that pained recall was very often triggered by dreaming about the dead, usually of someone who died in the Pol Pot period; and that Cambodians have a complex system of interpretation of dreams of the deceased that frequently causes those dreams to give rise to great distress. Cases are provided that further illustrate the centrality of dreams of the dead in the Cambodian experiencing of grief and PTSD. The article shows that not assessing dreams and concerns about the spiritual status of the deceased in the evaluation of bereavement results in "category truncation," i.e., a lack of content validity, a form of category fallacy.

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2011 CFR

2011-07-01

... dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead center). c. Valve... (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top-dead center or...

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2010 CFR

2010-07-01

... dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead center). c. Valve... (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top-dead center or...

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Interstate movement of dead birds and... (END) § 82.6 Interstate movement of dead birds and dead poultry from a quarantined area. (a) Except as provided in paragraph (b) of this section for dressed carcasses, dead birds and dead poultry, including any...

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Interstate movement of dead birds and... (END) § 82.6 Interstate movement of dead birds and dead poultry from a quarantined area. (a) Except as provided in paragraph (b) of this section for dressed carcasses, dead birds and dead poultry, including any...

46 CFR 169.623 - Power-driven steering systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... systems must have means to be brought into operation from a dead ship condition, without external aid. The... steering systems from the main steering control location must include, as applicable— (1) Control of any...

46 CFR 169.623 - Power-driven steering systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... systems must have means to be brought into operation from a dead ship condition, without external aid. The... steering systems from the main steering control location must include, as applicable— (1) Control of any...

46 CFR 169.623 - Power-driven steering systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... systems must have means to be brought into operation from a dead ship condition, without external aid. The... steering systems from the main steering control location must include, as applicable— (1) Control of any...

Complement component 3 (C3)

MedlinePlus

... of a certain protein. This protein is part of the complement system. The complement system is a group of proteins ... system and play a role in the development of inflammation. The complement system protects the body from infections, dead cells and ...

The dead spot phenomenon in prosthetic gait: Quantified with an analysis of center of pressure progression and its velocity in the sagittal plane.

PubMed

Klenow, Tyler D; Kahle, Jason T; Highsmith, M Jason

2016-10-01

The "dead spot" phenomenon in prosthetics is a disruption in forward progression observed in the rearfoot of passive prosthetic foot-ankle systems which results in a compensatory and inefficient gait pattern by amputees. A metric to quantify the dead spot as a kinetic event has not yet been introduced. The present study implements a three-part metric to evaluate the dead spot in terms of time, magnitude, and total area using center of pressure velocity and a novel threshold value calculation. The metrics are implemented for proof of efficacy using a convenient sample of four amputees (2 transtibial, 2 transfemoral) who walked in a 3D motion capture system with integrated force plates over five foot conditions. "Continuous-lever" feet designs showed the most favorable metric results between subjects (p<0.05) and in an ad hoc analysis compared to an ideal foot condition within subjects (p>0.05). Ten of 18 (55.6%) foot conditions found to be similar to the ideal were continuous-lever feet. Lack of significant similarity between the feet and ideal conditions (1 of 18, 5.6%) were found in transfemoral subjects. The metric calculations were able to show statistical difference among foot conditions between subjects. One foot (continuous-lever, glass composite) had no detectable dead spot in the transtibial subjects. The lack of significant findings in transfemoral subjects indicates a different coefficient in threshold calculations may be more appropriate for these subjects versus transtibial subjects. Further research with larger sample is needed to determine clinically significant findings among feet and between transtibial and transfemoral subjects. Published by Elsevier Ltd.

The circulation of the Dead Sea brine in the regional aquifer

NASA Astrophysics Data System (ADS)

Weber, Nurit; Yechieli, Yoseph; Stein, Mordechai; Yokochi, Reika; Gavrieli, Ittai; Zappala, Jake; Mueller, Peter; Lazar, Boaz

2018-07-01

Ca-chloride brines have circulated between the lakes and the adjacent aquifers throughout the history of the Dead Sea lacustrine-hydrology system. The Ein-Qedem (EQ) hydrothermal saline springs system discharging at the western shores of the modern Dead Sea is the modern manifestation of this essential and continuous process. The EQ springs comprise the most significant source of Ca-chloride brine that currently discharges into the lake. The chemical composition of EQ brine has remained virtually uniform during the past ca. 40 yr, indicating that the brine represents a large groundwater reservoir. The EQ brine evolved from ancient Ca-chloride brine that occupied the tectonic depression of the Dead Sea Basin during the Quaternary. During this period, the composition of lake's brine was affected by mixing with freshwater and formation of primary minerals. Based on chronological and geochemical data, we argue that the EQ brine comprises the epilimnetic solution of last glacial Lake Lisan that penetrated and circulated through the adjacent Judea Group aquifer. 14C and 81Kr dating indicates recharge ages spanning the time interval of ∼40-20 ka, coinciding with the period when the lake reached its highest stand (of ∼ 200 ± 30 m below msl, at ∼31-17.4 ka) and maintained a stable layered (stratified) configuration for a period of several ten thousand years. The presented evidence suggests that the circulation of the Ca-chloride brine involves penetration into the aquifer during high stands (EQ brine recharge) and its discharge back into the lake during the modern low stands (∼400 to 430 m below msl). Accordingly, the mechanism of brine circulation between the lake and the marginal aquifers is related to the long-term hydro-climate history of the Dead Sea basin and its vicinity.

A 300m-width sinkhole threatens the stability of the embankment of a saltpan in Jordan, Dead Sea Region

NASA Astrophysics Data System (ADS)

Closson, Damien; Abou Karaki, Najib; Pasquali, Paolo; Riccardi, Paolo

2013-04-01

Since the 1980s, the Dead Sea coastal zone is affected by sinkholes. The dynamic of the salt karst system is attested by a drastic increase of collapse events. The energy available for sub-surface erosion (or cavities genesis) is related to the head difference between the water table and the lake level which drop down at an accelerating rate of more than 1 m/yr. In the region of Ghor Al Haditha, Jordan, the size of the craters increased significantly during the last decade. Up to now, the greatest compound structure observed (association of metric subsidence, decametric sinkholes, and landslides) was about 150-200 m in diameter. End of December 2012, a single circular structure having 250-300 m in diameter was identified within a 10 km x 1.5 km saltpan of the Arab Potash Company. This finding raises questions regarding the origin of the underlying cavity and the capability of prediction of all models developed up to now in Israel and Jordan regarding the Dead Sea sinkholes. The analysis of satellite images of the past shows that the appearance of this unique depression is very recent (probably less than 5 years). Cosmo-SkyMed radar images have been processed to map the associated deformation field. Ground motions attest that the overall diameter could be around 600 m. Currently, this sinkhole is threatening the stability of more than one kilometer of a 12 km long dike holding 90 million m3 of Dead Sea brine. This case study underlines the great fragility of the Dead Sea salt karst and demonstrates the need for the setting up of an early warning system.

Local potential evolutions during proton exchange membrane fuel cell operation with dead-ended anode - Part II: Aging mitigation strategies based on water management and nitrogen crossover

NASA Astrophysics Data System (ADS)

Abbou, S.; Dillet, J.; Maranzana, G.; Didierjean, S.; Lottin, O.

2017-02-01

Proton exchange membrane (PEM) fuel cells operate with dead-ended anode in order to reduce system cost and complexity when compared with hydrogen re-circulation systems. In the first part of this work, we showed that localized fuel starvation events may occur, because of water and nitrogen accumulation in the anode side, which could be particularly damaging to the cell performance. To prevent these degradations, the anode compartment must be purged which may lead to an overall system efficiency decrease because of significant hydrogen waste. In the second part, we present several purge strategies in order to minimize both hydrogen waste and membrane-electrode assembly degradations during dead-ended anode operation. A linear segmented cell with reference electrodes was used to monitor simultaneously the current density distribution along the gas channel and the time evolution of local anode and cathode potentials. To asses MEA damages, Platinum ElectroChemical Surface Area (ECSA) and cell performance were periodically measured. The results showed that dead-end mode operation with an anode plate maintained at a temperature 5 °C hotter than the cathode plate limits water accumulation in the anode side, reducing significantly purge frequency (and thus hydrogen losses) as well as MEA damages. As nitrogen contribution to hydrogen starvation is predominant in this thermal configuration, we also tested a microleakage solution to discharge continuously most the nitrogen accumulating in the anode side while ensuring low hydrogen losses and minimum ECSA losses provided the right microleakage flow rate is chosen.

Erratum to “Estimating the effective system dead time parameter for correlated neutron counting” [Nucl. Instrum. Methods Phys. Res. A 871 (2017) 154–160

DOE PAGES

Croft, S.; Cleveland, S.; Favalli, A.; ...

2018-02-23

The expressions given for φ, the ratio of effective system dead time to gate width, are wrong for the case of the third and fourth order forms because the simple square root is used when the 3rd and 4th roots, respectively, are required. We failed to notice during proof reading that this change from the submitted manuscript had crept in. The correct form should, however, be clear from the steps of the derivations outlined in the text; and so we hope our mistake has not misled anyone.

Erratum to “Estimating the effective system dead time parameter for correlated neutron counting” [Nucl. Instrum. Methods Phys. Res. A 871 (2017) 154–160

DOE Office of Scientific and Technical Information (OSTI.GOV)

Croft, S.; Cleveland, S.; Favalli, A.

The expressions given for φ, the ratio of effective system dead time to gate width, are wrong for the case of the third and fourth order forms because the simple square root is used when the 3rd and 4th roots, respectively, are required. We failed to notice during proof reading that this change from the submitted manuscript had crept in. The correct form should, however, be clear from the steps of the derivations outlined in the text; and so we hope our mistake has not misled anyone.

Observed-Based Adaptive Fuzzy Tracking Control for Switched Nonlinear Systems With Dead-Zone.

PubMed

Tong, Shaocheng; Sui, Shuai; Li, Yongming

2015-12-01

In this paper, the problem of adaptive fuzzy output-feedback control is investigated for a class of uncertain switched nonlinear systems in strict-feedback form. The considered switched systems contain unknown nonlinearities, dead-zone, and immeasurable states. Fuzzy logic systems are utilized to approximate the unknown nonlinear functions, a switched fuzzy state observer is designed and thus the immeasurable states are obtained by it. By applying the adaptive backstepping design principle and the average dwell time method, an adaptive fuzzy output-feedback tracking control approach is developed. It is proved that the proposed control approach can guarantee that all the variables in the closed-loop system are bounded under a class of switching signals with average dwell time, and also that the system output can track a given reference signal as closely as possible. The simulation results are given to check the effectiveness of the proposed approach.

Solanaceae IV: Atropa belladonna, deadly nightshade.

PubMed

Lee, M R

2007-03-01

The Deadly Nightshade, Atropa belladonna, is a plant surrounded by myth, fear and awe. In antiquity, the Greeks and the Romans knew that it contained a deadly poison. In medieval times, it was widely used by witches, sorcerors and professional poisoners. Linnaeus later codified its remarkable properties as the genus Atropa, the Fate that slits the thin spun life and the species belladonna because of its power to dilate the pupils. In the 1830s, the pure alkaloid I-atropine was isolated from the plant. This proved to be a significant tool in the study of the autonomic nervous system leading to the identification of acetylcholine as an important neurotransmitter in mammals. When pure atropine became available, it caused a large number of deaths, whether by accident, suicide or homicide.

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2014 CFR

2014-07-01

... valve lash dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead.... Opening timing (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top...

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2014 CFR

2014-01-01

... for the disposal of dead birds or dead poultry that are infected with Newcastle disease, or dead birds or dead poultry from flocks infected with Newcastle disease, or manure generated by or eggs from... following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and...

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2012 CFR

2012-07-01

... valve lash dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead.... Opening timing (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top...

40 CFR Appendix II to Part 1068 - Emission-Related Parameters and Specifications

Code of Federal Regulations, 2013 CFR

2013-07-01

... valve lash dimension. 4. Camshaft timing. a. Valve opening—intake exhaust (degrees from top-dead center or bottom-dead center). b. Valve closing—intake exhaust (degrees from top-dead center or bottom-dead.... Opening timing (degrees from top-dead center or bottom-dead center). c. Closing timing (degrees from top...

Diphtheria Symptoms

MedlinePlus

... into and attach to the lining of the respiratory system, which includes parts of the body that help ... neck The poison destroys healthy tissues in the respiratory system. Within two to three days, the dead tissue ...

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2012 CFR

2012-01-01

... required for the disposal of dead birds or dead poultry that are infected with END, or dead birds or dead..., the special permit will also include the following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and (ii) The number and type of birds, poultry, or other...

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2010 CFR

2010-01-01

... required for the disposal of dead birds or dead poultry that are infected with END, or dead birds or dead..., the special permit will also include the following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and (ii) The number and type of birds, poultry, or other...

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2013 CFR

2013-01-01

... required for the disposal of dead birds or dead poultry that are infected with END, or dead birds or dead..., the special permit will also include the following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and (ii) The number and type of birds, poultry, or other...

9 CFR 82.12 - Other interstate movements and special permits.

Code of Federal Regulations, 2011 CFR

2011-01-01

... required for the disposal of dead birds or dead poultry that are infected with END, or dead birds or dead..., the special permit will also include the following: (i) The address of the place where the dead birds, dead poultry, manure, or eggs are located; and (ii) The number and type of birds, poultry, or other...

Stomachaches (For Teens)

MedlinePlus

... When bacteria or viruses get into a person's digestive system, the body reacts by trying to rid itself ... small amount could be deadly. Reproductive Problems The digestive system isn't the only cause of bellyaches. Menstrual ...

Determination of power system component parameters using nonlinear dead beat estimation method

NASA Astrophysics Data System (ADS)

Kolluru, Lakshmi

Power systems are considered the most complex man-made wonders in existence today. In order to effectively supply the ever increasing demands of the consumers, power systems are required to remain stable at all times. Stability and monitoring of these complex systems are achieved by strategically placed computerized control centers. State and parameter estimation is an integral part of these facilities, as they deal with identifying the unknown states and/or parameters of the systems. Advancements in measurement technologies and the introduction of phasor measurement units (PMU) provide detailed and dynamic information of all measurements. Accurate availability of dynamic measurements provides engineers the opportunity to expand and explore various possibilities in power system dynamic analysis/control. This thesis discusses the development of a parameter determination algorithm for nonlinear power systems, using dynamic data obtained from local measurements. The proposed algorithm was developed by observing the dead beat estimator used in state space estimation of linear systems. The dead beat estimator is considered to be very effective as it is capable of obtaining the required results in a fixed number of steps. The number of steps required is related to the order of the system and the number of parameters to be estimated. The proposed algorithm uses the idea of dead beat estimator and nonlinear finite difference methods to create an algorithm which is user friendly and can determine the parameters fairly accurately and effectively. The proposed algorithm is based on a deterministic approach, which uses dynamic data and mathematical models of power system components to determine the unknown parameters. The effectiveness of the algorithm is tested by implementing it to identify the unknown parameters of a synchronous machine. MATLAB environment is used to create three test cases for dynamic analysis of the system with assumed known parameters. Faults are introduced in the virtual test systems and the dynamic data obtained in each case is analyzed and recorded. Ideally, actual measurements are to be provided to the algorithm. As the measurements are not readily available the data obtained from simulations is fed into the determination algorithm as inputs. The obtained results are then compared to the original (or assumed) values of the parameters. The results obtained suggest that the algorithm is able to determine the parameters of a synchronous machine when crisp data is available.

SlDEAD31, a Putative DEAD-Box RNA Helicase Gene, Regulates Salt and Drought Tolerance and Stress-Related Genes in Tomato.

PubMed

Zhu, Mingku; Chen, Guoping; Dong, Tingting; Wang, Lingling; Zhang, Jianling; Zhao, Zhiping; Hu, Zongli

2015-01-01

The DEAD-box RNA helicases are involved in almost every aspect of RNA metabolism, associated with diverse cellular functions including plant growth and development, and their importance in response to biotic and abiotic stresses is only beginning to emerge. However, none of DEAD-box genes was well characterized in tomato so far. In this study, we reported on the identification and characterization of two putative DEAD-box RNA helicase genes, SlDEAD30 and SlDEAD31 from tomato, which were classified into stress-related DEAD-box proteins by phylogenetic analysis. Expression analysis indicated that SlDEAD30 was highly expressed in roots and mature leaves, while SlDEAD31 was constantly expressed in various tissues. Furthermore, the expression of both genes was induced mainly in roots under NaCl stress, and SlDEAD31 mRNA was also increased by heat, cold, and dehydration. In stress assays, transgenic tomato plants overexpressing SlDEAD31 exhibited dramatically enhanced salt tolerance and slightly improved drought resistance, which were simultaneously demonstrated by significantly enhanced expression of multiple biotic and abiotic stress-related genes, higher survival rate, relative water content (RWC) and chlorophyll content, and lower water loss rate and malondialdehyde (MDA) production compared to wild-type plants. Collectively, these results provide a preliminary characterization of SlDEAD30 and SlDEAD31 genes in tomato, and suggest that stress-responsive SlDEAD31 is essential for salt and drought tolerance and stress-related gene regulation in plants.

Accuracy increase of self-compensator

NASA Astrophysics Data System (ADS)

Zhambalova, S. Ts; Vinogradova, A. A.

2018-03-01

In this paper, the authors consider a self-compensation system and a method for increasing its accuracy, without compromising the condition of the information theory of measuring devices. The result can be achieved using the pulse control of the tracking system in the dead zone (the zone of the proportional section of the amplifier's characteristic). Pulse control allows one to increase the control power, but the input signal of the amplifier is infinitesimal. To do this, the authors use the conversion scheme for the input quantity. It is also possible to reduce the dead band, but the system becomes unstable. The amount of information received from the instrument, correcting circuits complicates the system, and, reducing the feedback coefficient dramatically, reduces the speed. Thanks to this, without compromising the measurement condition, the authors increase the accuracy of the self-compensation system. The implementation technique allows increasing the power of the input signal by many orders of magnitude.

Scientific evidence of the therapeutic effects of dead sea treatments: a systematic review.

PubMed

Katz, Uriel; Shoenfeld, Yehuda; Zakin, Varda; Sherer, Yaniv; Sukenik, Shaul

2012-10-01

The Dead Sea, the deepest and most saline lake on earth, has been known from biblical times for its healing properties. The aim of this systematic review was to present critically the level of evidence for the claims of therapeutic effects of Dead Sea treatments in several rheumatologic diseases and psoriasis as well as to review these treatments' safety. All articles cited in MEDLINE under the query, "Dead Sea," were reviewed. We found bona fide evidence that Dead Sea treatments are especially effective in psoriasis due to both the special characteristics of solar ultraviolet radiation in the Dead Sea and the Dead Sea water balneotherapy. Dead Sea mud and Dead Sea balneotherapy have been found to be beneficial in rheumatologic diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and knee osteoarthritis. In the safety analysis, we found no evidence for an increase in skin neoplasia, although skin actinic damage seems to be increased in patients treated in the Dead Sea. Dead Sea treatments do not lead to worsening of blood pressure. Substantial ingestion of Dead Sea water (generally in unusual near-drowning cases) is toxic and can result in cardiac rhythm disturbances because of electrolyte concentration abnormalities. Laboratory analysis of Dead Sea mud did not reveal mineral concentrations that could represent a health concern for their intended use. Dead Sea treatments are beneficial in several rheumatologic diseases and psoriasis and have a good safety profile. Copyright © 2012 Elsevier Inc. All rights reserved.

The Works of Archimedes

NASA Astrophysics Data System (ADS)

Archimedes; Heath, Thomas L.

2009-09-01

Part I. Introduction: 1. Archimedes; 2. Manuscripts and principle editions; 3. Relation of Archimedes to his predecessors; 4. Arithmetic in Archimedes; 5. On the problem known as neuseis; 6. Cubic equations; 7. Anticipations by Archimedes of the integral calculus; 8. The terminology of Archimedes; Part II. The Works of Archimedes: 1. On the sphere and cylinder; 2. Measurement of a circle; 3. On conoids and spheroids; 4. On spirals; 5. On the equilibrium of planes; 6. The sand-reckoner; 7. Quadrature of the parabola; 8. On floating bodies; 9. Book of lemmas; 10. The cattle-problem.

Geologic time

USGS Publications Warehouse

Newman, William L.

2000-01-01

The Earth is very old 4 1/2 billion years or more according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science.

Accuracy of Computed Tomographic Perfusion in Diagnosis of Brain Death: A Prospective Cohort Study.

PubMed

Sawicki, Marcin; Sołek-Pastuszka, Joanna; Chamier-Ciemińska, Katarzyna; Walecka, Anna; Bohatyrewicz, Romuald

2018-05-04

BACKGROUND This study was designed to determine diagnostic accuracy of computed tomographic perfusion (CTP) compared to computed tomographic angiography (CTA) for the diagnosis of brain death (BD). MATERIAL AND METHODS Whole-brain CTP was performed in patients diagnosed with BD and in patients with devastating brain injury with preserved brainstem reflexes. CTA was derived from CTP datasets. Cerebral blood flow (CBF) and volume (CBV) were calculated in all brain regions. CTP findings were interpreted as confirming diagnosis of BD (positive) when CBF and CBV in all ROIs were below 10 mL/100 g/min and 1.0 mL/100 g, respectively. CTA findings were interpreted using a 4-point system. RESULTS Fifty brain-dead patients and 5 controls were included. In brain-dead patients, CTP results revealed CBF 0.00-9.98 mL/100 g/min and CBV 0.00-0.99 mL/100 g, and were thus interpreted as positive in all patients. CTA results suggested 7 negative cases, providing 86% sensitivity. In the non-brain-dead group, CTP results revealed CBF 2.37-37.59 mL/100 g/min and CBV 0.73-2.34 mL/100 g. The difference between values of CBF and CBV in the brain-dead and non-brain-dead groups was statistically significant (p=0.002 for CBF and p=0.001 for CBV). CTP findings in all non-brain-dead patients were interpreted as negative. This resulted in a specificity of 100% (95% CI, 0.31-1.00) for CTP in the diagnosis of BD. In all non-brain-dead patients, CTA revealed preserved intracranial filling and was interpreted as negative. This resulted in a specificity of 100% (95% CI, 0.31-1.00) for CTA in diagnosis of BD. CONCLUSIONS Whole-brain CTP seems to be a highly sensitive and specific method in diagnosis of BD.

Coding for Communication Channels with Dead-Time Constraints

NASA Technical Reports Server (NTRS)

Moision, Bruce; Hamkins, Jon

2004-01-01

Coding schemes have been designed and investigated specifically for optical and electronic data-communication channels in which information is conveyed via pulse-position modulation (PPM) subject to dead-time constraints. These schemes involve the use of error-correcting codes concatenated with codes denoted constrained codes. These codes are decoded using an interactive method. In pulse-position modulation, time is partitioned into frames of Mslots of equal duration. Each frame contains one pulsed slot (all others are non-pulsed). For a given channel, the dead-time constraints are defined as a maximum and a minimum on the allowable time between pulses. For example, if a Q-switched laser is used to transmit the pulses, then the minimum allowable dead time is the time needed to recharge the laser for the next pulse. In the case of bits recorded on a magnetic medium, the minimum allowable time between pulses depends on the recording/playback speed and the minimum distance between pulses needed to prevent interference between adjacent bits during readout. The maximum allowable dead time for a given channel is the maximum time for which it is possible to satisfy the requirement to synchronize slots. In mathematical shorthand, the dead-time constraints for a given channel are represented by the pair of integers (d,k), where d is the minimum allowable number of zeroes between ones and k is the maximum allowable number of zeroes between ones. A system of the type to which the present schemes apply is represented by a binary- input, real-valued-output channel model illustrated in the figure. At the transmitting end, information bits are first encoded by use of an error-correcting code, then further encoded by use of a constrained code. Several constrained codes for channels subject to constraints of (d,infinity) have been investigated theoretically and computationally. The baseline codes chosen for purposes of comparison were simple PPM codes characterized by M-slot PPM frames separated by d-slot dead times.

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Interstate movement of dead birds and dead poultry from a quarantined area. 82.6 Section 82.6 Animals and Animal Products ANIMAL AND PLANT... (END) § 82.6 Interstate movement of dead birds and dead poultry from a quarantined area. (a) Except as...

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Interstate movement of dead birds and dead poultry from a quarantined area. 82.6 Section 82.6 Animals and Animal Products ANIMAL AND PLANT... movement of dead birds and dead poultry from a quarantined area. (a) Except as provided in paragraph (b) of...

9 CFR 82.6 - Interstate movement of dead birds and dead poultry from a quarantined area.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Interstate movement of dead birds and dead poultry from a quarantined area. 82.6 Section 82.6 Animals and Animal Products ANIMAL AND PLANT... (END) § 82.6 Interstate movement of dead birds and dead poultry from a quarantined area. (a) Except as...

Exchange bias induced by the fully strained La{sub 2/3}Ca{sub 1/3}MnO{sub 3} dead layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Q. Y.; College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210046; Wu, X. S., E-mail: xswu@nju.edu.cn

A pure compressively strained La{sub 2/3}Ca{sub 1/3}MnO{sub 3} (LCMO) dead layer grown on (001)-oriented LaAlO{sub 3} substrate can show all the rich phenomenon of large bias field shift, coercive field enhancement, and high blocking temperature. The obtained exchange bias field (∼350 Oe) and the enhanced coercivity of about 1160 Oe at 5 K under 500 Oe cooling field are superior to that have been reported in LCMO-based ferromagnetic/antiferromagnetic superlattices or nanoscale systems. Our results clearly demonstrate that the inhomogeneous magnetic dead layer of LCMO can induce a strong exchange bias effect, which may be exploited as a very simple structure for spin-valve device application.

Small step tracking - Implications for the oculomotor 'dead zone'. [eye response failure below threshold target displacements

NASA Technical Reports Server (NTRS)

Wyman, D.; Steinman, R. M.

1973-01-01

Recently Timberlake, Wyman, Skavenski, and Steinman (1972) concluded in a study of the oculomotor error signal in the fovea that 'the oculomotor dead zone is surely smaller than 10 min and may even be less than 5 min (smaller than the 0.25 to 0.5 deg dead zone reported by Rashbass (1961) with similar stimulus conditions).' The Timberlake et al. speculation is confirmed by demonstrating that the fixating eye consistently and accurately corrects target displacements as small as 3.4 min. The contact lens optical lever technique was used to study the manner in which the oculomotor system responds to small step displacements of the fixation target. Subjects did, without prior practice, use saccades to correct step displacements of the fixation target just as they correct small position errors during maintained fixation.

Scene of Multiple Explosions

NASA Image and Video Library

2007-03-07

This composite image NASA Galaxy Evolution Explorer shows Z Camelopardalis, or Z Cam, a double-star system featuring a collapsed, dead star, called a white dwarf, and a companion star, as well as a ghostly shell around the system.

Mitochondrial and morphological variation of Tilapia zillii in Israel.

PubMed

Szitenberg, Amir; Goren, Menachem; Huchon, Dorothée

2012-04-02

Tilapia zillii is widespread in the East Levant inland aquatic systems as well as in artificial water reservoirs. In this study we explore the genetic and morphological variation of this widespread species, using mitochondrial control region sequences and meristic characters. We examine the hypothesis that T. zillii's population structure corresponds to the four Israeli aquatic systems. Out of seven natural water bodies, only two were found to possess genetically divergent populations of T. zillii. In addition to its presence in fish farms, the species was found in two artificial recreational ponds which were supposed to have been stocked only with other fish species. In these two artificial habitats, the haplotype frequencies diverged significantly from those of natural populations. Finally, fish from the Dead Sea springs of Ne'ot HaKikar appear to differ both genetically and morphologically from fish of the same aquatic system but not from fish of other water systems. Our results show that the population structure of T. zillii does not match the geography of the Israeli water-basins, with the exception of the Dead Sea and Kishon River, when considering natural populations only. The absence of a significant divergence between basins is discussed. Our results and observations suggest that the Ne'ot HaKikar Dead Sea population and those of artificial ponds could have originated from the "hitchhiking" of T. zillii, at the expense of some other cultivated tilapiine species.

Priority effects of early successional insects influence late successional fungi in dead wood.

PubMed

Jacobsen, Rannveig Margrete; Birkemoe, Tone; Sverdrup-Thygeson, Anne

2015-11-01

Community assembly is an integral process in all ecosystems, producing patterns of species distributions, biodiversity, and ecosystem functioning. Environmental filters and colonization history govern the assembly process, but their relative importance varies depending on the study system. Dead wood decomposition is a slow process, allowing decomposer communities to develop within a slowly changing substrate for decades. Despite this, there are few long-term studies of priority effects from colonization history in this ecosystem. In this study, we investigate the importance of insects in early succession of dead wood on the fungal community present one decade later. Sixty aspen trees were killed in two study landscapes, each tree producing one aspen high stump and log. Insects were sampled with flight interception traps during the first 4 years after tree death, and fungal fruiting bodies were registered in year twelve. We found positive priority effects of two fungivorous beetles, the sap beetle Glischrochilus quadripunctatus and the round fungus beetle Agathidium nigripenne, on the Artist's bracket (Ganoderma applanatum) and a positive priority effect of wood-boring beetles on the ascomycete Yellow fairy cup (Bisporella citrina). The Aspen bracket (Phellinus tremulae) did not respond to insects in early succession of the dead wood. Our results suggest that early successional insects can have significant, long-lasting effects on the late successional fungal community in dead wood. Also, the effect can be specific, with one fungus species depending on one or a few fungivorous beetle species. This has implications for decomposition and biodiversity in dead wood, as loss of early colonizing beetles may also affect the successional pathways they seem to initiate.

Proceedings of the symposium on the ecology and management of dead wood in western forests

Treesearch

William F. Laudenslayer; Patrick J. Shea; Bradley E. Valentine; C. Phillip Weatherspoon; Thomas E. Lisle

2002-01-01

Dead trees, both snags (standing dead trees) and logs (downed dead trees), are critical elements of healthy and productive forests. The “Symposium on the Ecology and Management of Dead Wood in Western Forests” was convened to bring together forest researchers and managers to share the current state of knowledge relative to the values and interactions of dead wood to...

Long non-coding RNAs as molecular players in plant defense against pathogens.

PubMed

Zaynab, Madiha; Fatima, Mahpara; Abbas, Safdar; Umair, Muhammad; Sharif, Yasir; Raza, Muhammad Ammar

2018-05-31

Long non-coding RNAs (lncRNAs) has significant role in of gene expression and silencing pathways for several biological processes in eukaryotes. lncRNAs has been reported as key player in remodeling chromatin and genome architecture, RNA stabilization and transcription regulation, including enhancer-associated activity. Host lncRNAs are reckoned as compulsory elements of plant defense. In response to pathogen attack, plants protect themselves with the help of lncRNAs -dependent immune systems in which lncRNAs regulate pathogen-associated molecular patterns (PAMPs) and other effectors. Role of lncRNAs in plant microbe interaction has been studied extensively but regulations of several lncRNAs still need extensive research. In this study we discussed and provide as overview the topical advancements and findings relevant to pathogen attack and plant defense mediated by lncRNAs. It is hoped that lncRNAs would be exploited as a mainstream player to achieve food security by tackling different plant diseases. Copyright © 2018. Published by Elsevier Ltd.

Roman vs. Arabic Computistics in Twelfth-Century England: A Newly Discovered Source (Collatio Compoti Romani et Arabici).

PubMed

Nothaft, C Philipp E

2015-01-01

A frequently overlooked aspect of the knowledge transfer from Arabic into Latin in the twelfth century is the introduction of the Islamo-Arabic calendar, which confronted Western computists with a radically different scheme of lunar reckoning that was in some ways superior to the 19-year lunar cycle of the Roman Church. One of the earliest sources to properly discuss this new system and compare it to the old one is the anonymous Collatio Compoti Romani et Arabici, found in a manuscript from Tewkesbury Abbey, Gloucestershire. This article contains the first edition and translation of this previously unknown text, preceded by an analysis of its content and sources. As will be argued, the text was written in the second quarter of the twelfth century as a reaction to the astronomical tables of al-Khwāizmī, recently translated by Adelard of Bath, as well as to eclipse observations that had exposed the flaws of the 'Roman' computation.

Paternity and inheritance of wealth

NASA Astrophysics Data System (ADS)

Hartung, John

1981-06-01

One of the oldest conjectures in anthropology is that men transfer wealth to their sister's son when the biological paternity of their `own' children is in doubt1-12. Because maternity is certain, a man is necessarily related to his sister's son and his brother (see Fig. 1). It is argued here that relatedness to male heirs can be assured by passing wealth to sister's sons or down a line of brothers, whether the prevailing kinship system reckons those brothers matrilineally or patrilineally. It is also argued that when several transfers of wealth are considered, a man's likelihood of being cuckolded need not be unrealistically high13 for his successive matrilineal heirs to be more related to him than his successive patrilineal heirs (see Fig. 2). Cross-cultural data on sister's son/brother inheritance14 and frequency of extramarital sex for females15 support the hypothesis that men tend to transmit wealth to their sister's son and/or brother when the probability that their putative children are their genetic children is relatively low.

A high dynamic range pulse counting detection system for mass spectrometry.

PubMed

Collings, Bruce A; Dima, Martian D; Ivosev, Gordana; Zhong, Feng

2014-01-30

A high dynamic range pulse counting system has been developed that demonstrates an ability to operate at up to 2e8 counts per second (cps) on a triple quadrupole mass spectrometer. Previous pulse counting detection systems have typically been limited to about 1e7 cps at the upper end of the systems dynamic range. Modifications to the detection electronics and dead time correction algorithm are described in this paper. A high gain transimpedance amplifier is employed that allows a multi-channel electron multiplier to be operated at a significantly lower bias potential than in previous pulse counting systems. The system utilises a high-energy conversion dynode, a multi-channel electron multiplier, a high gain transimpedance amplifier, non-paralysing detection electronics and a modified dead time correction algorithm. Modification of the dead time correction algorithm is necessary due to a characteristic of the pulse counting electronics. A pulse counting detection system with the capability to count at ion arrival rates of up to 2e8 cps is described. This is shown to provide a linear dynamic range of nearly five orders of magnitude for a sample of aprazolam with concentrations ranging from 0.0006970 ng/mL to 3333 ng/mL while monitoring the m/z 309.1 → m/z 205.2 transition. This represents an upward extension of the detector's linear dynamic range of about two orders of magnitude. A new high dynamic range pulse counting system has been developed demonstrating the ability to operate at up to 2e8 cps on a triple quadrupole mass spectrometer. This provides an upward extension of the detector's linear dynamic range by about two orders of magnitude over previous pulse counting systems. Copyright © 2013 John Wiley & Sons, Ltd.

Adaptive fuzzy prescribed performance control for MIMO nonlinear systems with unknown control direction and unknown dead-zone inputs.

PubMed

Shi, Wuxi; Luo, Rui; Li, Baoquan

2017-01-01

In this study, an adaptive fuzzy prescribed performance control approach is developed for a class of uncertain multi-input and multi-output (MIMO) nonlinear systems with unknown control direction and unknown dead-zone inputs. The properties of symmetric matrix are exploited to design adaptive fuzzy prescribed performance controller, and a Nussbaum-type function is incorporated in the controller to estimate the unknown control direction. This method has two prominent advantages: it does not require the priori knowledge of control direction and only three parameters need to be updated on-line for this MIMO systems. It is proved that all the signals in the resulting closed-loop system are bounded and that the tracking errors converge to a small residual set with the prescribed performance bounds. The effectiveness of the proposed approach is validated by simulation results. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

46 CFR 171.117 - Dead covers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Dead covers. 171.117 Section 171.117 Shipping COAST... Dead covers. (a) Except as provided in paragraph (b) of this section, each port light with the sill located below the margin line must have a hinged, inside dead cover. (b) The dead cover on a port light...

A new modelling and identification scheme for time-delay systems with experimental investigation: a relay feedback approach

NASA Astrophysics Data System (ADS)

Pandey, Saurabh; Majhi, Somanath; Ghorai, Prasenjit

2017-07-01

In this paper, the conventional relay feedback test has been modified for modelling and identification of a class of real-time dynamical systems in terms of linear transfer function models with time-delay. An ideal relay and unknown systems are connected through a negative feedback loop to bring the sustained oscillatory output around the non-zero setpoint. Thereafter, the obtained limit cycle information is substituted in the derived mathematical equations for accurate identification of unknown plants in terms of overdamped, underdamped, critically damped second-order plus dead time and stable first-order plus dead time transfer function models. Typical examples from the literature are included for the validation of the proposed identification scheme through computer simulations. Subsequently, the comparisons between estimated model and true system are drawn through integral absolute error criterion and frequency response plots. Finally, the obtained output responses through simulations are verified experimentally on real-time liquid level control system using Yokogawa Distributed Control System CENTUM CS3000 set up.

Dead bacteria reverse antibiotic-induced host defense impairment in burns.

PubMed

Chen, Lee-Wei; Chen, Pei-Hsuan; Fung, Chang-Phone; Hsu, Ching-Mei

2014-10-01

Burn patients can incur high rates of hospital-acquired infections. The mechanism of antibiotic exposure on inducing infection vulnerability has not been determined. This study aimed to examine the effects of antibiotic treatment on host defense mechanisms. First we treated C57/BL6 mice with combined antibiotic treatment after 30% to 35% total body surface area burn. Animals were sacrificed at 48 hours after sham or thermal injury treatment. Bacterial counts in intestinal lumen and mucosa were measured. Next, we treated animals with or without oral dead Escherichia coli or Staphylococcus aureus supplementation to stimulate Toll-like receptor in the intestinal mucosa. Toll-like receptor 4, antibacterial protein expression, nuclear factor (NF)-κB DNA-binding activity, and bacteria-killing activity in the intestinal mucosa; intestinal permeability; bacterial translocation to mesenteric lymph nodes; Klebsiella pneumoniae translocation; interleukin-6 in the blood; and phagocytic activity of alveolar macrophages, were assessed. Thermal injury increased microflora and NF-κB DNA-binding activity of the intestine. Systemic antibiotic treatment decreased gut microflora and increased bacterial translocation to mesenteric lymph nodes, intestinal permeability, and interleukin-6 levels in the blood. Antibiotic treatment also decreased bacteria-killing activity in intestinal mucosa and phagocytic activity of alveolar macrophages. Oral dead E coli and S aureus supplementation induced NF-κB DNA-binding activity, Toll-like receptor 4, and antibacterial protein expression of the intestinal mucosa. Taken together with the fact that dead bacteria reversed antibiotic-induced K pneumoniae translocation and intestinal and pulmonary defense impairment, we conclude that combined antibiotic treatment results in systemic host defense impairment in burns through the decrease in intestinal flora. We suggest that dead bacteria supplementation could induce nondefensin protein expression and reverse antibiotic-induced gut and lung defense impairment in burn patients. Copyright © 2014 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Size-dependent control of colloid transport via solute gradients in dead-end channels

PubMed Central

Shin, Sangwoo; Um, Eujin; Sabass, Benedikt; Ault, Jesse T.; Rahimi, Mohammad; Warren, Patrick B.; Stone, Howard A.

2016-01-01

Transport of colloids in dead-end channels is involved in widespread applications including drug delivery and underground oil and gas recovery. In such geometries, Brownian motion may be considered as the sole mechanism that enables transport of colloidal particles into or out of the channels, but it is, unfortunately, an extremely inefficient transport mechanism for microscale particles. Here, we explore the possibility of diffusiophoresis as a means to control the colloid transport in dead-end channels by introducing a solute gradient. We demonstrate that the transport of colloidal particles into the dead-end channels can be either enhanced or completely prevented via diffusiophoresis. In addition, we show that size-dependent diffusiophoretic transport of particles can be achieved by considering a finite Debye layer thickness effect, which is commonly ignored. A combination of diffusiophoresis and Brownian motion leads to a strong size-dependent focusing effect such that the larger particles tend to concentrate more and reside deeper in the channel. Our findings have implications for all manners of controlled release processes, especially for site-specific delivery systems where localized targeting of particles with minimal dispersion to the nontarget area is essential. PMID:26715753

Extra and Intracellular Synthesis of Nickel Oxide Nanoparticles Mediated by Dead Fungal Biomass

PubMed Central

Salvadori, Marcia Regina; Ando, Rômulo Augusto; Oller Nascimento, Cláudio Augusto; Corrêa, Benedito

2015-01-01

The use of dead biomass of the fungus Hypocrea lixii as a biological system is a new, effective and environmentally friendly bioprocess for the production and uptake of nickel oxide nanoparticles (NPs), which has become a promising field in nanobiotechnology. Dead biomass of the fungus was successfully used to convert nickel ions into nickel oxide NPs in aqueous solution. These NPs accumulated intracellularly and extracellularly on the cell wall surface through biosorption. The average size, morphology and location of the NPs were characterized by transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The NPs were mainly spherical and extra and intracellular NPs had an average size of 3.8 nm and 1.25 nm, respectively. X-ray photoelectron spectroscopy analysis confirmed the formation of nickel oxide NPs. Infrared spectroscopy detected the presence of functional amide groups, which are probable involved in particle binding to the biomass. The production of the NPs by dead biomass was analyzed by determining physicochemical parameters and equilibrium concentrations. The present study opens new perspectives for the biosynthesis of nanomaterials, which could become a potential biosorbent for the removal of toxic metals from polluted sites. PMID:26043111

77 FR 64373 - Culturally Significant Objects Imported for Exhibition Determinations: “The Dead Sea Scrolls...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-19

... Determinations: ``The Dead Sea Scrolls: Life and Faith in Ancient Times,'' Formerly Titled ``The Dead Sea Scrolls... the Department of State pertaining to the exhibition ``The Dead Sea Scrolls: Life and Faith in Biblical Times.'' The referenced notice is corrected here to change the exhibition name to ``The Dead Sea...

78 FR 62354 - Culturally Significant Objects Imported for Exhibition Determinations: “The Dead Sea Scrolls...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-18

... Determinations: ``The Dead Sea Scrolls: Life and Faith in Ancient Times'' Formerly Titled ``The Dead Sea Scrolls... Department of State pertaining to the exhibition ``The Dead Sea Scrolls: Life and Faith in Biblical Times... of the Federal Register (volume 77, number 203) to change the exhibition name to ``The Dead Sea...

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare DEPARTMENT OF HEALTH AND HUMAN... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

78 FR 24462 - Culturally Significant Objects Imported for Exhibition; Determinations: “The Dead Sea Scrolls...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-25

...; Determinations: ``The Dead Sea Scrolls: Life and Faith in Ancient Times'' Formerly Titled ``The Dead Sea Scrolls... Department of State pertaining to the exhibition ``The Dead Sea Scrolls: Life and Faith in Biblical Times... of the Federal Register (volume 77, number 203) to change the exhibition name to ``The Dead Sea...

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare DEPARTMENT OF HEALTH AND HUMAN... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare DEPARTMENT OF HEALTH AND HUMAN... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare Department of Health and Human... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

78 FR 16565 - Culturally Significant Objects Imported for Exhibition Determinations: “The Dead Sea Scrolls...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-15

... Determinations: ``The Dead Sea Scrolls: Life and Faith in Ancient Times'' Formerly Titled ``The Dead Sea Scrolls... Department of State pertaining to the exhibition ``The Dead Sea Scrolls: Life and Faith in Biblical Times... of the Federal Register (volume 77, number 203) to change the exhibition name to ``The Dead Sea...

45 CFR 46.206 - Research involving, after delivery, the placenta, the dead fetus or fetal material.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., the dead fetus or fetal material. 46.206 Section 46.206 Public Welfare DEPARTMENT OF HEALTH AND HUMAN... placenta, the dead fetus or fetal material. (a) Research involving, after delivery, the placenta; the dead fetus; macerated fetal material; or cells, tissue, or organs excised from a dead fetus, shall be...

More Dead than Dead: Perceptions of Persons in the Persistent Vegetative State

ERIC Educational Resources Information Center

Gray, Kurt; Knickman, T. Anne; Wegner, Daniel M.

2011-01-01

Patients in persistent vegetative state (PVS) may be biologically alive, but these experiments indicate that people see PVS as a state curiously more dead than dead. Experiment 1 found that PVS patients were perceived to have less mental capacity than the dead. Experiment 2 explained this effect as an outgrowth of afterlife beliefs, and the…

Oil industry and road traffic fatalities in contemporary Colombia.

PubMed

Tasciotti, Luca; Alejo, Didier; Romero, Andrés

2016-12-01

This paper studies the effects that oil extraction activities in Colombia have on the number of dead/injured people as a consequence of road-related accidents. Starting in 2004, the increasing exploitation of oil wells in some Colombian departments has worsened the traffic conditions due to the increased presence of trucks transporting crude oil from the wells to the refineries; this phenomenon has not been accompanied by an improvement in the road system with dramatic consequences in terms of road viability. The descriptive and empirical analysis presented here focuses on the period 2004-2011; results from descriptive statistics indicate a positive relationship between the presence of oil extraction activities and the number of either dead/injured people. Panel regressions for the period 2004-2011 confirm that, among other factors, the presence of oil-extraction activities did play a positive and statistical significant role in increasing the number of dead/injured people.

Correlation between the silica concentration and the orifice temperature in the warm springs along the jordan-dead sea rift valley

USGS Publications Warehouse

Levitte, D.; Eckstein, Y.

1978-01-01

Analysis of twenty-one thermal springs emerging along the Jordan-Dead Sea Rift Valley in Israel indicates a very good correlation between the concentration of dissolved silica and the temperature of the spring orifice. Dissolution of quartz was identified as the apparent source of the silica in the water. Application of the silica geothermometer for mixed systems suggests that the springs in the Tiberias Lake Basin are supplied with hot water from deep reservoir (or reservoirs) at a temperature of 115??C (239??F). The same temperature was postulated earlier by the application of the Na-K-Ca hydro-geothermometer to a group of thermal springs in the same basin. The temperature of the reservoir supplying hot brines to the springs emerging along the western shore of the Dead Sea is estimated at 90??C (194??F).

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... following articles may not be moved interstate from a quarantined area: (1) Dead birds and dead poultry...) Dressed carcasses of birds and poultry, and other dead birds and dead poultry, including any parts of the...

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... following articles may not be moved interstate from a quarantined area: (1) Dead birds and dead poultry...) Dressed carcasses of birds and poultry, and other dead birds and dead poultry, including any parts of the...

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... following articles may not be moved interstate from a quarantined area: (1) Dead birds and dead poultry...) Dressed carcasses of birds and poultry, and other dead birds and dead poultry, including any parts of the...

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... following articles may not be moved interstate from a quarantined area: (1) Dead birds and dead poultry...) Dressed carcasses of birds and poultry, and other dead birds and dead poultry, including any parts of the...

Investigation of the disposal of dead pigs by pig farmers in mainland China by simulation experiment.

PubMed

Wu, Linhai; Xu, Guoyan; Li, Qingguang; Hou, Bo; Hu, Wuyang; Wang, Jianhua

2017-01-01

Dead pigs are a major waste by-product of pig farming. Thus, safe disposal of dead pigs is important to the protection of consumer health and the ecological environment by preventing marketing of slaughtered and processed dead pigs and improper dumping of dead pigs. In this study, a probability model was constructed for the disposal of dead pigs by pig farmers by selecting factors affecting disposal. To that end, we drew on the definition and meaning of behavior probability based on survey data collected from 654 pig farmers in Funing County, Jiangsu Province, China. Moreover, the role of influencing factors in pig farmers' behavioral choices regarding the disposal of dead pigs was simulated by simulation experiment. The results indicated that years of farming had a positive impact on pig farmers' choice of negative disposal of dead pigs. Moreover, there was not a simple linear relationship between scale of farming and pig farmers' behavioral choices related to the disposal of dead pigs. The probability for farmers to choose the safe disposal of dead pigs increased with the improvement of their knowledge of government policies and relevant laws and regulations. Pig farmers' behavioral choice about the disposal of dead pigs was also affected by government subsidy policies, regulation, and punishment. Government regulation and punishment were more effective than subsidy. The findings of our simulation experiment provide important decision-making support for the governance in preventing the marketing of dead pigs at the source.

Comparative growth and development of spiders reared on live and dead prey.

PubMed

Peng, Yu; Zhang, Fan; Gui, Shaolan; Qiao, Huping; Hose, Grant C

2013-01-01

Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific.

Comparative Growth and Development of Spiders Reared on Live and Dead Prey

PubMed Central

Peng, Yu; Zhang, Fan; Gui, Shaolan; Qiao, Huping; Hose, Grant C.

2013-01-01

Scavenging (feeding on dead prey) has been demonstrated across a number of spider families, yet the implications of feeding on dead prey for the growth and development of individuals and population is unknown. In this study we compare the growth, development, and predatory activity of two species of spiders that were fed on live and dead prey. Pardosa astrigera (Lycosidae) and Hylyphantes graminicola (Lyniphiidae) were fed live or dead fruit flies, Drosophila melanogaster. The survival of P. astrigera and H. graminicola was not affected by prey type. The duration of late instars of P. astrigera fed dead prey were longer and mature spiders had less protein content than those fed live prey, whereas there were no differences in the rate of H. graminicola development, but the mass of mature spiders fed dead prey was greater than those fed live prey. Predation rates by P. astrigera did not differ between the two prey types, but H. graminicola had a higher rate of predation on dead than alive prey, presumably because the dead flies were easier to catch and handle. Overall, the growth, development and reproduction of H. graminicola reared with dead flies was better than those reared on live flies, yet for the larger P. astrigera, dead prey may suit smaller instars but mature spiders may be best maintained with live prey. We have clearly demonstrated that dead prey may be suitable for rearing spiders, although the success of the spiders fed such prey appears size- and species specific. PMID:24386248

How a visual surveillance system hypothesizes how you behave.

PubMed

Micheloni, C; Piciarelli, C; Foresti, G L

2006-08-01

In the last few years, the installation of a large number of cameras has led to a need for increased capabilities in video surveillance systems. It has, indeed, been more and more necessary for human operators to be helped in the understanding of ongoing activities in real environments. Nowadays, the technology and the research in the machine vision and artificial intelligence fields allow one to expect a new generation of completely autonomous systems able to reckon the behaviors of entities such as pedestrians, vehicles, and so forth. Hence, whereas the sensing aspect of these systems has been the issue considered the most so far, research is now focused mainly on more newsworthy problems concerning understanding. In this article, we present a novel method for hypothesizing the evolution of behavior. For such purposes, the system is required to extract useful information by means of low-level techniques for detecting and maintaining track of moving objects. The further estimation of performed trajectories, together with objects classification, enables one to compute the probability distribution of the normal activities (e.g., trajectories). Such a distribution is defined by means of a novel clustering technique. The resulting clusters are used to estimate the evolution of objects' behaviors and to speculate about any intention to act dangerously. The provided solution for hypothesizing behaviors occurring in real environments was tested in the context of an outdoor parking lot

5nsec Dead time multichannel scaling system for Mössbauer spectrometer

NASA Astrophysics Data System (ADS)

Verrastro, C.; Trombetta, G.; Pita, A.; Saragovi, C.; Duhalde, S.

1991-11-01

A PC programmable and fast multichannel scaling module has been designed to use a commercial Mössbauer spectrometer. This module is based on a 10 single chip 8 bits microcomputer (MC6805) and on a 35 fast ALU, which allows a high performance and low cost system. The module can operate in a stand-alone mode. Data analysis are performed in real time display, on XT/AT IBM PC or compatibles. The channels are ranged between 256 and 4096, the maximum number of counts is 232-1 per channel, the dwell time is 3 μsec and the dead time between channels is 5 nsec. A friendly software display the real time spectrum and offers menues with different options at each state.

PMA-PhyloChip DNA Microarray to Elucidate Viable Microbial Community Structure

NASA Technical Reports Server (NTRS)

Venkateswaran, Kasthuri J.; Stam, Christina N.; Andersen, Gary L.; DeSantis, Todd

2011-01-01

Since the Viking missions in the mid-1970s, traditional culture-based methods have been used for microbial enumeration by various NASA programs. Viable microbes are of particular concern for spacecraft cleanliness, for forward contamination of extraterrestrial bodies (proliferation of microbes), and for crew health/safety (viable pathogenic microbes). However, a "true" estimation of viable microbial population and differentiation from their dead cells using the most sensitive molecular methods is a challenge, because of the stability of DNA from dead cells. The goal of this research is to evaluate a rapid and sensitive microbial detection concept that will selectively estimate viable microbes. Nucleic acid amplification approaches such as the polymerase chain reaction (PCR) have shown promise for reducing time to detection for a wide range of applications. The proposed method is based on the use of a fluorescent DNA intercalating agent, propidium monoazide (PMA), which can only penetrate the membrane of dead cells. The PMA-quenched reaction mixtures can be screened, where only the DNA from live cells will be available for subsequent PCR reaction and microarray detection, and be identified as part of the viable microbial community. An additional advantage of the proposed rapid method is that it will detect viable microbes and differentiate from dead cells in only a few hours, as opposed to less comprehensive culture-based assays, which take days to complete. This novel combination approach is called the PMA-Microarray method. DNA intercalating agents such as PMA have previously been used to selectively distinguish between viable and dead bacterial cells. Once in the cell, the dye intercalates with the DNA and, upon photolysis under visible light, produces stable DNA adducts. DNA cross-linked in this way is unavailable for PCR. Environmental samples suspected of containing a mixture of live and dead microbial cells/spores will be treated with PMA, and then incubated in the dark. Thereafter, the sample is exposed to visible light for five minutes, so that the DNA from dead cells will be cross-linked. Following this PMA treatment step, the sample is concentrated by centrifugation and washed (to remove excessive PMA) before DNA is extracted. The 16S rRNA gene fragments will be amplified by PCR to screen the total microbial community using PhyloChip DNA microarray analysis. This approach will detect only the viable microbial community since the PMA intercalated DNA from dead cells would be unavailable for PCR amplification. The total detection time including PCR reaction for low biomass samples will be a few hours. Numerous markets may use this technology. The food industry uses spore detection to validate new alternative food processing technologies, sterility, and quality. Pharmaceutical and medical equipment companies also detect spores as a marker for sterility. This system can be used for validating sterilization processes, water treatment systems, and in various public health and homeland security applications.

9 CFR 82.4 - General provisions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... moved interstate from a quarantined area: (1) Dead birds and dead poultry, including any parts of the... poultry, and other dead birds and dead poultry, including any parts of the birds or poultry, that are not...

Plant Responses to Pathogen Attack: Small RNAs in Focus.

PubMed

Islam, Waqar; Noman, Ali; Qasim, Muhammad; Wang, Liande

2018-02-08

Small RNAs (sRNA) are a significant group of gene expression regulators for multiple biological processes in eukaryotes. In plants, many sRNA silencing pathways produce extensive array of sRNAs with specialized roles. The evidence on record advocates for the functions of sRNAs during plant microbe interactions. Host sRNAs are reckoned as mandatory elements of plant defense. sRNAs involved in plant defense processes via different pathways include both short interfering RNA (siRNA) and microRNA (miRNA) that actively regulate immunity in response to pathogenic attack via tackling pathogen-associated molecular patterns (PAMPs) and other effectors. In response to pathogen attack, plants protect themselves with the help of sRNA-dependent immune systems. That sRNA-mediated plant defense responses play a role during infections is an established fact. However, the regulations of several sRNAs still need extensive research. In this review, we discussed the topical advancements and findings relevant to pathogen attack and plant defense mediated by sRNAs. We attempted to point out diverse sRNAs as key defenders in plant systems. It is hoped that sRNAs would be exploited as a mainstream player to achieve food security by tackling different plant diseases.

Plant Responses to Pathogen Attack: Small RNAs in Focus

PubMed Central

2018-01-01

Small RNAs (sRNA) are a significant group of gene expression regulators for multiple biological processes in eukaryotes. In plants, many sRNA silencing pathways produce extensive array of sRNAs with specialized roles. The evidence on record advocates for the functions of sRNAs during plant microbe interactions. Host sRNAs are reckoned as mandatory elements of plant defense. sRNAs involved in plant defense processes via different pathways include both short interfering RNA (siRNA) and microRNA (miRNA) that actively regulate immunity in response to pathogenic attack via tackling pathogen-associated molecular patterns (PAMPs) and other effectors. In response to pathogen attack, plants protect themselves with the help of sRNA-dependent immune systems. That sRNA-mediated plant defense responses play a role during infections is an established fact. However, the regulations of several sRNAs still need extensive research. In this review, we discussed the topical advancements and findings relevant to pathogen attack and plant defense mediated by sRNAs. We attempted to point out diverse sRNAs as key defenders in plant systems. It is hoped that sRNAs would be exploited as a mainstream player to achieve food security by tackling different plant diseases. PMID:29419801

NASA's Hubble Space Telescope Finds Dead Stars 'Polluted with Planet Debris'

NASA Image and Video Library

2017-12-08

This is an artist’s impression of a white dwarf (burned-out) star accreting rocky debris left behind by the star’s surviving planetary system. It was observed by Hubble in the Hyades star cluster. At lower right, an asteroid can be seen falling toward a Saturn-like disk of dust that is encircling the dead star. Infalling asteroids pollute the white dwarf’s atmosphere with silicon. Credit: NASA, ESA, and G. Bacon (STScI) --- NASA's Hubble Space Telescope has found the building blocks for Earth-sized planets in an unlikely place-- the atmospheres of a pair of burned-out stars called white dwarfs. These dead stars are located 150 light-years from Earth in a relatively young star cluster, Hyades, in the constellation Taurus. The star cluster is only 625 million years old. The white dwarfs are being polluted by asteroid-like debris falling onto them. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The space density of post-period minimum Cataclysmic Variables

NASA Astrophysics Data System (ADS)

Hernández Santisteban, J. V.; Knigge, C.; Pretorius, M. L.; Sullivan, M.; Warner, B.

2018-01-01

Binary evolution theory predicts that accreting white dwarfs with substellar companions dominate the Galactic population of cataclysmic variables (CVs). In order to test these predictions, it is necessary to identify these systems, which may be difficult if the signatures of accretion become too weak to be detected. The only chance to identify such 'dead' CVs is by exploiting their close binary nature. We have therefore searched the Sloan Digital Sky Survey (SDSS) Stripe 82 area for apparently isolated white dwarfs that undergo eclipses by a dark companion. We found no such eclipses in either the SDSS or Palomar Transient Factory data sets among our sample of 2264 photometrically selected white dwarf candidates within Stripe 82. This null result allows us to set a firm upper limit on the space density, ρ0, of dead CVs. In order to determine this limit, we have used Monte Carlo simulations to fold our selection criteria through a simple model of the Galactic CV distribution. Assuming a TWD = 7500 K, the resulting 2σ limit on the space density of dead CVs is ρ0 ≲ 2 × 10-5 pc-3, where TWD is the typical effective temperature of the white dwarf in such systems.

(abstract) ARGOS: a System to Monitor Ulysses Nutation and Thruster Firings from Variations of the Spacecraft Radio Signal

NASA Technical Reports Server (NTRS)

McElrath, T. P.; Cangahuala, L. A.; Miller, K. J.; Stravert, L. R.; Garcia-Perez, Raul

1995-01-01

Ulysses is a spin-stabilized spacecraft that experienced significant nutation after its launch in October 1990. This was due to the Sun-spacecraft-Earth geometry, and a study of the phenomenon predicted that the nutation would again be a problem during 1994-95. The difficulty of obtaining nutation estimates in real time from the spacecraft telemetry forced the ESA/NASA Ulysses Team to explore alternative information sources. The work performed by the ESA Operations Team provided a model for a system that uses the radio signal strength measurements to monitor the spacecraft dynamics. These measurements (referred to as AGC) are provided once per second by the tracking stations of the DSN. The system was named ARGOS (Attitude Reckoning from Ground Observable Signals) after the ever-vigilant, hundred-eyed giant of Greek Mythology. The ARGOS design also included Doppler processing, because Doppler shifts indicate thruster firings commanded by the active nutation control carried out onboard the spacecraft. While there is some visibility into thruster activity from telemetry, careful processing of the high-sample-rate Doppler data provides an accurate means of detecting the presence and time of thruster firings. DSN Doppler measurements are available at a ten-per-second rate in the same tracking data block as the AGC data.

Bending-Tolerant Anodes for Lithium-Metal Batteries.

PubMed

Wang, Aoxuan; Tang, Shan; Kong, Debin; Liu, Shan; Chiou, Kevin; Zhi, Linjie; Huang, Jiaxing; Xia, Yong-Yao; Luo, Jiayan

2018-01-01

Bendable energy-storage systems with high energy density are demanded for conformal electronics. Lithium-metal batteries including lithium-sulfur and lithium-oxygen cells have much higher theoretical energy density than lithium-ion batteries. Reckoned as the ideal anode, however, Li has many challenges when directly used, especially its tendency to form dendrite. Under bending conditions, the Li-dendrite growth can be further aggravated due to bending-induced local plastic deformation and Li-filaments pulverization. Here, the Li-metal anodes are made bending tolerant by integrating Li into bendable scaffolds such as reduced graphene oxide (r-GO) films. In the composites, the bending stress is largely dissipated by the scaffolds. The scaffolds have increased available surface for homogeneous Li plating and minimize volume fluctuation of Li electrodes during cycling. Significantly improved cycling performance under bending conditions is achieved. With the bending-tolerant r-GO/Li-metal anode, bendable lithium-sulfur and lithium-oxygen batteries with long cycling stability are realized. A bendable integrated solar cell-battery system charged by light with stable output and a series connected bendable battery pack with higher voltage is also demonstrated. It is anticipated that this bending-tolerant anode can be combined with further electrolytes and cathodes to develop new bendable energy systems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Active Structure of the Greater Dead Sea Basin

NASA Astrophysics Data System (ADS)

Shamir, G.

2002-12-01

The Greater Dead Sea Basin (GDSB) is a 220km long depression situated along the southern section of the Dead Sea Transform (DST), between two structurally and gravitationally elevated points, Wadi Malih in the north and Paran fault zone in the south. In its center is the Dead Sea basin 'sensu strictu' (DSB), which has been described since the 1970s as a pull-apart basin at a left step-over along the DST. However, several observations, or their lack thereof, contradict this scheme, e.g. (i) It is not supported by recent seismological and geomorphic data; (ii) It does not explain the fault pattern and mixed sinistral and dextral offset along the DSB western boundary; (iii) It does not simply explain the presence of intense deformation outside the presumed fault step zone; (iv) It is inconsistent with the orientation of seismically active faults within the Dead Sea and Jericho Valley; (v) The length of the DSB exceeds the total offset along the Dead Sea Transform, while its subsidence is about the age of the DST. In this study, newly acquired and analyzed data (high resolution seismic reflection and earthquake relocation and fault plane solutions) has been integrated with previously published data (structural mapping, fracture orientation distribution, Bouguer anomaly maps, sinkhole distribution, geomorphic lineaments). The results show that the GDSB is dominated by two active fault systems, one trending NNE and showing normal-dextral motion, the other trending NW. These systems are identified by earthquake activity, seismic reflection observations, alignment of recent sinkholes, and distribution of Bouguer anomaly gradients. As a result, the intra-basin structure is of a series of rectangular blocks. The dextral slip component along NNE trending faults, the mixed sense of lateral offset along the western boundary of the DSB and temporal change in fracture orientation in the Jericho Valley suggest that the intra-basin blocks have rotated counterclockwise since the Pleistocene. The overall sinistral motion between the Arabian and Israel-Sinai plates along the GDSB may thus be accommodated by the postulated, internally rotating shear zone. Then, the subsidence of the DSB may possibly be explained if the rate of the resulting internal E-W shortening is greater than the rate of plate convergence.

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

20 CFR 404.721 - Evidence to presume a person is dead.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Evidence to presume a person is dead. 404.721... person is dead. If you cannot prove the person is dead but evidence of death is needed, we will presume... person is presumed to be dead as set out in Federal law (5 U.S.C. 5565). Unless we have other evidence...

Estimating dead-space fraction for secondary analyses of ARDS clinical trials

PubMed Central

Beitler, Jeremy R.; Thompson, B. Taylor; Matthay, Michael A.; Talmor, Daniel; Liu, Kathleen D.; Zhuo, Hanjing; Hayden, Douglas; Spragg, Roger G.; Malhotra, Atul

2015-01-01

Objective Pulmonary dead-space fraction is one of few lung-specific independent predictors of mortality from acute respiratory distress syndrome (ARDS). However, it is not measured routinely in clinical trials and thus altogether ignored in secondary analyses that shape future research directions and clinical practice. This study sought to validate an estimate of dead-space fraction for use in secondary analyses of clinical trials. Design Analysis of patient-level data pooled from ARDS clinical trials. Four approaches to estimate dead-space fraction were evaluated: three required estimating metabolic rate; one estimated dead-space fraction directly. Setting U.S. academic teaching hospitals. Patients Data from 210 patients across three clinical trials were used to compare performance of estimating equations with measured dead-space fraction. A second cohort of 3,135 patients from six clinical trials without measured dead-space fraction was used to confirm whether estimates independently predicted mortality. Interventions None. Measurements and Main Results Dead-space fraction estimated using the unadjusted Harris-Benedict equation for energy expenditure was unbiased (mean ± SD Harris-Benedict 0.59 ± 0.13; measured 0.60 ± 0.12). This estimate predicted measured dead-space fraction to within ± 0.10 in 70% of patients and ± 0.20 in 95% of patients. Measured dead-space fraction independently predicted mortality (OR 1.36 per 0.05 increase in dead-space fraction, 95% CI 1.10–1.68; p < .01). The Harris-Benedict estimate closely approximated this association with mortality in the same cohort (OR 1.55, 95% CI 1.21–1.98; p < .01) and remained independently predictive of death in the larger ARDSNet cohort. Other estimates predicted measured dead-space fraction or its association with mortality less well. Conclusions Dead-space fraction should be measured in future ARDS clinical trials to facilitate incorporation into secondary analyses. For analyses where dead-space fraction was not measured, the Harris-Benedict estimate can be used to estimate dead-space fraction and adjust for its association with mortality. PMID:25738857

Preliminary experiments on dynamic biology of micro-organisms to avoid any specific full-blown syndrome on humans

NASA Astrophysics Data System (ADS)

Meer, Sneer

2002-06-01

The aim of this paper is to apply an efficient system to detect, identify and quicken suppression of any dangerous micro-organism which threatens the health of the human body in any form. It is well known that some specimens of this kind of possess a specific energy related to their speed of division, toxin emissions and high-powered interaction with human and animal cells which have the capacity to provide certain deadly full-blown syndromes. Many problems relating to the above-mentioned properties have not been clarified to date, and it is vital to find a rapid and valid reply as soon as possible. Inter-disciplinary sciences directed us to start some experiments to solve such problems, considering that the human body is dotted with a multiple interactive system of energy release, a fact which can explain the source of the micro-organism's energy also, for their necessity to manifest their deadly pathology. From practical preliminary experiments with some micro-mechanical systems using light-microscopy, connected to video TV Recorder System, one obtains optical enlarged TV images of certain processes which indicated the right way towards our crucial target; ie: the preparation of safe vaccines and safe medicines. This will constitute a basic system to a void deadly manifestations of dangerous micro-organisms and/or even regular infections on earth and in space, a system which will probably be applied at the ISS Space Station and other future actions in space in long and very long flights. We look forward to applying this system of dynamic biology towards preparation of a real and valid vaccine(s) against HIV virus on AIDS diseases.

Effects of Bacteria on Artemia franciscana Cultured in Different Gnotobiotic Environments

PubMed Central

Marques, Antonio; Dinh, Thi; Ioakeimidis, Christos; Huys, Geert; Swings, Jean; Verstraete, Willy; Dhont, Jean; Sorgeloos, Patrick; Bossier, Peter

2005-01-01

The use of probiotics is receiving considerable attention as an alternative approach to control microbiota in aquaculture farms, especially in hatching facilities. However, application with consistent results is hampered by insufficient information on their modes of action. To investigate whether dead bacteria (allowing investigation of their nutritional effect) or live bacteria (allowing evaluation of their probiotic effect) have any beneficial effect towards Artemia franciscana and, subsequently, if live bacteria have probiotic effects beyond the effects observed with dead bacteria, a model system was employed using gnotobiotic Artemia as a test organism. Nauplii were cultured in the presence of 10 bacterial strains combined with four different major axenic live feeds (two strains of Saccharomyces cerevisiae and two strains of Dunaliella tertiolecta) differing in their nutritional values. In combination with poor- and medium-quality live feeds, dead bacteria exerted a strong effect on Artemia survival but a rather weak or no effect on individual length and constituted a maximum of only 5.9% of the total ash-free dry weight supplied. These effects were reduced or even disappeared when medium- to good-quality major feed sources were used, possibly due to improvements in the health status of Artemia. Some probiotic bacteria, such as GR 8 (Cytophaga spp.), improved (not always significantly) the performance of nauplii beyond the effect observed with dead bacteria, independently of the feed supplied. The present approach can be an excellent system to study the exact mode of action of bacteria, especially if combined with challenge tests or other types of analysis (e.g., transcriptome and proteonomic analysis). PMID:16085818

Biological object recognition in μ-radiography images

NASA Astrophysics Data System (ADS)

Prochazka, A.; Dammer, J.; Weyda, F.; Sopko, V.; Benes, J.; Zeman, J.; Jandejsek, I.

2015-03-01

This study presents an applicability of real-time microradiography to biological objects, namely to horse chestnut leafminer, Cameraria ohridella (Insecta: Lepidoptera, Gracillariidae) and following image processing focusing on image segmentation and object recognition. The microradiography of insects (such as horse chestnut leafminer) provides a non-invasive imaging that leaves the organisms alive. The imaging requires a high spatial resolution (micrometer scale) radiographic system. Our radiographic system consists of a micro-focus X-ray tube and two types of detectors. The first is a charge integrating detector (Hamamatsu flat panel), the second is a pixel semiconductor detector (Medipix2 detector). The latter allows detection of single quantum photon of ionizing radiation. We obtained numerous horse chestnuts leafminer pupae in several microradiography images easy recognizable in automatic mode using the image processing methods. We implemented an algorithm that is able to count a number of dead and alive pupae in images. The algorithm was based on two methods: 1) noise reduction using mathematical morphology filters, 2) Canny edge detection. The accuracy of the algorithm is higher for the Medipix2 (average recall for detection of alive pupae =0.99, average recall for detection of dead pupae =0.83), than for the flat panel (average recall for detection of alive pupae =0.99, average recall for detection of dead pupae =0.77). Therefore, we conclude that Medipix2 has lower noise and better displays contours (edges) of biological objects. Our method allows automatic selection and calculation of dead and alive chestnut leafminer pupae. It leads to faster monitoring of the population of one of the world's important insect pest.

Self-accelerated development of salt karst during flash floods along the Dead Sea Coast, Israel

NASA Astrophysics Data System (ADS)

Avni, Yoav; Lensky, Nadav; Dente, Elad; Shviro, Maayan; Arav, Reuma; Gavrieli, Ittai; Yechieli, Yoseph; Abelson, Meir; Lutzky, Hallel; Filin, Sagi; Haviv, Itai; Baer, Gidon

2016-01-01

We document and analyze the rapid development of a real-time karst system within the subsurface salt layers of the Ze'elim Fan, Dead Sea, Israel by a multidisciplinary study that combines interferometric synthetic aperture radar and light detection and ranging measurements, sinkhole mapping, time-lapse camera monitoring, groundwater level measurements and chemical and isotopic analyses of surface runoff and groundwater. The >1 m/yr drop of Dead Sea water level and the subsequent change in the adjacent groundwater system since the 1960s resulted in flushing of the coastal aquifer by fresh groundwater, subsurface salt dissolution, gradual land subsidence and formation of sinkholes. Since 2010 this process accelerated dramatically as flash floods at the Ze'elim Fan were drained by newly formed sinkholes. During and immediately after these flood events the dissolution rates of the subsurface salt layer increased dramatically, the overlying ground surface subsided, a large number of sinkholes developed over short time periods (hours to days), and salt-saturated water resurged downstream. Groundwater flow velocities increased by more than 2 orders of magnitudes compared to previously measured velocities along the Dead Sea. The process is self-accelerating as salt dissolution enhances subsidence and sinkhole formation, which in turn increase the ponding areas of flood water and generate additional draining conduits to the subsurface. The rapid terrain response is predominantly due to the highly soluble salt. It is enhanced by the shallow depth of the salt layer, the low competence of the newly exposed unconsolidated overburden and the moderate topographic gradients of the Ze'elim Fan.

Setting Dead at Zero: Applying Scale Properties to the QALY Model.

PubMed

Roudijk, Bram; Donders, A Rogier T; Stalmeier, Peep F M

2018-04-01

Scaling severe states can be a difficult task. First, the method of measurement affects whether a health state is considered better or worse than dead. Second, in discrete choice experiments, different models to anchor health states on 0 (dead) and 1 (perfect health) produce varying amounts of health states worse than dead. Within the context of the quality-adjusted life-year (QALY) model, this article provides insight into the value assigned to dead and its consequences for decision making. Our research questions are 1) what are the arguments set forth to assign dead the number 0 on the health-utility scale? And 2) what are the effects of the position of dead on the health-utility scale on decision making? A literature review was conducted to explore the arguments set forth to assign dead a value of 0 in the QALY model. In addition, scale properties and transformations were considered. The review uncovered several practical and theoretical considerations for setting dead at 0. In the QALY model, indifference between 2 health episodes is not preserved under changes of the origin of the duration scale. Ratio scale properties are needed for the duration scale to preserve indifferences. In combination with preferences and zero conditions for duration and health, it follows that dead should have a value of 0. The health-utility and duration scales have ratio scale properties, and dead should be assigned the number 0. Furthermore, the position of dead should be carefully established, because it determines how life-saving and life-improving values are weighed in cost-utility analysis.

Experimental evaluation of the extended Dytlewski-style dead time correction formalism for neutron multiplicity counting

NASA Astrophysics Data System (ADS)

Lockhart, M.; Henzlova, D.; Croft, S.; Cutler, T.; Favalli, A.; McGahee, Ch.; Parker, R.

2018-01-01

Over the past few decades, neutron multiplicity counting has played an integral role in Special Nuclear Material (SNM) characterization pertaining to nuclear safeguards. Current neutron multiplicity analysis techniques use singles, doubles, and triples count rates because a methodology to extract and dead time correct higher order count rates (i.e. quads and pents) was not fully developed. This limitation is overcome by the recent extension of a popular dead time correction method developed by Dytlewski. This extended dead time correction algorithm, named Dytlewski-Croft-Favalli(DCF), is detailed in reference Croft and Favalli (2017), which gives an extensive explanation of the theory and implications of this new development. Dead time corrected results can then be used to assay SNM by inverting a set of extended point model equations which as well have only recently been formulated. The current paper discusses and presents the experimental evaluation of practical feasibility of the DCF dead time correction algorithm to demonstrate its performance and applicability in nuclear safeguards applications. In order to test the validity and effectiveness of the dead time correction for quads and pents, 252Cf and SNM sources were measured in high efficiency neutron multiplicity counters at the Los Alamos National Laboratory (LANL) and the count rates were extracted up to the fifth order and corrected for dead time. In order to assess the DCF dead time correction, the corrected data is compared to traditional dead time correction treatment within INCC. The DCF dead time correction is found to provide adequate dead time treatment for broad range of count rates available in practical applications.

BASIC CONCEPTS TO BE RECKONED IN A PROPER HISTORY OF ALCHEMY

PubMed Central

Mahdihassan, S.

1986-01-01

Use of simple synthetic drug called Chin – Yeh, Gold – plus – plant juice or red colloidal gold. Gold made body everlasting and the herbal principle, as soul, increased life-span. Dialectally it was called Kim – Iya. Arabicized as Al – Kimiya it finally appeared as Alchemy. Chin – Yeh as drug was only brick – red when mercury, and sulphur – with traces of gold were sublimated there resulted Chin – Tan, Gold – plus – cinnabar. It was blood – red and with redness as soul it became the ideal drug of longevity. PMID:22557523

Exact solutions for STO and (3+1)-dimensional KdV-ZK equations using (G‧/G2) -expansion method

NASA Astrophysics Data System (ADS)

Bibi, Sadaf; Mohyud-Din, Syed Tauseef; Ullah, Rahmat; Ahmed, Naveed; Khan, Umar

This article deals with finding some exact solutions of nonlinear fractional differential equations (NLFDEs) by applying a relatively new method known as (G‧/G2) -expansion method. Solutions of space-time fractional Sharma-Tasso-Olever (STO) equation of fractional order and (3+1)-dimensional KdV-Zakharov Kuznetsov (KdV-ZK) equation of fractional order are reckoned to demonstrate the validity of this method. The fractional derivative version of modified Riemann-Liouville, linked with Fractional complex transform is employed to transform fractional differential equations into the corresponding ordinary differential equations.

Mitochondrial and morphological variation of Tilapia zillii in Israel

PubMed Central

2012-01-01

Background Tilapia zillii is widespread in the East Levant inland aquatic systems as well as in artificial water reservoirs. In this study we explore the genetic and morphological variation of this widespread species, using mitochondrial control region sequences and meristic characters. We examine the hypothesis that T. zillii's population structure corresponds to the four Israeli aquatic systems. Results Out of seven natural water bodies, only two were found to possess genetically divergent populations of T. zillii. In addition to its presence in fish farms, the species was found in two artificial recreational ponds which were supposed to have been stocked only with other fish species. In these two artificial habitats, the haplotype frequencies diverged significantly from those of natural populations. Finally, fish from the Dead Sea springs of Ne'ot HaKikar appear to differ both genetically and morphologically from fish of the same aquatic system but not from fish of other water systems. Conclusions Our results show that the population structure of T. zillii does not match the geography of the Israeli water-basins, with the exception of the Dead Sea and Kishon River, when considering natural populations only. The absence of a significant divergence between basins is discussed. Our results and observations suggest that the Ne'ot HaKikar Dead Sea population and those of artificial ponds could have originated from the "hitchhiking" of T. zillii, at the expense of some other cultivated tilapiine species. PMID:22469095

Conjunctival microcirculatory blood flow is altered but not abolished in brain dead patients: a prospective observational study.

PubMed

Tamosuitis, Tomas; Pranskunas, Andrius; Balciuniene, Neringa; Pilvinis, Vidas; Boerma, E Christiaan

2016-07-11

The conjunctival microcirculation has potential as a window to cerebral perfusion due to related blood supply, close anatomical proximity and easy accessibility for microcirculatory imaging technique, such as sidestream dark field (SDF) imaging. Our study aims to evaluate conjunctival and sublingual microcirculation in brain dead patients and to compare it with healthy volunteers in two diametrically opposed conditions: full stop versus normal arterial blood supply to the brain. In a prospective observational study we analyzed conjunctival and sublingual microcirculation using SDF imaging in brain dead patients after reaching systemic hemodynamic targets to optimize perfusion of donor organs, and in healthy volunteers. All brain death diagnoses were confirmed by cerebral angiography. Microcirculatory images were obtained and analyzed using standardized published recommendations. Study registered at ClinicalTrials.gov, number NCT02483273. Eleven brain dead patients and eleven apparently healthy controls were enrolled in the study. Microvascular flow index (MFI) of small vessels was significantly lower in brain dead patients in comparison to healthy controls in ocular conjunctiva (2.7 [2.4-2.9] vs. 3.0 [2.9-3.0], p = 0.01) and in sublingual mucosa (2.8 [2.6-2.9] vs. 3.0 [2.9-3.0], p = 0.02). Total vessel density (TVD) and perfused vessel density (PVD) of small vessels were significantly lower in brain dead patients in comparison to healthy controls in ocular conjunctiva (10.2 [6.6-14.8] vs. 18.0 [18.0-25.4] mm/mm(2), p = 0.001 and 5.0 [3.5-7.3] vs. 10.9 [10.9-13.5] 1/mm, p = 0.001), but not in sublingual mucosa. In comparison to healthy controls brain dead patients had a significant reduction in conjunctival microvascular blood flow and density. However, the presence of conjunctival flow in case general cerebral flow is completely absent makes it impossible to use the conjunctival microcirculation as a substitute for brain flow, and further research should focus on the link between the ocular microcirculation, intracranial pressure and alternative ocular circulation.

The DESIRE Airborne gravity project in the Dead Sea Basin and 3D numerical gravity modeling

NASA Astrophysics Data System (ADS)

Choi, S.; Goetze, H.; Meyer, U.; Group, D.

2008-12-01

This geo-scientific research focuses on the geological setting of the Dead Sea Transform (DST) and the Dead Sea Basin (DSB) and its resulting pull-apart basins. Since the late 1970s, crustal scale geophysical experiments have been carried out in this region. However, the nature of the crust underlying the eastern and western shoulders of the DSB and underneath the DST itself is still a hotly debated topic among researchers. To address one of the central questions of plate tectonics - How do large transform systems work and what are their typical features? - An international geoscientific Dead Sea Integrated Research project (DESIRE) is being conducted by colleagues from Germany, Israel, Palestine, and Jordan. In order to provide a high resolution gravity database that support 3D numerical modeling and hence a more comprehensive understanding of the nature and segmentation of the DST, an airborne gravity survey as a part of the DESIRE project has been carried out from February to March 2007. The airborne gravity survey covered the DST from Elat/Aqaba in the South to the northern rim of the Dead Sea. The low speed and terrain-following helicopter gravity flights were performed to acquire the highest possible data quality. In total, 32 north-south profiles and 16 west-east profiles crossing the DST have been measured. Most of the profiles concentrated in areas that lacked terrestrial gravity data coverage, e. g. over the shoulders of the DSB. The airborne gravity data are merged with existing conventional (terrestrial) data sets to provide a seamless gravity map of the area of interest. Using that combined gravity dataset and DESIRE wide angle refractions seismic interpretation we modified density structures in the DSB. As results we estimated that (1) the Moho depth varies from 26 km in the Israel side to 34 km in the Jordan side. (2) The maximum thickness of the Dead Sea sediment Basin is about 15 km. (3) The salt rock with an average thickness of about 5 km is present not only in the southern part of the DSB but also in northern part underlying the entire Dead Sea.

Comet 'Bites the Dust' Around Dead Star

NASA Technical Reports Server (NTRS)

2006-01-01

[figure removed for brevity, see original site] Infrared Spectrometer Graph

This artist's concept illustrates a comet being torn to shreds around a dead star, or white dwarf, called G29-38. NASA's Spitzer Space Telescope observed a cloud of dust around this white dwarf that may have been generated from this type of comet disruption. The findings suggest that a host of other comet survivors may still orbit in this long-dead solar system.

The white dwarf G29-38 began life as a star that was about three times as massive as our sun. Its death involved the same steps that the sun will ultimately undergo billions of years from now. According to theory, the G29-38 star became brighter and brighter as it aged, until it bloated up into a dying star called a red giant. This red giant was large enough to engulf and evaporate any terrestrial planets like Earth that happened to be in its way. Later, the red giant shed its outer atmosphere, leaving behind a shrunken skeleton of star, called a white dwarf. If the star did host a planetary system, outer planets akin to Jupiter and Neptune and a remote ring of icy comets would remain.

The Spitzer observations provide observational evidence for this orbiting outpost of comet survivors. Astronomers speculate that one such comet was knocked into the inner regions of G29-38, possibly by an outer planet. As the comet approached very close to the white dwarf, it may have been torn apart by the star's tidal forces. Eventually, all that would be left of the comet is a disk of dust.

This illustration shows a comet in the process of being pulverized: part of it still exists as a chain of small clumps, while the rest has already spread out into a dusty disk. Comet Shoemaker-Levy 9 broke apart in a similar fashion when it plunged into Jupiter in 1994. Evidence for Comets Found in Dead Star's Dust The graph of data, or spectrum, from NASA's Spitzer Space Telescope indicates that a dead star, or white dwarf, called G29-38, is shrouded by a cloud of dust. The data also demonstrate that this dust contains some of the same types of minerals found in comet Hale-Bopp.

The findings tell a possible tale of solar system survival. Though the dust seen by Spitzer is likely from a comet that recently perished, its presence suggests that an icy distant ring of comets may still orbit the dead star.

These data were collected by Spitzer's infrared spectrometer, an instrument that cracks light open like a geode, revealing its coveted components. In this spectrum, light from the white dwarf is on the left, at ultraviolet and visible wavelengths. The spectrum on the right, at infrared wavelengths longer than about 2 microns, shows much more light than can be explained by a white dwarf alone. The bump seen around a wavelength of 10 microns offers a clue to the source of this excess infrared light. It signifies the presence of silicate minerals, which are found in our own solar system on Earth, in sandy beaches, and in comets and asteroids. These silicate grains appear to be very small like those in comets, so astronomers favor the theory that a comet recently broke apart around the dead star.

Long-term dead wood changes in a Sierra Nevada mixed conifer forest: habitat and fire hazard implications

Treesearch

Eric E. Knapp

2015-01-01

Dead trees play an important role in forests, with snags and coarse woody debris (CWD) used by many bird and mammal species for nesting, resting, or foraging. However, too much dead wood can also contribute to extreme fire behavior. This tension between dead wood as habitat and dead wood as fuel has raised questions about appropriate quantities in fire-dependent...

The Role of Dead Wood in Maintaining Arthropod Diversity on the Forest Floor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanula, James L.; Horn, Scott; Wade, Dale D.

2006-08-01

Dead wood is a major component of forests and contributes to overall diversity, primarily by supporting insects that feed directly on or in it. Further, a variety of organisms benefit by feeding on those insects. What is not well known is how or whether dead wood influences the composition of the arthropod community that is not solely dependent on it as a food resource, or whether woody debris influences prey available to generalist predators. One group likely to be affected by dead wood is ground-dwelling arthropods. We studied the effect of adding large dead wood to unburned and frequently burnedmore » pine stands to determine if dead wood was used more when the litter and understory plant community are removed. We also studied the effect of annual removal of dead wood from large (10-ha) plots over a 5-year period on ground-dwelling arthropods. In related studies, we examined the relationships among an endangered woodpecker that forages for prey on live trees, its prey, and dead wood in the forest. Finally, the results of these and other studies show that dead wood can influence the abundance and diversity of the ground-dwelling arthropod community and of prey available to generalist predators not foraging directly on dead trees.« less

Never Declared Brain Dead Potential Organ Donors-An Additional Source of Donor Organs?

PubMed

Webster, Patricia A; Markham, Lori E

2018-03-01

Patients never declared brain dead may represent an additional source of donor organs. To determine the number of likely brain dead potential donors who are never declared brain dead and to compare them with brain dead and donation after cardiac death potential organ donors. This study was a retrospective chart review of all catastrophically brain-injured patients referred to a single-organ procurement organization (OPO) over a 4-year period. This study identified 159 likely brain dead potential organ donors, 902 brain dead potential organ donors, and 357 potential donation after circulatory death donors over a 4-year period. None. This study did not predetermine outcome measures before data collection because the study group, likely brain dead potential organ donors, had not previously been described. Likely brain dead potential donors were significantly older than brain dead potential donors ( P < .0001) but were otherwise not different demographically. They were more likely to be a late referral to the OPO ( P < .0001) and less likely to be in the donor registry ( P < .0001). The most commonly identified factors associated with a failure to declare brain death were an unwillingness to continue supportive care by the family, premention of donation, a nontimely imminent death referral, known prior objection to donation, terminal instability, and a lack of cooperation with the OPO.

The ecosystem service value of living versus dead biogenic reef

NASA Astrophysics Data System (ADS)

Sheehan, E. V.; Bridger, D.; Attrill, M. J.

2015-03-01

Mixed maerl beds (corralline red algae) comprise dead thalli with varying amounts of live maerl fragments, but previously it was not known whether the presence of the live maerl increases the ecosystem service 'habitat provision' of the dead maerl for the associated epibenthos. A 'flying array' towed sled with high definition video was used to film transects of the epibenthos in dead maerl and mixed maerl beds in two locations to the north and south of the English Channel (Falmouth and Jersey). Mixed maerl beds supported greater number of taxa and abundance than dead beds in Falmouth, while in Jersey, mixed and dead beds supported similar number of taxa and dead beds had a greater abundance of epifauna. Scallops tended to be more abundant on mixed beds than dead beds. Tube worms were more abundant on mixed beds in Falmouth and dead beds in Jersey. An increasing percentage occurrence of live maerl thalli correlated with increasing number of taxa in Falmouth but not Jersey. It was concluded that while live thalli can increase the functional role of dead maerl beds for the epibenthos, this is dependent on location and response variable. As a result of this work, maerl habitat in SE Jersey has been protected from towed demersal fishing gear.

Potential Evaporite Biomarkers from the Dead Sea

NASA Technical Reports Server (NTRS)

Morris, Penny A.; Wentworth, Susan J.; Thomas-Keprta, Kathie; Allen, Carlton C.; McKay, David S.

2001-01-01

The Dead Sea is located on the northern branch of the African-Levant Rift systems. The rift system, according to one model, was formed by a series of strike slip faults, initially forming approximately two million years ago. The Dead Sea is an evaporite basin that receives freshwater from springs and from the Jordan River. The Dead Sea is different from other evaporite basins, such as the Great Salt Lake, in that it possesses high concentrations of magnesium and has an average pH of 6.1. The dominant cation in the Great Salt Lake is sodium, and the pH is 7.7. Calcium concentrations are also higher in the Dead Sea than in the Great Salt Lake. Both basins are similar in that the dominant anion is chlorine and the salinity levels are approximately 20 %. Other common cations that have been identified from the waters of the Dead Sea and the Great Salt Lake include sodium and potassium. A variety of Archea, Bacteria, and a single genus of a green algal, Dunaliella, has been described from the Dead Sea. Earlier studies concentrated on microbial identification and analysis of their unique physiology that allows them to survive in this type of extreme environment. Potential microbial fossilization processes, microbial fossils, and the metallic ions associated with fossilization have not been studied thoroughly. The present study is restricted to identifying probable microbial morphologies and associated metallic ions. XRD (X Ray Diffraction) analysis indicates the presence of halite, quartz, and orthoclase feldspar. In addition to these minerals, other workers have reported potassium chloride, magnesium bromide, magnesium chloride, calcium chloride, and calcium sulfate. Halite, calcium sulfate, and orthoclase were examined in this report for the presence of microbes, microbially induced deposits or microbial alteration. Neither the gypsum nor the orthoclase surfaces possesses any obvious indications of microbial life or fossilization. The sand-sized orthoclase particles are weathered with 122 extensive fan-shaped mineral deposits. The gypsum deposits are associated with halite minerals and also exhibit extensive weathering. Halite minerals represent the only substrates that have probable rod-shaped microbial structures with long, filamentous, apical extensions. EDS (energy dispersive x-ray) analysis of the putative microbes indicates elevated calcium levels that are enriched with magnesium. The rod-shaped structures exhibit possible fossilization stages. Rhombohedralshaped minerals of magnesium-enriched calcium carbonate are deposited on the microbial surfaces, and eventually coat the entire microbial surface. The sodium chloride continues to crystallize on nearby halite surface and even crystallizes on the fossilized microbial remains. The putative fossils are found exclusively on halite surfaces, and all contained elevated levels of calcium magnesium cations. Both of these metallic cations are associated with microbial activity and fossilization. Their morphological diversity is low in comparison with the reported living Dead Sea microbial population. If we examine the fossil record for multicellular organisms, fossilization rates are lower for soft-bodied organisms than for those possessing hard parts, i.e. shells, bones. For example, smaller, single celled organisms would have a smaller chance of fossilization; their fossilized shapes could be mistaken for abiotic products. Another consideration is that dead organisms in the water column are probably utilized as a food source by other microbes before fossilization processes are completed. This may be an important consideration as we attempt to model and interpret ancient microbial environments either on Earth or on Mars.

Experimental evaluation of the extended Dytlewski-style dead time correction formalism for neutron multiplicity counting

DOE PAGES

Lockhart, M.; Henzlova, D.; Croft, S.; ...

2017-09-20

Over the past few decades, neutron multiplicity counting has played an integral role in Special Nuclear Material (SNM) characterization pertaining to nuclear safeguards. Current neutron multiplicity analysis techniques use singles, doubles, and triples count rates because a methodology to extract and dead time correct higher order count rates (i.e. quads and pents) was not fully developed. This limitation is overcome by the recent extension of a popular dead time correction method developed by Dytlewski. This extended dead time correction algorithm, named Dytlewski-Croft-Favalli (DCF), is detailed in reference Croft and Favalli (2017), which gives an extensive explanation of the theory andmore » implications of this new development. Dead time corrected results can then be used to assay SNM by inverting a set of extended point model equations which as well have only recently been formulated. Here, we discuss and present the experimental evaluation of practical feasibility of the DCF dead time correction algorithm to demonstrate its performance and applicability in nuclear safeguards applications. In order to test the validity and effectiveness of the dead time correction for quads and pents, 252Cf and SNM sources were measured in high efficiency neutron multiplicity counters at the Los Alamos National Laboratory (LANL) and the count rates were extracted up to the fifth order and corrected for dead time. To assess the DCF dead time correction, the corrected data is compared to traditional dead time correction treatment within INCC. In conclusion, the DCF dead time correction is found to provide adequate dead time treatment for broad range of count rates available in practical applications.« less

How dead is dead? Qualitative findings from participants of combined traditional and lead-time time trade-off valuations.

PubMed

Al Sayah, Fatima; Mladenovic, Ana; Gaebel, Kathryn; Xie, Feng; Johnson, Jeffrey A

2016-01-01

The EuroQol Valuation Technology (EQ-VT) uses traditional time trade-off (tTTO) for health states better than dead and lead-time TTO (LT-TTO) for states worse than dead to elicit a value (-1.0 to +1.0) for each health state. In the Canadian EQ-5D-5L Valuation study which used the EQVT platform, we observed an unexpected peak in frequency of "0" values and few negative values, particularly in the range of 0 to -0.5. To better understand this finding, we sought to explore respondents' thought processes while valuing a health state, and their understanding of the tTTO and LT-TTO exercises. Qualitative semi-structured interviews were conducted with EQVT task respondents. Questions focused on valuations of health states as: (a) Same as dead in tTTO, (b) Worse than dead in tTTO but changed to same as dead in LT-TTO, (c) Worse than dead in LT-TTO, and (d) Worse than dead in LT-TTO with trading off all 10 years. Data were analyzed using content and thematic analysis. Mean age of participants (N = 70) was 40 ± 18.1 years, 60% female, and 76% Caucasian. Participants provided similar reasons for valuing a health state same as or worse than dead. Many participants expressed confusion about worse than dead valuations, distinction between same as and worse than dead, and the transition from tTTO to LT-TTO. A few indicated that the addition of 10 years of full health in the LT-TTO influenced their valuations. The transition from tTTO to LT-TTO in the EQVT was confusing to participants, whereby some health state valuations around this transition appeared to be arbitrary.

Experimental evaluation of the extended Dytlewski-style dead time correction formalism for neutron multiplicity counting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lockhart, M.; Henzlova, D.; Croft, S.

Over the past few decades, neutron multiplicity counting has played an integral role in Special Nuclear Material (SNM) characterization pertaining to nuclear safeguards. Current neutron multiplicity analysis techniques use singles, doubles, and triples count rates because a methodology to extract and dead time correct higher order count rates (i.e. quads and pents) was not fully developed. This limitation is overcome by the recent extension of a popular dead time correction method developed by Dytlewski. This extended dead time correction algorithm, named Dytlewski-Croft-Favalli (DCF), is detailed in reference Croft and Favalli (2017), which gives an extensive explanation of the theory andmore » implications of this new development. Dead time corrected results can then be used to assay SNM by inverting a set of extended point model equations which as well have only recently been formulated. Here, we discuss and present the experimental evaluation of practical feasibility of the DCF dead time correction algorithm to demonstrate its performance and applicability in nuclear safeguards applications. In order to test the validity and effectiveness of the dead time correction for quads and pents, 252Cf and SNM sources were measured in high efficiency neutron multiplicity counters at the Los Alamos National Laboratory (LANL) and the count rates were extracted up to the fifth order and corrected for dead time. To assess the DCF dead time correction, the corrected data is compared to traditional dead time correction treatment within INCC. In conclusion, the DCF dead time correction is found to provide adequate dead time treatment for broad range of count rates available in practical applications.« less

High-resolution echocardiography

NASA Technical Reports Server (NTRS)

Nathan, R.

1979-01-01

High resolution computer aided ultrasound system provides two-and three-dimensional images of beating heart from many angles. System provides means for determining whether small blood vessels around the heart are blocked or if heart wall is moving normally without interference of dead and noncontracting muscle tissue.

A system for the automated data-acquisition of fast transient signals in excitable membranes.

PubMed

Bustamante, J O

1988-01-01

This paper provides a description of a system for the acquisition of fast transient currents flowing across excitable membranes. The front end of the system consists of a CAMAC crate with plug-in modules. The modules provide control of CAMAC operations, analog to digital conversion, electronic memory storage and timing of events. The signals are transferred under direct memory access to an IBM PC microcomputer through a special-purpose interface. Voltage levels from a digital to analog board in the microcomputer are passed through multiplexers to produce the desired voltage pulse patterns to elicit the transmembrane currents. The dead time between consecutive excitatory voltage pulses is limited only by the computer data bus and the software characteristics. The dead time between data transfers can be reduced to the order of milliseconds, which is sufficient for most experiments with transmembrane ionic currents.

Dead simple OWL design patterns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osumi-Sutherland, David; Courtot, Melanie; Balhoff, James P.

Bio-ontologies typically require multiple axes of classification to support the needs of their users. Development of such ontologies can only be made scalable and sustainable by the use of inference to automate classification via consistent patterns of axiomatization. Many bio-ontologies originating in OBO or OWL follow this approach. These patterns need to be documented in a form that requires minimal expertise to understand and edit and that can be validated and applied using any of the various programmatic approaches to working with OWL ontologies. We describe a system, Dead Simple OWL Design Patterns (DOS-DPs), which fulfills these requirements, illustrating themore » system with examples from the Gene Ontology. In conclusion, the rapid adoption of DOS-DPs by multiple ontology development projects illustrates both the ease-of use and the pressing need for the simple design pattern system we have developed.« less

Dead simple OWL design patterns

DOE PAGES

Osumi-Sutherland, David; Courtot, Melanie; Balhoff, James P.; ...

2017-06-05

Bio-ontologies typically require multiple axes of classification to support the needs of their users. Development of such ontologies can only be made scalable and sustainable by the use of inference to automate classification via consistent patterns of axiomatization. Many bio-ontologies originating in OBO or OWL follow this approach. These patterns need to be documented in a form that requires minimal expertise to understand and edit and that can be validated and applied using any of the various programmatic approaches to working with OWL ontologies. We describe a system, Dead Simple OWL Design Patterns (DOS-DPs), which fulfills these requirements, illustrating themore » system with examples from the Gene Ontology. In conclusion, the rapid adoption of DOS-DPs by multiple ontology development projects illustrates both the ease-of use and the pressing need for the simple design pattern system we have developed.« less

Heat transfer and thermal management of electric vehicle batteries with phase change materials

NASA Astrophysics Data System (ADS)

Ramandi, M. Y.; Dincer, I.; Naterer, G. F.

2011-07-01

This paper examines a passive thermal management system for electric vehicle batteries, consisting of encapsulated phase change material (PCM) which melts during a process to absorb the heat generated by a battery. A new configuration for the thermal management system, using double series PCM shells, is analyzed with finite volume simulations. A combination of computational fluid dynamics (CFD) and second law analysis is used to evaluate and compare the new system against the single PCM shells. Using a finite volume method, heat transfer in the battery pack is examined and the results are used to analyse the exergy losses. The simulations provide design guidelines for the thermal management system to minimize the size and cost of the system. The thermal conductivity and melting temperature are studied as two important parameters in the configuration of the shells. Heat transfer from the surroundings to the PCM shell in a non-insulated case is found to be infeasible. For a single PCM system, the exergy efficiency is below 50%. For the second case for other combinations, the exergy efficiencies ranged from 30-40%. The second shell content did not have significant influence on the exergy efficiencies. The double PCM shell system showed higher exergy efficiencies than the single PCM shell system (except a case for type PCM-1). With respect to the reference environment, it is found that in all cases the exergy efficiencies decreased, when the dead-state temperatures rises, and the destroyed exergy content increases gradually. For the double shell systems for all dead-state temperatures, the efficiencies were very similar. Except for a dead-state temperature of 302 K, with the other temperatures, the exergy efficiencies for different combinations are well over 50%. The range of exergy efficiencies vary widely between 15 and 85% for a single shell system, and between 30-80% for double shell systems.

A general dead-time correction method based on live-time stamping. Application to the measurement of short-lived radionuclides.

PubMed

Chauvenet, B; Bobin, C; Bouchard, J

2017-12-01

Dead-time correction formulae are established in the general case of superimposed non-homogeneous Poisson processes. Based on the same principles as conventional live-timed counting, this method exploits the additional information made available using digital signal processing systems, and especially the possibility to store the time stamps of live-time intervals. No approximation needs to be made to obtain those formulae. Estimates of the variances of corrected rates are also presented. This method is applied to the activity measurement of short-lived radionuclides. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Insulin Therapy using Hyper-insulinemic Normoglycemic Clamp on Inflammatory Response in Brain Dead Organ Donors.

PubMed

Aljiffry, M; Hassanain, M; Schricker, T; Shaheen, M; Nouh, T; Lattermann, R; Salman, A; Wykes, L; Metrakos, P

2016-05-01

Brain death is a major stress that is associated with a massive inflammatory response and systemic hyperglycemia. Severe inflammation leads to increased graft immunogenicity and risk of graft dysfunction; while acute hyperglycemia aggravates the inflammatory response and increases the risk of morbidity and mortality. Insulin therapy not only controls hyperglycemia but also suppresses inflammation. The present study is to investigate the anti-inflammatory properties and the normoglycemia maintenance of high dose insulin on brain dead organ donors. 15 brain dead organ donors were divided into 2 groups, insulin treated (n=6) and controls (n=9). Insulin was provided for a minimum of 6 h using the hyperinsulinemic normoglycemic clamp technique. The changes of serum cytokines, including IL-6, IL-10, IL-1β, IL-8, TNFα, TGFα and MCP-1, were measured by suspension bead array immunoassay and glucose by a glucose monitor. Compared to controls, insulin treated donors had a significant lower blood glucose 4.8 (4-6.9) vs. 9 (5.6-11.7) mmol/L, p<0.01); the net decreases of pro-inflammatory cytokines, such as IL-6 and MCP-1, and the net increase of anti-inflammatory cytokine, such as IL-10, reached significant level in insulin treated donors compared with those in controls. High dose insulin therapy decreases the concentrations of inflammatory cytokines in brain dead donors and preserves normoglycemia. High dose of insulin may have anti-inflammatory effects in brain dead organ donors and therefore, improve the quality of donor organs and potentially improve outcomes. © Georg Thieme Verlag KG Stuttgart · New York.

Structural and Functional Analysis of DDX41: a bispecific immune receptor for DNA and cyclic dinucleotide

PubMed Central

Omura, Hiroki; Oikawa, Daisuke; Nakane, Takanori; Kato, Megumi; Ishii, Ryohei; Ishitani, Ryuichiro; Tokunaga, Fuminori; Nureki, Osamu

2016-01-01

In the innate immune system, pattern recognition receptors (PRRs) specifically recognize ligands derived from bacteria or viruses, to trigger the responsible downstream pathways. DEAD box protein 41 (DDX41) is an intracellular PRR that triggers the downstream pathway involving the adapter STING, the kinase TBK1, and the transcription factor IRF3, to activate the type I interferon response. DDX41 is unique in that it recognizes two different ligands; i.e., double-stranded DNA (dsDNA) and cyclic dinucleotides (CDN), via its DEAD domain. However, the structural basis for the ligand recognition by the DDX41 DEAD domain has remained elusive. Here, we report two crystal structures of the DDX41 DEAD domain in apo forms, at 1.5 and 2.2 Å resolutions. A comparison of the two crystal structures revealed the flexibility in the ATP binding site, suggesting its formation upon ATP binding. Structure-guided functional analyses in vitro and in vivo demonstrated the overlapped binding surface for dsDNA and CDN, which is distinct from the ATP-binding site. We propose that the structural rearrangement of the ATP binding site is crucial for the release of ADP, enabling the fast turnover of DDX41 for the dsDNA/CDN-induced STING activation pathway. PMID:27721487

Detection and Classification of Live and Dead Escherichia coli by Laser-Induced Breakdown Spectroscopy

PubMed Central

Sivakumar, P.; Fernández-Bravo, A.; Taleh, L.; Biddle, J.F.

2015-01-01

Abstract A common goal for astrobiology is to detect organic materials that may indicate the presence of life. However, organic materials alone may not be representative of currently living systems. Thus, it would be valuable to have a method with which to determine the health of living materials. Here, we present progress toward this goal by reporting on the application of laser-induced breakdown spectroscopy (LIBS) to study characteristics of live and dead cells using Escherichia coli (E. coli) strain K12 cells as a model organism since its growth and death in the laboratory are well understood. Our goal is to determine whether LIBS, in its femto- and/or nanosecond forms, could ascertain the state of a living organism. E. coli strain K12 cells were grown, collected, and exposed to one of two types of inactivation treatments: autoclaving and sonication. Cells were also kept alive as a control. We found that LIBS yields key information that allows for the discrimination of live and dead E. coli bacteria based on ionic shifts reflective of cell membrane integrity. Key Words: E. coli—Trace elements—Live and dead cells—Laser-induced breakdown spectroscopy—Atomic force microscopy. Astrobiology 15, 144–153. PMID:25683088

RNA-based analyses reveal fungal communities structured by a senescence gradient in the moss Dicranum scoparium and the presence of putative multi-trophic fungi.

PubMed

Chen, Ko-Hsuan; Liao, Hui-Ling; Arnold, A Elizabeth; Bonito, Gregory; Lutzoni, François

2018-06-01

Diverse plant-associated fungi are thought to have symbiotrophic and saprotrophic states because they can be isolated from both dead and living plant tissues. However, such tissues often are separated in time and space, and fungal activity at various stages of plant senescence is rarely assessed directly in fungal community studies. We used fungal ribosomal RNA metatranscriptomics to detect active fungal communities across a natural senescence gradient within wild-collected gametophytes of Dicranum scoparium (Bryophyta) to understand the distribution of active fungal communities in adjacent living, senescing and dead tissues. Ascomycota were active in all tissues across the senescence gradient. By contrast, Basidiomycota were prevalent and active in senescing and dead tissues. Several fungi were detected as active in living and dead tissues, suggesting their capacity for multi-trophy. Differences in community assembly detected by metatranscriptomics were echoed by amplicon sequencing of cDNA and compared to culture-based inferences and observation of fungal fruit bodies in the field. The combination of amplicon sequencing of cDNA and metatranscriptomics is promising for studying symbiotic systems with complex microbial diversity, allowing for the simultaneous detection of their presence and activity. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Development of 72/84kV Dry Air Insulated Dead Tank Type VCB

NASA Astrophysics Data System (ADS)

Saito, Hitoshi; Nagatake, Kazuhiro; Komatsu, Hideki; Takeshita, Yukihiro; Matsui, Yoshihiko; Katsumata, Kiyohito; Sakaki, Masayuki

As a circuit breaker for over 84kV, SF6 gas circuit breaker (GCB) has been used for a long time, in virtue of its excellent characteristics as arc extinction and insulating medium. Although, SF6 gas has very high global warming potential (GWP) of 23,900, and it was designated to regulation object in COP3 in Kyoto in 1997. A lot of efforts have been done to reduce the amount of SF6 gas usage and emission from conventional equipments. On the other hand, SF6 gas free equipment has been researching and one strong candidate is air-insulated type switchgears with vacuum interrupters. In last few years, air-insulated switchgears, which include GIS, Cubicle type GIS (C-GIS) and dead tank type VCB, have been developed in succession. So far, we have already more than three years operation record for the air-insulated dead tank type VCB, and over 100 units is in-service in power systems. Recently, VCB technology, that is essential for SF6 gas-free equipments, has been advanced in the field of high-voltage, large current interruption and environment-conscious design. In this paper, the advanced dead tank type VCB and its technology is descried.

No Time for Dead Time: Use the Fourier Amplitude Differences to Normalize Dead-time-affected Periodograms

NASA Astrophysics Data System (ADS)

Bachetti, Matteo; Huppenkothen, Daniela

2018-02-01

Dead time affects many of the instruments used in X-ray astronomy, by producing a strong distortion in power density spectra. This can make it difficult to model the aperiodic variability of the source or look for quasi-periodic oscillations. Whereas in some instruments a simple a priori correction for dead-time-affected power spectra is possible, this is not the case for others such as NuSTAR, where the dead time is non-constant and long (∼2.5 ms). Bachetti et al. (2015) suggested the cospectrum obtained from light curves of independent detectors within the same instrument as a possible way out, but this solution has always only been a partial one: the measured rms was still affected by dead time because the width of the power distribution of the cospectrum was modulated by dead time in a frequency-dependent way. In this Letter, we suggest a new, powerful method to normalize dead-time-affected cospectra and power density spectra. Our approach uses the difference of the Fourier amplitudes from two independent detectors to characterize and filter out the effect of dead time. This method is crucially important for the accurate modeling of periodograms derived from instruments affected by dead time on board current missions like NuSTAR and Astrosat, but also future missions such as IXPE.

[THE EFFECT OF 5 DAYS IMMERSION IN DEAD SEA WATER ON BLOOD GLUCOSE LEVELS IN TYPE 2 DIABETES MELLITUS PATIENTS].

PubMed

Brzezinski Sinai, Isaac; Lior, Yotam; Brzezinski Sinai, Noa; Harari, Marco; Liberty, Idit F

2016-02-01

Body immersion in plain water or mineral water induces significant and unique physiological changes in most body systems. In a previous pilot study, a significant reduction in blood glucose levels among diabetes mellitus (DM) patients was found following a single immersion in Dead Sea water but not after immersion in plain water. To study the immediate and long term effects of immersion in mineral water for five consecutive days on blood glucose in patients with type 2 DM. A total of 34 patients with type 2 DM were divided into 2 groups: The first immersed in a plain water pool and the second immersed in a Dead Sea water pool; both pools were warmed to a temperature of 35°C. Immersions for 20 minutes occurred twice daily: two hours after breakfast and before dinner. Seven samples of capillary blood glucose levels were taken: fasting, before and after every immersion, prior to lunch and before bedtime. Hemoglobin A1C (HbA1c) was taken prior to the study and a re-check was conducted during the 12 weeks following the study. Blood glucose levels significantly decreased immediately after immersion both in Dead Sea water and plain water compared to their values prior to immersion (p<0.001). No significant difference was noted between both types of water. A decrease in fasting glucose levels was observed only in the group immersed in Dead Sea water when compared to plain water (6.83±5.68 mg/dl versus 4.37±1.79 respectively and the difference was close to statistical significance (p=0.071. There were no changes in HbA1c levels. Immersion for 20 minutes in water (Dead Sea or plain water) at a temperature of 35°C induced an immediate reduction in glucose levels in patients with type 2 DM.

Fatal Systemic Salmonellosis in a Florida Manatee ( Trichechus manatus latirostris).

PubMed

Vorbach, Bryan S; Rotstein, David S; Stacy, Nicole I; Mavian, Carla; Salemi, Marco; Waltzek, Thomas B; de Wit, Martine

2017-10-01

A subadult male Florida manatee ( Trichechus manatus latirostris) stranded dead on Florida's Atlantic coast in January 2015. Necropsy and histopathologic findings confirmed chronic systemic bacterial infection caused by Salmonella enterica serotype IV 50:z4,z23,:- involving renal, respiratory, lymphatic, and skeletal systems. This was a unique case of systemic salmonellosis in a Florida manatee.

Hydrothermal synthesis of novel Mn3O4 nano-octahedrons with enhanced supercapacitors performances

NASA Astrophysics Data System (ADS)

Jiang, Hao; Zhao, Ting; Yan, Chaoyi; Ma, Jan; Li, Chunzhong

2010-10-01

Uniform and single-crystalline Mn3O4 nano-octahedrons have been successfully synthesized by a simple ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) assisted hydrothermal route. The octahedron structures exhibit a high geometric symmetry with smooth surfaces and the mean side length of square base of octahedrons is ~160 nm. The structure is reckoned to provide superior functional properties and the nano-size achieved in the present work is noted to further facilitate the material property enhancement. The formation process was proposed to begin with a ``dissolution-recrystallization'' which is followed by an ``Ostwald ripening'' mechanism. The Mn3O4 nano-octahedrons exhibited an enhanced specific capacitance of 322 F g-1 compared with the truncated octahedrons with specific capacitances of 244 F g-1, making them a promising electrode material for supercapacitors.Uniform and single-crystalline Mn3O4 nano-octahedrons have been successfully synthesized by a simple ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) assisted hydrothermal route. The octahedron structures exhibit a high geometric symmetry with smooth surfaces and the mean side length of square base of octahedrons is ~160 nm. The structure is reckoned to provide superior functional properties and the nano-size achieved in the present work is noted to further facilitate the material property enhancement. The formation process was proposed to begin with a ``dissolution-recrystallization'' which is followed by an ``Ostwald ripening'' mechanism. The Mn3O4 nano-octahedrons exhibited an enhanced specific capacitance of 322 F g-1 compared with the truncated octahedrons with specific capacitances of 244 F g-1, making them a promising electrode material for supercapacitors. Electronic supplementary information (ESI) available: TEM images; EDTA-2Na reaction details. See DOI: 10.1039/c0nr00257g

46 CFR 92.10-30 - Dead end corridors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Dead end corridors. 92.10-30 Section 92.10-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Means of Escape § 92.10-30 Dead end corridors. (a) Dead end corridors, or the...

46 CFR 92.10-30 - Dead end corridors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Dead end corridors. 92.10-30 Section 92.10-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Means of Escape § 92.10-30 Dead end corridors. (a) Dead end corridors, or the...

46 CFR 92.10-30 - Dead end corridors.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Dead end corridors. 92.10-30 Section 92.10-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Means of Escape § 92.10-30 Dead end corridors. (a) Dead end corridors, or the...

46 CFR 108.161 - Dead end corridors.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Dead end corridors. 108.161 Section 108.161 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Means of Escape § 108.161 Dead end corridors. No dead end corridor...

46 CFR 108.161 - Dead end corridors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Dead end corridors. 108.161 Section 108.161 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Means of Escape § 108.161 Dead end corridors. No dead end corridor...

7 CFR 322.29 - Dead bees.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 5 2012-01-01 2012-01-01 false Dead bees. 322.29 Section 322.29 Agriculture..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation and Transit of Restricted Articles § 322.29 Dead bees. (a) Dead bees imported into or transiting the United States must be...

7 CFR 322.29 - Dead bees.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 5 2013-01-01 2013-01-01 false Dead bees. 322.29 Section 322.29 Agriculture..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation and Transit of Restricted Articles § 322.29 Dead bees. (a) Dead bees imported into or transiting the United States must be...

7 CFR 322.29 - Dead bees.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Dead bees. 322.29 Section 322.29 Agriculture..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation and Transit of Restricted Articles § 322.29 Dead bees. (a) Dead bees imported into or transiting the United States must be...

7 CFR 322.29 - Dead bees.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 5 2011-01-01 2011-01-01 false Dead bees. 322.29 Section 322.29 Agriculture..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation and Transit of Restricted Articles § 322.29 Dead bees. (a) Dead bees imported into or transiting the United States must be...

7 CFR 322.29 - Dead bees.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 5 2014-01-01 2014-01-01 false Dead bees. 322.29 Section 322.29 Agriculture..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation and Transit of Restricted Articles § 322.29 Dead bees. (a) Dead bees imported into or transiting the United States must be...

78 FR 32622 - Endangered Species; File Nos. 17557 and 17273

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-31

... Northeast Region (File No. 17273) requests authorization to collect, receive and transport 100 dead shortnose and 100 dead Atlantic sturgeon, or parts thereof, annually. Researchers also request authorization for the receipt and transport of up to 350 captive bred, dead shortnose sturgeon and up to 75 dead...

46 CFR 108.161 - Dead end corridors.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Dead end corridors. 108.161 Section 108.161 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Means of Escape § 108.161 Dead end corridors. No dead end corridor...

46 CFR 92.10-30 - Dead end corridors.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Dead end corridors. 92.10-30 Section 92.10-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Means of Escape § 92.10-30 Dead end corridors. (a) Dead end corridors, or the...

46 CFR 108.161 - Dead end corridors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Dead end corridors. 108.161 Section 108.161 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Means of Escape § 108.161 Dead end corridors. No dead end corridor...

46 CFR 92.10-30 - Dead end corridors.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Dead end corridors. 92.10-30 Section 92.10-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Means of Escape § 92.10-30 Dead end corridors. (a) Dead end corridors, or the...

46 CFR 108.161 - Dead end corridors.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Dead end corridors. 108.161 Section 108.161 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Means of Escape § 108.161 Dead end corridors. No dead end corridor...

9 CFR 314.8 - Dead animal carcasses.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Dead animal carcasses. 314.8 Section 314.8 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... Dead animal carcasses. (a) With the exception of dead livestock which have died en route and are...

9 CFR 314.8 - Dead animal carcasses.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Dead animal carcasses. 314.8 Section 314.8 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... Dead animal carcasses. (a) With the exception of dead livestock which have died en route and are...

9 CFR 314.8 - Dead animal carcasses.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Dead animal carcasses. 314.8 Section 314.8 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... Dead animal carcasses. (a) With the exception of dead livestock which have died en route and are...

9 CFR 314.8 - Dead animal carcasses.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Dead animal carcasses. 314.8 Section 314.8 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... Dead animal carcasses. (a) With the exception of dead livestock which have died en route and are...

9 CFR 314.8 - Dead animal carcasses.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Dead animal carcasses. 314.8 Section 314.8 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY... Dead animal carcasses. (a) With the exception of dead livestock which have died en route and are...

Adaptive NN controller design for a class of nonlinear MIMO discrete-time systems.

PubMed

Liu, Yan-Jun; Tang, Li; Tong, Shaocheng; Chen, C L Philip

2015-05-01

An adaptive neural network tracking control is studied for a class of multiple-input multiple-output (MIMO) nonlinear systems. The studied systems are in discrete-time form and the discretized dead-zone inputs are considered. In addition, the studied MIMO systems are composed of N subsystems, and each subsystem contains unknown functions and external disturbance. Due to the complicated framework of the discrete-time systems, the existence of the dead zone and the noncausal problem in discrete-time, it brings about difficulties for controlling such a class of systems. To overcome the noncausal problem, by defining the coordinate transformations, the studied systems are transformed into a special form, which is suitable for the backstepping design. The radial basis functions NNs are utilized to approximate the unknown functions of the systems. The adaptation laws and the controllers are designed based on the transformed systems. By using the Lyapunov method, it is proved that the closed-loop system is stable in the sense that the semiglobally uniformly ultimately bounded of all the signals and the tracking errors converge to a bounded compact set. The simulation examples and the comparisons with previous approaches are provided to illustrate the effectiveness of the proposed control algorithm.

40 CFR 264.195 - Inspections.

Code of Federal Regulations, 2013 CFR

2013-07-01

... externally accessible portion of the tank system, including the secondary containment system (e.g., dikes) to detect erosion or signs of releases of hazardous waste (e.g., wet spots, dead vegetation). (d) Owners or... gathered from monitoring and leak detection equipment (e.g., pressure or temperature gauges, monitoring...

40 CFR 264.195 - Inspections.

Code of Federal Regulations, 2010 CFR

2010-07-01

... externally accessible portion of the tank system, including the secondary containment system (e.g., dikes) to detect erosion or signs of releases of hazardous waste (e.g., wet spots, dead vegetation). (d) Owners or... gathered from monitoring and leak detection equipment (e.g., pressure or temperature gauges, monitoring...

40 CFR 264.195 - Inspections.

Code of Federal Regulations, 2014 CFR

2014-07-01

... externally accessible portion of the tank system, including the secondary containment system (e.g., dikes) to detect erosion or signs of releases of hazardous waste (e.g., wet spots, dead vegetation). (d) Owners or... gathered from monitoring and leak detection equipment (e.g., pressure or temperature gauges, monitoring...

40 CFR 264.195 - Inspections.

Code of Federal Regulations, 2011 CFR

2011-07-01

... externally accessible portion of the tank system, including the secondary containment system (e.g., dikes) to detect erosion or signs of releases of hazardous waste (e.g., wet spots, dead vegetation). (d) Owners or... gathered from monitoring and leak detection equipment (e.g., pressure or temperature gauges, monitoring...

40 CFR 264.195 - Inspections.

Code of Federal Regulations, 2012 CFR

2012-07-01

... externally accessible portion of the tank system, including the secondary containment system (e.g., dikes) to detect erosion or signs of releases of hazardous waste (e.g., wet spots, dead vegetation). (d) Owners or... gathered from monitoring and leak detection equipment (e.g., pressure or temperature gauges, monitoring...

Cochlear Dead Regions in Typical Hearing Aid Candidates: Prevalence and Implications for Use of High-Frequency Speech Cues

PubMed Central

Cox, Robyn M; Alexander, Genevieve C; Johnson, Jani; Rivera, Izel

2011-01-01

We investigated the prevalence of cochlear dead regions in listeners with hearing losses similar to those of many hearing aid wearers, and explored the impact of these dead regions on speech perception. Prevalence of dead regions was assessed using the Threshold Equalizing Noise test (TEN(HL)). Speech recognition was measured using high-frequency emphasis (HFE) Quick Speech In Noise (QSIN) test stimuli and low-pass filtered HFE QSIN stimuli. About one third of subjects tested positive for a dead region at one or more frequencies. Also, groups without and with dead regions both benefited from additional high-frequency speech cues. PMID:21522068

Can dead bacterial cells be defined and are genes expressed after cell death?

PubMed

Trevors, J T

2012-07-01

There is a paucity of knowledge on gene expression in dead bacterial cells. Why would this knowledge be useful? The cells are dead. However, the time duration of gene expression following cell death is often unknown, and possibly in the order of minutes. In addition, it is a challenge to determine if bacterial cells are dead, or viable but non-culturable (VBNC), and what is an agreed upon correct definition of dead bacteria. Cells in the bacterial population or community may die at different rates or times and this complicates both the viability and gene expression analysis. In this article, the definition of dead bacterial cells is discussed and its significance in continued gene expression in cells following death. The definition of living and dead has implications for possible, completely, synthetic bacterial cells that may be capable of growth and division. Copyright © 2012 Elsevier B.V. All rights reserved.

50 CFR 14.24 - Scientific specimens.

Code of Federal Regulations, 2011 CFR

2011-10-01

... or 23 of this subchapter, dead, preserved, dried, or embedded scientific specimens or parts thereof... international mail system. Provided, that this exception will not apply to any specimens or parts thereof taken...

50 CFR 14.24 - Scientific specimens.

Code of Federal Regulations, 2012 CFR

2012-10-01

... or 23 of this subchapter, dead, preserved, dried, or embedded scientific specimens or parts thereof... international mail system. Provided, that this exception will not apply to any specimens or parts thereof taken...

50 CFR 14.24 - Scientific specimens.

Code of Federal Regulations, 2013 CFR

2013-10-01

... or 23 of this subchapter, dead, preserved, dried, or embedded scientific specimens or parts thereof... international mail system. Provided, that this exception will not apply to any specimens or parts thereof taken...

50 CFR 14.24 - Scientific specimens.

Code of Federal Regulations, 2014 CFR

2014-10-01

... or 23 of this subchapter, dead, preserved, dried, or embedded scientific specimens or parts thereof... international mail system. Provided, that this exception will not apply to any specimens or parts thereof taken...

Pediatric Brain Tumor Foundation

MedlinePlus

... navigate their brain tumor diagnosis. WATCH AND SHARE Brain tumors and their treatment can be deadly so ... Pediatric Central Nervous System Cancers Read more >> Pediatric Brain Tumor Foundation 302 Ridgefield Court, Asheville, NC 28806 ...