Omnidirectional sparse visual path following with occlusion-robust feature tracking

OpenAIRE

Goedemé, Toon; Tuytelaars, Tinne; Van Gool, Luc; Vanacker, Gerolf; Nuttin, Marnix

2005-01-01

Goedemé T., Tuytelaars T., Van Gool L., Vanacker G., Nuttin M., ''Omnidirectional sparse visual path following with occlusion-robust feature tracking'', Proceedings 6th workshop on omnidirectional vision, camera networks and non-classical cameras, 8 pp., October 21, 2005, Beijing, China.

Vision-Based Leader Vehicle Trajectory Tracking for Multiple Agricultural Vehicles.

Science.gov (United States)

Zhang, Linhuan; Ahamed, Tofael; Zhang, Yan; Gao, Pengbo; Takigawa, Tomohiro

2016-04-22

The aim of this study was to design a navigation system composed of a human-controlled leader vehicle and a follower vehicle. The follower vehicle automatically tracks the leader vehicle. With such a system, a human driver can control two vehicles efficiently in agricultural operations. The tracking system was developed for the leader and the follower vehicle, and control of the follower was performed using a camera vision system. A stable and accurate monocular vision-based sensing system was designed, consisting of a camera and rectangular markers. Noise in the data acquisition was reduced by using the least-squares method. A feedback control algorithm was used to allow the follower vehicle to track the trajectory of the leader vehicle. A proportional-integral-derivative (PID) controller was introduced to maintain the required distance between the leader and the follower vehicle. Field experiments were conducted to evaluate the sensing and tracking performances of the leader-follower system while the leader vehicle was driven at an average speed of 0.3 m/s. In the case of linear trajectory tracking, the RMS errors were 6.5 cm, 8.9 cm and 16.4 cm for straight, turning and zigzag paths, respectively. Again, for parallel trajectory tracking, the root mean square (RMS) errors were found to be 7.1 cm, 14.6 cm and 14.0 cm for straight, turning and zigzag paths, respectively. The navigation performances indicated that the autonomous follower vehicle was able to follow the leader vehicle, and the tracking accuracy was found to be satisfactory. Therefore, the developed leader-follower system can be implemented for the harvesting of grains, using a combine as the leader and an unloader as the autonomous follower vehicle.

Continuous-Curvature Path Generation Using Fermat's Spiral

Directory of Open Access Journals (Sweden)

Anastasios M. Lekkas

2013-10-01

Full Text Available This paper proposes a novel methodology, based on Fermat's spiral (FS, for constructing curvature-continuous parametric paths in a plane. FS has a zero curvature at its origin, a property that allows it to be connected with a straight line smoothly, that is, without the curvature discontinuity which occurs at the transition point between a line and a circular arc when constructing Dubins paths. Furthermore, contrary to the computationally expensive clothoids, FS is described by very simple parametric equations that are trivial to compute. On the downside, computing the length of an FS arc involves a Gaussian hypergeometric function. However, this function is absolutely convergent and it is also shown that it poses no restrictions to the domain within which the length can be calculated. In addition, we present an alternative parametrization of FS which eliminates the parametric speed singularity at the origin, hence making the spiral suitable for path-tracking applications. A detailed description of how to construct curvature-continuous paths with FS is given.

Market penetration of intersection AEB: Characterizing avoided and residual straight crossing path accidents.

Science.gov (United States)

Sander, Ulrich; Lubbe, Nils

2018-06-01

Car occupants account for one third of all junction fatalities in the European Union. Driver warning can reduce intersection accidents by up to 50 percent; adding Autonomous Emergency Braking (AEB) delivers a reduction of up to 70 percent. However, these findings are based on an assumed 100 percent equipment rate, which may take decades to achieve. Our study investigates the relationship between intersection AEB market penetration rates and avoidance of accidents and injuries in order to guide implementation strategies. Additionally, residual accident characteristics (impact configurations and severity) are analyzed to provide a basis for future in-crash protection requirements. We determined which accidents would have been avoided through the use of an Intersection AEB system with different sensor field-of-views (180° and 120°) by means of re-simulating the pre-crash phase of 792 straight crossing path (SCP) car-to-car accidents recorded in the German In-Depth Accident Study (GIDAS) and the associated Pre-Crash Matrix (PCM). Intersection AEB was activated when neither of the conflict opponents could avoid the crash through reasonable braking or steering reactions. For not-avoided accidents, we used the Kudlich-Slibar rigid body impulse model to calculate the change of velocity during the impact as a measure of impact severity and the principal direction of force. Accident avoidance over market penetration is not linear but exponential, with higher gains at low penetration rates and lower gains at higher rates. A wide field-of-view sensor (180°) substantially increased accident avoidance and injury mitigation rates compared to a 120° field-of-view sensor. For a 180° field-of-view sensor at 100 percent market penetration, about 80 percent of the accidents and 90 percent of the MAIS2 + F injuries could be avoided. For the remaining accidents, AEB intervention rarely affected side of impact. The median change of velocity (delta-V) of the remaining crashes

Pose estimation-based path planning for a tracked mobile robot traversing uneven terrains

OpenAIRE

Jun , Jae-Yun; Saut , Jean-Philippe; Benamar , Faïz

2015-01-01

International audience; A novel path-planning algorithm is proposed for a tracked mobile robot to traverse uneven terrains, which can efficiently search for stability sub-optimal paths. This algorithm consists of combining two RRT-like algorithms (the Transition-based RRT (T-RRT) and the Dynamic-Domain RRT (DD-RRT) algorithms) bidirectionally and of representing the robot-terrain interaction with the robot’s quasi-static tip-over stability measure (assuming that the robot traverses uneven ter...

Transition duct system with straight ceramic liner for delivering hot-temperature gases in a combustion turbine engine

Science.gov (United States)

Wiebe, David J.

2017-05-16

A transition duct system (10) for delivering hot-temperature gases from a plurality of combustors in a combustion turbine engine is provided. The system includes an exit piece (16) for each combustor. The exit piece may include a straight path segment (26) for receiving a gas flow from a respective combustor. A straight ceramic liner (40) may be inwardly disposed onto a metal outer shell (38) along the straight path segment of the exit piece. Structural arrangements are provided to securely attach the ceramic liner in the presence of substantial flow path pressurization. Cost-effective serviceability of the transition duct systems is realizable since the liner can be readily removed and replaced as needed.

Fuzzy path tracking and position estimation of autonomous vehicles using differential GPS

OpenAIRE

Rodríguez Castaño, Ángel; Heredia Benot, José Guillermo; Ollero Baturone, Aníbal

2000-01-01

This paper presents an autonomous vehicle position estimation system based on GPS, that uses a fuzzy sensor fusion technique. A fuzzy path tracking algorithm is also proposed. Both systems have been implemented in the ROMEO-4R vehicle developed at the University of Seville.

A Leader-path-following formation system for AGVs with multi-sensor data fusion based vehicle tracking

Science.gov (United States)

Yao, Wen; Zhao, Xijun; Yu, Yufeng; Fang, Yongkun; Wang, Chao; Yang, Tianfu

2017-09-01

Caravans composed of vehicles with different functionality or trafficability raise the demand that formation system structure shall allow vehicles to deviate from the path to be followed when necessary. In this paper, a formation system is developed for autonomous ground vehicles (AGVs) who follow the path of a leader vehicle while retaining the ability of deviation from the reference path. In addition, it improves robustness of preceding vehicle localization by fusing Lidar tracking, camera tracking results with predecessor’s global position within an extended Kalman filter (EKF) in case that one or more sources of preceding vehicle localization is not reliable. The system is applied on real AGV platforms and won the 3rd place in an AGV competition in China.

Column Number Density Expressions Through M = 0 and M = 1 Point Source Plumes Along Any Straight Path

Science.gov (United States)

Woronowicz, Michael

2017-01-01

Providers of payloads carried aboard the International Space Station must conduct analyses to demonstrate that any planned gaseous venting events generate no more than a certain level of material that may interfere with optical measurements from other experiments or payloads located nearby. This requirement is expressed in terms of a maximum column number density (CND). Depending on the level of rarefaction, such venting may be characterized by effusion for low flow rates, or by a sonic distribution at higher levels. Since the relative locations of other sensitive payloads are often unknown because they may refer to future projects, this requirement becomes a search for the maximum CND along any path.In another application, certain astronomical observations make use of CND to estimate light attenuation from a distant star through gaseous plumes, such as the Fermi Bubbles emanating from the vicinity of the black hole at the center of our Milky Way galaxy, in order to infer the amount of material being expelled via those plumes.This paper presents analytical CND expressions developed for general straight paths based upon a free molecule point source model for steady effusive flow and for a distribution fitted to model flows from a sonic orifice. Among other things, in this Mach number range it is demonstrated that the maximum CND from a distant location occurs along the path parallel to the source plane that intersects the plume axis. For effusive flows this value is exactly twice the CND found along the ray originating from that point of intersection and extending to infinity along the plumes axis. For sonic plumes this ratio is reduced to about 43.

Artificial Potential Field Approach to Path Tracking for a Non-Holonomic Mobile Robot

DEFF Research Database (Denmark)

Sørensen, M.J.

2003-01-01

This paper introduces a novel path tracking controller for an over-actuated robotic vehicle moving in an agricultural field. The vehicle itself is a four wheel steered, four wheel driven vehicle subject to the two non-holonomic constraints of free rolling and non-slipping wheels. A dynamic model...

A Velocity-Level Bi-Criteria Optimization Scheme for Coordinated Path Tracking of Dual Robot Manipulators Using Recurrent Neural Network.

Science.gov (United States)

Xiao, Lin; Zhang, Yongsheng; Liao, Bolin; Zhang, Zhijun; Ding, Lei; Jin, Long

2017-01-01

A dual-robot system is a robotic device composed of two robot arms. To eliminate the joint-angle drift and prevent the occurrence of high joint velocity, a velocity-level bi-criteria optimization scheme, which includes two criteria (i.e., the minimum velocity norm and the repetitive motion), is proposed and investigated for coordinated path tracking of dual robot manipulators. Specifically, to realize the coordinated path tracking of dual robot manipulators, two subschemes are first presented for the left and right robot manipulators. After that, such two subschemes are reformulated as two general quadratic programs (QPs), which can be formulated as one unified QP. A recurrent neural network (RNN) is thus presented to solve effectively the unified QP problem. At last, computer simulation results based on a dual three-link planar manipulator further validate the feasibility and the efficacy of the velocity-level optimization scheme for coordinated path tracking using the recurrent neural network.

Steering Angle Control of Car for Dubins Path-tracking Using Model Predictive Control

Science.gov (United States)

Kusuma Rahma Putri, Dian; Subchan; Asfihani, Tahiyatul

2018-03-01

Car as one of transportation is inseparable from technological developments. About ten years, there are a lot of research and development on lane keeping system(LKS) which is a system that automaticaly controls the steering to keep the vehicle especially car always on track. This system can be developed for unmanned cars. Unmanned system car requires navigation, guidance and control which is able to direct the vehicle to move toward the desired path. The guidance system is represented by using Dubins-Path that will be controlled by using Model Predictive Control. The control objective is to keep the car’s movement that represented by dinamic lateral motion model so car can move according to the path appropriately. The simulation control on the four types of trajectories that generate the value for steering angle and steering angle changes are at the specified interval.

A Path Tracking Algorithm Using Future Prediction Control with Spike Detection for an Autonomous Vehicle Robot

Directory of Open Access Journals (Sweden)

Muhammad Aizzat Zakaria

2013-08-01

Full Text Available Trajectory tracking is an important aspect of autonomous vehicles. The idea behind trajectory tracking is the ability of the vehicle to follow a predefined path with zero steady state error. The difficulty arises due to the nonlinearity of vehicle dynamics. Therefore, this paper proposes a stable tracking control for an autonomous vehicle. An approach that consists of steering wheel control and lateral control is introduced. This control algorithm is used for a non-holonomic navigation problem, namely tracking a reference trajectory in a closed loop form. A proposed future prediction point control algorithm is used to calculate the vehicle's lateral error in order to improve the performance of the trajectory tracking. A feedback sensor signal from the steering wheel angle and yaw rate sensor is used as feedback information for the controller. The controller consists of a relationship between the future point lateral error, the linear velocity, the heading error and the reference yaw rate. This paper also introduces a spike detection algorithm to track the spike error that occurs during GPS reading. The proposed idea is to take the advantage of the derivative of the steering rate. This paper aims to tackle the lateral error problem by applying the steering control law to the vehicle, and proposes a new path tracking control method by considering the future coordinate of the vehicle and the future estimated lateral error. The effectiveness of the proposed controller is demonstrated by a simulation and a GPS experiment with noisy data. The approach used in this paper is not limited to autonomous vehicles alone since the concept of autonomous vehicle tracking can be used in mobile robot platforms, as the kinematic model of these two platforms is similar.

Auditory perception of motor vehicle travel paths.

Science.gov (United States)

Ashmead, Daniel H; Grantham, D Wesley; Maloff, Erin S; Hornsby, Benjamin; Nakamura, Takabun; Davis, Timothy J; Pampel, Faith; Rushing, Erin G

2012-06-01

These experiments address concerns that motor vehicles in electric engine mode are so quiet that they pose a risk to pedestrians, especially those with visual impairments. The "quiet car" issue has focused on hybrid and electric vehicles, although it also applies to internal combustion engine vehicles. Previous research has focused on detectability of vehicles, mostly in quiet settings. Instead, we focused on the functional ability to perceive vehicle motion paths. Participants judged whether simulated vehicles were traveling straight or turning, with emphasis on the impact of background traffic sound. In quiet, listeners made the straight-or-turn judgment soon enough in the vehicle's path to be useful for deciding whether to start crossing the street. This judgment is based largely on sound level cues rather than the spatial direction of the vehicle. With even moderate background traffic sound, the ability to tell straight from turn paths is severely compromised. The signal-to-noise ratio needed for the straight-or-turn judgment is much higher than that needed to detect a vehicle. Although a requirement for a minimum vehicle sound level might enhance detection of vehicles in quiet settings, it is unlikely that this requirement would contribute to pedestrian awareness of vehicle movements in typical traffic settings with many vehicles present. The findings are relevant to deliberations by government agencies and automobile manufacturers about standards for minimum automobile sounds and, more generally, for solutions to pedestrians' needs for information about traffic, especially for pedestrians with sensory impairments.

Representation of the three-body Coulomb Green's function in parabolic coordinates: paths of integration

International Nuclear Information System (INIS)

Zaytsev, S A

2010-01-01

The possibility of using straight-line paths of integration in computing the integral representation of the three-body Coulomb Green's function is discussed. In our numerical examples two different kinds of integration contours in the complex energy planes are considered. It is demonstrated that straight-line paths, which cross the positive real axis, are suitable for numerical computation.

PTRACK: A particle tracking program for evaluation travel path/travel time uncertainties

International Nuclear Information System (INIS)

Thompson, B.M.; Campbell, J.E.; Longsine, D.E.

1987-12-01

PTRACK is a model which tracks the path of a radionuclide particle released from a nuclear waste repository into a ground-water flow system in a two-dimensional representation of stratified geologic medium. The code calculates the time required for the particle to travel from the release point (the edge of the disturbed zone) to the specified horizontal or vertical boundary (the accessible environment). The physical properties of the geologic setting and the ground-water flow system can be treated as fixed values or as random variables sampled from their respective probability distributions. In the latter case, PTRACK assigns a sampled value for each parameter and tracks a particle for this trial (realization) of the system. Repeated realizations allow the effects of parameter uncertainty on travel paths/travel times to be quantified. The code can also calculate partial correlation coefficients between dependent variables and independent variables, which are useful in identifying important independent variables. This documentation describes the mathematical basis for the model, the algorithms and solution techniques used, and the computer code design. It also contains a detailed user's manual. The implementation of PTRACK is verified with several systems for which solutions have been calculated by hand. The integration of PTRACK with a Latin hypercube sampling (LHS) code is also discussed, although other sampling methods can be employed in place of LHS. 11 refs., 14 figs., 22 tabs

Unzip instabilities: Straight to oscillatory transitions in the cutting of thin polymer sheets

Science.gov (United States)

Reis, P. M.; Kumar, A.; Shattuck, M. D.; Roman, B.

2008-06-01

We report an experimental investigation of the cutting of a thin brittle polymer sheet with a blunt tool. It was recently shown that the fracture path becomes oscillatory when the tool is much wider than the sheet thickness. Here we uncover two novel transitions from straight to oscillatory fracture by varying either the tilt angle of the tool or the speed of cutting, respectively. We denote these by angle and speed unzip instabilities and analyze them by quantifying both the dynamics of the crack tip and the final shapes of the fracture paths. Moreover, for the speed unzip instability, the straight crack lip obtained at low speeds exhibits out-of-plane buckling undulations (as opposed to being flat above the instability threshold) suggesting a transition from ductile to brittle fracture.

The Planning of Straight Line Trajectory in Robotics Using Interactive Graphics

Directory of Open Access Journals (Sweden)

Kesheng Wang

1987-07-01

Full Text Available The planning of straight line trajectory using the interactive computer graphics simulation of robot manipulator movement is discussed. This new approach to straight line motion planning improves the 'bound deviation joint paths' developed by R. M. Taylor (1979. The new approach has three characteristics: (1 linear interpolation in joint space; (2 unequal intervals for interpolating knot points; (3 using interactive computer graphics to assure that the maximum deviation in the whole segment is less than the pre-specified values. The structure and mathematical basis of a computer program developed for this purpose are presented.

The deep fovea, sideways vision and spiral flight paths in raptors.

Science.gov (United States)

Tucker, V A

2000-12-01

the raptor down. Raptors could resolve this conflict by diving along a logarithmic spiral path with their head straight and one eye looking sideways at the prey, rather than following the straight path to the prey with their head turned sideways. Although the spiral path is longer than the straight path, a mathematical model for an 'ideal falcon' shows that the falcon could reach the prey more quickly along the spiral path because the speed advantage of a straight head more than compensates for the longer path.

Time optimal paths for high speed maneuvering

Energy Technology Data Exchange (ETDEWEB)

Reister, D.B.; Lenhart, S.M.

1993-01-01

Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.

Path following mobile robot in the presence of velocity constraints

DEFF Research Database (Denmark)

Bak, Martin; Poulsen, Niels Kjølstad; Ravn, Ole

2001-01-01

This paper focuses on path following algorithms for mobile robots with velocity constraints on the wheels. The path considered consists of straight lines intersected with given angles. We present a fast real-time receding horizon controller which anticipates the intersections and smoothly control...

Interaction mean free path measurements for relativistic heavy ion fragments using CR39 plastic track detectors

International Nuclear Information System (INIS)

Drechsel, H.; Brechtmann, C.; Dreute, J.; Sonntag, S.; Trakowski, W.; Beer, J.; Heinrich, W.

1984-01-01

This paper describes an experiment measuring the interaction mean free paths for charge changing nuclear collisions of relativistic heavy ion fragments. We use a stack of CR39 plastic nuclear track detectors that was irradiated with 1.8 GeV/nucleon 40 Ar ions at the Berkeley Bevalac. About 1.5 x 10 7 etch cones were measured in this experiment using an automatic measuring system. By tracing the etch cones over successive plastic foils the particle trajectories in the stack were reconstructed. For 14185 trajectories with 6444 nuclear collisions of fragments with charge 9-15 the interaction mean free path in the plastic was determined. (orig.)

Trends in Canadian Newspaper Coverage of Gay-Straight Alliances, 2000-2009

Science.gov (United States)

Herriot, Lindsay

2011-01-01

Gay-straight alliances (GSAs) in Canadian public schools have gained considerable attention from print media since reports first surfaced in the year 2000. This study tracked and analyzed Canadian newspaper reporting about GSA creation. It summarized the shift in public opinion toward lesbian, gay, bisexual, transgender, and queer (LGBTQ) youth…

Flying Boresight for Advanced Testing and Calibration of Tracking Antennas and Flight Path Simulations

Science.gov (United States)

Hafner, D.

2015-09-01

The application of ground-based boresight sources for calibration and testing of tracking antennas usually entails various difficulties, mostly due to unwanted ground effects. To avoid this problem, DLR MORABA developed a small, lightweight, frequency-adjustable S-band boresight source, mounted on a small remote-controlled multirotor aircraft. Highly accurate GPS-supported, position and altitude control functions allow both, very steady positioning of the aircraft in mid-air, and precise waypoint-based, semi-autonomous flights. In contrast to fixed near-ground boresight sources this flying setup enables to avoid obstructions in the Fresnel zone between source and antenna. Further, it minimizes ground reflections and other multipath effects which can affect antenna calibration. In addition, the large operating range of a flying boresight simplifies measurements in the far field of the antenna and permits undisturbed antenna pattern tests. A unique application is the realistic simulation of sophisticated flight paths, including overhead tracking and demanding trajectories of fast objects such as sounding rockets. Likewise, dynamic tracking tests are feasible which provide crucial information about the antenna pedestal performance — particularly at high elevations — and reveal weaknesses in the autotrack control loop of tracking antenna systems. During acceptance tests of MORABA's new tracking antennas, a manned aircraft was never used, since the Flying Boresight surpassed all expectations regarding usability, efficiency, and precision. Hence, it became an integral part of MORABA's standard antenna setup and calibration procedures.

Optimal path planning for video-guided smart munitions via multitarget tracking

Science.gov (United States)

Borkowski, Jeffrey M.; Vasquez, Juan R.

2006-05-01

An advent in the development of smart munitions entails autonomously modifying target selection during flight in order to maximize the value of the target being destroyed. A unique guidance law can be constructed that exploits both attribute and kinematic data obtained from an onboard video sensor. An optimal path planning algorithm has been developed with the goals of obstacle avoidance and maximizing the value of the target impacted by the munition. Target identification and classification provides a basis for target value which is used in conjunction with multi-target tracks to determine an optimal waypoint for the munition. A dynamically feasible trajectory is computed to provide constraints on the waypoint selection. Results demonstrate the ability of the autonomous system to avoid moving obstacles and revise target selection in flight.

Rotational symmetric HMD with eye-tracking capability

Science.gov (United States)

Liu, Fangfang; Cheng, Dewen; Wang, Qiwei; Wang, Yongtian

2016-10-01

As an important auxiliary function of head-mounted displays (HMDs), eye tracking has an important role in the field of intelligent human-machine interaction. In this paper, an eye-tracking HMD system (ET-HMD) is designed based on the rotational symmetric system. The tracking principle in this paper is based on pupil-corneal reflection. The ET-HMD system comprises three optical paths for virtual display, infrared illumination, and eye tracking. The display optics is shared by three optical paths and consists of four spherical lenses. For the eye-tracking path, an extra imaging lens is added to match the image sensor and achieve eye tracking. The display optics provides users a 40° diagonal FOV with a ״ 0.61 OLED, the 19 mm eye clearance, and 10 mm exit pupil diameter. The eye-tracking path can capture 15 mm × 15 mm of the users' eyes. The average MTF is above 0.1 at 26 lp/mm for the display path, and exceeds 0.2 at 46 lp/mm for the eye-tracking path. Eye illumination is simulated using LightTools with an eye model and an 850 nm near-infrared LED (NIR-LED). The results of the simulation show that the illumination of the NIR-LED can cover the area of the eye model with the display optics that is sufficient for eye tracking. The integrated optical system HMDs with eye-tracking feature can help improve the HMD experience of users.

NuFact muon storage ring: study of a triangle design based on solenoid focusing decay straights

Energy Technology Data Exchange (ETDEWEB)

Meot, F. [Service Accelerateurs, Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier / CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble (France)]|[Commissariat a l' Energie Atomique, CEA, 31-33, rue de la Federation (Paris 15e), BP 510, 75752 Paris Cedex 15 (France); Reesy, G. [Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0QX (United Kingdom)

2006-06-15

Properties of acceptance and beam transmission in a triangle design of the neutrino factory muon decay ring, with decay straights based on solenoidal focusing, are reported.The muon storage ring in the neutrino factory, NuFact, is located at the high energy end of the muon acceleration chain. It delivers the {mu}{sup +}/{mu}{sup -} decay neutrinos to physics detectors. The design of concern here, is a triangle geometry 20 GeV storage ring, upgradable to 50 GeV, (the parameters are given), which features two decay straight sections, each one aiming at a distant detector. The third straight section of the ring is devoted to tuning, collimation and RF. A particularity of the proposed design, is in its being based on solenoid focusing decay straights, which has the virtue of minimizing the betatron amplitudes, compared to equivalent quadrupole focusing. The solenoidal focusing ensures the requested ratio, for the r.m.s. divergences of the 20 GeV muon and the neutrino beam, of 0.1 for an assumed muon normalized r.m.s. emittance of 4800 {pi} mm mr (3 {pi} cm, total). The goal of the present work is to show the viability of this design, in particular as concerns the impact of the solenoid focusing on machine behavior. It addresses the questions of residual coupling, machine acceptance, and concludes with a computation of beam transmission over 1000 turns. The paper has the following structure: 1. Introduction; 2. Working hypothesis; 3. Building-up ray-tracing data; 3.1. Arcs; 3.2. Solenoid straight; 3.3. Tuning/Collimation/RF straight; 3.4. Full ring; 3.4.1. Beam envelopes; 3.4.2. Closed orbits; 3.4.3. Momentum dispersion; 3.5 Large amplitude tracking, preliminary tests; 4. Tracking, linear machine; 4.1. Large amplitude tracking; 4.1.1. 2-D horizontal initial conditions; 4.1.2. 2-D vertical initial conditions; 4.1.3. 4-D + {delta}p/p initial conditions; 4.2. Transmission, 4-D + {delta}p/p, no sextupoles; 4.2.1. {epsilon}{sub x} {epsilon}{sub z} = 3 {pi} cm (norm.), {delta

NuFact muon storage ring: study of a triangle design based on solenoid focusing decay straights

International Nuclear Information System (INIS)

Meot, F.; Reesy, G.

2006-06-01

Properties of acceptance and beam transmission in a triangle design of the neutrino factory muon decay ring, with decay straights based on solenoidal focusing, are reported.The muon storage ring in the neutrino factory, NuFact, is located at the high energy end of the muon acceleration chain. It delivers the μ + /μ - decay neutrinos to physics detectors. The design of concern here, is a triangle geometry 20 GeV storage ring, upgradable to 50 GeV, (the parameters are given), which features two decay straight sections, each one aiming at a distant detector. The third straight section of the ring is devoted to tuning, collimation and RF. A particularity of the proposed design, is in its being based on solenoid focusing decay straights, which has the virtue of minimizing the betatron amplitudes, compared to equivalent quadrupole focusing. The solenoidal focusing ensures the requested ratio, for the r.m.s. divergences of the 20 GeV muon and the neutrino beam, of 0.1 for an assumed muon normalized r.m.s. emittance of 4800 π mm mr (3 π cm, total). The goal of the present work is to show the viability of this design, in particular as concerns the impact of the solenoid focusing on machine behavior. It addresses the questions of residual coupling, machine acceptance, and concludes with a computation of beam transmission over 1000 turns. The paper has the following structure: 1. Introduction; 2. Working hypothesis; 3. Building-up ray-tracing data; 3.1. Arcs; 3.2. Solenoid straight; 3.3. Tuning/Collimation/RF straight; 3.4. Full ring; 3.4.1. Beam envelopes; 3.4.2. Closed orbits; 3.4.3. Momentum dispersion; 3.5 Large amplitude tracking, preliminary tests; 4. Tracking, linear machine; 4.1. Large amplitude tracking; 4.1.1. 2-D horizontal initial conditions; 4.1.2. 2-D vertical initial conditions; 4.1.3. 4-D + δp/p initial conditions; 4.2. Transmission, 4-D + δp/p, no sextupoles; 4.2.1. ε x ε z = 3 π cm (norm.), δp/p = ±1%; 4.2.2. ε x ε z = 6 π cm (norm.), δp/p ±4

The processing of spatial information in short-term memory: insights from eye tracking the path length effect.

Science.gov (United States)

Guérard, Katherine; Tremblay, Sébastien; Saint-Aubin, Jean

2009-10-01

Serial memory for spatial locations increases as the distance between successive stimuli locations decreases. This effect, known as the path length effect [Parmentier, F. B. R., Elford, G., & Maybery, M. T. (2005). Transitional information in spatial serial memory: Path characteristics affect recall performance. Journal of Experimental Psychology: Learning, Memory & Cognition, 31, 412-427], was investigated in a systematic manner using eye tracking and interference procedures to explore the mechanisms responsible for the processing of spatial information. In Experiment 1, eye movements were monitored during a spatial serial recall task--in which the participants have to remember the location of spatially and temporally separated dots on the screen. In the experimental conditions, eye movements were suppressed by requiring participants to incessantly move their eyes between irrelevant locations. Ocular suppression abolished the path length effect whether eye movements were prevented during item presentation or during a 7s retention interval. In Experiment 2, articulatory suppression was combined with a spatial serial recall task. Although articulatory suppression impaired performance, it did not alter the path length effect. Our results suggest that rehearsal plays a key role in serial memory for spatial information, though the effect of path length seems to involve other processes located at encoding, such as the time spent fixating each location and perceptual organization.

Drift chamber tracking with neural networks

International Nuclear Information System (INIS)

Lindsey, C.S.; Denby, B.; Haggerty, H.

1992-10-01

We discuss drift chamber tracking with a commercial log VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed

Even the Best Have Difficulties: A Study of Finnish Straight-A Graduates' Resource-Oriented Solutions

Science.gov (United States)

Salmela, Mari; Määttä, Kaarina

2015-01-01

To achieve top scores, students need not only talents and study skills but also they have to conquer various adversities successfully. This research focused on the study paths, the concept adopted from Hickman, Bartholomew, Mathwig, and Heinrich (2008), of Finnish straight-A graduates in general upper secondary education. In this article, we refer…

Standing "Straight" up to Homophobia: Straight Allies' Involvement in GSAs

Science.gov (United States)

Lapointe, Alicia Anne

2015-01-01

This qualitative study captures the experiences of four straight allies' and one gay youth involvement in gay--straight alliances (GSAs) at their Ontario, Canada, high schools. Participants' motivations for becoming GSA members and their roles as allies are examined. Queer theoretical perspectives, as espoused by Britzman (1995, 1998) and Linville…

Safeguards and security benefits of project straight-line

International Nuclear Information System (INIS)

Jaeger, C.D.; Waddoups, I.G.

1995-01-01

As a result of a number of events the inventory of fissile materials no longer in nuclear weapons in the United States is increasing. This has led to a growing concern regarding the potential for theft and/or diversion and accountability of this material. Straight-Line is a project whose purpose is to demonstrate a site-independent system to monitor stored nuclear material (e.g. plutonium) and integrate the collection, processing and dissemination of information regarding this material. Safeguards and security (S ampersand S) goals of this project include data transfer of information on nuclear material to appropriate users to enhance S ampersand S, continuous on-line accountability, reduction of hands-on access to nuclear materials, incorporation of information security technologies, and early detection of tampering or unauthorized material movement. This paper addresses threat considerations, S ampersand S requirements, S ampersand S objectives, and issues for the Straight-Line project. S ampersand S features and benefits of this project are discussed with respect to existing item monitoring systems and/or other material tracking systems being developed

Electron track reconstruction and improved modulation for photoelectric X-ray polarimetry

Energy Technology Data Exchange (ETDEWEB)

Li, Tenglin [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Zeng, Ming, E-mail: zengming@tsinghua.edu.cn [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Feng, Hua [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Center for Astrophysics, Tsinghua University, Beijing 100084 (China); Cang, Jirong [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Li, Hong; Zhang, Heng [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Center for Astrophysics, Tsinghua University, Beijing 100084 (China); Zeng, Zhi; Cheng, Jianping; Ma, Hao; Liu, Yinong [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China)

2017-06-21

The key to photoelectric X-ray polarimetry is the determination of the emission direction of photoelectrons. Because of the low mass of an electron, the ionisation trajectory is not straight and the useful information needed for polarimetry is stored mostly in the initial part of the track where less energy is deposited. We present a new algorithm, based on the shortest path problem in graph theory, to reconstruct the 2D electron track from the measured image that is blurred due to transversal diffusion along drift and multiplication in the gas chamber. Compared with previous methods based on moment analysis, this algorithm allows us to identify the photoelectric interaction point more accurately and precisely for complicated tracks resulting from high energy photons or low pressure chambers. This leads to a better position resolution and a higher degree of modulation toward high energy X-rays. The new algorithm is justified using simulations and measurements with the gas pixel detector (GPD), and it should also work for other polarimetric techniques such as a time projection chamber (TPC). As the improvement is restricted in the high energy band, this new algorithm shows limited improvement for the sensitivity of GPD polarimeters, but it may have a larger potential for low-pressure TPC polarimeters.

Assessment of comparative skills between hand-assisted and straight laparoscopic colorectal training on an augmented reality simulator.

Science.gov (United States)

Leblanc, F; Delaney, C P; Neary, P C; Rose, J; Augestad, K M; Senagore, A J; Ellis, C N; Champagne, B J

2010-09-01

The aim of this study was to compare skills sets during a hand-assisted and straight laparoscopic colectomy on an augmented reality simulator. Twenty-nine surgeons, assigned randomly in 2 groups, performed laparoscopic sigmoid colectomies on a simulator: group A (n = 15) performed hand-assisted then straight procedures; group B (n = 14) performed straight then hand-assisted procedures. Groups were compared according to prior laparoscopic colorectal experience, performance (time, instrument path length, and instrument velocity changes), technical skills, and operative error. Prior laparoscopic colorectal experience was similar in both groups. Both groups had better performances with the hand-assisted approach, although technical skill scores were similar between approaches. The error rate was higher with the hand-assisted approach in group A, but similar between both approaches in group B. These data define the metrics of performance for hand-assisted and straight laparoscopic colectomy on an augmented reality simulator. The improved scores with the hand-assisted approach suggest that with this simulator a hand-assisted model may be technically easier to perform, although it is associated with increased intraoperative errors.

Experimental Study on the Vibration Control Effect of Long Elastic Sleeper Track in Subways

Directory of Open Access Journals (Sweden)

Xiaopei Cai

2018-01-01

Full Text Available The vibration effect of urban rail transit has gained attention from both academia and the industry sector. Long Elastic Sleeper Track (LEST is a new structure for vibration reduction which has recently been designed and applied to Chinese subways. However, little research has been devoted to its vibration reduction effect. In this study, field tests were conducted during peak transit hours on Beijing Subway Line 15 to examine the vibration reduction effects of the common ballastless track and LEST on both straight and curved sections. The results demonstrate that although LEST increases the wheel-rail vertical forces, rail vertical displacements, and rail accelerations to some extent, these effects do not threaten subway operational safety, and vibrations of track bed and tunnel wall are positively mitigated. LEST has an obvious vibration reduction effect at frequencies above 40 Hz. In straight track, the vibration of bottom of the tunnel wall measured in one-third octave bands is reduced by 10.52 dB, while the vibration at point on the tunnel wall at 1.5 m height is reduced by 9.60 dB. For the curved track, the vibrations at those two points are reduced by 9.35 dB and 8.44 dB, respectively. This indicates that LEST reduces vibrations slightly more for the straight track than for the curved track.

Filtered backprojection proton CT reconstruction along most likely paths

Energy Technology Data Exchange (ETDEWEB)

Rit, Simon; Dedes, George; Freud, Nicolas; Sarrut, David; Letang, Jean Michel [Universite de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Universite Lyon 1, Centre Leon Berard, 69008 Lyon (France)

2013-03-15

Purpose: Proton CT (pCT) has the potential to accurately measure the electron density map of tissues at low doses but the spatial resolution is prohibitive if the curved paths of protons in matter is not accounted for. The authors propose to account for an estimate of the most likely path of protons in a filtered backprojection (FBP) reconstruction algorithm. Methods: The energy loss of protons is first binned in several proton radiographs at different distances to the proton source to exploit the depth-dependency of the estimate of the most likely path. This process is named the distance-driven binning. A voxel-specific backprojection is then used to select the adequate radiograph in the distance-driven binning in order to propagate in the pCT image the best achievable spatial resolution in proton radiographs. The improvement in spatial resolution is demonstrated using Monte Carlo simulations of resolution phantoms. Results: The spatial resolution in the distance-driven binning depended on the distance of the objects from the source and was optimal in the binned radiograph corresponding to that distance. The spatial resolution in the reconstructed pCT images decreased with the depth in the scanned object but it was always better than previous FBP algorithms assuming straight line paths. In a water cylinder with 20 cm diameter, the observed range of spatial resolutions was 0.7 - 1.6 mm compared to 1.0 - 2.4 mm at best with a straight line path assumption. The improvement was strongly enhanced in shorter 200 Degree-Sign scans. Conclusions: Improved spatial resolution was obtained in pCT images with filtered backprojection reconstruction using most likely path estimates of protons. The improvement in spatial resolution combined with the practicality of FBP algorithms compared to iterative reconstruction algorithms makes this new algorithm a candidate of choice for clinical pCT.

Fast and accurate global multiphase arrival tracking: the irregular shortest-path method in a 3-D spherical earth model

Science.gov (United States)

Huang, Guo-Jiao; Bai, Chao-Ying; Greenhalgh, Stewart

2013-09-01

The traditional grid/cell-based wavefront expansion algorithms, such as the shortest path algorithm, can only find the first arrivals or multiply reflected (or mode converted) waves transmitted from subsurface interfaces, but cannot calculate the other later reflections/conversions having a minimax time path. In order to overcome the above limitations, we introduce the concept of a stationary minimax time path of Fermat's Principle into the multistage irregular shortest path method. Here we extend it from Cartesian coordinates for a flat earth model to global ray tracing of multiple phases in a 3-D complex spherical earth model. The ray tracing results for 49 different kinds of crustal, mantle and core phases show that the maximum absolute traveltime error is less than 0.12 s and the average absolute traveltime error is within 0.09 s when compared with the AK135 theoretical traveltime tables for a 1-D reference model. Numerical tests in terms of computational accuracy and CPU time consumption indicate that the new scheme is an accurate, efficient and a practical way to perform 3-D multiphase arrival tracking in regional or global traveltime tomography.

Modeling and Solving the Train Pathing Problem

Directory of Open Access Journals (Sweden)

Chuen-Yih Chen

2009-04-01

Full Text Available In a railroad system, train pathing is concerned with the assignment of trains to links and tracks, and train timetabling allocates time slots to trains. In this paper, we present an optimization heuristic to solve the train pathing and timetabling problem. This heuristic allows the dwell time of trains in a station or link to be dependent on the assigned tracks. It also allows the minimum clearance time between the trains to depend on their relative status. The heuristic generates a number of alternative paths for each train service in the initialization phase. Then it uses a neighborhood search approach to find good feasible combinations of these paths. A linear program is developed to evaluate the quality of each combination that is encountered. Numerical examples are provided.

An in-situ measuring method for planar straightness error

Science.gov (United States)

Chen, Xi; Fu, Luhua; Yang, Tongyu; Sun, Changku; Wang, Zhong; Zhao, Yan; Liu, Changjie

2018-01-01

According to some current problems in the course of measuring the plane shape error of workpiece, an in-situ measuring method based on laser triangulation is presented in this paper. The method avoids the inefficiency of traditional methods like knife straightedge as well as the time and cost requirements of coordinate measuring machine(CMM). A laser-based measuring head is designed and installed on the spindle of a numerical control(NC) machine. The measuring head moves in the path planning to measure measuring points. The spatial coordinates of the measuring points are obtained by the combination of the laser triangulation displacement sensor and the coordinate system of the NC machine, which could make the indicators of measurement come true. The method to evaluate planar straightness error adopts particle swarm optimization(PSO). To verify the feasibility and accuracy of the measuring method, simulation experiments were implemented with a CMM. Comparing the measurement results of measuring head with the corresponding measured values obtained by composite measuring machine, it is verified that the method can realize high-precise and automatic measurement of the planar straightness error of the workpiece.

Tracking development paths: Monitoring driving forces and the impact of carbon-free energy sources in Spain

International Nuclear Information System (INIS)

O’ Mahony, Tadhg; Dufour, Javier

2015-01-01

Highlights: • The development path of Spain is analysed using an extended Kaya identity. • Effect of carbon free energy sources separated. • Nuclear energy acted to increase emissions as it declined in share. • Renewable energy penetration recently began to reduce carbon emissions. • Future policy must address wider factors of sustainable development. - Abstract: The evolution of the national development path has gravity in determining the future emissions outcomes of all nations. Deep reductions in emissions require a focus not just on energy and mitigation policy but on factors underlying this development. The Kaya identity has been recommended to track national progress with respect to sustainability and carbon emissions in the development path. This study applies an extended Kaya identity to the energy-related carbon emissions of Spain. Implemented through a divisia index decomposition annually from 1990 to 2011, it highlights the impact of factors such as affluence and energy intensity. A marked departure from previous studies is the separation of the effects of the carbon-free energy sources; both renewables and nuclear as fundamental mitigation measures. The results show that affluence and population have acted to increase emissions and energy intensity was increasing until recent years. Fuel substitution has acted to decrease emissions but while renewable energy has reduced emissions with the increasing importance of biomass, wind and solar, the decline in share of nuclear has acted to increase emissions. Implications for the development path and policy are discussed and lessons are relevant both for industrialised and industrialising nations

Aircraft path planning with the use of smooth trajectories

Science.gov (United States)

Belokon', S. A.; Zolotukhin, Yu. N.; Nesterov, A. A.

2017-01-01

A simplified method of plane trajectory calculation is proposed for solving the problem of planning a path defined by a sequence of waypoints. The trajectory consists of oriented segments of straight lines joined by clothoids (Cornu spirals). The efficiency of the method is validated by means of numerical simulations in the MATLAB/Simulink environment.

Straight scaling FFAG beam line

International Nuclear Information System (INIS)

Lagrange, J.-B.; Planche, T.; Yamakawa, E.; Uesugi, T.; Ishi, Y.; Kuriyama, Y.; Qin, B.; Okabe, K.; Mori, Y.

2012-01-01

Fixed field alternating gradient (FFAG) accelerators are recently subject to a strong revival. They are usually designed in a circular shape; however, it would be an asset to guide particles with no overall bend in this type of accelerator. An analytical development of a straight FFAG cell which keeps zero-chromaticity is presented here. A magnetic field law is thus obtained, called “straight scaling law”, and an experiment has been conducted to confirm this zero-chromatic law. A straight scaling FFAG prototype has been designed and manufactured, and horizontal phase advances of two different energies are measured. Results are analyzed to clarify the straight scaling law.

Straight scaling FFAG beam line

Science.gov (United States)

Lagrange, J.-B.; Planche, T.; Yamakawa, E.; Uesugi, T.; Ishi, Y.; Kuriyama, Y.; Qin, B.; Okabe, K.; Mori, Y.

2012-11-01

Fixed field alternating gradient (FFAG) accelerators are recently subject to a strong revival. They are usually designed in a circular shape; however, it would be an asset to guide particles with no overall bend in this type of accelerator. An analytical development of a straight FFAG cell which keeps zero-chromaticity is presented here. A magnetic field law is thus obtained, called "straight scaling law", and an experiment has been conducted to confirm this zero-chromatic law. A straight scaling FFAG prototype has been designed and manufactured, and horizontal phase advances of two different energies are measured. Results are analyzed to clarify the straight scaling law.

Path stability of a crack with an eigenstrain

International Nuclear Information System (INIS)

Beom, Hyeon Gyu; Kim, Yu Hwan; Cho, Chong Du; Kim, Chang Boo

2006-01-01

A slightly curved crack with an eigenstrain is considered. Solutions for a slightly curved crack in a linear isotropic material under asymptotic loading as well as for a slightly curved crack in a linear isotropic material with a concentrated force are obtained from perturbation analyses, which are accurate to the first order of the parameter representing the non-straightness. Stress intensity factors for a slightly curved crack with an eigenstrain are obtained from the perturbation solutions by using a body force analogy. Particular attention is given to the crack path stability under mode I loading. A new parameter of crack path stability is proposed for a crack with an eigenstrain. The path stability of a crack with steady state growth in a transforming material and a ferroelectric material is examined

An artificial retina for fast track finding

International Nuclear Information System (INIS)

Ristori, Luciano

2000-01-01

A new approach is proposed for fast track finding in position-sensitive detectors. The basic working principle is modeled on what is widely believed to be the low-level mechanism used by the eye to recognize straight edges. A number of receptors are tuned such that each one responds to a different range of track orientations, each track actually fires several receptors and an estimate of the orientation is obtained through interpolation. The feasibility of a practical device based on this principle and its possible implementation using currently available digital logic is discussed

Path planning algorithms for assembly sequence planning. [in robot kinematics

Science.gov (United States)

Krishnan, S. S.; Sanderson, Arthur C.

1991-01-01

Planning for manipulation in complex environments often requires reasoning about the geometric and mechanical constraints which are posed by the task. In planning assembly operations, the automatic generation of operations sequences depends on the geometric feasibility of paths which permit parts to be joined into subassemblies. Feasible locations and collision-free paths must be present for part motions, robot and grasping motions, and fixtures. This paper describes an approach to reasoning about the feasibility of straight-line paths among three-dimensional polyhedral parts using an algebra of polyhedral cones. A second method recasts the feasibility conditions as constraints in a nonlinear optimization framework. Both algorithms have been implemented and results are presented.

Straight until proven gay: A systematic bias toward straight categorizations in sexual orientation judgments.

Science.gov (United States)

Lick, David J; Johnson, Kerri L

2016-06-01

Perceivers achieve above chance accuracy judging others' sexual orientations, but they also exhibit a notable response bias by categorizing most targets as straight rather than gay. Although a straight categorization bias is evident in many published reports, it has never been the focus of systematic inquiry. The current studies therefore document this bias and test the mechanisms that produce it. Studies 1-3 revealed the straight categorization bias cannot be explained entirely by perceivers' attempts to match categorizations to the number of gay targets in a stimulus set. Although perceivers were somewhat sensitive to base rate information, their tendency to categorize targets as straight persisted when they believed each target had a 50% chance of being gay (Study 1), received explicit information about the base rate of gay targets in a stimulus set (Study 2), and encountered stimulus sets with varying base rates of gay targets (Study 3). The remaining studies tested an alternate mechanism for the bias based upon perceivers' use of gender heuristics when judging sexual orientation. Specifically, Study 4 revealed the range of gendered cues compelling gay judgments is smaller than the range of gendered cues compelling straight judgments despite participants' acknowledgment of equal base rates for gay and straight targets. Study 5 highlighted perceptual experience as a cause of this imbalance: Exposing perceivers to hyper-gendered faces (e.g., masculine men) expanded the range of gendered cues compelling gay categorizations. Study 6 linked this observation to our initial studies by demonstrating that visual exposure to hyper-gendered faces reduced the magnitude of the straight categorization bias. Collectively, these studies provide systematic evidence of a response bias in sexual orientation categorization and offer new insights into the mechanisms that produce it. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

A model based approach to reference-free straightness measurement at the Nanometer Comparator

Science.gov (United States)

Weichert, C.; Stavridis, M.; Walzel, M.; Elster, C.; Wiegmann, A.; Schulz, M.; Köning, R.; Flügge, J.; Tutsch, R.

2009-06-01

The Nanometer Comparator is the PTB reference length measuring machine for high precision calibrations of line scales and encoder systems. Up to now the Nanometer Comparator allows to measure the position of line structures in one dimension only. For high precision characterisations of masks, scales and incremental encoders, the measurement of the straightness of graduations is a requirement from emerging lithography techniques. Therefore the Nanometer Comparator will be equipped with an additional short range measurement system in the Y-direction, realized as a single path plane mirror interferometer and supposed to achieve sub-nm uncertainties. To compensate the topography of the Y-mirror, the Traceable Multi Sensor (TMS) method will be implemented to achieve a reference-free straightness measurement. Virtual experiments are used to estimate the lower accuracy limit and to determine the sensitive parameters. The virtual experiments contain the influence of the positioning devices, interferometer errors as well as non-perfect adjustment and fabrication of the machine geometry. The whole dynamic measurement process of the Nanometer Comparator including its influence on the TMS analysis, e.g. non-equally spaced measurement points, is simulated. We will present the results of these virtual experiments as well as the most relevant error sources for straightness measurement, incorporating the low uncertainties of the existing and planned measurement systems.

Straightness measurement of large machine guideways

Directory of Open Access Journals (Sweden)

W. Ptaszyñski

2011-10-01

Full Text Available This paper shows the guideway types of large machines and describes problems with their straightness measurement. A short description of straightness measurement methods and the results of investigation in straightness of 10 meter long guideways of a CNC machine by means of the XL-10 Renishaw interferometer are also presented.

Weighted straight skeletons in the plane.

Science.gov (United States)

Biedl, Therese; Held, Martin; Huber, Stefan; Kaaser, Dominik; Palfrader, Peter

2015-02-01

We investigate weighted straight skeletons from a geometric, graph-theoretical, and combinatorial point of view. We start with a thorough definition and shed light on some ambiguity issues in the procedural definition. We investigate the geometry, combinatorics, and topology of faces and the roof model, and we discuss in which cases a weighted straight skeleton is connected. Finally, we show that the weighted straight skeleton of even a simple polygon may be non-planar and may contain cycles, and we discuss under which restrictions on the weights and/or the input polygon the weighted straight skeleton still behaves similar to its unweighted counterpart. In particular, we obtain a non-procedural description and a linear-time construction algorithm for the straight skeleton of strictly convex polygons with arbitrary weights.

Straight line foraging in yellow-eyed penguins: new insights into cascading fisheries effects and orientation capabilities of marine predators.

Science.gov (United States)

Mattern, Thomas; Ellenberg, Ursula; Houston, David M; Lamare, Miles; Davis, Lloyd S; van Heezik, Yolanda; Seddon, Philip J

2013-01-01

Free-ranging marine predators rarely search for prey along straight lines because dynamic ocean processes usually require complex search strategies. If linear movement patterns occur they are usually associated with travelling events or migratory behaviour. However, recent fine scale tracking of flying seabirds has revealed straight-line movements while birds followed fishing vessels. Unlike flying seabirds, penguins are not known to target and follow fishing vessels. Yet yellow-eyed penguins from New Zealand often exhibit directed movement patterns while searching for prey at the seafloor, a behaviour that seems to contradict common movement ecology theories. While deploying GPS dive loggers on yellow-eyed penguins from the Otago Peninsula we found that the birds frequently followed straight lines for several kilometres with little horizontal deviation. In several cases individuals swam up and down the same line, while some of the lines were followed by more than one individual. Using a remote operated vehicle (ROV) we found a highly visible furrow on the seafloor most likely caused by an otter board of a demersal fish trawl, which ran in a straight line exactly matching the trajectory of a recent line identified from penguin tracks. We noted high abundances of benthic scavengers associated with fisheries-related bottom disturbance. While our data demonstrate the acute way-finding capabilities of benthic foraging yellow-eyed penguins, they also highlight how hidden cascading effects of coastal fisheries may alter behaviour and potentially even population dynamics of marine predators, an often overlooked fact in the examination of fisheries' impacts.

Straight line foraging in yellow-eyed penguins: new insights into cascading fisheries effects and orientation capabilities of marine predators.

Directory of Open Access Journals (Sweden)

Thomas Mattern

Full Text Available Free-ranging marine predators rarely search for prey along straight lines because dynamic ocean processes usually require complex search strategies. If linear movement patterns occur they are usually associated with travelling events or migratory behaviour. However, recent fine scale tracking of flying seabirds has revealed straight-line movements while birds followed fishing vessels. Unlike flying seabirds, penguins are not known to target and follow fishing vessels. Yet yellow-eyed penguins from New Zealand often exhibit directed movement patterns while searching for prey at the seafloor, a behaviour that seems to contradict common movement ecology theories. While deploying GPS dive loggers on yellow-eyed penguins from the Otago Peninsula we found that the birds frequently followed straight lines for several kilometres with little horizontal deviation. In several cases individuals swam up and down the same line, while some of the lines were followed by more than one individual. Using a remote operated vehicle (ROV we found a highly visible furrow on the seafloor most likely caused by an otter board of a demersal fish trawl, which ran in a straight line exactly matching the trajectory of a recent line identified from penguin tracks. We noted high abundances of benthic scavengers associated with fisheries-related bottom disturbance. While our data demonstrate the acute way-finding capabilities of benthic foraging yellow-eyed penguins, they also highlight how hidden cascading effects of coastal fisheries may alter behaviour and potentially even population dynamics of marine predators, an often overlooked fact in the examination of fisheries' impacts.

Subsea Cable Tracking by Autonomous Underwater Vehicle with Magnetic Sensing Guidance.

Science.gov (United States)

Xiang, Xianbo; Yu, Caoyang; Niu, Zemin; Zhang, Qin

2016-08-20

The changes of the seabed environment caused by a natural disaster or human activities dramatically affect the life span of the subsea buried cable. It is essential to track the cable route in order to inspect the condition of the buried cable and protect its surviving seabed environment. The magnetic sensor is instrumental in guiding the remotely-operated vehicle (ROV) to track and inspect the buried cable underseas. In this paper, a novel framework integrating the underwater cable localization method with the magnetic guidance and control algorithm is proposed, in order to enable the automatic cable tracking by a three-degrees-of-freedom (3-DOF) under-actuated autonomous underwater vehicle (AUV) without human beings in the loop. The work relies on the passive magnetic sensing method to localize the subsea cable by using two tri-axial magnetometers, and a new analytic formulation is presented to compute the heading deviation, horizontal offset and buried depth of the cable. With the magnetic localization, the cable tracking and inspection mission is elaborately constructed as a straight-line path following control problem in the horizontal plane. A dedicated magnetic line-of-sight (LOS) guidance is built based on the relative geometric relationship between the vehicle and the cable, and the feedback linearizing technique is adopted to design a simplified cable tracking controller considering the side-slip effects, such that the under-actuated vehicle is able to move towards the subsea cable and then inspect its buried environment, which further guides the environmental protection of the cable by setting prohibited fishing/anchoring zones and increasing the buried depth. Finally, numerical simulation results show the effectiveness of the proposed magnetic guidance and control algorithm on the envisioned subsea cable tracking and the potential protection of the seabed environment along the cable route.

Straight nearness spaces | Bentley | Quaestiones Mathematicae

African Journals Online (AJOL)

Straight spaces are spaces for which a continuous map defined on the space which is uniformly continuous on each set of a finite closed cover is then uniformly continuous on the whole space. Previously, straight spaces have been studied in the setting of metric spaces. In this paper, we present a study of straight spaces in ...

Straight sinus thrombosis during neurosurgical operation.

Science.gov (United States)

Kawano, Hiroto; Nitta, Naoki; Nozaki, Kazuhiko

2016-01-01

Perioperative straight sinus thrombosis is extremely rare. A 59-year-old female was admitted to our department because of incidentally found small anterior cerebral artery (A1) aneurysm with microbleeding. After clipping the cerebral aneurysm, she had delayed emergence from anesthesia, total aphasia, and right hemiparesis. Fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) of the head showed hyperintensity in the bilateral caudate nuclei, putamina, and thalami, and computed tomography of the head showed a hyperdense straight sinus, suggesting straight sinus thrombosis. Her neurologic symptoms improved gradually, and she achieved a full clinical recovery, with radiological evidence of recanalization of the straight sinus at follow-up. The possibility of straight sinus thrombosis should be considered in postoperative patients with unexplained postoperative deficits when MRI demonstrates hyperintensity in the bilateral basal ganglia and thalami on FLAIR signal images.

The vacuum system for the PEP II high energy ring straight sections

International Nuclear Information System (INIS)

Wienands, U.; Daly, E.; Heifets, S.A.; Kulikov, A.; Kurita, N.; Nordby, M.; Perkins, C.; Reuter, E.; Seeman, J.T.; Belser, F.C.; Berg, J.; Holdener, F.R.; Kerns, J.A.; McDaniel, M.R.; Stoeffl, W.

1995-01-01

The six straight sections of the PEP II High Energy Ring (HER) serve various functions: lattice tuning, beam injection and abort, providing space for rf cavities, longitudinal and transverse feedback, beam diagnostics and the interaction point. A stainless steel vacuum system has been designed; prototypes are currently being built. Cooling is required due to radiation coming from the last arc dipole and resistive losses in the vacuum chamber. Although the nominal beam current of the HER is 1 A the vacuum system is designed for 3 A to provide margin and an upgrade path. 5 refs., 7 figs

Using road topology to improve cyclist path prediction

NARCIS (Netherlands)

Pool, E.A.I.; Kooij, J.F.P.; Gavrila, D.; Ioannou, Petros; Zhang, Wei-Bin; Lu, Meng

2017-01-01

We learn motion models for cyclist path prediction on real-world tracks obtained from a moving vehicle, and propose to exploit the local road topology to obtain better predictive distributions. The tracks are extracted from the Tsinghua-Daimler Cyclist Benchmark for cyclist detection, and corrected

Calculation of the Intensity of electrical field at the end of the loaded path in the solid-state nuclear track detectors by using the numerical calculation of Laplace equations

International Nuclear Information System (INIS)

Kolahdooz, M.; Abotalebi, A.; Sheikh Aleslam, F.

2011-01-01

The goal of this article is calculation of the electric field at the end of loaded path in solid-state track detectors. For the calculation, Laplace-Equation has been solved numerically. By solving the equation, upon considering a specific potential at the boundary of the region, in addition to calculating the electric field at the end of path, the parameters which are affecting the electric field have also been investigated.

Dynamics of a novel robotic leg based on the Peaucellier–Lipkin mechanism on linear paths during the transfer phase

Directory of Open Access Journals (Sweden)

Diego Alfredo Núñez-Altamirano

2016-07-01

Full Text Available This article deals with the kinematics and dynamics of a novel leg based on the Peaucellier–Lipkin mechanism, which is better known as the straight path tracer. The basic Peaucellier–Lipkin linkage with 1 degree of freedom was transformed into a more skillful mechanism, through the addition of 4 more degrees of freedom. The resulting 5-degree-of-freedom leg enables the walking machine to move along paths that are straight lines and/or concave or convex curves. Three degrees of freedom transform the leg in relation to a reachable center of rotation that the machine walks around. Once the leg is transformed, the remaining 2 degrees of freedom position the foot at a desirable Cartesian point during the transfer or support phase. We analyzed the direct and inverse kinematics developed for the leg when the foot describes a straight line and found some interesting relationships among the motion parameters. The dynamic model equations of motion for the leg were derived from the Lagrangian dynamic formulation to calculate the required torques during a particular transfer phase.

Gliding flight: drag and torque of a hawk and a falcon with straight and turned heads, and a lower value for the parasite drag coefficient.

Science.gov (United States)

Tucker, V A

2000-12-01

Raptors - falcons, hawks and eagles in this study - such as peregrine falcons (Falco peregrinus) that attack distant prey from high-speed dives face a paradox. Anatomical and behavioral measurements show that raptors of many species must turn their heads approximately 40 degrees to one side to see the prey straight ahead with maximum visual acuity, yet turning the head would presumably slow their diving speed by increasing aerodynamic drag. This paper investigates the aerodynamic drag part of this paradox by measuring the drag and torque on wingless model bodies of a peregrine falcon and a red-tailed hawk (Buteo jamaicensis) with straight and turned heads in a wind tunnel at a speed of 11.7 m s(-)(1). With a turned head, drag increased more than 50 %, and torque developed that tended to yaw the model towards the direction in which the head pointed. Mathematical models for the drag required to prevent yawing showed that the total drag could plausibly more than double with head-turning. Thus, the presumption about increased drag in the paradox is correct. The relationships between drag, head angle and torque developed here are prerequisites to the explanation of how a raptor could avoid the paradox by holding its head straight and flying along a spiral path that keeps its line of sight for maximum acuity pointed sideways at the prey. Although the spiral path to the prey is longer than the straight path, the raptor's higher speed can theoretically compensate for the difference in distances; and wild peregrines do indeed approach prey by flying along curved paths that resemble spirals. In addition to providing data that explain the paradox, this paper reports the lowest drag coefficients yet measured for raptor bodies (0.11 for the peregrine and 0.12 for the red-tailed hawk) when the body models with straight heads were set to pitch and yaw angles for minimum drag. These values are markedly lower than value of the parasite drag coefficient (C(D,par)) of 0.18 previously

A Minimum Path Algorithm Among 3D-Polyhedral Objects

Science.gov (United States)

Yeltekin, Aysin

1989-03-01

In this work we introduce a minimum path theorem for 3D case. We also develop an algorithm based on the theorem we prove. The algorithm will be implemented on the software package we develop using C language. The theorem we introduce states that; "Given the initial point I, final point F and S be the set of finite number of static obstacles then an optimal path P from I to F, such that PA S = 0 is composed of straight line segments which are perpendicular to the edge segments of the objects." We prove the theorem as well as we develop the following algorithm depending on the theorem to find the minimum path among 3D-polyhedral objects. The algorithm generates the point Qi on edge ei such that at Qi one can find the line which is perpendicular to the edge and the IF line. The algorithm iteratively provides a new set of initial points from Qi and exploits all possible paths. Then the algorithm chooses the minimum path among the possible ones. The flowchart of the program as well as the examination of its numerical properties are included.

Injury mitigation estimates for an intersection driver assistance system in straight crossing path crashes in the United States.

Science.gov (United States)

Scanlon, John M; Sherony, Rini; Gabler, Hampton C

2017-05-29

Accounting for one fifth of all crashes and one sixth of all fatal crashes in the United States, intersection crashes are among the most frequent and fatal crash modes. Intersection advanced driver assistance systems (I-ADAS) are emerging vehicle-based active safety systems that aim to help drivers safely navigate intersections. The objective of this study was to estimate the number of crashes and number of vehicles with a seriously injured driver (Maximum Abbreviated Injury Scale [MAIS] 3+) that could be prevented or reduced if, for every straight crossing path (SCP) intersection crash, one of the vehicles had been equipped with an I-ADAS. This study retrospectively simulated 448 U.S. SCP crashes as if one of the vehicles had been equipped with I-ADAS. Crashes were reconstructed to determine the path and speeds traveled by the vehicles. Cases were then simulated with I-ADAS. A total of 30 variations of I-ADAS were considered in this study. These variations consisted of 5 separate activation timing thresholds, 3 separate computational latency times, and 2 different I-ADAS response modalities (i.e., a warning or autonomous braking). The likelihood of a serious driver injury was computed for every vehicle in every crash using impact delta-V. The results were then compiled across all crashes in order to estimate system effectiveness. The model predicted that an I-ADAS that delivers an alert to the driver has the potential to prevent 0-23% of SCP crashes and 0-25% of vehicles with a seriously injured driver. Conversely, an I-ADAS that autonomously brakes was found to have the potential to prevent 25-59% of crashes and 38-79% of vehicles with a seriously injured driver. I-ADAS effectiveness is a strong function of design. Increasing computational latency time from 0 to 0.5 s was found to reduce crash and injury prevention estimates by approximately one third. For an I-ADAS that delivers an alert, crash/injury prevention effectiveness was found to be very sensitive to

Path-finding in real and simulated rats

DEFF Research Database (Denmark)

Tamosiunaite, Minija; Ainge, James; Kulvicius, Tomas

2008-01-01

without affecting the path characteristic two additional mechanisms are implemented: a gradual drop of the learned weights (weight decay) and path length limitation, which prevents learning if the reward is not found after some expected time. Both mechanisms limit the memory of the system and thereby......A large body of experimental evidence suggests that the hippocampal place field system is involved in reward based navigation learning in rodents. Reinforcement learning (RL) mechanisms have been used to model this, associating the state space in an RL-algorithm to the place-field map in a rat...... convergence of RL-algorithms is also influenced by the state space characteristics, different PF-sizes and densities, leading to a different degree of overlap, were also investigated. The model rat learns finding a reward opposite to its starting point. We observed that the combination of biased straight...

[Dual insertion paths design characteristics and short-term clinical observation of rotational path removable partial dentures].

Science.gov (United States)

Li, Jian; Jiang, Ting; Li, Sai; Chen, Wei

2013-02-18

. Rotational path incorporated an initial straight path of placement, which gained access to undercut areas by rigid guide plate, followed by a final curved path of placement. Without showing clasps in the anterior part of the mouth, esthetics could be improved remarkably. The results of this preliminary study suggest that rotational path RPDs can get the similar retention, stability and mastication function as linear path RPDs. Meanwhile, simulative preparation on diagnostic casts, oral preparation under the guidance of indices and precise fabrication of framework are indispensable procedures.

The Accuracy Assessment of Determining the Axis of Railway Track Basing on the Satellite Surveying

Science.gov (United States)

Koc, Władysław; Specht, Cezary; Chrostowski, Piotr; Palikowska, Katarzyna

2012-09-01

In 2009, at the Gdansk University of Technology there have been carried out, for the first time, continuous satellite surveying of railway track by the use of the relative phase method based on geodesic active network ASG-EUPOS and NAVGEO service. Still continuing research works focused on the GNSS multi-receivers platform evaluation for projecting and stock-taking. In order to assess the accuracy of the railway track axis position, the values of deviations of transverse position XTE (Cross Track Error) were evaluated. In order to eliminate the influence of random measurement errors and to obtain the coordinates representing the actual shape of the track, the XTE variable was analyzed by signal analysis methods (Chebyshev low-pass filtering and fast Fourier transform). At the end the paper presents the module of the computer software SATTRACK which currently has been developing at the Gdansk University of Technology. The program serves visualization, assessment and design process of railway track, adapted to the technique of continuous satellite surveying. The module called TRACK STRAIGHT is designed to assess the straight sections. A description of its operation as well as examples of its functions has been presented.

Path-Constrained Motion Planning for Robotics Based on Kinematic Constraints

NARCIS (Netherlands)

Dijk, van N.J.M.; Wouw, van de N.; Pancras, W.C.M.; Nijmeijer, H.

2007-01-01

Common robotic tracking tasks consist of motions along predefined paths. The design of time-optimal path-constrained trajectories for robotic applications is discussed in this paper. To increase industrial applicability, the proposed method accounts for robot kinematics together with actuator

Column Number Density Expressions Through M = 0 and M = 1 Point Source Plumes Along Any Straight Path

Science.gov (United States)

Woronowicz, Michael

2016-01-01

Analytical expressions for column number density (CND) are developed for optical line of sight paths through a variety of steady free molecule point source models including directionally-constrained effusion (Mach number M = 0) and flow from a sonic orifice (M = 1). Sonic orifice solutions are approximate, developed using a fair simulacrum fitted to the free molecule solution. Expressions are also developed for a spherically-symmetric thermal expansion (M = 0). CND solutions are found for the most general paths relative to these sources and briefly explored. It is determined that the maximum CND from a distant location through directed effusion and sonic orifice cases occurs along the path parallel to the source plane that intersects the plume axis. For the effusive case this value is exactly twice the CND found along the ray originating from that point of intersection and extending to infinity along the plume's axis. For sonic plumes this ratio is reduced to about 4/3. For high Mach number cases the maximum CND will be found along the axial centerline path. Keywords: column number density, plume flows, outgassing, free molecule flow.

Olfaction Contributes to Pelagic Navigation in a Coastal Shark.

Science.gov (United States)

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

2016-01-01

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

Altered orientation and flight paths of pigeons reared on gravity anomalies: a GPS tracking study.

Directory of Open Access Journals (Sweden)

Nicole Blaser

Full Text Available The mechanisms of pigeon homing are still not understood, in particular how they determine their position at unfamiliar locations. The "gravity vector" theory holds that pigeons memorize the gravity vector at their home loft and deduct home direction and distance from the angular difference between memorized and actual gravity vector. However, the gravity vector is tilted by different densities in the earth crust leading to gravity anomalies. We predicted that pigeons reared on different gravity anomalies would show different initial orientation and also show changes in their flight path when crossing a gravity anomaly. We reared one group of pigeons in a strong gravity anomaly with a north-to-south gravity gradient, and the other group of pigeons in a normal area but on a spot with a strong local anomaly with a west-to-east gravity gradient. After training over shorter distances, pigeons were released from a gravitationally and geomagnetically normal site 50 km north in the same direction for both home lofts. As expected by the theory, the two groups of pigeons showed divergent initial orientation. In addition, some of the GPS-tracked pigeons also showed changes in their flight paths when crossing gravity anomalies. We conclude that even small local gravity anomalies at the birth place of pigeons may have the potential to bias the map sense of pigeons, while reactivity to gravity gradients during flight was variable and appeared to depend on individual navigational strategies and frequency of position updates.

Nonlinear Motion Tracking by Deep Learning Architecture

Science.gov (United States)

Verma, Arnav; Samaiya, Devesh; Gupta, Karunesh K.

2018-03-01

In the world of Artificial Intelligence, object motion tracking is one of the major problems. The extensive research is being carried out to track people in crowd. This paper presents a unique technique for nonlinear motion tracking in the absence of prior knowledge of nature of nonlinear path that the object being tracked may follow. We achieve this by first obtaining the centroid of the object and then using the centroid as the current example for a recurrent neural network trained using real-time recurrent learning. We have tweaked the standard algorithm slightly and have accumulated the gradient for few previous iterations instead of using just the current iteration as is the norm. We show that for a single object, such a recurrent neural network is highly capable of approximating the nonlinearity of its path.

26 CFR 1.167(b)-1 - Straight line method.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Straight line method. 1.167(b)-1 Section 1.167(b... Straight line method. (a) In general. Under the straight line method the cost or other basis of the... may be reduced to a percentage or fraction. The straight line method may be used in determining a...

7 CFR 29.6128 - Straight Stripped (X Group).

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Straight Stripped (X Group). 29.6128 Section 29.6128... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.6128 Straight Stripped (X Group). This group consists of..., and tolerances X1 Fine Quality Straight Stripped. Heavy, ripe, firm, semielastic, normal strength and...

Line-of-Sight Path Following for Dubins Paths with Adaptive Sideslip Compensation of Drift Forces

DEFF Research Database (Denmark)

Fossen, Thor Inge; Pettersen, Kristin Ytterstad; Galeazzi, Roberto

2015-01-01

guidance law is intended for maneuvering in the horizontal-plane at given speeds and typical applications are marine craft, autonomous underwater vehicles (AUVs), unmanned aerial vehicles (UAVs) as well as other vehicles and craft where the goal is to follow a predefined parametrized curve without time......-sight (LOS) guidance principle used by ancient navigators, which is here extended to path following of Dubins paths. The unknown sideslip angle is treated as a constant parameter, which is estimated using an adaptation law. The equilibrium points of the cross-track and parameter estimation errors are proven...

14 CFR 417.215 - Straight-up time analysis.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Straight-up time analysis. 417.215 Section..., DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.215 Straight-up time analysis. A flight safety analysis must establish the straight-up time for a launch for use as a flight...

A high resolution scintillating fibre (SCIFI) tracking device with CCD readout

International Nuclear Information System (INIS)

Atkinson, M.N.; Crennell, D.J.; Fisher, C.M.; Hughes, P.T.; Kirkby, J.; Fent, J.; Freund, P.; Osthoff, A.; Pretzl, K.

1987-06-01

The authors present initial test beam measurements of a high resolution scintillating fibre detector with charge coupled device readout. The analysis procedure is discussed and the performance of the detector and its readout assembly is evaluated. A detected photon density is found along minimum ionising tracks of 2.0 mm -1 , with a straight-line RMS residual of 19.3 +- 2.9 μm, giving rise to a track impact parameter precision of 8.8 +- 2.0 μm. The two-track resolution is found to be 52 μm. (author)

Neuromuscular Activation During Short-Track Speed Skating in Young Athletes.

Science.gov (United States)

Felser, Sabine; Behrens, Martin; Fischer, Susanne; Baeumler, Mario; Salomon, Ralf; Bruhn, Sven

2016-10-01

To investigate differences in muscle activation of both legs between the straight and the curve and changes in muscle activity during a 1000-m time trial (TT) and their relationship to the change in skating velocity in 9 young short-track speed skaters. The authors recorded skating times and EMG data from different leg muscles during maximum-effort skating trials on the straight and in the curve, as well as during a 1000-m TT. Muscle activation differs between the straight and the curves and between legs; ie, average activities of selected muscles of the right leg were significantly higher during skating through the curves than in the straights. This could not be observed for the left leg. The reduction in speed during the 1000-m TT highly correlates with the decrease in the muscle activity of both the tibialis anterior and the rectus femoris of the right leg. Muscle recruitment is different in relation to lap section (straight vs curve) and leg (right vs left leg). The decreased muscle activity of the tibialis anterior and rectus femoris of the right leg showed the highest relationships with the reduction in skating speed during the 1000-m TT.

Straight and White: Talking with My Mouth Full

Science.gov (United States)

Myers, W. Benjamin

2008-01-01

By using straight and white teeth as a metaphor for a straight and White identity, the author reflects on how this identity is performed, maintained, and often problematic. Using literature about identity performance, three different voices speak to and from straight and White identity. Using irony by blending arrogance and ignorance in the voice…

Proof of the path integral representation of the nonlinear Fokker-Planck equation by means of Fourier series

International Nuclear Information System (INIS)

Dekker, H.

1978-01-01

The lagrangian for the action occurring in the path integral solution of the nonlinear Fokker-Planck equation with constant diffusion function is derived by means of a straightforward Fourier series analysis. In this manner the path between the prepoint and the postpoint in the short time propagator is not restricted a priori to the usually considered straight line. Earlier results by Graham, Stratonovich, Horsthemke and Back, and the author's are recovered and thus put on much safer ground. (Auth.)

Randomized path optimization for thevMitigated counter detection of UAVS

Science.gov (United States)

2017-06-01

to tracking, such as sea state, altitude, and the position of the sun, could all be used 1 in designing a program that allows for the recovery of...qgoal , an infinite set of possible paths exists in between them. In order to scale down the problem from an infinite number of paths, a polynomial path...flight to a vehicle that used 70%. With 100 potential waypoints and five different time profiles, the set of infinite paths was narrowed down to a set

Integrated robust controller for vehicle path following

Energy Technology Data Exchange (ETDEWEB)

Mashadi, Behrooz; Ahmadizadeh, Pouyan, E-mail: p-ahmadizadeh@iust.ac.ir; Majidi, Majid, E-mail: m-majidi@iust.ac.ir [Iran University of Science and Technology, School of Automotive Engineering (Iran, Islamic Republic of); Mahmoodi-Kaleybar, Mehdi, E-mail: m-mahmoodi-k@iust.ac.ir [Iran University of Science and Technology, School of Mechanical Engineering (Iran, Islamic Republic of)

2015-02-15

The design of an integrated 4WS+DYC control system to guide a vehicle on a desired path is presented. The lateral dynamics of the path follower vehicle is formulated by considering important parameters. To reduce the effect of uncertainties in vehicle parameters, a robust controller is designed based on a μ-synthesis approach. Numerical simulations are performed using a nonlinear vehicle model in MATLAB environment in order to investigate the effectiveness of the designed controller. Results of simulations show that the controller has a profound ability to making the vehicle track the desired path in the presence of uncertainties.

Integrated robust controller for vehicle path following

International Nuclear Information System (INIS)

Mashadi, Behrooz; Ahmadizadeh, Pouyan; Majidi, Majid; Mahmoodi-Kaleybar, Mehdi

2015-01-01

The design of an integrated 4WS+DYC control system to guide a vehicle on a desired path is presented. The lateral dynamics of the path follower vehicle is formulated by considering important parameters. To reduce the effect of uncertainties in vehicle parameters, a robust controller is designed based on a μ-synthesis approach. Numerical simulations are performed using a nonlinear vehicle model in MATLAB environment in order to investigate the effectiveness of the designed controller. Results of simulations show that the controller has a profound ability to making the vehicle track the desired path in the presence of uncertainties

Assembling the LHC short straight sections

CERN Document Server

Maximilien Brice

2005-01-01

The building where the short straight sections are being assembled, was often called ‘Lego Land’ by the workers because of the wide variety of sets of magnets and cryostats. Short straight sections contain magnets for manipulating the beam inside cryostats with liquid helium to keep the magnets at a cool 1.9 K (-271.3°C).

Indigenous approach to nuclear track studies in academics

Energy Technology Data Exchange (ETDEWEB)

Tsuruta, T., E-mail: tsuruta@msa.kindai.ac.j [Atomic Energy Research Institute, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan); Interdisciplinary Graduate School of Science and Engineering, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan); Hohara, S. [Atomic Energy Research Institute, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan); Nakanishi, Y. [Interdisciplinary Graduate School of Science and Engineering, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan); Shimba, H. [Faculty of Science and Engineering, Kinki University, Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan)

2009-10-15

In a study aimed at introduction of the nuclear tracks in solids into high school education, several experimental methods were developed and proposed. From the experiments of the basic course, students will be able to learn various characteristics of alpha-particles such as straight-line motion, short range in material, formation of the track, etc. From the experiments of the advanced course, the students will be able to learn various characteristics of neutrons such as (n,alpha) reaction, recoil reaction, neutron fluence, the relationship between neutron energy and cross section, etc. It is an advantage of the solid state track detector that the trails of invisible radiation can be observed as clearly visible tracks. The tracks must arouse student's interest in radiation. It is expected that more complete education of radiation in school cultivate people's better understanding of this field.

Heading-vector navigation based on head-direction cells and path integration.

Science.gov (United States)

Kubie, John L; Fenton, André A

2009-05-01

Insect navigation is guided by heading vectors that are computed by path integration. Mammalian navigation models, on the other hand, are typically based on map-like place representations provided by hippocampal place cells. Such models compute optimal routes as a continuous series of locations that connect the current location to a goal. We propose a "heading-vector" model in which head-direction cells or their derivatives serve both as key elements in constructing the optimal route and as the straight-line guidance during route execution. The model is based on a memory structure termed the "shortcut matrix," which is constructed during the initial exploration of an environment when a set of shortcut vectors between sequential pairs of visited waypoint locations is stored. A mechanism is proposed for calculating and storing these vectors that relies on a hypothesized cell type termed an "accumulating head-direction cell." Following exploration, shortcut vectors connecting all pairs of waypoint locations are computed by vector arithmetic and stored in the shortcut matrix. On re-entry, when local view or place representations query the shortcut matrix with a current waypoint and goal, a shortcut trajectory is retrieved. Since the trajectory direction is in head-direction compass coordinates, navigation is accomplished by tracking the firing of head-direction cells that are tuned to the heading angle. Section 1 of the manuscript describes the properties of accumulating head-direction cells. It then shows how accumulating head-direction cells can store local vectors and perform vector arithmetic to perform path-integration-based homing. Section 2 describes the construction and use of the shortcut matrix for computing direct paths between any pair of locations that have been registered in the shortcut matrix. In the discussion, we analyze the advantages of heading-based navigation over map-based navigation. Finally, we survey behavioral evidence that nonhippocampal

A Faster Algorithm for Computing Straight Skeletons

KAUST Repository

Cheng, Siu-Wing

2014-09-01

We present a new algorithm for computing the straight skeleton of a polygon. For a polygon with n vertices, among which r are reflex vertices, we give a deterministic algorithm that reduces the straight skeleton computation to a motorcycle graph computation in O(n (logn)logr) time. It improves on the previously best known algorithm for this reduction, which is randomized, and runs in expected O(n√h+1log2n) time for a polygon with h holes. Using known motorcycle graph algorithms, our result yields improved time bounds for computing straight skeletons. In particular, we can compute the straight skeleton of a non-degenerate polygon in O(n (logn) logr + r 4/3 + ε ) time for any ε > 0. On degenerate input, our time bound increases to O(n (logn) logr + r 17/11 + ε ).

A Faster Algorithm for Computing Straight Skeletons

KAUST Repository

Mencel, Liam A.

2014-05-06

We present a new algorithm for computing the straight skeleton of a polygon. For a polygon with n vertices, among which r are reflex vertices, we give a deterministic algorithm that reduces the straight skeleton computation to a motorcycle graph computation in O(n (log n) log r) time. It improves on the previously best known algorithm for this reduction, which is randomised, and runs in expected O(n √(h+1) log² n) time for a polygon with h holes. Using known motorcycle graph algorithms, our result yields improved time bounds for computing straight skeletons. In particular, we can compute the straight skeleton of a non-degenerate polygon in O(n (log n) log r + r^(4/3 + ε)) time for any ε > 0. On degenerate input, our time bound increases to O(n (log n) log r + r^(17/11 + ε))

A Faster Algorithm for Computing Straight Skeletons

KAUST Repository

Cheng, Siu-Wing; Mencel, Liam A.; Vigneron, Antoine E.

2014-01-01

We present a new algorithm for computing the straight skeleton of a polygon. For a polygon with n vertices, among which r are reflex vertices, we give a deterministic algorithm that reduces the straight skeleton computation to a motorcycle graph computation in O(n (logn)logr) time. It improves on the previously best known algorithm for this reduction, which is randomized, and runs in expected O(n√h+1log2n) time for a polygon with h holes. Using known motorcycle graph algorithms, our result yields improved time bounds for computing straight skeletons. In particular, we can compute the straight skeleton of a non-degenerate polygon in O(n (logn) logr + r 4/3 + ε ) time for any ε > 0. On degenerate input, our time bound increases to O(n (logn) logr + r 17/11 + ε ).

Final Technical Report for ``Paths to Discovery at the LHC : Dark Matter and Track Triggering"

Energy Technology Data Exchange (ETDEWEB)

Hahn, Kristian [Northwestern Univ., Evanston, IL (United States)

2016-10-24

Particle Dark Matter (DM) is perhaps the most compelling and experimentally well-motivated new physics scenario anticipated at the Large Hadron Collider (LHC). The DE-SC0014073 award allowed the PI to define and pursue a path to the discovery of Dark Matter in Run-2 of the LHC with the Compact Muon Solenoid (CMS) experiment. CMS can probe regions of Dark Matter phase-space that direct and indirect detection experiments are unable to constrain. The PI’s team initiated the exploration of these regions, searching specifically for the associated production of Dark Matter with top quarks. The effort focuses on the high-yield, hadronic decays of W bosons produced in top decay, which provides the highest sensitivity to DM produced via through low-mass spin-0 mediators. The group developed identification algorithms that achieve high efficiency and purity in the selection of hadronic top decays, and analysis techniques that provide powerful signal discrimination in Run-2. The ultimate reach of new physics searches with CMS will be established at the high-luminosity LHC (HL-LHC). To fully realize the sensitivity the HL-LHC promises, CMS must minimize the impact of soft, inelastic (“pileup”) interactions on the real-time “trigger” system the experiment uses for data refinement. Charged particle trajectory information (“tracking”) will be essential for pileup mitigation at the HL-LHC. The award allowed the PI’s team to develop firmware-based data delivery and track fitting algorithms for an unprecedented, real-time tracking trigger to sustain the experiment’s sensitivity to new physics in the next decade.

A straightness error measurement method matched new generation GPS

International Nuclear Information System (INIS)

Zhang, X B; Lu, H; Jiang, X Q; Li, Z

2005-01-01

The axis of the non-diffracting beam produced by an axicon is very stable and can be adopted as the datum line to measure the spatial straightness error in continuous working distance, which may be short, medium or long. Though combining the non-diffracting beam datum-line with LVDT displace detector, a new straightness error measurement method is developed. Because the non-diffracting beam datum-line amends the straightness error gauged by LVDT, the straightness error is reliable and this method is matchs new generation GPS

Analysis of a Steerable Needle for Fine Needle Aspiration and Biopsy: Efficiency and Radiation Dose Compared With a Conventional Straight Needle.

Science.gov (United States)

Rutigliano, Sandra; Abraham, John A; Kenneally, Barry E; Zoga, Adam C; Nevalainen, Mika; Roedl, Johannes B

Percutaneous computed tomography (CT)-guided needle biopsy has proven to be an efficacious method for sampling of many soft tissue lesions, especially deep-seated masses in the abdomen and pelvis. This study sought to test the potential for a novel steerable needle to improve localization and to reduce procedure duration and radiation dose compared with a conventional straight needle. A fresh, raw meat sample (lean bovine flank) was imbedded with cylindrical radiopaque and radiolucent obstacles designed to simulate vessels (radiolucent objects) and bones (radiopaque objects) on CT. A pit-containing olive (partially radiopaque) was imbedded beyond the obstacles to represent the target. Two sites on the surface of the meat were selected and marked to determine initial needle placement. Two radiologists with different levels of experience proceeded to position a straight needle and the steerable needle from each skin site to the target using CT guidance as efficiently as possible, avoiding the obstacles. The total positioning time, the number of CT scans required for positioning, and the number of repositioning events (partial withdrawal followed by advancement) were tracked for the straight and steerable needles. For the straight needle, total time to reach the target was 499 to 667 seconds (mean, 592 seconds); for the steerable needle, total time to reach the target was 281 to 343 seconds (mean, 309 seconds), on average, 48% lower. The number of CT scans needed for needle positioning averaged 6.25 for the straight needle and 3.5 for the steerable needle, which is 44% lower. Repositioning events (withdrawing and readvancing the needle) ranged from 3 to 10 for the straight needle (mean, 6.5) and 0 for the steerable needle. Using an in vitro model embedded with obstacles, the steerable needle performed better than a straight needle with regard to procedure time, needle repositioning events, and CT scans required for placement.

Research on Navigation Path Planning for An Underground Load Haul Dump

Directory of Open Access Journals (Sweden)

Qi Yulong

2015-11-01

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

A Synthetic Algorithm for Tracking a Moving Object in a Multiple-Dynamic Obstacles Environment Based on Kinematically Planar Redundant Manipulators

Directory of Open Access Journals (Sweden)

Hongzhe Jin

2017-01-01

Full Text Available This paper presents a synthetic algorithm for tracking a moving object in a multiple-dynamic obstacles environment based on kinematically planar manipulators. By observing the motions of the object and obstacles, Spline filter associated with polynomial fitting is utilized to predict their moving paths for a period of time in the future. Several feasible paths for the manipulator in Cartesian space can be planned according to the predicted moving paths and the defined feasibility criterion. The shortest one among these feasible paths is selected as the optimized path. Then the real-time path along the optimized path is planned for the manipulator to track the moving object in real-time. To improve the convergence rate of tracking, a virtual controller based on PD controller is designed to adaptively adjust the real-time path. In the process of tracking, the null space of inverse kinematic and the local rotation coordinate method (LRCM are utilized for the arms and the end-effector to avoid obstacles, respectively. Finally, the moving object in a multiple-dynamic obstacles environment is thus tracked via real-time updating the joint angles of manipulator according to the iterative method. Simulation results show that the proposed algorithm is feasible to track a moving object in a multiple-dynamic obstacles environment.

21 CFR 82.5 - General specifications for straight colors.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false General specifications for straight colors. 82.5... LISTING OF CERTIFIED PROVISIONALLY LISTED COLORS AND SPECIFICATIONS General Provisions § 82.5 General specifications for straight colors. No batch of a straight color listed in subpart B, C, or D shall be certified...

Non-etching nuclear track visualization in polymers: fluorescent and dyed tracks

International Nuclear Information System (INIS)

Somogyi, G.; Toth-Szilagyi, M.; Monnin, M.; Gourcy, J.

1979-01-01

A report is presented on progress in two methods of non-etching nuclear track visualization. The basis for one method is to graft polymer chains in the vicinity of the ion path in a polymer, and then to dye it, making the track visible. The second method is similar, but in this case saturated organic molecules can be used, which prevents subsequent polymerization. The detector is soaked with a solution of a sensitization molecule that can react with a convenient dye and fix it. The sensitization molecules may diffuse into the detector either through the bulk of it or/ and along the region damaged by a charged particle. Depending on the detailed procedure used, the tracks may be seen as 'dyed tracks' with visible-light illumination or as 'fluorescent tracks' with u.v. illumination. Experimental procedures and results are given and discussed. (U.K.)

Design of an MgB2 race track coil for a wind generator pole demonstration

DEFF Research Database (Denmark)

Abrahamsen, Asger Bech; Magnusson, Niklas; Jensen, Bogi Bech

2014-01-01

An MgB2 race track coil intended for demonstrating a down scaled pole of a 10 MW direct drive wind turbine generator has been designed. The coil consists of 10 double pancake coils stacked into a race track coil with a cross section of 84 mm × 80 mm. The length of the straight section is 0.5 m...

Equilibrium depth of scour at straight guide banks

Science.gov (United States)

Gjunsburgs, B.; Bulankina, V.

2017-10-01

The equilibrium stage of scour at the head of straight guide banks with a uniform and stratified bed conditions have been studied. The contraction of the river by bridge crossing with straight guide banks considerably alters the flow pattern. The streamlines become curve and the concentration of streamlines, longitudinal and transverse slopes of the water surface, a local increase in velocity, vortex and eddy structures, and the origin of a flow separation zone between the extreme streamlines and the guide bank are observed and local scour is developing at the head of the straight guide banks. New formulae for calculation of equilibrium depth of scour at straight guide banks at uniform and stratified river bed is elaborated and confirmed by tests and computer modelling results.

Vision-based Navigation and Reinforcement Learning Path Finding for Social Robots

OpenAIRE

Pérez Sala, Xavier

2010-01-01

We propose a robust system for automatic Robot Navigation in uncontrolled en- vironments. The system is composed by three main modules: the Arti cial Vision module, the Reinforcement Learning module, and the behavior control module. The aim of the system is to allow a robot to automatically nd a path that arrives to a pre xed goal. Turn and straight movements in uncontrolled environments are automatically estimated and controlled using the proposed modules. The Arti cial Vi...

Attitudes toward straight, gay male, and transsexual parenting.

Science.gov (United States)

Weiner, Brittany A; Zinner, Leah

2015-01-01

This study examined American attitudes toward transsexual and gay male parenting, compared to straight parenting. After reporting levels of transphobia, participants read a vignette regarding a couple seeking child adoption. Individuals high in transphobia perceived nontraditional couples as more emotionally unstable than straight couples and were less willing to grant custody of a child to the nontraditional couples vs. the straight couples. In addition, the transsexual couple faced more prejudice and discrimination than the gay male couple. Implications of these findings are discussed.

Straight Talk for Good Health | NIH MedlinePlus the Magazine

Science.gov (United States)

... of this page please turn Javascript on. Feature: Straight Talk for Good Health Straight Talk for Good Health Past Issues / Spring 2013 ... with your Doctor nihseniorhealth.gov/talkingwithyourdoctor/toc.html Straight talk with your healthcare provider is important. You ...

Mechanism of track formation by charged particles in inorganic and organic solid-state track detectors

International Nuclear Information System (INIS)

Doerschel, B.; Pretzsch, G.; Streubel, G.

1979-01-01

Knowledge of the individual phases of track formation mechanism is necessary in some applications of solid-state track detectors. The generation of latent tracks is described by energy transfer processes of the charged particles along their paths using several different models. Etchability of the latent tracks is discussed on the basis of some distinct criteria taking into account different fractions of energy release by the primary and secondary particles during track generation. If these etchability criteria for latent tracks are fulfilled, visual particle tracks can be produced by a chemical etching process. Etch pit formation depends on the etching conditions. The geometrical parameters of the etching pits are given on the basis of known etching rates. Evaluation of individual particle tracks or determination of track density yields results depending on both the properties of the particles and the etching conditions. Determination of particle energy and particle fluence is discussed as an example. (author)

Design of an arbitrary path-following controller for a non-holonomic mobile platform

CSIR Research Space (South Africa)

Sabatta, DG

2009-11-01

Full Text Available required for the platform to asymptotically track the path. The controller derived in this paper is implemented on the Seekur platform from Mobile Robots. Results showing the following of a pre-recorded path from differential GPS are discussed....

Straight leg elevation to rule out pelvic injury.

Science.gov (United States)

Bolt, Caroline; O'Keeffe, Francis; Finnegan, Pete; Dickson, Kristofer; Smit, De Villiers; Fitzgerald, Mark C; Mitra, Biswadev

2018-02-01

Pelvic x-ray is frequently used as a screening tool during initial assessment of injured patients. However routine use in the awake and alert blunt trauma patient may be questioned due to low yield. We propose a clinical tool that may avoid unnecessary imaging by examining whether the ability to straight leg raise, without pain, can rule out pelvic injury. We conducted a prospective cohort study with the exposure variables of ability to straight leg raise and presence of pain on doing so, and presence of pelvic fracture on x-ray as the primary outcome variable. Of the 328 participants, 35 had pelvic fractures, and of these 32 were either unable to straight leg raise, or had pain on doing so, with a sensitivity of 91.43% (95% CI: 76.94-98.2%) and a negative predictive value of 98.57% (95% CI: 95.88-99.70%). The 3 participants with a pelvic fracture who could straight leg raise with no pain, all had a GCS of less than 15, and therefore, among the sub-group of patients with GCS15, a 100% sensitivity and 100% negative predictive value for straight leg raise with no pain to rule out pelvic fracture was demonstrated. Among awake, alert patients, painless straight leg raise can exclude pelvic fractures and be incorporated into initial examination during reception and resuscitation of injured patients. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

"Fast Track" and "Traditional Path" Coaches: Affordances, Agency and Social Capital

Science.gov (United States)

Rynne, Steven

2014-01-01

A recent development in large-scale coach accreditation (certification) structures has been the "fast tracking" of former elite athletes. Former elite athletes are often exempted from entry-level qualifications and are generally granted access to fast track courses that are shortened versions of the accreditation courses undertaken by…

Particle tracking at the SSC

International Nuclear Information System (INIS)

Freeman, J.E.; Williams, H.H.

1984-01-01

The intent of this study was to get some idea of how difficult tracking will be at √s = 40 TeV for events involving momentum transfers in the vicinity of several hundred GeV. While some studies have been done to determine the minimum separation between two random tracks as a function of radius, the authors know of no previous study in this energy range which has considered the ''observability'' of a track along its entire path length, including the effects of magnetic field and finite double track resolution. They have not considered the effects of pileup due to multiple events, concentrating instead of the inherent difficulties of single high p/sub T/ events

Target Centroid Position Estimation of Phase-Path Volume Kalman Filtering

Directory of Open Access Journals (Sweden)

Fengjun Hu

2016-01-01

Full Text Available For the problem of easily losing track target when obstacles appear in intelligent robot target tracking, this paper proposes a target tracking algorithm integrating reduced dimension optimal Kalman filtering algorithm based on phase-path volume integral with Camshift algorithm. After analyzing the defects of Camshift algorithm, compare the performance with the SIFT algorithm and Mean Shift algorithm, and Kalman filtering algorithm is used for fusion optimization aiming at the defects. Then aiming at the increasing amount of calculation in integrated algorithm, reduce dimension with the phase-path volume integral instead of the Gaussian integral in Kalman algorithm and reduce the number of sampling points in the filtering process without influencing the operational precision of the original algorithm. Finally set the target centroid position from the Camshift algorithm iteration as the observation value of the improved Kalman filtering algorithm to fix predictive value; thus to make optimal estimation of target centroid position and keep the target tracking so that the robot can understand the environmental scene and react in time correctly according to the changes. The experiments show that the improved algorithm proposed in this paper shows good performance in target tracking with obstructions and reduces the computational complexity of the algorithm through the dimension reduction.

Supercavitating Projectile Tracking System and Method

Science.gov (United States)

2009-12-30

Distribution is unlimited 20100104106 Attorney Docket No. 96681 SUPERCAVITATING PROJECTILE TRACKING SYSTEM AND METHOD STATEMENT OF GOVERNMENT...underwater track or path 14 of a supercavitating vehicle under surface 16 of a body of water. In this embodiment, passive acoustic or pressure...transducers 12 are utilized to measure a pressure field produced by a moving supercavitating vehicle. The present invention provides a low-cost, reusable

Visual straight-ahead preference in saccadic eye movements.

Science.gov (United States)

Camors, Damien; Trotter, Yves; Pouget, Pierre; Gilardeau, Sophie; Durand, Jean-Baptiste

2016-03-15

Ocular saccades bringing the gaze toward the straight-ahead direction (centripetal) exhibit higher dynamics than those steering the gaze away (centrifugal). This is generally explained by oculomotor determinants: centripetal saccades are more efficient because they pull the eyes back toward their primary orbital position. However, visual determinants might also be invoked: elements located straight-ahead trigger saccades more efficiently because they receive a privileged visual processing. Here, we addressed this issue by using both pro- and anti-saccade tasks in order to dissociate the centripetal/centrifugal directions of the saccades, from the straight-ahead/eccentric locations of the visual elements triggering those saccades. Twenty participants underwent alternating blocks of pro- and anti-saccades during which eye movements were recorded binocularly at 1 kHz. The results confirm that centripetal saccades are always executed faster than centrifugal ones, irrespective of whether the visual elements have straight-ahead or eccentric locations. However, by contrast, saccades triggered by elements located straight-ahead are consistently initiated more rapidly than those evoked by eccentric elements, irrespective of their centripetal or centrifugal direction. Importantly, this double dissociation reveals that the higher dynamics of centripetal pro-saccades stem from both oculomotor and visual determinants, which act respectively on the execution and initiation of ocular saccades.

Straight eye for the gay guy: composing queerness.

Science.gov (United States)

Alexander, Jonathan

2010-01-01

Drawing on the work of Didier Eribon and his theorization of the construction of gay male subjectivity, this article examines different "texts," broadly defined, that grapple specifically with straight men attempting to represent male homosexuality: Norman Mailer's essay, "The Homosexual Villain"; the Bravo reality television series Boy Meets Boy, and Michael Griffith's short story, "Hooper Gets a Perm." These texts represent attempts by straight authors to grapple with queer experience in ways that move the imagination of queers beyond simple stereotypes or uncritical explorations of the sexual "other." In the process of examining these texts, the following questions are addressed: What happens when a straight man attempts to represent a gay man? Does he "get it right," and is such a question even useful? More specifically, what is the value in having straights imagine queerness? Is such an imagining possible? Is such desirable? And, if so, what are the contours of such an imagining-as well as its possibilities and limitations, pedagogically, personally, and politically? Ultimately, I contend that the straight imagining of queerness offers rich potential for mutual understanding; furthermore, attempting to understand what goes into the making of those representations tells us much about how queerness circulates in our culture as a subject, a figure of discussion, contention, and representation.

Autonomous Path Planning for Road Vehicles in Narrow Environments: An Efficient Continuous Curvature Approach

Directory of Open Access Journals (Sweden)

Domokos Kiss

2017-01-01

Full Text Available In this paper we introduce a novel method for obtaining good quality paths for autonomous road vehicles (e.g., cars or buses in narrow environments. There are many traffic situations in urban scenarios where nontrivial maneuvering in narrow places is necessary. Navigating in cluttered parking lots or having to avoid obstacles blocking the way and finding a detour even in narrow streets are challenging, especially if the vehicle has large dimensions like a bus. We present a combined approximation-based approach to solve the path planning problem in such situations. Our approach consists of a global planner which generates a preliminary path consisting of straight and turning-in-place primitives and a local planner which is used to make the preliminary path feasible to car-like vehicles. The approximation methodology is well known in the literature; however, both components proposed in this paper differ from existing similar planning methods. The approximation process with the proposed local planner is proven to be convergent for any preliminary global paths. The resulting path has continuous curvature which renders our method well suited for application on real vehicles. Simulation experiments show that the proposed method outperforms similar approaches in terms of path quality in complicated planning tasks.

Uncertainty of spatial straightness in 3D measurement

International Nuclear Information System (INIS)

Wang Jinxing; Jiang Xiangqian; Ma Limin; Xu Zhengao; Li Zhu

2005-01-01

The least-square method is commonly employed to verify the spatial straightness in actual three-dimensional measurement process, but the uncertainty of the verification result is usually not given by the coordinate measuring machines. According to the basic principle of spatial straightness least-square verification and the uncertainty propagation formula given by ISO/TS 14253-2, a calculation method for the uncertainty of spatial straightness least-square verification is proposed in this paper. By this method, the coefficients of the line equation are regarded as a statistical vector, so that the line equation, the result of the spatial straightness verification and the uncertainty of the result can be obtained after the expected value and covariance matrix of the vector are determined. The method not only assures the integrity of the verification result, but also accords with the requirement of the new generation of GPS standards, which can improve the veracity of verification

Path tracking control of an omni-directional walker considering pressures from a user.

Science.gov (United States)

Tan, Renpeng; Wang, Shuoyu; Jiang, Yinlai; Ishida, Kenji; Fujie, Masakatsu G

2013-01-01

An omni-directional walker (ODW) is being developed to support the people with walking disabilities to do walking rehabilitation. The training paths, which the user follows in the rehabilitation, are defined by physical therapists and stored in the ODW. In order to obtain a good training effect, the defined training paths need to be performed accurately. However, the ODW deviates from the training path in real rehabilitation, which is caused by the variation of the whole system's parameters due to the force from the user. In this paper, the characteristics of pressures from a user are measured, based on which an adaptive controller is proposed to deal with this problem, and validated in an experiment in which a pseudo handicapped person follows the ODW. The experimental results show that the proposed method can control the ODW to accurately follow the defined path with or without a user.

The Theory and Assessment of Spatial Straightness Error Matched New Generation GPS

International Nuclear Information System (INIS)

Zhang, X B; Sheng, X L; Jiang, X Q; Li, Z

2006-01-01

In order to assess spatial straightness error matched new generation Dimensional Geometrical Product Specification and Verification (GPS), the theory of spatial straightness error assessing is proposed and its advantages are analyzed based on metrology and statistics in this paper. Then, the assessing parameter system is proposed and it is testified in real application comparing to assessment result of the geometric tolerance theory. Statistical parameters of this assessing system post the different characteristics of spatial straightness error, and can reveal the impact of spatial straightness error on the accessory function more roundly to complement the single assessing parameter of geometrical tolerance for straightness error. The statistical spatial straightness tolerance and statistical spatial straightness error proposed in this paper is possible to be applied in evaluation of other error of form, orientation, location and run-out

A novel straightness measurement system applied to the position monitoring of large Particle Physics Detectors

CERN Document Server

Goudard, R; Ribeiro, R; Klumb, F

1999-01-01

The Compact Muon Solenoid experiment, CMS, is one of the two general purpose experiments foreseen to operate at the Large Hadron Collider, LHC, at CERN, the European Laboratory for Particle Physics. The experiment aims to study very high energy collisions of proton beams. Investigation of the most fundamental properties of matter, in particular the study of the nature of the electroweak symmetry breaking and the origin of mass, is the experiment scope. The central Tracking System, a six meter long cylinder with 2.4 m diameter, will play a major role in all physics searches of the CMS experiment. Its performance depends upon the intrinsic detector performance, on the stability of the supporting structure and on the overall survey, alignment and position monitoring system. The proposed position monitoring system is based on a novel lens-less laser straightness measurement method able to detect deviations from a nominal position of all structural elements of the Central Tracking system. It is based on the recipr...

Radical heterosexuality: Straight teacher activism in schools : Does ally-led activism work?

Directory of Open Access Journals (Sweden)

Leigh Potvin

2016-06-01

Here, I explore the efficacy of straight teacher allies, the importance of understanding straight privilege, and the significance of radical heterosexuality for straight people doing LGBTQ activism. Relying on queer theory and decolonizing/Indigenous queer theory, I argue that it is necessary for straight teachers to acknowledge their straight privilege in order to challenge homophobia's companions: heterosexism and heteronormativity. In addressing the latter two covert forms of oppression in schools, teachers and students could shift into deeper, more effective resistance measures.

A fracture-controlled path-following technique for phase-field modeling of brittle fracture

NARCIS (Netherlands)

Singh, N.; Verhoosel, C.V.; De Borst, R.; Van Brummelen, E.H.

2016-01-01

In the phase-field description of brittle fracture, the fracture-surface area can be expressed as a functional of the phase field (or damage field). In this work we study the applicability of this explicit expression as a (non-linear) path-following constraint to robustly track the equilibrium path

Quadcopter Path Following Control Design Using Output Feedback with Command Generator Tracker LOS Based At Square Path

Science.gov (United States)

Nugraha, A. T.; Agustinah, T.

2018-01-01

Quadcopter an unstable system, underactuated and nonlinear in quadcopter control research developments become an important focus of attention. In this study, following the path control method for position on the X and Y axis, used structure-Generator Tracker Command (CGT) is tested. Attitude control and position feedback quadcopter is compared using the optimal output. The addition of the H∞ performance optimal output feedback control is used to maintain the stability and robustness of quadcopter. Iterative numerical techniques Linear Matrix Inequality (LMI) is used to find the gain controller. The following path control problems is solved using the method of LQ regulators with output feedback. Simulations show that the control system can follow the paths that have been defined in the form of a reference signal square shape. The result of the simulation suggest that the method which used can bring the yaw angle at the expected value algorithm. Quadcopter can do automatically following path with cross track error mean X=0.5 m and Y=0.2 m.

Bent versus straight tips in micropulsed longitudinal phacoemulsification.

Science.gov (United States)

Stagg, Brian C; Gupta, Isha; Cahoon, Judd; Ronquillo, Cecinio; Shi, Dallas; Zaugg, Brian; Gardiner, Gareth; Barlow, William R; Pettey, Jeff H; Aabid Farukhi, M; Jensen, Jason; Olson, Randall J

2015-10-01

The aim of this study was to evaluate bent and straight phacoemulsification tips to determine which tip is more efficient in removal of lens fragments, using micropulsed longitudinal ultrasound in phacoemulsification. In vitro laboratory study. The John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, was the study setting. Pig lenses hardened in a manner comparable with dense human cataracts were cut into 2-mm cubes and removed with micropulsed longitudinal ultrasound using settings previously shown to be optimally efficient (6 milliseconds on and 6 milliseconds off for a bent tip). To verify this time as most efficient for a straight tip, we also tested times of 5, 6, and 7 milliseconds time on and off. The tips were either straight or with a 20-degree bend. Twenty cubes were used for each comparative run. For the straight tip, 6 milliseconds on (1.56 ± 0.815 seconds) was significantly more efficient than 7 milliseconds on (2.45 ± 1.56 seconds, p = 0.001) and not significantly more efficient than 5 milliseconds on (1.69 ± 0.86 seconds, p = 0.43). Five milliseconds off time (1.45 ± 0.76s) was more efficient than 6 milliseconds (2.06 ± 1.37 seconds, p = 0.004) and 7 milliseconds off (2.18 ± 1.24s, p = 0.001). The straight tip was more efficient than the bent tip (1.38 ± 0.83 versus 2.93 ± 2.14 seconds, p = 0.006). Results are contrary to accepted common belief. Micropulsed longitudinal phacoemulsification is more efficient with a straight rather than a bent tip. Copyright © 2015 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Straight-Line: A nuclear material storage information management system

International Nuclear Information System (INIS)

Nilsen, C.; Mangan, D.

1995-01-01

Sandia National Laboratories is developing Straight-Line -- a pilot system to demonstrate comprehensive monitoring of nuclear material in storage. Straight-Line is an integrated system of sensors providing information that will enhance the safety, security, and international accountability of stored nuclear material. The goals of this effort are to: (1) Provide the right sensor information to the right user immediately. (2) Reduce the expenses, risks, and frequency of human inspection of the material. (3) Provide trustworthy data to international inspectors to minimize their need to make on site inspections. In pursuit of these goals, Straight-Line unites technology from Sandia's Authenticated Item Monitoring System (AIMS) and other programs to communicate the authenticated status of the monitored item back to central magazine receivers. Straight-Line, however, incorporates several important features not found in previous systems: (1) Information Security -- the ability to collect and safely disseminate both classified and unclassified sensor data to users on a need-to-know basis. (2) Integrate into a single system the monitoring needs of safety, security, and international accountability. (3) Incorporate the use of sensors providing analog or digital output. This paper will present the overall architecture and status of the Straight-Line project

Straight-Line: A nuclear material storage information management system

Energy Technology Data Exchange (ETDEWEB)

Nilsen, C.; Mangan, D.

1995-07-01

Sandia National Laboratories is developing Straight-Line -- a pilot system to demonstrate comprehensive monitoring of nuclear material in storage. Straight-Line is an integrated system of sensors providing information that will enhance the safety, security, and international accountability of stored nuclear material. The goals of this effort are to: (1) Provide the right sensor information to the right user immediately. (2) Reduce the expenses, risks, and frequency of human inspection of the material. (3) Provide trustworthy data to international inspectors to minimize their need to make on site inspections. In pursuit of these goals, Straight-Line unites technology from Sandia`s Authenticated Item Monitoring System (AIMS) and other programs to communicate the authenticated status of the monitored item back to central magazine receivers. Straight-Line, however, incorporates several important features not found in previous systems: (1) Information Security -- the ability to collect and safely disseminate both classified and unclassified sensor data to users on a need-to-know basis. (2) Integrate into a single system the monitoring needs of safety, security, and international accountability. (3) Incorporate the use of sensors providing analog or digital output. This paper will present the overall architecture and status of the Straight-Line project.

Trajectory generation for manipulators using linear quadratic optimal tracking

Directory of Open Access Journals (Sweden)

Olav Egeland

1989-04-01

Full Text Available The reference trajectory is normally known in advance in manipulator control which makes it possible to apply linear quadratic optimal tracking. This gives a control system which rounds corners and generates optimal feedforward. The method may be used for references consisting of straight-line segments as an alternative to the two-step method of using splines to smooth the reference and then applying feedforward. In addition, the method can be used for more complex trajectories. The actual dynamics of the manipulator are taken into account, and this results in smooth and accurate tracking. The method has been applied in combination with the computed torque technique and excellent performance was demonstrated in a simulation study. The method has also been applied experimentally to an industrial spray-painting robot where a saw-tooth reference was tracked. The corner was rounded extremely well, and the steady-state tracking error was eliminated by the optimal feedforward.

Bragg peak prediction from quantitative proton computed tomography using different path estimates

International Nuclear Information System (INIS)

Wang Dongxu; Mackie, T Rockwell; Tome, Wolfgang A

2011-01-01

This paper characterizes the performance of the straight-line path (SLP) and cubic spline path (CSP) as path estimates used in reconstruction of proton computed tomography (pCT). The GEANT4 Monte Carlo simulation toolkit is employed to simulate the imaging phantom and proton projections. SLP, CSP and the most-probable path (MPP) are constructed based on the entrance and exit information of each proton. The physical deviations of SLP, CSP and MPP from the real path are calculated. Using a conditional proton path probability map, the relative probability of SLP, CSP and MPP are calculated and compared. The depth dose and Bragg peak are predicted on the pCT images reconstructed using SLP, CSP, and MPP and compared with the simulation result. The root-mean-square physical deviations and the cumulative distribution of the physical deviations show that the performance of CSP is comparable to MPP while SLP is slightly inferior. About 90% of the SLP pixels and 99% of the CSP pixels lie in the 99% relative probability envelope of the MPP. Even at an imaging dose of ∼0.1 mGy the proton Bragg peak for a given incoming energy can be predicted on the pCT image reconstructed using SLP, CSP, or MPP with 1 mm accuracy. This study shows that SLP and CSP, like MPP, are adequate path estimates for pCT reconstruction, and therefore can be chosen as the path estimation method for pCT reconstruction, which can aid the treatment planning and range prediction of proton radiation therapy.

Bragg peak prediction from quantitative proton computed tomography using different path estimates

Energy Technology Data Exchange (ETDEWEB)

Wang Dongxu; Mackie, T Rockwell; Tome, Wolfgang A, E-mail: tome@humonc.wisc.edu [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 (United States)

2011-02-07

This paper characterizes the performance of the straight-line path (SLP) and cubic spline path (CSP) as path estimates used in reconstruction of proton computed tomography (pCT). The GEANT4 Monte Carlo simulation toolkit is employed to simulate the imaging phantom and proton projections. SLP, CSP and the most-probable path (MPP) are constructed based on the entrance and exit information of each proton. The physical deviations of SLP, CSP and MPP from the real path are calculated. Using a conditional proton path probability map, the relative probability of SLP, CSP and MPP are calculated and compared. The depth dose and Bragg peak are predicted on the pCT images reconstructed using SLP, CSP, and MPP and compared with the simulation result. The root-mean-square physical deviations and the cumulative distribution of the physical deviations show that the performance of CSP is comparable to MPP while SLP is slightly inferior. About 90% of the SLP pixels and 99% of the CSP pixels lie in the 99% relative probability envelope of the MPP. Even at an imaging dose of {approx}0.1 mGy the proton Bragg peak for a given incoming energy can be predicted on the pCT image reconstructed using SLP, CSP, or MPP with 1 mm accuracy. This study shows that SLP and CSP, like MPP, are adequate path estimates for pCT reconstruction, and therefore can be chosen as the path estimation method for pCT reconstruction, which can aid the treatment planning and range prediction of proton radiation therapy.

Bragg peak prediction from quantitative proton computed tomography using different path estimates

Science.gov (United States)

Wang, Dongxu; Mackie, T Rockwell

2015-01-01

This paper characterizes the performance of the straight-line path (SLP) and cubic spline path (CSP) as path estimates used in reconstruction of proton computed tomography (pCT). The GEANT4 Monte Carlo simulation toolkit is employed to simulate the imaging phantom and proton projections. SLP, CSP and the most-probable path (MPP) are constructed based on the entrance and exit information of each proton. The physical deviations of SLP, CSP and MPP from the real path are calculated. Using a conditional proton path probability map, the relative probability of SLP, CSP and MPP are calculated and compared. The depth dose and Bragg peak are predicted on the pCT images reconstructed using SLP, CSP, and MPP and compared with the simulation result. The root-mean-square physical deviations and the cumulative distribution of the physical deviations show that the performance of CSP is comparable to MPP while SLP is slightly inferior. About 90% of the SLP pixels and 99% of the CSP pixels lie in the 99% relative probability envelope of the MPP. Even at an imaging dose of ~0.1 mGy the proton Bragg peak for a given incoming energy can be predicted on the pCT image reconstructed using SLP, CSP, or MPP with 1 mm accuracy. This study shows that SLP and CSP, like MPP, are adequate path estimates for pCT reconstruction, and therefore can be chosen as the path estimation method for pCT reconstruction, which can aid the treatment planning and range prediction of proton radiation therapy. PMID:21212472

Control system design for UAV trajectory tracking

Science.gov (United States)

Wang, Haitao; Gao, Jinyuan

2006-11-01

In recent years, because of the emerging requirements for increasing autonomy, the controller of uninhabited air vehicles must be augmented with a very sophisticated autopilot design which is capable of tracking complex and agile maneuvering trajectory. This paper provides a simplified control system framework to solve UAV maneuvering trajectory tracking problem. The flight control system is divided into three subsystems including command generation, transformation and allocation. According to the kinematics equations of the aircraft, flight path angle commands can be generated by desired 3D position from path planning. These commands are transformed to body angular rates through direct nonlinear mapping, which is simpler than common multi-loop method based on time scale separation assumption. Then, by using weighted pseudo-inverse method, the control surface deflections are allocated to follow body angular rates from the previous step. In order to improve the robustness, a nonlinear disturbance observer-based approach is used to compensate the uncertainty of system. A 6DOF nonlinear UAV model is controlled to demonstrate the performance of the trajectory tracking control system. Simulation results show that the control strategy is easy to be realized and the precision of tracking is satisfying.

[Glide path management of rotary nickel-titanium instruments in simulated root canals].

Science.gov (United States)

Han, Y; Bai, Y H; Hou, X M

2018-02-18

To compare the shaping ability of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 with that of PathFile and stainless steel K-file hand instruments in simulated root canals. A total of 60 simulated resin blocks were divided randomly into five groups (n=12), each group prepared with each instrument, respectively. Preparation time was recorded. Pre- and post-operative images were obtained using a scanner and superimposed using Photoshop. The material removal from the inner and outer canal walls beginning from 0 mm at the end point of the canal were measured using ImageJ. Centering ability was determined, accordingly. The data were analyzed using the One-Way ANOVA at a significance level of P0.05). The removal of resin from the outer wall at the apical portion was significantly lower for HyFlex EDM Glidepath File than for ProGlider (PEDM Glidepath File the second most, and the other 3 groups among the same levels. As far as the centering ability was concerned, at the apical portion, HyFlex EDM Glidepath File was the best, ProGlider the second best, no significant difference identified among the other 3 groups. At the curvature portion, ProGlider and HyFlex EDM Glidepath File were the best, PathFile the second, RaCe ISO 10 the third, the worst was the SS K-file. At the straight portion, the difference amongt the 5 groups was not significant. The shaping abilities of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 were better or comparable to that of PathFile, while the preparation time for ProGlider reduced significantly, and HyFlex EDM Glidepath File and RaCe ISO 10 removed significantly more resin at the straight portion of the canal.

Optimal Trajectory Tracking Control for a Wheeled Mobile Robot Using Fractional Order PID Controller

Directory of Open Access Journals (Sweden)

Ameer L. Saleh

2018-02-01

Full Text Available This paper present an optimal Fractional Order PID (FOPID controller based on Particle Swarm Optimization (PSO for controlling the trajectory tracking of Wheeled Mobile Robot(WMR.The issue of trajectory tracking with given a desired reference velocity is minimized to get the distance and deviation angle equal to zero, to realize the objective of trajectory tracking a two FOPID controllers are used for velocity control and azimuth control to implement the trajectory tracking control. A path planning and path tracking methodologies are used to give different desired tracking trajectories.  PSO algorithm is using to find the optimal parameters of FOPID controllers. The kinematic and dynamic models of wheeled mobile robot for desired trajectory tracking with PSO algorithm are simulated in Simulink-Matlab. Simulation results show that the optimal FOPID controllers are more effective and has better dynamic performance than the conventional methods.

Autonomous path planning solution for industrial robot manipulator using backpropagation algorithm

Directory of Open Access Journals (Sweden)

PeiJiang Yuan

2015-12-01

Full Text Available Here, we propose an autonomous path planning solution using backpropagation algorithm. The mechanism of movement used by humans in controlling their arms is analyzed and then applied to control a robot manipulator. Autonomous path planning solution is a numerical method. The model of industrial robot manipulator used in this article is a KUKA KR 210 R2700 EXTRA robot. In order to show the performance of the autonomous path planning solution, an experiment validation of path tracking is provided. Experiment validation consists of implementation of the autonomous path planning solution and the control of physical robot. The process of converging to target solution is provided. The mean absolute error of position for tool center point is also analyzed. Comparison between autonomous path planning solution and the numerical methods based on Newton–Raphson algorithm is provided to demonstrate the efficiency and accuracy of the autonomous path planning solution.

Mathematical model of dynamic interaction between wheel-set and rail track

Directory of Open Access Journals (Sweden)

G. Bureika

2002-04-01

Full Text Available The main goal of this title is to show how the effects on maximum bending tensions at different locations in the track caused by simultaneous changes of the various parameters can be estimated in a rational manner The dynamic of vertical interaction between a moving rigid wheel and a flexible railway track is investigated. A round and smooth wheel tread and an initially straight and non-corrugated rail surface are assumed in the present optimisation study. Asymmetric linear three-dimensional beam structure model of a finite length of the track is suggested including rail, pads, sleepers and ballast with spatially non-proportional damping. Transient bending tensions in sleepers and rail are calculated. The influence of eight selected track parameters on the dynamic behaviour of the track is investigated. A two-level fractional factorial design method is used in the search for a combination of numerical levels of these parameters making the maximum bending tensions the minimum. Finally, the main conclusions are given.

JAVA PathFinder

Science.gov (United States)

Mehhtz, Peter

2005-01-01

JPF is an explicit state software model checker for Java bytecode. Today, JPF is a swiss army knife for all sort of runtime based verification purposes. This basically means JPF is a Java virtual machine that executes your program not just once (like a normal VM), but theoretically in all possible ways, checking for property violations like deadlocks or unhandled exceptions along all potential execution paths. If it finds an error, JPF reports the whole execution that leads to it. Unlike a normal debugger, JPF keeps track of every step how it got to the defect.

Straight-Line -- A nuclear material storage information management system

International Nuclear Information System (INIS)

Nilsen, C.; Mangan, D.

1995-01-01

Sandia National Laboratories is developing Straight-Line -- a pilot system to demonstrate comprehensive monitoring of nuclear material in storage. Straight-Line is an integrated system of sensors providing information that will enhance the safety, security, and international accountability of stored nuclear material. The goals of this effort are to (1) Provide the right sensor information to the right user in a timely manner. (2) Reduce the expenses, risks, and frequency of human inspection of the material. (3) Provide trustworthy data to international inspectors to minimize their need to make on site inspections. In pursuit of these goals, Straight-Line unites technology from Sandia's Authenticated Item Monitoring System (AIMS) and other programs to communicate the authenticated status of the monitored item back to central magazine receivers. Straight-Line, however, incorporates several important features not found in previous systems: (1) Information Security -- the ability to collect and safely disseminate both classified and unclassified sensor data to users on a need-to-know basis. (2) Integrate into a single system the monitoring needs of safety, security, and international accountability. (3) Incorporate the use of sensors providing analog or digital output. This paper will present the overall architecture and status of the Straight-Line project

Straight-Line -- A nuclear material storage information management system

Energy Technology Data Exchange (ETDEWEB)

Nilsen, C. [Sandia National Labs., Livermore, CA (United States); Mangan, D. [Sandia National Labs., Albuquerque, NM (United States)

1995-12-31

Sandia National Laboratories is developing Straight-Line -- a pilot system to demonstrate comprehensive monitoring of nuclear material in storage. Straight-Line is an integrated system of sensors providing information that will enhance the safety, security, and international accountability of stored nuclear material. The goals of this effort are to (1) Provide the right sensor information to the right user in a timely manner. (2) Reduce the expenses, risks, and frequency of human inspection of the material. (3) Provide trustworthy data to international inspectors to minimize their need to make on site inspections. In pursuit of these goals, Straight-Line unites technology from Sandia`s Authenticated Item Monitoring System (AIMS) and other programs to communicate the authenticated status of the monitored item back to central magazine receivers. Straight-Line, however, incorporates several important features not found in previous systems: (1) Information Security -- the ability to collect and safely disseminate both classified and unclassified sensor data to users on a need-to-know basis. (2) Integrate into a single system the monitoring needs of safety, security, and international accountability. (3) Incorporate the use of sensors providing analog or digital output. This paper will present the overall architecture and status of the Straight-Line project.

Straight line closure of congenital macrostomia

Directory of Open Access Journals (Sweden)

Schwarz Richard

2004-01-01

Full Text Available The results of patients operated on by Nepal Cleft Lip and Palate Association (NECLAPA surgeons for congenital macrostomia were prospectively studied between January 2000 and December 2002. There were four males and three females with a median age of 10 years. Three had an associated branchial arch syndrome. In all patients an overlapping repair of orbicularis oris was done. Six patients had a straight line closure with excellent cosmetic results and one a Z-plasty with a more obvious scar. All had a normal appearing commissure. Overlapping orbicularis repair with straight line skin closure for this rare congenital anomaly is recommended.

NASA-FAA helicopter Microwave Landing System curved path flight test

Science.gov (United States)

Swenson, H. N.; Hamlin, J. R.; Wilson, G. W.

1984-01-01

An ongoing series of joint NASA/FAA helicopter Microwave Landing System (MLS) flight tests was conducted at Ames Research Center. This paper deals with tests done from the spring through the fall of 1983. This flight test investigated and developed solutions to the problem of manually flying curved-path and steep glide slope approaches into the terminal area using the MLS and flight director guidance. An MLS-equipped Bell UH-1H helicopter flown by NASA test pilots was used to develop approaches and procedures for flying these approaches. The approaches took the form of Straight-in, U-turn, and S-turn flightpaths with glide slopes of 6 deg, 9 deg, and 12 deg. These procedures were evaluated by 18 pilots from various elements of the helicopter community, flying a total of 221 hooded instrument approaches. Flying these curved path and steep glide slopes was found to be operationally acceptable with flight director guidance using the MLS.

Highly sensitive straightness measurement system using a ball-lens

International Nuclear Information System (INIS)

Lee, Minho; Yang, Hyun-Ik; Cho, Nahm-Gyoo

2016-01-01

In this paper, a new and simple optical technique to accurately measure the straightness errors of a linear stage is proposed. To improve the performance, including the measurement sensitivity and resolution of the measurement system, and to simultaneously measure two-dimensional straightness errors (2D straightness errors), an optical system was designed using a laser, a retro-reflector, a ball-lens, and a two-dimensional position sensitive detector (2D PSD). The characteristics of the measurement system were analytically and experimentally investigated. A prototype measurement system was manufactured based on the investigated results, and the performances of this system have been tested. The measuring performance of the system was easily improved by about 12 times using the proposed technique and it can be further improved. It is shown that the proposed technique can easily and effectively improve the performance of a conventional straightness measurement system based on the geometric optical method using a PSD. (paper)

Gibbon travel paths are goal oriented.

Science.gov (United States)

Asensio, Norberto; Brockelman, Warren Y; Malaivijitnond, Suchinda; Reichard, Ulrich H

2011-05-01

Remembering locations of food resources is critical for animal survival. Gibbons are territorial primates which regularly travel through small and stable home ranges in search of preferred, limited and patchily distributed resources (primarily ripe fruit). They are predicted to profit from an ability to memorize the spatial characteristics of their home range and may increase their foraging efficiency by using a 'cognitive map' either with Euclidean or with topological properties. We collected ranging and feeding data from 11 gibbon groups (Hylobates lar) to test their navigation skills and to better understand gibbons' 'spatial intelligence'. We calculated the locations at which significant travel direction changes occurred using the change-point direction test and found that these locations primarily coincided with preferred fruit sources. Within the limits of biologically realistic visibility distances observed, gibbon travel paths were more efficient in detecting known preferred food sources than a heuristic travel model based on straight travel paths in random directions. Because consecutive travel change-points were far from the gibbons' sight, planned movement between preferred food sources was the most parsimonious explanation for the observed travel patterns. Gibbon travel appears to connect preferred food sources as expected under the assumption of a good mental representation of the most relevant sources in a large-scale space.

Ratcheting failure of pressurised straight pipes and elbows under reversed bending

International Nuclear Information System (INIS)

Vishnuvardhan, S.; Raghava, G.; Gandhi, P.; Saravanan, M.; Goyal, Sumit; Arora, Punit; Gupta, Suneel K.; Bhasin, Vivek

2013-01-01

Ratcheting studies were carried out on Type 304LN stainless steel straight pipes and elbows subjected to steady internal pressure and cyclic bending load. The internal pressure for all the straight pipes was 35 MPa and in the case of elbows the internal pressure was varied for different elbows, ranging from 27.6 MPa to 39.2 MPa. Cyclic bending load was applied on the specimens by subjecting them to different levels of load-line displacement. The specimens have undergone significant ratchet swelling (ballooning), ovalization and consequent thinning of the cross-section during ratcheting. The straight pipes failed either by occurrence of through-wall crack accompanied by simultaneous ballooning, or bursting with simultaneous ballooning. All the elbows failed by occurrence of through-wall crack accompanied by simultaneous ballooning. Ratcheting behaviour of straight pipes and elbows were compared and it was generally inferred that ratcheting was more pronounced in straight pipes than in elbows. -- Graphical abstract: Strain history for the specimen QCE-RAT-6-L1. Highlights: • Studies were carried out under combined internal pressure and cyclic bending. • Ratcheting strains were measured at critical locations of the specimens. • Quantified the percentage of ballooning, ovalization and reduction in thickness. • Modes of ratcheting failure of straight pipes and elbows are studied. • Inferred that ratcheting is more pronounced in straight pipes than in elbows

Diffraction at a Straight Edge

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 5. Diffraction at a Straight Edge: A Gem from Sommerfeld's Work in Classical Physics. Rajaram Nityananda. General Article Volume 20 Issue 5 May 2015 pp 389-400 ...

An Anatomically Constrained Model for Path Integration in the Bee Brain.

Science.gov (United States)

Stone, Thomas; Webb, Barbara; Adden, Andrea; Weddig, Nicolai Ben; Honkanen, Anna; Templin, Rachel; Wcislo, William; Scimeca, Luca; Warrant, Eric; Heinze, Stanley

2017-10-23

Path integration is a widespread navigational strategy in which directional changes and distance covered are continuously integrated on an outward journey, enabling a straight-line return to home. Bees use vision for this task-a celestial-cue-based visual compass and an optic-flow-based visual odometer-but the underlying neural integration mechanisms are unknown. Using intracellular electrophysiology, we show that polarized-light-based compass neurons and optic-flow-based speed-encoding neurons converge in the central complex of the bee brain, and through block-face electron microscopy, we identify potential integrator cells. Based on plausible output targets for these cells, we propose a complete circuit for path integration and steering in the central complex, with anatomically identified neurons suggested for each processing step. The resulting model circuit is thus fully constrained biologically and provides a functional interpretation for many previously unexplained architectural features of the central complex. Moreover, we show that the receptive fields of the newly discovered speed neurons can support path integration for the holonomic motion (i.e., a ground velocity that is not precisely aligned with body orientation) typical of bee flight, a feature not captured in any previously proposed model of path integration. In a broader context, the model circuit presented provides a general mechanism for producing steering signals by comparing current and desired headings-suggesting a more basic function for central complex connectivity, from which path integration may have evolved. Copyright © 2017 Elsevier Ltd. All rights reserved.

FITNESS TRAINING AS PREPARATION FOR BICYCLE TRACKING TOURS

Directory of Open Access Journals (Sweden)

Dragan Martinović

2007-05-01

Full Text Available Track, tracking“(English – a trail, to follow a trail. Tracking means hiking on marked tracks, roads and mountain paths, with the aim of being physically active surrounded by fresh air, natural beauties and cultural/historical monuments. Physical preparation (fi tness training is a very specifi c and complex process that has an active positive infl uence on the maintenance of health, on forming of good bodily posture, as well as on growth and development of physical and psycho-social values of an individual.

49 CFR Appendix A to Part 1035 - Uniform Straight Bill of Lading

Science.gov (United States)

2010-10-01

... 49 Transportation 8 2010-10-01 2010-10-01 false Uniform Straight Bill of Lading A Appendix A to Part 1035 Transportation Other Regulations Relating to Transportation (Continued) SURFACE... Appendix A to Part 1035—Uniform Straight Bill of Lading Uniform Straight Bill of Lading Original—Not...

Relay exchanges in elite short track speed skating.

Science.gov (United States)

Hext, Andrew; Heller, Ben; Kelley, John; Goodwill, Simon

2017-06-01

In short track speed skating, the relay exchange provides an additional strategic component to races by allowing a team to change the skater involved in the pack race. Typically executed every 1½ laps, it is the belief of skaters and coaches that during this period of the race, time can be gained or lost due to the execution of the relay exchange. As such, the aim of this study was to examine the influence of the relay exchange on a team's progression through a 5000 m relay race. Using data collected from three World Cup relay events during the 2012-2013 season, the time taken to complete the straight for the scenarios with and without the relay exchange were compared at different skating speeds for the corner exit prior to the straight. Overall, the influence of the relay exchange was found to be dependent on this corner exit speed. At slower corner exit speeds (12.01-13.5 m/s), relay exchange straight times were significantly faster than the free skating scenario (P < 0.01). While at faster corner exit speeds (14.01-15 m/s), straight times were significantly slower (P < 0.001). The findings of this study suggest that the current norm of executing relay exchanges every 1½ laps may not be optimal. Instead, varying the frequency of relay exchange execution throughout the race could allow: (1) time to be gained relative to other teams; and (2) facilitate other race strategies by providing an improved opportunity to overtake.

Setting the Record Straight. The Truth About Fad Diets.

Science.gov (United States)

Wheat Foods Council, Parker, CO.

The Setting the Record Straight information packet presents facts to set the record straight about nutrition and debunk fad diets. The kit features materials designed to communicate the importance of balanced eating. Materials include: a time line of fad diets; four reproducible fad diet book review handouts that show the misleading claims rampant…

The Dynamics of a Railway Vehicle on a Disturbed Track

DEFF Research Database (Denmark)

Christiansen, Lasse Engbo

This work studies a mathematical model of a bogie, the aim being to investigate the correlation between the lateral motion of the bogie and lateral irregularities of the track that the bogie is running along. When modelling the wheel-rail forces real wheel and rail profiles are used. One...... describing how the wheel-rail interaction is modelled. The fourth chapter gives a presentation of the numerical algorithms used in this work. The fifth chapter presents the results obtained during this work, it begins with an brief investigation of the dynamics when running on a straight track. The second...... section introduces some statistical measures and treats centerline irregularities when running with a fixed speed of 30 m/s. The following section investigates the behaviour of the model when the track possesses gauge irregularities. The fourth and fifth sections describe the changes observed when...

Preferences of AP position of the straight Caucasian facial profile.

Science.gov (United States)

Mees, Steven; Jiménez Bellinga, Raúl; Mommaerts, Maurice Y; De Pauw, Guy A M

2013-12-01

Several investigators have compared the perception of profile attractiveness between professional and non-professional people, different groups of clinicians, and different ethnic groups. Our aim was to study preferences for facial protrusion in the lateral view for a straight Class I profile and to study the influence of gender, age, sex preference, and profession. Portrait images of one male and one female model with a Class I occlusal relationship were warped into nine different antero-posterior positions. An internet site was established to reach as many people as possible, and a request was sent by email to participate in a scientific experiment. Finally, 1707 Caucasion assessors could be grouped. The preferred male profile is the straight full ante profile. For a feminine facial profile, the straight average and the straight 2/3 ante profiles were perceived as the most attractive. Surgeons tended to give significantly higher scores to attractive (ante) profiles, which correlated strongly with scores of the orthodontists. Whenever possible with combined orthodontic/surgery treatment, straight ante profiles should be aimed for. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Conceptual Design of ILC Damping Ring Wiggler Straight Vacuum System

International Nuclear Information System (INIS)

Marks, S.; Kennedy, K.; Plate, D.; Schlueter, R.D.; Zisman, M.

2007-01-01

The positron and electron damping rings for the International Linear Collider will contain long straight sections consisting of twenty wiggler/quadrupole pairs. The wigglers will be based upon the CESR superconducting design. There are a number of challenges associated with the design of the wiggler straight vacuum system, in particular, the absorption of photon power generated by the wigglers. This paper will present the overall conceptual design of the wiggler straight vacuum system developed for the ILC Reference Design Report. Particular emphasis will be placed on photon power load calculations and the absorber design

Evolution of the SOFIA tracking control system

Science.gov (United States)

Fiebig, Norbert; Jakob, Holger; Pfüller, Enrico; Röser, Hans-Peter; Wiedemann, Manuel; Wolf, Jürgen

2014-07-01

The airborne observatory SOFIA (Stratospheric Observatory for Infrared Astronomy) is undergoing a modernization of its tracking system. This included new, highly sensitive tracking cameras, control computers, filter wheels and other equipment, as well as a major redesign of the control software. The experiences along the migration path from an aged 19" VMbus based control system to the application of modern industrial PCs, from VxWorks real-time operating system to embedded Linux and a state of the art software architecture are presented. Further, the concept is presented to operate the new camera also as a scientific instrument, in parallel to tracking.

Visual recognition and tracking of objects for robot sensing

International Nuclear Information System (INIS)

Lowe, D.G.

1994-01-01

An overview is presented of a number of techniques used for recognition and motion tracking of articulated 3-D objects. With recent advances in robust methods for model-based vision and improved performance of computer systems, it will soon be possible to build low-cost, high-reliability systems for model-based motion tracking. Such systems can be expected to open up a wide range of applications in robotics by providing machines with real-time information about their environment. This paper describes a number of techniques for efficiently matching parameterized 3-D models to image features. The matching methods are robust with respect to missing and ambiguous features as well as measurement errors. Unlike most previous work on model-based motion tracking, this system provides for the integrated treatment of matching and measurement errors during motion tracking. The initial application is in a system for real-time motion tracking of articulated 3-D objects. With the future addition of an indexing component, these same techniques can also be used for general model-based recognition. The current real-time implementation is based on matching straight line segments, but some preliminary experiments on matching arbitrary curves are also described. (author)

The Lateral Tracking Control for the Intelligent Vehicle Based on Adaptive PID Neural Network.

Science.gov (United States)

Han, Gaining; Fu, Weiping; Wang, Wen; Wu, Zongsheng

2017-05-30

The intelligent vehicle is a complicated nonlinear system, and the design of a path tracking controller is one of the key technologies in intelligent vehicle research. This paper mainly designs a lateral control dynamic model of the intelligent vehicle, which is used for lateral tracking control. Firstly, the vehicle dynamics model (i.e., transfer function) is established according to the vehicle parameters. Secondly, according to the vehicle steering control system and the CARMA (Controlled Auto-Regression and Moving-Average) model, a second-order control system model is built. Using forgetting factor recursive least square estimation (FFRLS), the system parameters are identified. Finally, a neural network PID (Proportion Integral Derivative) controller is established for lateral path tracking control based on the vehicle model and the steering system model. Experimental simulation results show that the proposed model and algorithm have the high real-time and robustness in path tracing control. This provides a certain theoretical basis for intelligent vehicle autonomous navigation tracking control, and lays the foundation for the vertical and lateral coupling control.

The Lateral Tracking Control for the Intelligent Vehicle Based on Adaptive PID Neural Network

Directory of Open Access Journals (Sweden)

Gaining Han

2017-05-01

Full Text Available The intelligent vehicle is a complicated nonlinear system, and the design of a path tracking controller is one of the key technologies in intelligent vehicle research. This paper mainly designs a lateral control dynamic model of the intelligent vehicle, which is used for lateral tracking control. Firstly, the vehicle dynamics model (i.e., transfer function is established according to the vehicle parameters. Secondly, according to the vehicle steering control system and the CARMA (Controlled Auto-Regression and Moving-Average model, a second-order control system model is built. Using forgetting factor recursive least square estimation (FFRLS, the system parameters are identified. Finally, a neural network PID (Proportion Integral Derivative controller is established for lateral path tracking control based on the vehicle model and the steering system model. Experimental simulation results show that the proposed model and algorithm have the high real-time and robustness in path tracing control. This provides a certain theoretical basis for intelligent vehicle autonomous navigation tracking control, and lays the foundation for the vertical and lateral coupling control.

Magnetic Launch Assist Experimental Track

Science.gov (United States)

1999-01-01

In this photograph, a futuristic spacecraft model sits atop a carrier on the Magnetic Launch Assist System, formerly known as the Magnetic Levitation (MagLev) System, experimental track at the Marshall Space Flight Center (MSFC). Engineers at MSFC have developed and tested Magnetic Launch Assist technologies that would use magnetic fields to levitate and accelerate a vehicle along a track at very high speeds. Similar to high-speed trains and roller coasters that use high-strength magnets to lift and propel a vehicle a couple of inches above a guideway, a Magnetic Launch Assist system would electromagnetically drive a space vehicle along the track. A full-scale, operational track would be about 1.5-miles long and capable of accelerating a vehicle to 600 mph in 9.5 seconds. This track is an advanced linear induction motor. Induction motors are common in fans, power drills, and sewing machines. Instead of spinning in a circular motion to turn a shaft or gears, a linear induction motor produces thrust in a straight line. Mounted on concrete pedestals, the track is 100-feet long, about 2-feet wide, and about 1.5-feet high. The major advantages of launch assist for NASA launch vehicles is that it reduces the weight of the take-off, the landing gear, the wing size, and less propellant resulting in significant cost savings. The US Navy and the British MOD (Ministry of Defense) are planning to use magnetic launch assist for their next generation aircraft carriers as the aircraft launch system. The US Army is considering using this technology for launching target drones for anti-aircraft training.

A simultaneous localization and tracking method for a worm tracking system

Directory of Open Access Journals (Sweden)

Kowalski Mateusz

2014-09-01

Full Text Available The idea of worm tracking refers to the path analysis of Caenorhabditis elegans nematodes and is an important tool in neurobiology which helps to describe their behavior. Knowledge about nematode behavior can be applied as a model to study the physiological addiction process or other nervous system processes in animals and humans. Tracking is performed by using a special manipulator positioning a microscope with a camera over a dish with an observed individual. In the paper, the accuracy of a nematode’s trajectory reconstruction is investigated. Special attention is paid to analyzing errors that occurred during the microscope displacements. Two sources of errors in the trajectory reconstruction are shown. One is due to the difficulty in accurately measuring the microscope shift, the other is due to a nematode displacement during the microscope movement. A new method that increases path reconstruction accuracy based only on the registered sequence of images is proposed. The method Simultaneously Localizes And Tracks (SLAT the nematodes, and is robust to the positioning system displacement errors. The proposed method predicts the nematode position by using NonParametric Regression (NPR. In addition, two other methods of the SLAT problem are implemented to evaluate the NPR method. The first consists in ignoring the nematode displacement during microscope movement, and the second is based on a Kalman filter. The results suggest that the SLAT method based on nonparametric regression gives the most promising results and decreases the error of trajectory reconstruction by 25% compared with reconstruction based on data from the positioning system

On the spatial errors and resolution of near tracks when parallel tracing by their images on photographs

International Nuclear Information System (INIS)

Ehrglis, K.Eh.

1980-01-01

Errors in the determination of spatial reference point (SRP) coordinates being reconstructed on the basis of photograph reference points are considered. The width of paths of probable track positions on photographs and the length of intersection zones of these paths with hampering track images are estimated. Conditions for a stable automatic tracing of closely traversing in space tracks are determined. The conclusion is made that of 5-6 SRP are accumulated the method of spatial tracing when shifting local scanning centres on photographs with a corresponding speed permits to trace automatically closely traversing tracks in the middle zone of the Merabel chamber when the angle between them is approximately 1 deg and the distance in space - 3-7 mm. It is emphasized that, when forecasting 8-10 SRP, the spatial or angle track resolution improves 1.5 times more due to the diminution of forecasting errors and corresponding narrowing of sensitivity paths. The described method will be especially effective when processing photographs taken in bubble chambers of a new generation at particle energies being tens-hundreds GeV [ru

Trajectory control of robot manipulators with closed-kinematic chain mechanism

Science.gov (United States)

Nguyen, Charles C.; Pooran, Farhad J.; Premack, Timothy

1987-01-01

The problem of Cartesian trajectory control of a closed-kinematic chain mechanism robot manipulator, recently built at CAIR to study the assembly of NASA hardware for the future Space Station, is considered. The study is performed by both computer simulation and experimentation for tracking of three different paths: a straight line, a sinusoid, and a circle. Linearization and pole placement methods are employed to design controller gains. Results show that the controllers are robust and there are good agreements between simulation and experimentation. The results also show excellent tracking quality and small overshoots.

Classification of Birds and Bats Using Flight Tracks

Energy Technology Data Exchange (ETDEWEB)

Cullinan, Valerie I.; Matzner, Shari; Duberstein, Corey A.

2015-05-01

Classification of birds and bats that use areas targeted for offshore wind farm development and the inference of their behavior is essential to evaluating the potential effects of development. The current approach to assessing the number and distribution of birds at sea involves transect surveys using trained individuals in boats or airplanes or using high-resolution imagery. These approaches are costly and have safety concerns. Based on a limited annotated library extracted from a single-camera thermal video, we provide a framework for building models that classify birds and bats and their associated behaviors. As an example, we developed a discriminant model for theoretical flight paths and applied it to data (N = 64 tracks) extracted from 5-min video clips. The agreement between model- and observer-classified path types was initially only 41%, but it increased to 73% when small-scale jitter was censored and path types were combined. Classification of 46 tracks of bats, swallows, gulls, and terns on average was 82% accurate, based on a jackknife cross-validation. Model classification of bats and terns (N = 4 and 2, respectively) was 94% and 91% correct, respectively; however, the variance associated with the tracks from these targets is poorly estimated. Model classification of gulls and swallows (N ≥ 18) was on average 73% and 85% correct, respectively. The models developed here should be considered preliminary because they are based on a small data set both in terms of the numbers of species and the identified flight tracks. Future classification models would be greatly improved by including a measure of distance between the camera and the target.

Track filtering by robust neural network

International Nuclear Information System (INIS)

Baginyan, S.A.; Kisel', I.V.; Konotopskaya, E.V.; Ososkov, G.A.

1993-01-01

In the present paper we study the following problems of track information extraction by the artificial neural network (ANN) rotor model: providing initial ANN configuration by an algorithm general enough to be applicable for any discrete detector in- or out of a magnetic field; robustness to heavy contaminated raw data (up to 100% signal-to-noise ratio); stability to the growing event multiplicity. These problems were carried out by corresponding innovations of our model, namely: by a special one-dimensional histogramming, by multiplying weights by a specially designed robust multiplier, and by replacing the simulated annealing schedule by ANN dynamics with an optimally fixed temperature. Our approach is valid for both circular and straight (non-magnetic) tracks and tested on 2D simulated data contaminated by 100% noise points distributed uniformly. To be closer to some reality in our simulation, we keep parameters of the cylindrical spectrometer ARES. 12 refs.; 9 figs

Straight Gods, White Devils: Exploring Paths to Non-Religion in the Lives of Black LGBTQ People

OpenAIRE

Kolysh, Simone

2017-01-01

To examine paths to non-religion in the lives of black LGBTQ people, I analyze 10 interviews of black LGBTQ people who were raised Christian. Utilizing an intersectional lens, I conclude that lessons of the Christian home, reinforced in religious school and at church, drew a connection between Christianity, one’s racial and ethnic identity, and heterosexuality in such a way that being LGBTQ was marked un-Christian and foreign, and sometimes associated with whiteness. This further shaped how m...

SPS, preassembly of short straight sections

CERN Multimedia

1975-01-01

Short straight sections were preassembled with their vacuum chambers, ready for installation in the SPS. Here we see two, containing sextupoles for chromaticity adjustment. See also 7501017, 7501018, and Annual Report 1976, p.174.

SPS, short straight section with sextupole

CERN Multimedia

CERN PhotoLab

1975-01-01

Short straight sections were preassembled with their vacuum chambers, ready for installation in the SPS. This one contains a sextupole for chromaticity adjustment. See also 7501017, 7501009X, and Annual Report 1974, p.174.

Stigma and Stigma by Association in Perceptions of Straight Allies

Science.gov (United States)

Goldstein, Susan B.

2017-01-01

As evidence builds for straight allies' contributions to battling sexual prejudice, barriers to assuming this role must be identified and dismantled. This study investigated stigma and stigma by association in perceptions of straight allies in a college population. Adjective rating items were completed by 505 participants who identified as…

Spider diffraction: a comparison of curved and straight legs

International Nuclear Information System (INIS)

Richter, J.L.

1984-01-01

It has been known for some time that, if curved legs rather than the usual straight ones are used in the spider that supports the secondary optics in certain telescopes, the visible diffraction effect is reduced. Fraunhofer theory is used to calculate the diffraction effects due to the curved leg spider. Calculated and photographic diffraction patterns are compared for straight and curved leg spiders

Kit with track detectors aiming at didactic

International Nuclear Information System (INIS)

Cesar, M.F.; Koskinas, M.F.

1988-01-01

The kit intends to improve the possibilities in performing experiments of Nuclear Physics in Modern Physics Laboratories of Physics Course introducing the solid state nuclear track detectors. In these materials the passage of heavily ionizing nuclear particles creates paths (tracks) that may be revealed and made visible in an optical microscope. By the help of the kit several experiments and/or demonstrations may be performed. The kit contains solid state nuclear track detectors unirradiated and irradiated, irradiated etched and uneteched sheets; an alpha source of 241 Am and an instrution text with photomicrographs. To use the kit the laboratory must have an ordinary optical microscope. (author) [pt

Bubble chamber: colour enhanced tracks

CERN Multimedia

1998-01-01

This artistically-enhanced image of real particle tracks was produced in the Big European Bubble Chamber (BEBC). Liquid hydrogen is used to create bubbles along the paths of the particles as a piston expands the medium. A magnetic field is produced in the detector causing the particles to travel in spirals, allowing charge and momentum to be measured.

Production of short straight sections hits 100 units

CERN Multimedia

2005-01-01

The 100th short straight section for the Large Hadron Collider was assembled at CERN at the beginning of April. These units combine superconducting quadrupoles and other multipole corrector magnets, housed in their cryostats, which are used to guide, focus and fine-tune the beam in the LHC. Building 904, where the 474 short straight sections are being assembled, is often called "Lego Land" by the workers, with a touch of humor and pride because of the wide variety of these sets of magnets and cryostats .

Spherical Projection Based Straight Line Segment Extraction for Single Station Terrestrial Laser Point Cloud

Directory of Open Access Journals (Sweden)

ZHANG Fan

2015-06-01

Full Text Available Due to the discrete distribution computing errors and lack of adaptability are ubiquitous in the current straight line extraction for TLS data methods. A 3D straight line segment extraction method is proposed based on spherical projection for single station terrestrial laser point clouds. Firstly, horizontal and vertical angles of each laser point are calculated by means of spherical coordinates, intensity panoramic image according to the two angles is generated. Secondly, edges which include straight line features are detected from intensity panoramic image by using of edge detection algorithm. Thirdly, great circles are detected from edges of panoramic image using spherical Hough transform. According to the axiom that a straight line segment in 3D space is a spherical great circle after spherical projection, detecting great circles from spherical projected data sets is essentially detecting straight line segments from 3D data sets without spherical projection. Finally, a robust 3D straight line fitting method is employed to fitting the straight lines and calculating parameters of the straight line segments. Experiments using different data sets and comparison with other methods show the accuracy and applicability of the proposed method.

Measuring Oscillating Walking Paths with a LIDAR

Directory of Open Access Journals (Sweden)

Jordi Palacín

2011-05-01

Full Text Available This work describes the analysis of different walking paths registered using a Light Detection And Ranging (LIDAR laser range sensor in order to measure oscillating trajectories during unsupervised walking. The estimate of the gait and trajectory parameters were obtained with a terrestrial LIDAR placed 100 mm above the ground with the scanning plane parallel to the floor to measure the trajectory of the legs without attaching any markers or modifying the floor. Three different large walking experiments were performed to test the proposed measurement system with straight and oscillating trajectories. The main advantages of the proposed system are the possibility to measure several steps and obtain average gait parameters and the minimum infrastructure required. This measurement system enables the development of new ambulatory applications based on the analysis of the gait and the trajectory during a walk.

26 CFR 1.9001 - Statutory provisions; Retirement-Straight Line Adjustment Act of 1958.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 13 2010-04-01 2010-04-01 false Statutory provisions; Retirement-Straight Line... provisions; Retirement-Straight Line Adjustment Act of 1958. Section 94 of the Technical Amendments Act of 1958 (72 Stat. 1669) provides as follows: Sec. 94. Change from retirement to straight line method of...

Scan path entropy and Arrow plots: Capturing scanning behavior of multiple observers

Directory of Open Access Journals (Sweden)

Ignace T C Hooge

2013-12-01

Full Text Available Designers of visual communication material want their material to attract and retain attention. In marketing research, heat maps, dwell time, and time to AOI first hit are often used as evaluation parameters. Here we present two additional measures 1 scan path entropy to quantify gaze guidance and 2 the arrow plot to visualize the average scan path. Both are based on string representations of scan paths. The latter also incorporates transition matrices and time required for 50% of the observers to first hit AOIs (T50. The new measures were tested in an eye tracking study (48 observers, 39 advertisements. Scan path entropy is a sensible measure for gaze guidance and the new visualization method reveals aspects of the average scan path and gives a better indication in what order global scanning takes place.

Low Horizontal Beta Function In Long Straights Of The NSLS-II Lattice

International Nuclear Information System (INIS)

Fanglei, L.; Bengtsson, J.; Guo, W.; Krinsky, S.; Li, Y.; Yang, L.

2011-01-01

The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 short straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this paper, we explore the possibility of maintaining three long straights with large horizontal beta function while providing the other 12 long straights with smaller horizontal beta function to optimize the brightness of insertion devices. Our study considers the possible linear lattice solutions as well as characterizing the nonlinear dynamics. Results are reported on optimization of dynamic aperture required for good injection efficiency and adequate Touschek lifetime. This paper discusses dynamic aperture optimization for the NSLS-II lattice with alternate high and low horizontal beta function in the long straights, which is proposed for the optimization of the brightness of insertion devices. The linear optics is optimized to meet the requirements of lattice function and source properties. Nonlinear optimization for a lattice with working point at (37.18, 16.2) is performed. Considering the realistic magnets errors and physical apertures, we calculate the frequency maps and plot the tune footprint. The results show that the lattice with high-low beta function has adequate dynamic aperture for good injection efficiency and sufficient Touschek lifetime.

Registration of airborne LiDAR data and aerial images based on straight lines and POS data

Science.gov (United States)

Du, Quanye; Xu, Biao; Cao, Hui

2009-10-01

This paper presents a registration method which based on straight lines primitive. Firstly, 2D straight lines are extracted from aerial images using Canny operator and straight line fitting. In the similar way, 3D straight lines are extracted from LiDAR range images which derive from laser scanning point cloud. Secondly, 3D straight lines are projected to aerial images using collinearity equations and Position and Orientation System (POS) data. Then the corresponding lines are determined by straight line error. At last, each image's new exterior orientation elements are calculated by generalized point (straight line) photogrammetry.

Straight Gods, White Devils: Exploring Paths to Non-Religion in the Lives of Black LGBTQ People

Directory of Open Access Journals (Sweden)

Simone Kolysh

2017-01-01

Full Text Available To examine paths to non-religion in the lives of black LGBTQ people, I analyze 10 interviews of black LGBTQ people who were raised Christian. Utilizing an intersectional lens, I conclude that lessons of the Christian home, reinforced in religious school and at church, drew a connection between Christianity, one’s racial and ethnic identity, and heterosexuality in such a way that being LGBTQ was marked un-Christian and foreign, and sometimes associated with whiteness. This further shaped how my participants navigated the urban public sphere, one of the only spheres where they could ‘be LGBTQ’ – some neighborhoods were constructed as Christian, connected to one’s childhood and hostile to LGBTQ people, while others were LGBTQ-friendly, albeit largely white and gentrified. The overall impact of Christianity across multiple spheres influenced which non-religious paths my participants took. One remained with a Christian denomination of her childhood and one remained with a Christian denomination of her mother but not her father. The other eight left Christianity behind, with one choosing a different religion and seven becoming non-religious, holding identities from Unitarian Universalist to atheist. Overall, black LGBTQ people struggle to find acceptance of their LGBTQ identities by people closest to them and acceptance of their racial, ethnic and non-religious identities in largely white and often non-religious LGBTQ spaces. In response, they use different strategies to find community and live coherent lives, whenever possible.

21 CFR 70.20 - Packaging requirements for straight colors (other than hair dyes).

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Packaging requirements for straight colors (other than hair dyes). 70.20 Section 70.20 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... straight colors (other than hair dyes). Straight colors shall be packaged in containers which prevent...

Optimum track fitting in the presence of multiple scattering

International Nuclear Information System (INIS)

Lutz, G.

1987-06-01

A method for track fitting is proposed which attempts to be as close as possible to the real track along the full path length. This is done by the introduction of scattering planes in which the particle is allowed to change its direction. A fit over the full track length includes the probability of direction change by scattering. Using matrix notation a fairly simple formalism for error estimation has been developed. Results of this method are compared to those of more widely used procedures for 'typical' examples of High Energy Spectrometers. (orig.)

Track reconstruction principle in ALICE for LHC run I and run II

CERN Multimedia

Maire, Antonin

2011-01-01

Principles of tracking for an ALICE event, showing the three successive paths allowing to build a track and refine its parameters. Numbers ranging from 1 to 10 mention the bits that are activated in case of success during the propgation of the Kalman filter at the considered stage.

Research and application of devices for synchronously tracking the sun

Energy Technology Data Exchange (ETDEWEB)

Wei, Ming; Sun, Youhong; Wang, Qinghua; Wu, Xiaohan [Jilin Univ. Changchun (China). College of Construction Engineering

2008-07-01

This paper introduces a concept of apparent motion orbit of the sun, and put forward the theory of synchronous (linear) tracking the sun. Using solarium mechanism to trail the running path of solar hour angel, and using modified sine function framework to trace solar apparent declination path, and then connect these two mechanisms with linear transmission chain. More than 45%{proportional_to}122% electricity can be output by the synchronous tracking photovoltaic (PV) devices compare with those fixed PV ones with the same area between the spring equinox to the summer solstice. The 17m{sup 2} heat collector of synchronous tracking, its static wind-driven power consumption is less than 3.5W (0.2W/m{sup 2}), and the gale consumption is less than 7W(0.34W/m{sup 2}). The apparatus can be utilized widely in solar power, heating, lighting systems and other solar energy utilization. (orig.)

Influence of the pneumatic tourniquet on patella tracking in total knee arthroplasty: a prospective randomized study in 100 patients

DEFF Research Database (Denmark)

Husted, Henrik; Toftgaard Jensen, T

2005-01-01

One hundred consecutive patients with osteoarthritis of the knee joint and scheduled for primary total knee arthroplasty performed in a bloodless field were prospectively randomized to have the tourniquet inflated on either straight leg or maximally flexed knee. There was no difference in the num...... deflation led to better patella tracking and saved 5 (31%) of 16 releases with no difference between groups. We recommend tourniquet deflation and reevaluation of patella tracking before performing lateral release in patellar maltracking....

Body image in gay and straight men: a qualitative study.

Science.gov (United States)

Morgan, John F; Arcelus, Jon

2009-11-01

Recent research has emphasized vulnerability to eating disorders in gay men, with calls for research on causality, cultural factors and focus on a younger age cohort. This study aimed to examine body image and related eating behaviours in younger gay and straight men. Qualitative study using a sample of gay and straight male university students, applying audiotaped and transcribed depth interview subjected to interpretative phenomenological analysis. Fifteen young men (18-24) with a spectrum of sexual orientation (gay, straight and bisexual) agreed to participate. Five dominant categories emerged: body image ideal, external influences, perception of body image, dieting, mechanisms for modification (diet, exercise, cosmetics) and sexual orientation. Health and aesthetic ideals appear less divorced for young men than women, offering some degree of protection from eating disorders. Nonetheless there is widespread body dissatisfaction. Media and social influences are powerful, particularly for single gay men, but the study suggests fewer differences than similarities between gay and straight men. Copyright (c) 2009 John Wiley & Sons, Ltd and Eating Disorders Association.

A laser interferometer for measuring straightness and its position based on heterodyne interferometry

International Nuclear Information System (INIS)

Chen Benyong; Zhang Enzheng; Yan Liping; Li Chaorong; Tang Wuhua; Feng Qibo

2009-01-01

Not only the magnitude but also the position of straightness errors are of concern to users. However, current laser interferometers used for measuring straightness seldom give the relative position of the straightness error. To solve this problem, a laser interferometer for measuring straightness and its position based on heterodyne interferometry is proposed. The optical configuration of the interferometer is designed and the measurement principle is analyzed theoretically. Two experiments were carried out. The first experiment verifies the validity and repeatability of the interferometer by measuring a linear stage. Also, the second one for measuring a flexure-hinge stage demonstrates that the interferometer is capable of nanometer measurement accuracy. These results show that this interferometer has advantages of simultaneously measuring straightness error and the relative position with high precision, and a compact structure.

Hybrid markerless tracking of complex articulated motion in golf swings.

Science.gov (United States)

Fung, Sim Kwoh; Sundaraj, Kenneth; Ahamed, Nizam Uddin; Kiang, Lam Chee; Nadarajah, Sivadev; Sahayadhas, Arun; Ali, Md Asraf; Islam, Md Anamul; Palaniappan, Rajkumar

2014-04-01

Sports video tracking is a research topic that has attained increasing attention due to its high commercial potential. A number of sports, including tennis, soccer, gymnastics, running, golf, badminton and cricket have been utilised to display the novel ideas in sports motion tracking. The main challenge associated with this research concerns the extraction of a highly complex articulated motion from a video scene. Our research focuses on the development of a markerless human motion tracking system that tracks the major body parts of an athlete straight from a sports broadcast video. We proposed a hybrid tracking method, which consists of a combination of three algorithms (pyramidal Lucas-Kanade optical flow (LK), normalised correlation-based template matching and background subtraction), to track the golfer's head, body, hands, shoulders, knees and feet during a full swing. We then match, track and map the results onto a 2D articulated human stick model to represent the pose of the golfer over time. Our work was tested using two video broadcasts of a golfer, and we obtained satisfactory results. The current outcomes of this research can play an important role in enhancing the performance of a golfer, provide vital information to sports medicine practitioners by providing technically sound guidance on movements and should assist to diminish the risk of golfing injuries. Copyright © 2013 Elsevier Ltd. All rights reserved.

Modified Hyperspheres Algorithm to Trace Homotopy Curves of Nonlinear Circuits Composed by Piecewise Linear Modelled Devices

Directory of Open Access Journals (Sweden)

H. Vazquez-Leal

2014-01-01

Full Text Available We present a homotopy continuation method (HCM for finding multiple operating points of nonlinear circuits composed of devices modelled by using piecewise linear (PWL representations. We propose an adaptation of the modified spheres path tracking algorithm to trace the homotopy trajectories of PWL circuits. In order to assess the benefits of this proposal, four nonlinear circuits composed of piecewise linear modelled devices are analysed to determine their multiple operating points. The results show that HCM can find multiple solutions within a single homotopy trajectory. Furthermore, we take advantage of the fact that homotopy trajectories are PWL curves meant to replace the multidimensional interpolation and fine tuning stages of the path tracking algorithm with a simple and highly accurate procedure based on the parametric straight line equation.

Self-Tracking: Reflections from the BodyTrack Project.

Science.gov (United States)

Wright, Anne

2016-07-06

Based on the author's experiences the practice of self-tracking can empower individuals to explore and address issues in their lives. This work is inspired by examples of people who have reclaimed their wellness through an iterative process of noticing patterns of ups and downs, trying out new ideas and strategies, and observing the results. In some cases, individuals have realized that certain foods, environmental exposures, or practices have unexpected effects for them, and that adopting custom strategies can greatly improve quality of life, overcoming chronic problems. Importantly, adopting the role of investigator of their own situation appears to be transformative: people who embarked on this path changed their relationship to their health situation even before making discoveries that helped lead to symptom improvement. The author co-founded the BodyTrack project in 2010 with the goal of empowering a broader set of people to embrace this investigator role in their own lives and better address their health and wellness concerns, particularly those with complex environmental or behavioral components. The core of the BodyTrack system is an open source web service called Fluxtream ( https://fluxtream.org ) that allows users to aggregate, visualize, and reflect on data from myriad sources on a common timeline. The project is also working to develop and spread peer coaching practices to help transfer the culture and skills of self-tracking while mentoring individuals in how to self-assess their own situation and guide the process for themselves.

Additional Quadrupoles At Center Of Long Straights In The NSLS-II Lattice

International Nuclear Information System (INIS)

Lin, F.; Bengtsson, J.; Guo, W.; Krinsky, S.; Li, Y.; Yang, L.

2011-01-01

The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 shorter straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this paper, we explore the possibility of installing additional quadrupoles at the center of selected long straight sections in order to provide two low-beta source locations for undulators in the same straight. The required modification to the linear lattice is discussed as well as the preservation of adequate dynamic aperture required for good injection efficiency and adequate Touschek lifetime. This paper discusses the possibility of producing two low-beta source locations for optimum brightness of undulators in the long straights of NSLS-II lattice by installing additional quadrupoles at the center. The linear optics is optimized to satisfy the requirements of lattice function and properties. Nonlinear optimization for a lattice with working point at (37.16, 17.22) is performed. Considering the magnets misalignment errors and physical apertures, we calculate the frequency maps and plot the tune footprint. The results show that the modified high-low beta function lattice can achieve a modest dynamic aperture in this preliminary study. Further work will continue to expand the dynamic aperture to meet the requirement of good injection efficiency and sufficient Touschek lifetime.

Straight, white teeth as a social prerogative.

Science.gov (United States)

Khalid, Abeer; Quiñonez, Carlos

2015-06-01

A distinguishing feature of North American society is preoccupation with self-image, as seen in the ritualistic nature of bodily practices aimed at constantly improving the body. Nowhere is this more apparent than in the prevailing fixation with straight, white teeth. While there is an ever-expanding literature on the sociology of body, very little has been written on teeth in this context. Using literature from anthropology, biology, dentistry, sociology and social psychology, this study attempts to answer: (1) Why have straight, white teeth become a beauty ideal in North American society? (2) What is the basis for this ideal? (3) How is this ideal propagated? It demonstrates that dental aesthetic tendencies are biologically, culturally and socially patterned. Concepts from the works of Pierre Bourdieu and Michel Foucault are used to illustrate how straight, white teeth contribute towards reinforcing class differences and how society exercises a disciplinary power on individuals through this ideal. It is concluded that modified teeth are linked to self and identity that are rooted in social structure. Moreover, teeth demonstrate the ways in which class differences are embodied and projected as symbols of social advantage or disadvantage. Implications on professional, public health, sociological and political levels are considered. © 2015 Foundation for the Sociology of Health & Illness.

Beam line from straight-section 16

CERN Multimedia

CERN PhotoLab

1971-01-01

The start of a long trail. The beam line from straight-section 16, where protons are fast ejected, is seen at the point where it crosses the Linac shielding wall as it leaves the PS en route to the ISR.

Propagation of ovalization along straight pipes and elbows

International Nuclear Information System (INIS)

Millard, A.; Roche, R.L.

1981-01-01

The aim of this paper is to present analytical solutions for the propagation of evalization and the variation of the flexibility factor along pipe bends terminated by straight pipes or flanges, under in-plane bending, assuming an elastic material behaviour. The influence of the various strains in analysed in the simple case of a straight pipe, subjected to an elliptical cross-section shape deformation at one end. The results enlighten the very important part played by the distorsion in the propagation. They have been compared with finite elements solutions and with simple experiments. The solution is developed for an elbow terminated by a straight pipe or a flange, following the Von Karman's approach: local displacements are expanded in Fourier series, the coefficients of which vary along the curvilinear abscissa, like the rotation of the cross-section as a whole; the differential equations as well as the boundary conditions are found by minimization of the total potential energy of the assembly. The solutions are compared to existing and experimental results. (orig./HP)

A Run-Length Encoding Approach for Path Analysis of C. elegans Search Behavior

Directory of Open Access Journals (Sweden)

Li Huang

2016-01-01

Full Text Available The nematode Caenorhabditis elegans explores the environment using a combination of different movement patterns, which include straight movement, reversal, and turns. We propose to quantify C. elegans movement behavior using a computer vision approach based on run-length encoding of step-length data. In this approach, the path of C. elegans is encoded as a string of characters, where each character represents a path segment of a specific type of movement. With these encoded string data, we perform k-means cluster analysis to distinguish movement behaviors resulting from different genotypes and food availability. We found that shallow and sharp turns are the most critical factors in distinguishing the differences among the movement behaviors. To validate our approach, we examined the movement behavior of tph-1 mutants that lack an enzyme responsible for serotonin biosynthesis. A k-means cluster analysis with the path string-encoded data showed that tph-1 movement behavior on food is similar to that of wild-type animals off food. We suggest that this run-length encoding approach is applicable to trajectory data in animal or human mobility data.

Straight configuration saphenous vein transposition to popliteal artery for vascular access.

Science.gov (United States)

Caco, Gentian; Golemi, Dhurata; Likaj, Eriola

2017-03-21

The saphenous vein is commonly used as a vascular graft in peripheral artery surgery but rarely used for vascular access. The literature on straight configuration saphenous vein transposition to the popliteal artery is scarce. Here we present two cases of straight configuration saphenous vein transposition to the popliteal artery for vascular access, the surgical technique and respective follow-up. Two young men, aged 29 and 36 years, were chosen for lower-limb vascular access for hemodialysis. The first patient was paraplegic since birth. He used his arms to move so upper extremity vascular access was avoided. The second patient presented with an infected upper extremity arteriovenous graft (AVG) and after multiple closed AVFs he had no more available arm veins. Both patients received autologous lower extremity straight configuration saphenous vein transpositions to the popliteal artery under spinal anesthesia in May and October 2012, respectively. Cannulation of the fistula was allowed after one month. There were no early complications. Slight swelling on the leg appeared in one of the patients. Both fistulas were still functional after 36 and 32 months, respectively. The straight configuration saphenous vein transposition to popliteal artery is simple to perform, offers a long and straight segment for cannulation and may be a suitable autologous vascular access in selected patients.

Qingping Straight Sword: The Last Remaining Chinese Sword System?

Directory of Open Access Journals (Sweden)

Stephan Berwick

2012-07-01

Full Text Available The following examination of classical Chinese straight sword (jian details the very rare Qingping straight sword system. The study meshes Chinese- and English-sourced research with a revealing interview (conducted by America’s senior Qingping disciples, Reza Momenan and Hon Lee with Lu Junhai—the grandmaster of this unique sword system. The author presents Qingping system as perhaps the only known, complete Chinese sword system surviving from China’s pre-Rebulican era (1911-1949.

Design of Smooth Ramp Feedrate for Machining Complex NURBS Paths

Science.gov (United States)

Sekar, M.; Suresha, B.; Kantharaj, I.

2017-10-01

The feedrate scheduling algorithms proposed in this work permit the complex NURBS tool paths to be traversed quickly in those areas not limited by dynamic constraints, but slowdown in critical areas just enough to keep the machine within its dynamic limits and the specified tolerance zone. Due to the typically improved path tracking performance, surface finish can improve greatly, reducing the need for secondary finishing operations such as polishing. This work implements the Acceleration Deceleration Before Interpolation (ADBI) approach which is desired in modern CNC controller design and high speed machining of complex micro profiles common in Aerospace applications.

A mathematical model for camera calibration based on straight lines

Directory of Open Access Journals (Sweden)

Antonio M. G. Tommaselli

2005-12-01

Full Text Available In other to facilitate the automation of camera calibration process, a mathematical model using straight lines was developed, which is based on the equivalent planes mathematical model. Parameter estimation of the developed model is achieved by the Least Squares Method with Conditions and Observations. The same method of adjustment was used to implement camera calibration with bundles, which is based on points. Experiments using simulated and real data have shown that the developed model based on straight lines gives results comparable to the conventional method with points. Details concerning the mathematical development of the model and experiments with simulated and real data will be presented and the results with both methods of camera calibration, with straight lines and with points, will be compared.

Cherry Picking: Virginity Loss Definitions Among Gay and Straight Cisgender Men.

Science.gov (United States)

Huang, Howard

2017-08-03

Virginity loss is a vital milestone in the development of one's sexual identity. Unfortunately, there is very little literature available studying virginity loss definitions among the wider straight population, and even less examining virginity loss among LGBTQ+ populations. The present study recruited 251 (45.4%) cisgender straight men and 114 (54.6%) cisgender gay men. An online, anonymous survey was administered to explore whether they considered various male-on-male (M-M) and male-on-female (M-F) sexual behaviors as constitutive of virginity loss. Results indicate that more gay men than straight considered M-M receptive anal intercourse (i.e., bottoming) and M-F penetrative anal intercourse to be constitutive of virginity loss. Results also indicate that both gay and straight men almost unanimously endorsed M-F penovaginal sex to be constitutive of virginity loss. This study is a first-step toward gaining a better understanding of LGBTQ+ virginity loss conceptualizations. Future research is strongly encouraged.

Straight vegetable oils usage in a compression ignition engine - A review

Energy Technology Data Exchange (ETDEWEB)

Misra, R.D.; Murthy, M.S. [Mechanical Engineering Department, National Institute of Technology, Silchar 788010, Assam (India)

2010-12-15

The ever increasing fossil fuel usage and cost, environmental concern has forced the world to look for alternatives. Straight vegetable oils in compression ignition engine are a ready solution available, however, with certain limitations and with some advantages as reported by many researchers. A comprehensive and critical review is presented specifically pertaining to straight vegetable oils usage in diesel engine. A detailed record of historical events described. Research carried out specifically under Indian conditions and international research work on the usage of straight vegetable oils in the diesel engine is separately reviewed. Many researchers have reported that straight vegetable oils in small percentage blends with diesel when used lower capacity diesel engines have shown great promise with regards to the thermal performance as well exhaust emissions. This has been explained in detail. Finally based on the review of international as well as Indian research a SWOT analysis is carried out. The review concludes that there is still scope for research in this area. (author)

Curved-straight neutron guide system with uniform spatial intensity distribution

International Nuclear Information System (INIS)

Mildner, D.F.R.; Cook, J.C.

2008-01-01

The spatial intensity distribution of neutrons emerging from a curved guide is asymmetric, and straight guide sections are sometimes appended to curved guides to make the intensity distribution more nearly uniform. For idealized uniform illumination and in the perfect reflectivity approximation, the spatial-angular acceptance at the exit of the combination can be made exactly uniform for a range of long wavelengths by using a sufficiently long straight section, together with a curved guide whose outer wall coating has a critical angle slightly greater than those of the other guide walls. We refer to this as a 'phase space tailoring guide' where the coatings on the inner wall and straight section are used to define the required divergence at the end of the guide. Increasing the critical angle of the outer wall of the curved section reduces the characteristic wavelength of the curved guide as well as the wavelength at which ideal uniformity can be obtained. The outer wall coating need only be of sufficiently high critical angle to fill the transmittable phase space area of the straight guide uniformly to adequately short wavelength

OpenCV and TYZX : video surveillance for tracking.

Energy Technology Data Exchange (ETDEWEB)

He, Jim; Spencer, Andrew; Chu, Eric

2008-08-01

As part of the National Security Engineering Institute (NSEI) project, several sensors were developed in conjunction with an assessment algorithm. A camera system was developed in-house to track the locations of personnel within a secure room. In addition, a commercial, off-the-shelf (COTS) tracking system developed by TYZX was examined. TYZX is a Bay Area start-up that has developed its own tracking hardware and software which we use as COTS support for robust tracking. This report discusses the pros and cons of each camera system, how they work, a proposed data fusion method, and some visual results. Distributed, embedded image processing solutions show the most promise in their ability to track multiple targets in complex environments and in real-time. Future work on the camera system may include three-dimensional volumetric tracking by using multiple simple cameras, Kalman or particle filtering, automated camera calibration and registration, and gesture or path recognition.

OpenCV and TYZX : video surveillance for tracking

International Nuclear Information System (INIS)

He, Jim; Spencer, Andrew; Chu, Eric

2008-01-01

As part of the National Security Engineering Institute (NSEI) project, several sensors were developed in conjunction with an assessment algorithm. A camera system was developed in-house to track the locations of personnel within a secure room. In addition, a commercial, off-the-shelf (COTS) tracking system developed by TYZX was examined. TYZX is a Bay Area start-up that has developed its own tracking hardware and software which we use as COTS support for robust tracking. This report discusses the pros and cons of each camera system, how they work, a proposed data fusion method, and some visual results. Distributed, embedded image processing solutions show the most promise in their ability to track multiple targets in complex environments and in real-time. Future work on the camera system may include three-dimensional volumetric tracking by using multiple simple cameras, Kalman or particle filtering, automated camera calibration and registration, and gesture or path recognition

Exact equivalent straight waveguide model for bent and twisted waveguides

DEFF Research Database (Denmark)

Shyroki, Dzmitry

2008-01-01

Exact equivalent straight waveguide representation is given for a waveguide of arbitrary curvature and torsion. No assumptions regarding refractive index contrast, isotropy of materials, or particular morphology in the waveguide cross section are made. This enables rigorous full-vector modeling...... of in-plane curved or helically wound waveguides with use of available simulators for straight waveguides without the restrictions of the known approximate equivalent-index formulas....

Automated positioning dual-axis solar tracking system with precision elevation and azimuth angle control

International Nuclear Information System (INIS)

Sidek, M.H.M.; Azis, N.; Hasan, W.Z.W.; Ab Kadir, M.Z.A.; Shafie, S.; Radzi, M.A.M.

2017-01-01

This paper presents a study on an automated positioning open-loop dual-axis solar tracking system. The solar tracker was designed and fabricated using standard cylindrical aluminium hollow and Polyuthrene (PE). The control system of the solar tracker was governed by Micro Controller Unit (MCU) with auxiliary devices which includes encoder and Global Positioning System (GPS). The sun path trajectory algorithm utilizing the astronomical equation and GPS information was also embedded in the system. The power generation performance of the dual-axis solar tracking system was compared with the fixed-tilted Photovoltaic (PV) system. It is found that the solar tracker is able to position itself automatically based on sun path trajectory algorithm with an accuracy of ±0.5°. The embedded Proportional Integral Derivative (PID) positioning system improves the tracking of elevation and azimuth angles with minimum energy consumption. It is reveals that the proposed solar tracker is able generate 26.9% and 12.8% higher power than fixed-tilted PV system on a clear and heavy overcast conditions respectively. Overall, the open-loop dual-axis solar tracker can be deployed automatically at any location on the earth with minimal configurations and is suitable for mobile solar tracking system. - Highlights: • Self-positioning dual-axis solar tracking system. • Precise control of elevation and azimuth angle. • Sun path trajectory based on astronomical equation and GPS. • Can achieve up to 26.9% higher power than fixed-tilted PV system under clear weather condition.

Spatial Updating Strategy Affects the Reference Frame in Path Integration.

Science.gov (United States)

He, Qiliang; McNamara, Timothy P

2018-06-01

This study investigated how spatial updating strategies affected the selection of reference frames in path integration. Participants walked an outbound path consisting of three successive waypoints in a featureless environment and then pointed to the first waypoint. We manipulated the alignment of participants' final heading at the end of the outbound path with their initial heading to examine the adopted reference frame. We assumed that the initial heading defined the principal reference direction in an allocentric reference frame. In Experiment 1, participants were instructed to use a configural updating strategy and to monitor the shape of the outbound path while they walked it. Pointing performance was best when the final heading was aligned with the initial heading, indicating the use of an allocentric reference frame. In Experiment 2, participants were instructed to use a continuous updating strategy and to keep track of the location of the first waypoint while walking the outbound path. Pointing performance was equivalent regardless of the alignment between the final and the initial headings, indicating the use of an egocentric reference frame. These results confirmed that people could employ different spatial updating strategies in path integration (Wiener, Berthoz, & Wolbers Experimental Brain Research 208(1) 61-71, 2011), and suggested that these strategies could affect the selection of the reference frame for path integration.

Comparison of 21G curved and straight phacotips designs in transversal microcoaxial phacoemulsification

Directory of Open Access Journals (Sweden)

Süleyman Demircan

2015-12-01

Full Text Available AIM:To compare the intraoperative performance and postoperative outcomes after microcoaxial torsional phacoemulsification using the straight and the curved phacotip configurations.METHODS:Cataracts were treated using 2.2mm microcoaxial transversal phacoemulsification with either a 30°straight or 30° curved phaco tip. Intraoperative measurements analyzed included the average ultrasound(U/Spower, the total phacoemulsification time, and the effective phacoemulsification time(EPT. The central endothelial cell density(ECDand the central corneal thickness(CCTwere evaluated preoperatively and postoperatively at 1, 7 and 30d after surgery using noncontact specular microscopy. RESULTS:The study enrolled a total of 190 eyes(190 patients, 95 eyes in the curved tip group and 95 eyes in straight tip group. Intraoperative measurements showed significantly reduced total phacoemulsification time, and EPT in the curved-tip group, compared to the straight-tip group(Pst-3rd quartilesand 18.0(9.0-30.0s in curved-tip group, and 38.8(16.5-73.5s and 26.0(11.0-49.0s in the straight-tip group, respectively. CONCLUSION:Transversal phacoemulsification performed with a curved tip provided more effective lens removal with a less total UST and EPT in all grades, except for grades IV, compared to a straight tip.

An intersection graph of straight lines

DEFF Research Database (Denmark)

Thomassen, Carsten

2002-01-01

G. Ehrlich, S. Even, and R.E. Tarjan conjectured that the graph obtained from a complete 3 partite graph K4,4,4 by deleting the edges of four disjoint triangles is not the intersection graph of straight line segments in the plane. We show that it is....

Straight-line string with curvature

International Nuclear Information System (INIS)

Solov'ev, L.D.

1995-01-01

Classical and quantum solutions for the relativistic straight-line string with arbitrary dependence on the world surface curvature are obtained. They differ from the case of the usual Nambu-Goto interaction by the behaviour of the Regge trajectory which in general can be non-linear. A regularization of the action is considered and a comparison with relativistic point with curvature is made. 5 refs

Gender, health behavior, and intimate relationships: lesbian, gay, and straight contexts.

Science.gov (United States)

Reczek, Corinne; Umberson, Debra

2012-06-01

Many studies focus on health behavior within the context of intimate ties. However, this literature is limited by reliance on gender socialization theory and a focus on straight (i.e., heterosexual) marriage. We extend this work with an analysis of relationship dynamics around health behavior in 20 long-term straight marriages as well as 15 gay and 15 lesbian long-term cohabiting partnerships in the United States (N = 100 individual in-depth interviews). We develop the concept of "health behavior work" to align activities done to promote health behavior with theories on unpaid work in the home. Respondents in all couple types describe specialized health behavior work, wherein one partner works to shape the other partner's health behavior. In straight couples, women perform the bulk of specialized health behavior work. Most gay and lesbian respondents-but few straight respondents--also describe cooperative health behavior work, wherein partners mutually influence one another's health behaviors. Findings suggest that the gendered relational context of an intimate partnership shapes the dynamics of and explanations for health behavior work. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analysis of explicit model predictive control for path-following control.

Science.gov (United States)

Lee, Junho; Chang, Hyuk-Jun

2018-01-01

In this paper, explicit Model Predictive Control(MPC) is employed for automated lane-keeping systems. MPC has been regarded as the key to handle such constrained systems. However, the massive computational complexity of MPC, which employs online optimization, has been a major drawback that limits the range of its target application to relatively small and/or slow problems. Explicit MPC can reduce this computational burden using a multi-parametric quadratic programming technique(mp-QP). The control objective is to derive an optimal front steering wheel angle at each sampling time so that autonomous vehicles travel along desired paths, including straight, circular, and clothoid parts, at high entry speeds. In terms of the design of the proposed controller, a method of choosing weighting matrices in an optimization problem and the range of horizons for path-following control are described through simulations. For the verification of the proposed controller, simulation results obtained using other control methods such as MPC, Linear-Quadratic Regulator(LQR), and driver model are employed, and CarSim, which reflects the features of a vehicle more realistically than MATLAB/Simulink, is used for reliable demonstration.

Analysis of explicit model predictive control for path-following control

Science.gov (United States)

2018-01-01

In this paper, explicit Model Predictive Control(MPC) is employed for automated lane-keeping systems. MPC has been regarded as the key to handle such constrained systems. However, the massive computational complexity of MPC, which employs online optimization, has been a major drawback that limits the range of its target application to relatively small and/or slow problems. Explicit MPC can reduce this computational burden using a multi-parametric quadratic programming technique(mp-QP). The control objective is to derive an optimal front steering wheel angle at each sampling time so that autonomous vehicles travel along desired paths, including straight, circular, and clothoid parts, at high entry speeds. In terms of the design of the proposed controller, a method of choosing weighting matrices in an optimization problem and the range of horizons for path-following control are described through simulations. For the verification of the proposed controller, simulation results obtained using other control methods such as MPC, Linear-Quadratic Regulator(LQR), and driver model are employed, and CarSim, which reflects the features of a vehicle more realistically than MATLAB/Simulink, is used for reliable demonstration. PMID:29534080

Intubation of prehospital patients with curved laryngoscope blade is more successful than with straight blade.

Science.gov (United States)

Alter, Scott M; Haim, Eithan D; Sullivan, Alex H; Clayton, Lisa M

2018-02-17

Direct laryngoscopy can be performed using curved or straight blades, and providers usually choose the blade they are most comfortable with. However, curved blades are anecdotally thought of as easier to use than straight blades. We seek to compare intubation success rates of paramedics using curved versus straight blades. Design: retrospective chart review. hospital-based suburban ALS service with 20,000 annual calls. prehospital patients with any direct laryngoscopy intubation attempt over almost 9years. First attempt and overall success rates were calculated for attempts with curved and straight blades. Differences between the groups were calculated. 2299 patients were intubated by direct laryngoscopy. 1865 had attempts with a curved blade, 367 had attempts with a straight blade, and 67 had attempts with both. Baseline characteristics were similar between groups. First attempt success was 86% with a curved blade and 73% with a straight blade: a difference of 13% (95% CI: 9-17). Overall success was 96% with a curved blade and 81% with a straight blade: a difference of 15% (95% CI: 12-18). There was an average of 1.11 intubation attempts per patient with a curved blade and 1.13 attempts per patient with a straight blade (2% difference, 95% CI: -3-7). Our study found a significant difference in intubation success rates between laryngoscope blade types. Curved blades had higher first attempt and overall success rates when compared to straight blades. Paramedics should consider selecting a curved blade as their tool of choice to potentially improve intubation success. Copyright © 2018 Elsevier Inc. All rights reserved.

Are ship tracks useful analogs for studying the aerosol indirect effect?

Science.gov (United States)

Christensen, M.; Toll, V.; Stephens, G. L.

2017-12-01

Vessels transiting the ocean sometimes leave their mark on the clouds - leaving behind reflective cloud lines, known as ship tracks. Ship tracks have been looked upon by some as a possible Rosetta Stone connecting the effects of changing aerosol over the ocean and cloud albedo effects on climate (Porch et al. 1990, Atmos. Enviorn., 1051-1059). In this research, we establish whether ship tracks, and volcano tracks - a natural analog, can be used to relate these cloud-scale perturbations to the aerosol effects occurring at larger regional-scales. Two databases containing over 1,500 ship and 900 volcano tracks, all carefully hand-selected from satellite imagery, are utilized; showing that ship tracks exhibit very similar cloud albedo effect responses to that of volcano tracks. For comparison, our global dataset utilises over 7 million CloudSat profiles consisting of single-layer marine warm cloud in which the retrievals are co-located with the MODerate Imaging Spectroradiometer (MODIS) product so that statistical relationships between aerosol and cloud can be computed over 4x4 degree regions. All datasets show the same key physical processes that govern the cloud-aerosol indirect effect, namely, the strong negative responses in cloud droplet size and the bidirectional responses in liquid water path and cloud albedo depending on the meteorological conditions. Finally, this analysis is extended to a comparison against several general circulation models where it is suggested that key processes such as cloud-top entrainment and evaporation that regulates against strong liquid water path responses are likely underrepresented in most models.

A unified model of heading and path perception in primate MSTd.

Directory of Open Access Journals (Sweden)

Oliver W Layton

2014-02-01

Full Text Available Self-motion, steering, and obstacle avoidance during navigation in the real world require humans to travel along curved paths. Many perceptual models have been proposed that focus on heading, which specifies the direction of travel along straight paths, but not on path curvature, which humans accurately perceive and is critical to everyday locomotion. In primates, including humans, dorsal medial superior temporal area (MSTd has been implicated in heading perception. However, the majority of MSTd neurons respond optimally to spiral patterns, rather than to the radial expansion patterns associated with heading. No existing theory of curved path perception explains the neural mechanisms by which humans accurately assess path and no functional role for spiral-tuned cells has yet been proposed. Here we present a computational model that demonstrates how the continuum of observed cells (radial to circular in MSTd can simultaneously code curvature and heading across the neural population. Curvature is encoded through the spirality of the most active cell, and heading is encoded through the visuotopic location of the center of the most active cell's receptive field. Model curvature and heading errors fit those made by humans. Our model challenges the view that the function of MSTd is heading estimation, based on our analysis we claim that it is primarily concerned with trajectory estimation and the simultaneous representation of both curvature and heading. In our model, temporal dynamics afford time-history in the neural representation of optic flow, which may modulate its structure. This has far-reaching implications for the interpretation of studies that assume that optic flow is, and should be, represented as an instantaneous vector field. Our results suggest that spiral motion patterns that emerge in spatio-temporal optic flow are essential for guiding self-motion along complex trajectories, and that cells in MSTd are specifically tuned to extract

A Unified Model of Heading and Path Perception in Primate MSTd

Science.gov (United States)

Layton, Oliver W.; Browning, N. Andrew

2014-01-01

Self-motion, steering, and obstacle avoidance during navigation in the real world require humans to travel along curved paths. Many perceptual models have been proposed that focus on heading, which specifies the direction of travel along straight paths, but not on path curvature, which humans accurately perceive and is critical to everyday locomotion. In primates, including humans, dorsal medial superior temporal area (MSTd) has been implicated in heading perception. However, the majority of MSTd neurons respond optimally to spiral patterns, rather than to the radial expansion patterns associated with heading. No existing theory of curved path perception explains the neural mechanisms by which humans accurately assess path and no functional role for spiral-tuned cells has yet been proposed. Here we present a computational model that demonstrates how the continuum of observed cells (radial to circular) in MSTd can simultaneously code curvature and heading across the neural population. Curvature is encoded through the spirality of the most active cell, and heading is encoded through the visuotopic location of the center of the most active cell's receptive field. Model curvature and heading errors fit those made by humans. Our model challenges the view that the function of MSTd is heading estimation, based on our analysis we claim that it is primarily concerned with trajectory estimation and the simultaneous representation of both curvature and heading. In our model, temporal dynamics afford time-history in the neural representation of optic flow, which may modulate its structure. This has far-reaching implications for the interpretation of studies that assume that optic flow is, and should be, represented as an instantaneous vector field. Our results suggest that spiral motion patterns that emerge in spatio-temporal optic flow are essential for guiding self-motion along complex trajectories, and that cells in MSTd are specifically tuned to extract complex trajectory

The CLEO-III Trigger: Calorimetry and tracking

International Nuclear Information System (INIS)

Bergfeld, T.J.; Gollin, G.D.; Haney, M.J.

1996-01-01

The CLEO-III Trigger provides a trigger decision every 42ns, with a latency of approximately 2.5μs. This paper describes the pipelined signal processing and pattern recognition schemes used by the calorimeter, and the axial and stereo portions of the drift chamber, to provide the information necessary to make these decisions. Field programmable gate arrays are used extensively to provide cluster filtering and location sorting for calorimetry, and path finding for tracking. Analog processing is also employed in the calorimetry to provide additional leverage on the problem. Timing information is extracted from both calorimetry and tracking

Transmission of fast highly charged ions through straight and tapered glass capillaries

International Nuclear Information System (INIS)

Ayyad, Asma M; Keerthisinghe, D; Kayani, A; Tanis, J A; Dassanayake, B S; Ikeda, T

2013-01-01

The transmission of 1 and 3 MeV protons through a borosilicate straight glass capillary and a tapered glass capillary was investigated. The straight capillary had a diameter of ∼0.18 mm and a length of ∼14.4 mm, while the tapered capillary had an inlet diameter of ∼0.71 mm, an outlet diameter of ∼0.10 mm and a length of ∼28 mm. The results show that the 1 and 3 MeV protons traverse through both samples without energy loss, while the tapered capillary showed better transmission than the straight capillary. (paper)

Effect of iron catalyst thickness on vertically aligned carbon nanotube forest straightness for CNT-MEMS

International Nuclear Information System (INIS)

Moulton, Kellen; Jensen, Brian D; Morrill, Nicholas B; Konneker, Adam M; Vanfleet, Richard R; Allred, David D; Davis, Robert C

2012-01-01

This paper examines the effect of iron catalyst thickness on the straightness of growth of carbon nanotubes (CNTs) for microelectromechanical systems fabricated using the CNT-templated-microfabrication (CNT-M) process. SEM images of samples grown using various iron catalyst thicknesses show that both straight sidewalls and good edge definition are achieved using an iron thickness between 7 and 8 nm. Below this thickness, individual CNTs are well aligned, but the sidewalls of CNT forests formed into posts and long walls are not always straight. Above this thickness, the CNT forest sidewalls are relatively straight, but edge definition is poor, with significantly increased sidewall roughness. The proximity of a device or feature to other regions of iron catalyst also affects CNT growth. By using an iron catalyst thickness appropriate for straight growth, and by adding borders of iron around features or devices, a designer can greatly improve straightness of growth for CNT-MEMS. (paper)

A Fast-Track Path to DEMO Enabled by ITER and FNSF-AT

Energy Technology Data Exchange (ETDEWEB)

Garofalo, A. M.; Choi, M.; Humphreys, D. A.; Kinsey, J. E.; Lao, L. L.; Snyder, P. B.; John, H. E.St.; Turnbull, A. D.; Taylor, T.S., E-mail: garofalo@fusion.gat.com [General Atomics, San Diego (United States); Chan, V. S.; Canik, J. M. [Oak Ridge National Laboratory, Oak Ridge (United States); Sawan, M. E. [University of Wisconsin, Madison (United States); Stangeby, P. C. [University of Toronto Institute for Aerospace Studies, Toronto (Canada)

2012-09-15

Full text: A Fusion Nuclear Science Facility based on the Advanced Tokamak concept (FNSF-AT) [1] is a key element of a fast track plan to a commercially attractive fusion DEMO. The next step forward on the path towards fusion commercialization must be a device that complements ITER in addressing the community identified science and technology gaps to DEMO, and that enables a DEMO construction decision triggered by the achievement of Q = 10 in ITER, presently scheduled for the year 2030. This paper elucidates the logic flow leading to the FNSF-AT approach for such a next step forward, and presents the results of recent analysis resolving key physics and engineering issues. A FNSF-AT will show fusion can make its own fuel, provide a materials irradiation facility, show fusion can produce high-grade process heat and electricity. In order to accomplish these goals, the FNSF has to operate steady-state with significant duty cycle and significant neutron fluence. In FNSF-AT, advanced tokamak physics enables steady-state burning plasmas with the high fluence required for FNSF's nuclear science development objective, in the compact size required to demonstrate Tritium fuel self-sufficiency using only a moderate quantity of the limited supply of Tritium. Physics based integrated modeling has found a steady-state baseline equilibrium with good stability and controllability properties. 2-D analysis assuming ITER heat and particle diffusion coefficients in the SOL predicts peak heat flux < 10 MW/m{sup 2} at the outer divertor targets. High fidelity and high-resolution 3D neutronics calculations have also been carried out, showing acceptable cumulative end-of-life organic insulator dose levels in all the device coils, and TBR > 1 for two blanket concepts considered. This FNSF-AT baseline plasma scenario has significant margin to meet the FNSF nuclear science mission. Moreover, the facility allows the development of more advanced scenarios to close the physics gaps to DEMO

Particle-tracking code (track3d) for convective solute transport modelling in the geosphere: Description and user`s manual; Programme de reperage de particules (track3d) pour la modelisation du transport par convection des solutes dans la geosphere: description et manuel de l`utilisateur

Energy Technology Data Exchange (ETDEWEB)

Nakka, B W; Chan, T

1994-12-01

A deterministic particle-tracking code (TRACK3D) has been developed to compute convective flow paths of conservative (nonreactive) contaminants through porous geological media. TRACK3D requires the groundwater velocity distribution, which, in our applications, results from flow simulations using AECL`s MOTIF code. The MOTIF finite-element code solves the transient and steady-state coupled equations of groundwater flow, solute transport and heat transport in fractured/porous media. With few modifications, TRACK3D can be used to analyse the velocity distributions calculated by other finite-element or finite-difference flow codes. This report describes the assumptions, limitations, organization, operation and applications of the TRACK3D code, and provides a comprehensive user`s manual.

A novel validation algorithm allows for automated cell tracking and the extraction of biologically meaningful parameters.

Directory of Open Access Journals (Sweden)

Daniel H Rapoport

Full Text Available Automated microscopy is currently the only method to non-invasively and label-free observe complex multi-cellular processes, such as cell migration, cell cycle, and cell differentiation. Extracting biological information from a time-series of micrographs requires each cell to be recognized and followed through sequential microscopic snapshots. Although recent attempts to automatize this process resulted in ever improving cell detection rates, manual identification of identical cells is still the most reliable technique. However, its tedious and subjective nature prevented tracking from becoming a standardized tool for the investigation of cell cultures. Here, we present a novel method to accomplish automated cell tracking with a reliability comparable to manual tracking. Previously, automated cell tracking could not rival the reliability of manual tracking because, in contrast to the human way of solving this task, none of the algorithms had an independent quality control mechanism; they missed validation. Thus, instead of trying to improve the cell detection or tracking rates, we proceeded from the idea to automatically inspect the tracking results and accept only those of high trustworthiness, while rejecting all other results. This validation algorithm works independently of the quality of cell detection and tracking through a systematic search for tracking errors. It is based only on very general assumptions about the spatiotemporal contiguity of cell paths. While traditional tracking often aims to yield genealogic information about single cells, the natural outcome of a validated cell tracking algorithm turns out to be a set of complete, but often unconnected cell paths, i.e. records of cells from mitosis to mitosis. This is a consequence of the fact that the validation algorithm takes complete paths as the unit of rejection/acceptance. The resulting set of complete paths can be used to automatically extract important biological parameters

Modelling how drivers respond to a bicyclist crossing their path at an intersection: How do test track and driving simulator compare?

Science.gov (United States)

Boda, Christian-Nils; Dozza, Marco; Bohman, Katarina; Thalya, Prateek; Larsson, Annika; Lubbe, Nils

2018-02-01

Bicyclist fatalities are a great concern in the European Union. Most of them are due to crashes between motorized vehicles and bicyclists at unsignalised intersections. Different countermeasures are currently being developed and implemented in order to save lives. One type of countermeasure, active safety systems, requires a deep understanding of driver behaviour to be effective without being annoying. The current study provides new knowledge about driver behaviour which can inform assessment programmes for active safety systems such as Euro NCAP. This study investigated how drivers responded to bicyclists crossing their path at an intersection. The influences of car speed and cyclist speed on the driver response process were assessed for three different crossing configurations. The same experimental protocol was tested in a fixed-base driving simulator and on a test track. A virtual model of the test track was used in the driving simulator to keep the protocol as consistent as possible across testing environments. Results show that neither car speed nor bicycle speed directly influenced the response process. The crossing configuration did not directly influence the braking response process either, but it did influence the strategy chosen by the drivers to approach the intersection. The point in time when the bicycle became visible (which depended on the car speed, the bicycle speed, and the crossing configuration) and the crossing configuration alone had the largest effects on the driver response process. Dissimilarities between test-track and driving-simulator studies were found; however, there were also interesting similarities, especially in relation to the driver braking behaviour. Drivers followed the same strategy to initiate braking, independent of the test environment. On the other hand, the test environment affected participants' strategies for releasing the gas pedal and regulating deceleration. Finally, a mathematical model, based on both experiments

Effects of cavity on leakage loss in straight-through labyrinth seals

International Nuclear Information System (INIS)

Zhao, W; Nielsen, T K; Billdal, J T

2010-01-01

Labyrinth seals are widely used in rotating fluid machinery, due to its low-cost, simplicity and reliability. A straight-through labyrinth seal consists of a clearance between the stator and rotor, and sometimes cavities which are included on the stator or the rotator side. In this type of seals, making cavities are an effective way to convert turbulence kinetic energy into thermal energy by forming turbulence vortices, thereby reducing pressure difference and leakage flow. In this paper, the effect of cavities on leakage loss in straight-through labyrinth seals are studied by changing cavity dimensions such as depth and length, cavity number and cavity location. The influences of unilateral cavities and bilateral cavities on the leakage loss in straight-through labyrinth seals are also compared. The fluid flow characteristics through straight-through labyrinth seals were obtained by using viscous flow analysis along with a standard k-ωturbulence model. The cavity dimensions and cavity numbers have significant effects on the leakage as well as on the flow pattern in the seal. The bilateral cavity has better leakage performance than the unilateral cavity when cavity dimensions are identical. However, the cavity location shows no significant influences on the leakage flow.

Implanting straight into cochlea risks the facial nerve: a Cartesian coordinate study.

Science.gov (United States)

Deshpande, Anita S; Wendell Todd, N

2016-12-01

To describe the straight-into-cochlea line that affords the best access for an electrode array to enter via the round window, and how this line relates to the facial nerve, the incus, and mastoid size. The straight-into-cochlea line is important to minimize the cochlear trauma and maximize the likelihood of placement into the scala tympani. High-resolution CT scans were obtained for ten craniums with the extremes of large (N = 5) and small (N = 5) mastoid pneumatization; the specimens were from a series of 41 ear normal craniums. Using FIJI, a publicly available software program, the straight-into-cochlea insertion line was determined by defining the x-y-z coordinates of the middle of the round window and a point 6.0 mm into the cochlea on its centrifugal wall. Then, from the extended straight-into-cochlea insertion line, we determined the shortest perpendicular distance to the middle of the fallopian canal, and from that "fallopian point" to the apex of the posterior process of the incus. We found good repeatability of measurements. We found the extended straight-into-cochlea insertion lines routinely close to or in the midst of the fallopian canal (50 % ≤ 1.0 mm). We found the lines 4.7-7.8 mm from the apex of the posterior process of the incus. Line positions relative to "fallopian point" and incus showed no relation to mastoid pneumatization. For the distance "fallopian point" to incus, bilateral symmetry was suggested. Using landmarks registered in an x-y-z coordinate system, straight-into-cochlea insertion via the round window puts the facial nerve at risk.

Diffusion in periodic potentials with path integral hyperdynamics.

Science.gov (United States)

Ikonen, T; Khandkar, M D; Chen, L Y; Ying, S C; Ala-Nissila, T

2011-08-01

We consider the diffusion of brownian particles in one-dimensional periodic potentials as a test bench for the recently proposed stochastic path integral hyperdynamics (PIHD) scheme [Chen and Horing, J. Chem. Phys. 126, 224103 (2007)]. First, we consider the case where PIHD is used to enhance the transition rate of activated rare events. To this end, we study the diffusion of a single brownian particle moving in a spatially periodic potential in the high-friction limit at low temperature. We demonstrate that the boost factor as compared to straight molecular dynamics (MD) has nontrivial behavior as a function of the bias force. Instead of growing monotonically with the bias, the boost attains an optimal maximum value due to increased error in the finite path sampling induced by the bias. We also observe that the PIHD method can be sensitive to the choice of numerical integration algorithm. As the second case, we consider parallel resampling of multiple bias force values in the case of a brownian particle in a periodic potential subject to an external ac driving force. We confirm that there is no stochastic resonance in this system. However, while the PIHD method allows one to obtain data for multiple values of the ac bias, the boost with respect to MD remains modest due to the simplicity of the equation of motion in this case.

The appearance potency of gay and straight men’s websites

OpenAIRE

Jankowski, G.; Slater, A.; Tiggemann, M.; Fawkner, H.

2016-01-01

Gay men's greater body dissatisfaction compared to straight men has been explained as a result of gay men’s more 'appearance potent' subculture. This study aimed to critically appraise this explanation by assessing images of men and women for their physical characteristics and objectification across 8 popular gay and straight men's dating and porn websites. 1,415 images of men and 715 images of women across the website’s main pages were coded. Results showed that the gay men's websites featur...

A simple algorithm for computing positively weighted straight skeletons of monotone polygons☆

Science.gov (United States)

Biedl, Therese; Held, Martin; Huber, Stefan; Kaaser, Dominik; Palfrader, Peter

2015-01-01

We study the characteristics of straight skeletons of monotone polygonal chains and use them to devise an algorithm for computing positively weighted straight skeletons of monotone polygons. Our algorithm runs in O(nlog⁡n) time and O(n) space, where n denotes the number of vertices of the polygon. PMID:25648376

A simple algorithm for computing positively weighted straight skeletons of monotone polygons.

Science.gov (United States)

Biedl, Therese; Held, Martin; Huber, Stefan; Kaaser, Dominik; Palfrader, Peter

2015-02-01

We study the characteristics of straight skeletons of monotone polygonal chains and use them to devise an algorithm for computing positively weighted straight skeletons of monotone polygons. Our algorithm runs in [Formula: see text] time and [Formula: see text] space, where n denotes the number of vertices of the polygon.

A path-following driver/vehicle model with optimized lateral dynamic controller

Directory of Open Access Journals (Sweden)

Behrooz Mashadi

Full Text Available Reduction in traffic congestion and overall number of accidents, especially within the last decade, can be attributed to the enormous progress in active safety. Vehicle path following control with the presence of driver commands can be regarded as one of the important issues in vehicle active safety systems development and more realistic explanation of vehicle path tracking problem. In this paper, an integrated driver/DYC control system is presented that regulates the steering angle and yaw moment, considering driver previewed path. Thus, the driver previewed distance, the heading error and the lateral deviation between the vehicle and desired path are used as inputs. Then, the controller determines and applies a corrective steering angle and a direct yaw moment to make the vehicle follow the desired path. A PID controller with optimized gains is used for the control of integrated driver/DYC system. Genetic Algorithm as an intelligent optimization method is utilized to adapt PID controller gains for various working situations. Proposed integrated driver/DYC controller is examined on lane change manuvers andthe sensitivity of the control system is investigated through the changes in the driver model and vehicle parameters. Simulation results show the pronounced effectiveness of the controller in vehicle path following and stability.

26 CFR 7.57(d)-1 - Election with respect to straight line recovery of intangibles.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Election with respect to straight line recovery... ACT OF 1976 § 7.57(d)-1 Election with respect to straight line recovery of intangibles. (a) Purpose... Tax Reform Act of 1976. Under this election taxpayers may use cost depletion to compute straight line...

Commissioning of the PF Ring after the Reconstruction for the Straight-sections Upgrade

International Nuclear Information System (INIS)

Honda, T.; Asaoka, S.; Cheng, W. X.; Haga, K.; Harada, K.; Hori, Y.; Izawa, M.; Kasuga, T.; Kobayashi, Y.; Maezawa, H.; Mishina, A.; Mitsuhashi, T.; Miyajima, T.; Miyauchi, H.; Nagahashi, S.; Nogami, T.; Obina, T.; Pak, C. O.; Sakanaka, S.; Sasaki, H.

2007-01-01

At the 2.5-GeV ring of the Photon Factory, a large reconstruction of the lattice around the straight sections has been accomplished in 2005. Thus reconstruction is the main part of the straight-sections upgrade project to rebuild existing undulators and to increase the number of undulator beamlines. As a result of the reconstruction, four short straight sections have been newly created and the lengths of the existing straight sections have been much extended. To exploit the new straight sections, short-period narrow-gap undulators which have a sufficiently high brilliance in hard x-ray range have been developed. The reconstruction work of the ring was completed in a seven-month shutdown from March to September, 2005. In the area over two thirds of the storage ring, all the quadrupole magnets and all the beam ducts have been renewed and rearranged to construct the new lattice. Recommissioning of the storage ring was finished at the end of October, 2005. Though we made no in-situ baking for the beam ducts, recovery of the beam lifetime has favorably progressed due to the vacuum scrubbing by the synchrotron radiation

Principal-vector-directed fringe-tracking technique.

Science.gov (United States)

Zhang, Zhihui; Guo, Hongwei

2014-11-01

Fringe tracking is one of the most straightforward techniques for analyzing a single fringe pattern. This work presents a principal-vector-directed fringe-tracking technique. It uses Gaussian derivatives for estimating fringe gradients and uses hysteresis thresholding for segmenting singular points, thus improving the principal component analysis method. Using it allows us to estimate the principal vectors of fringes from a pattern with high noise. The fringe-tracking procedure is directed by these principal vectors, so that erroneous results induced by noise and other error-inducing factors are avoided. At the same time, the singular point regions of the fringe pattern are identified automatically. Using them allows us to determine paths through which the "seed" point for each fringe skeleton is easy to find, thus alleviating the computational burden in processing the fringe pattern. The results of a numerical simulation and experiment demonstrate this method to be valid.

Commissioning of the Cryogenics of the LHC Long Straight Sections

CERN Document Server

Perin, A; Claudet, S; Darve, C; Ferlin, G; Millet, F; Parente, C; Rabehl, R; Soubiran, M; van Weelderen, R; Wagner, U

2010-01-01

The LHC is made of eight circular arcs interspaced with eight Long Straight Sections (LSS). Most powering interfaces to the LHC are located in these sections where the particle beams are focused and shaped for collision, cleaning and acceleration. The LSSs are constituted of several unique cryogenic devices and systems like electrical feed-boxes, standalone superconducting magnets, superconducting links, RF cavities and final focusing superconducting magnets. This paper presents the cryogenic commissioning and the main results obtained during the first operation of the LHC Long Straight Sections.

Commissioning of the cryogenics of the LHC long straight sections

International Nuclear Information System (INIS)

Perin, A.; Casas-Cubillos, J.; Claudet, S.; Darve, C.; Ferlin, G.; Millet, F.; Parente, C.; Rabehl, R.; Soubiran, M.; van Weelderen, R.; Wagner, U.

2010-01-01

The LHC is made of eight circular arcs interspaced with eight Long Straight Sections (LSS). Most powering interfaces to the LHC are located in these sections where the particle beams are focused and shaped for collision, cleaning and acceleration. The LSSs are constituted of several unique cryogenic devices and systems like electrical feed-boxes, standalone superconducting magnets, superconducting links, RF cavities and final focusing superconducting magnets. This paper presents the cryogenic commissioning and the main results obtained during the first operation of the LHC Long Straight Sections.

Quadrotor trajectory tracking using PID cascade control

Science.gov (United States)

Idres, M.; Mustapha, O.; Okasha, M.

2017-12-01

Quadrotors have been applied to collect information for traffic, weather monitoring, surveillance and aerial photography. In order to accomplish their mission, quadrotors have to follow specific trajectories. This paper presents proportional-integral-derivative (PID) cascade control of a quadrotor for path tracking problem when velocity and acceleration are small. It is based on near hover controller for small attitude angles. The integral of time-weighted absolute error (ITAE) criterion is used to determine the PID gains as a function of quadrotor modeling parameters. The controller is evaluated in three-dimensional environment in Simulink. Overall, the tracking performance is found to be excellent for small velocity condition.

A generalized, periodic nonlinearity-reduced interferometer for straightness measurements

International Nuclear Information System (INIS)

Wu Chienming

2008-01-01

Periodic nonlinearity is a systematic error limiting the accuracy of displacement measurements at the nanometer level. However, an interferometer with a displacement measurement accuracy of less than 1 nm is required in nanometrology and in fundamental scientific research. To meet this requirement, a generalized, periodic nonlinearity-reduced interferometer, based on three construction principles has been developed for straightness measurements. These three construction principles have resulted in an interferometer with a highly stable design with reduced periodic nonlinearity. Verifications by a straightness interferometer have demonstrated that the periodic nonlinearity was less than 40 pm. The results also demonstrate that the interferometer design is capable of subnanometer accuracy and is useful in nanometrology

Friends with benefits, but without the sex: straight women and gay men exchange trustworthy mating advice.

Science.gov (United States)

Russell, Eric M; DelPriore, Danielle J; Butterfield, Max E; Hill, Sarah E

2013-02-09

Although research has made progress in elucidating the benefits exchanged within same- and opposite-sex friendships formed between heterosexual men and women, it is less clear why straight women and gay men form close relationships with one another. The current experiments begin to address this question by exploring a potential benefit hypothesized to be uniquely available to straight women and gay men in the context of these friendships: trustworthy mating advice. Experiment 1 revealed that straight women perceive mating-relevant advice from a gay man to be more trustworthy than similar advice offered by a straight man or woman. Experiment 2 demonstrated that gay men perceive mating advice offered by a straight woman to be more trustworthy than advice offered by a lesbian woman or another gay man. Overall, the results provide initial experimental evidence that relationships between gay men and straight women may be characterized by a mutual exchange of mating-relevant benefits in the absence of sexual interest or competition.

Friends with Benefits, but without the Sex: Straight Women and Gay Men Exchange Trustworthy Mating Advice

Directory of Open Access Journals (Sweden)

Eric M. Russell

2013-01-01

Full Text Available Although research has made progress in elucidating the benefits exchanged within same- and opposite-sex friendships formed between heterosexual men and women, it is less clear why straight women and gay men form close relationships with one another. The current experiments begin to address this question by exploring a potential benefit hypothesized to be uniquely available to straight women and gay men in the context of these friendships: trustworthy mating advice. Experiment 1 revealed that straight women perceive mating-relevant advice from a gay man to be more trustworthy than similar advice offered by a straight man or woman. Experiment 2 demonstrated that gay men perceive mating advice offered by a straight woman to be more trustworthy than advice offered by a lesbian woman or another gay man. Overall, the results provide initial experimental evidence that relationships between gay men and straight women may be characterized by a mutual exchange of mating-relevant benefits in the absence of sexual interest or competition.

Stereotactic biopsy of cerebellar lesions: straight versus oblique frame positioning.

Science.gov (United States)

Quick-Weller, Johanna; Brawanski, Nina; Dinc, Nazife; Behmanesh, Bedjahn; Kammerer, Sara; Dubinski, Daniel; Seifert, Volker; Marquardt, Gerhard; Weise, Lutz

2017-10-26

Biospies of brain lesions with unknown entity are an everyday procedure among many neurosurgical departments. Biopsies can be performed frame-guided or frameless. However, cerebellar lesions are a special entity with a more complex approach. All biopsies in this study were performed stereotactically frame guided. Therefore, only biopsies of cerebellar lesions were included in this study. We compared whether the frame was attached straight versus oblique and we focused on diagnostic yield and complication rate. We evaluated 20 patients who underwent the procedure between 2009 and 2017. Median age was 56.5 years. 12 (60%) Patients showed a left sided lesion, 6 (30%) showed a lesion in the right cerebellum and 2 (10%) patients showed a midline lesion. The stereotactic frame was mounted oblique in 12 (60%) patients and straight in 8 (40%) patients. Postoperative CT scan showed small, clinically silent blood collection in two (10%) of the patients, one (5%) patient showed haemorrhage, which caused a hydrocephalus. He received an external ventricular drain. In both patients with small haemorrhage the frame was positioned straight, while in the patient who showed a larger haemorrhage the frame was mounted oblique. In all patients a final histopathological diagnosis was established. Cerebellar lesions of unknown entity can be accessed transcerebellar either with the stereotactic frame mounted straight or oblique. Also for cerebellar lesions the procedure shows a high diagnostic yield with a low rate of severe complications, which need further treatment.

Cardiorespiratory and metabolic responses during straight and bent knee cycling.

Science.gov (United States)

Mandroukas, K; Angelopoulou, N; Christoulas, K; Vrabas, I S

2000-06-01

This study examined the influence of knee angle on the cardiorespiratory system loading during submaximal and maximal stationary cycle ergometry. Experimental design and participants: eighteen untrained women (age: 21+/-1.88 years, weight: 57+/-5.75 kg, height: 165+/-5.03 cm, values are mean+/-SD) volunteered as subjects and underwent two-cycle ergometer incremental (Jaeger ER900) tests: 1) straight knee (180 degrees), 2) bent knee (140 degrees). oxygen uptake (VO2), ventilation (VE) and respiratory exchange ratio (RER) were measured continuously during each test using an open circuit spirometry and blood lactate concentration was determined by means of an enzymatic method. Comparing cycling with "straight knee" to cycling with "bent knee" at 50 W, heart rate (HR), V(E) and VO2 were significantly higher (10.6%, 12.5%, 17.8%). At 100 W, blood lactate was significantly lower (10.8%) while VO2 and RER was higher (5.5%, 7.1%). During maximal exercise, the total exercise time was significantly longer (11.2%) and VE, VO2 and HR were significantly higher during cycling with "straight knee" compared to cycling with "bent knee". No significant difference in peak lactate was evident between the two sitting positions. The results of this study indicate that cycling with bent knee requires lower oxygen uptake while pedaling with straight knee is the only way to reach VO2max during cycle testing, since the cardiorespiratory system is fully taxed.

Improving the Lives of Students, Gay and Straight Alike: Gay-Straight Alliances and the Role of School Psychologists

Science.gov (United States)

Murphy, Heather Elise

2012-01-01

Lesbian, gay, bisexual, and transgender (LGBT) students face many risk factors every day when they enter their school's door. These students often fear for their safety at school, are victimized, have academic difficulties, suffer from issues with their identity development, and are at risk for suicide. School-based Gay-Straight Alliances (GSAs)…

Efficient odd straight medium chain free fatty acid production by metabolically engineered Escherichia coli.

Science.gov (United States)

Wu, Hui; San, Ka-Yiu

2014-11-01

Free fatty acids (FFAs) can be used as precursors for the production of biofuels or chemicals. Different composition of FFAs will be useful for further modification of the biofuel/biochemical quality. Microbial biosynthesis of even chain FFAs can be achieved by introducing an acyl-acyl carrier protein thioesterase gene into E. coli. In this study, odd straight medium chain FFAs production was investigated by using metabolic engineered E. coli carrying acyl-ACP thioesterase (TE, Ricinus communis), propionyl-CoA synthase (Salmonella enterica), and β-ketoacyl-acyl carrier protein synthase III (four different sources) with supplement of extracellular propionate. By using these metabolically engineered E. coli, significant quantity of C13 and C15 odd straight-chain FFAs could be produced from glucose and propionate. The highest concentration of total odd straight chain FFAs attained was 1205 mg/L by the strain HWK201 (pXZ18, pBHE2), and 85% of the odd straight chain FFAs was C15. However, the highest percentage of odd straight chain FFAs was achieved by the strain HWK201 (pXZ18, pBHE3) of 83.2% at 48 h. This strategy was also applied successfully in strains carrying different TE, such as the medium length acyl-ACP thioesterase gene from Umbellularia californica. C11 and C13 became the major odd straight-chain FFAs. © 2014 Wiley Periodicals, Inc.

Push-off forces in elite short-track speed skating.

Science.gov (United States)

van der Kruk, Eline; Reijne, Marco M; de Laat, Bjorn; Veeger, DirkJan H E J

2018-05-30

This study performed an analysis of the push-off forces of elite-short-track speed skaters using a new designed instrumented short-track speed skate with the aim to improve short-track skating performance. Four different skating strokes were distinguished for short-track speed skaters at speed. The strokes differed in stroke time, force level in both normal and lateral directions, and the centre of pressure (COP) on the blade. Within the homogeneous group of male elite speed skaters (N = 6), diversity of execution of the force patterns in the four phases of skating was evident, while skating at the same velocities. The male participants (N = 6) with a better personal record (PR) kept the COP more to the rear of their blades while hanging into the curve (r = 0.82, p < 0.05), leaving the curve (r = 0.86, p < 0.05), and entering the straight (r = 0.76, p < 0.10). Furthermore, the male skaters with a better PR showed a trend of a lower lateral peak force while entering the curve (r = 0.74, p < 0.10). Females showed a trend towards applying higher body weight normalised lateral forces than the males, while skating at imposed lower velocities.

A Mobile Asset Tracking System Architecture under Mobile-Stationary Co-Existing WSNs

Science.gov (United States)

Kim, Tae Hyon; Jo, Hyeong Gon; Lee, Jae Shin; Kang, Soon Ju

2012-01-01

The tracking of multiple wireless mobile nodes is not easy with current legacy WSN technologies, due to their inherent technical complexity, especially when heavy traffic and frequent movement of mobile nodes are encountered. To enable mobile asset tracking under these legacy WSN systems, it is necessary to design a specific system architecture that can manage numerous mobile nodes attached to mobile assets. In this paper, we present a practical system architecture including a communication protocol, a three-tier network, and server-side middleware for mobile asset tracking in legacy WSNs consisting of mobile-stationary co-existing infrastructures, and we prove the functionality of this architecture through careful evaluation in a test bed. Evaluation was carried out in a microwave anechoic chamber as well as on a straight road near our office. We evaluated communication mobility performance between mobile and stationary nodes, location-awareness performance, system stability under numerous mobile node conditions, and the successful packet transfer rate according to the speed of the mobile nodes. The results indicate that the proposed architecture is sufficiently robust for application in realistic mobile asset tracking services that require a large number of mobile nodes. PMID:23242277

A Mobile Asset Tracking System Architecture under Mobile-Stationary Co-Existing WSNs

Directory of Open Access Journals (Sweden)

Soon Ju Kang

2012-12-01

Full Text Available The tracking of multiple wireless mobile nodes is not easy with current legacy WSN technologies, due to their inherent technical complexity, especially when heavy traffic and frequent movement of mobile nodes are encountered. To enable mobile asset tracking under these legacy WSN systems, it is necessary to design a specific system architecture that can manage numerous mobile nodes attached to mobile assets. In this paper, we present a practical system architecture including a communication protocol, a three-tier network, and server-side middleware for mobile asset tracking in legacy WSNs consisting of mobile-stationary co-existing infrastructures, and we prove the functionality of this architecture through careful evaluation in a test bed. Evaluation was carried out in a microwave anechoic chamber as well as on a straight road near our office. We evaluated communication mobility performance between mobile and stationary nodes, location-awareness performance, system stability under numerous mobile node conditions, and the successful packet transfer rate according to the speed of the mobile nodes. The results indicate that the proposed architecture is sufficiently robust for application in realistic mobile asset tracking services that require a large number of mobile nodes.

Development of a Hough transformation track finder for time projection chambers

International Nuclear Information System (INIS)

Heinze, Isa

2013-12-01

The International Linear Collider (ILC) is a planned particle physics experiment. One of the two detector concepts is the International Large Detector (ILD) concept for which a time projection chamber is foreseen as the main tracking device. In the ILD the particle flow concept is followed which leads to special requirements for the detector. Especially for the tracking system a very good momentum resolution is required. Several prototypes were build to prove that it is possible to build a TPC which fulfills the requirements for a TPC in the ILD. One is the Large Prototype with which different readout technologies currently under development are tested. In parallel reconstruction software is developed for the reconstruction of Large Prototype data. In this thesis the development of a track finding algorithm based on the Hough transformation is described. It can find curved tracks (with magnetic field) as well as straight tracks (without magnetic field). This package was mainly developed for Large Prototype testbeam data but was also tested on Monte Carlo simulation of tracks in the ILD TPC. Furthermore the analysis of testbeam data regarding the single point resolution is presented. The data were taken with the Large Prototype and a readout module with GEM (gas electron multiplier) amplification. For the reconstruction of these data the software package mentioned above was used. The single point resolution is directly related to the momentum resolution of the detector, thus a good single point resolution is needed to achieve a good momentum resolution.

Development of a Hough transformation track finder for time projection chambers

Energy Technology Data Exchange (ETDEWEB)

Heinze, Isa

2013-12-15

The International Linear Collider (ILC) is a planned particle physics experiment. One of the two detector concepts is the International Large Detector (ILD) concept for which a time projection chamber is foreseen as the main tracking device. In the ILD the particle flow concept is followed which leads to special requirements for the detector. Especially for the tracking system a very good momentum resolution is required. Several prototypes were build to prove that it is possible to build a TPC which fulfills the requirements for a TPC in the ILD. One is the Large Prototype with which different readout technologies currently under development are tested. In parallel reconstruction software is developed for the reconstruction of Large Prototype data. In this thesis the development of a track finding algorithm based on the Hough transformation is described. It can find curved tracks (with magnetic field) as well as straight tracks (without magnetic field). This package was mainly developed for Large Prototype testbeam data but was also tested on Monte Carlo simulation of tracks in the ILD TPC. Furthermore the analysis of testbeam data regarding the single point resolution is presented. The data were taken with the Large Prototype and a readout module with GEM (gas electron multiplier) amplification. For the reconstruction of these data the software package mentioned above was used. The single point resolution is directly related to the momentum resolution of the detector, thus a good single point resolution is needed to achieve a good momentum resolution.

Adaptive tracking for pneumatic muscle actuators in bicep and tricep configurations.

Science.gov (United States)

Lilly, John H

2003-09-01

Adaptive tracking techniques are applied to pneumatic muscle actuators arranged in bicep and tricep configurations. The control objective is to force the joint angle to track a specified reference path. Mathematical models are derived for the bicep and tricep configurations. The models are nonlinear and in general time-varying, making adaptive control desirable. Stability results are derived, and the results of simulation studies are presented, contrasting the nonlinear adaptive control to a nonadaptive PID control approach.

Two-dimensional straightness measurement based on optical knife-edge sensing

Science.gov (United States)

Wang, Chen; Zhong, Fenghe; Ellis, Jonathan D.

2017-09-01

Straightness error is a parasitic translation along a perpendicular direction to the primary displacement axis of a linear stage. The parasitic translations could be coupled into other primary displacement directions of a multi-axis platform. Hence, its measurement and compensation are critical in precision multi-axis metrology, calibration, and manufacturing. This paper presents a two-dimensional (2D) straightness measurement configuration based on 2D optical knife-edge sensing, which is simple, light-weight, compact, and easy to align. It applies a 2D optical knife-edge to manipulate the diffraction pattern sensed by a quadrant photodetector, whose output voltages could derive 2D straightness errors after a calibration process. This paper analyzes the physical model of the configuration and performs simulations and experiments to study the system sensitivity, measurement nonlinearity, and error sources. The results demonstrate that the proposed configuration has higher sensitivity and insensitive to beam's vibration, compared with the conventional configurations without using the knife-edge, and could achieve ±0.25 μ m within a ±40 μ m measurement range along a 40 mm primary axial motion.

Variability of the North Atlantic summer storm track: mechanisms and impacts on European climate

OpenAIRE

Dong, Buwen; Sutton, Rowan T.; Woollings, Tim; Hodges, Kevin

2013-01-01

The summertime variability of the extratropical storm track over the Atlantic sector and its links to European climate have been analysed for the period 1948–2011 using observations and reanalyses. The main results are as follows. (1) The dominant mode of the summer storm track density variability is characterized by a meridional shift of the storm track between two distinct paths and is related to a bimodal distribution in the climatology for this region. It is also closely related to the Su...

Hard paths, soft paths or no paths? Cross-cultural perceptions of water solutions

Science.gov (United States)

Wutich, A.; White, A. C.; White, D. D.; Larson, K. L.; Brewis, A.; Roberts, C.

2014-01-01

In this study, we examine how development status and water scarcity shape people's perceptions of "hard path" and "soft path" water solutions. Based on ethnographic research conducted in four semi-rural/peri-urban sites (in Bolivia, Fiji, New Zealand, and the US), we use content analysis to conduct statistical and thematic comparisons of interview data. Our results indicate clear differences associated with development status and, to a lesser extent, water scarcity. People in the two less developed sites were more likely to suggest hard path solutions, less likely to suggest soft path solutions, and more likely to see no path to solutions than people in the more developed sites. Thematically, people in the two less developed sites envisioned solutions that involve small-scale water infrastructure and decentralized, community-based solutions, while people in the more developed sites envisioned solutions that involve large-scale infrastructure and centralized, regulatory water solutions. People in the two water-scarce sites were less likely to suggest soft path solutions and more likely to see no path to solutions (but no more likely to suggest hard path solutions) than people in the water-rich sites. Thematically, people in the two water-rich sites seemed to perceive a wider array of unrealized potential soft path solutions than those in the water-scarce sites. On balance, our findings are encouraging in that they indicate that people are receptive to soft path solutions in a range of sites, even those with limited financial or water resources. Our research points to the need for more studies that investigate the social feasibility of soft path water solutions, particularly in sites with significant financial and natural resource constraints.

Path coupling and aggregate path coupling

CERN Document Server

Kovchegov, Yevgeniy

2018-01-01

This book describes and characterizes an extension to the classical path coupling method applied to statistical mechanical models, referred to as aggregate path coupling. In conjunction with large deviations estimates, the aggregate path coupling method is used to prove rapid mixing of Glauber dynamics for a large class of statistical mechanical models, including models that exhibit discontinuous phase transitions which have traditionally been more difficult to analyze rigorously. The book shows how the parameter regions for rapid mixing for several classes of statistical mechanical models are derived using the aggregate path coupling method.

System Design and Implementation of Intelligent Fire Engine Path Planning based on SAT Algorithm

Institute of Scientific and Technical Information of China (English)

CAI Li-sha[1; ZENG Wei-peng[1; HAN Bao-ru[1

2016-01-01

In this paper, in order to make intelligent fi re car complete autonomy path planning in simulation map. Proposed system design of intelligent fi re car path planning based on SAT. The system includes a planning module, a communication module, a control module. Control module via the communication module upload the initial state and the goal state to planning module. Planning module solve this planning solution,and then download planning solution to control module, control the movement of the car fi re. Experiments show this the system is tracking short time, higher planning effi ciency.

Effects of track and threat information on judgments of hurricane strike probability.

Science.gov (United States)

Wu, Hao-Che; Lindell, Michael K; Prater, Carla S; Samuelson, Charles D

2014-06-01

Although evacuation is one of the best strategies for protecting citizens from hurricane threat, the ways that local elected officials use hurricane data in deciding whether to issue hurricane evacuation orders is not well understood. To begin to address this problem, we examined the effects of hurricane track and intensity information in a laboratory setting where participants judged the probability that hypothetical hurricanes with a constant bearing (i.e., straight line forecast track) would make landfall in each of eight 45 degree sectors around the Gulf of Mexico. The results from 162 participants in a student sample showed that the judged strike probability distributions over the eight sectors within each scenario were, unsurprisingly, unimodal and centered on the sector toward which the forecast track pointed. More significantly, although strike probability judgments for the sector in the direction of the forecast track were generally higher than the corresponding judgments for the other sectors, the latter were not zero. Most significantly, there were no appreciable differences in the patterns of strike probability judgments for hurricane tracks represented by a forecast track only, an uncertainty cone only, or forecast track with an uncertainty cone-a result consistent with a recent survey of coastal residents threatened by Hurricane Charley. The study results suggest that people are able to correctly process basic information about hurricane tracks but they do make some errors. More research is needed to understand the sources of these errors and to identify better methods of displaying uncertainty about hurricane parameters. © 2013 Society for Risk Analysis.

Control of wheeled mobile robot in restricted environment

Science.gov (United States)

Ali, Mohammed A. H.; En, Chang Yong

2018-03-01

This paper presents a simulation and practical control system for wheeled mobile robot in restricted environment. A wheeled mobile robot with 3 wheels is fabricated and controlled by proportional derivative active force control (PD-AFC) to move in a pre-planned restricted environment to maintain the tracking errors at zero level. A control system with two loops, outer by PD controller and inner loop by Active Force Control, are designed to control the wheeled mobile robot. Fuzzy logic controller is implemented in the Active force Control to estimate the inertia matrix that will be used to calculate the actual torque applied on the wheeled mobile robot. The mobile robot is tested in two different trajectories, namely are circular and straight path. The actual path and desired path are compared.

Simulation and analysis of the transmission properties of curved-straight neutron guide systems

International Nuclear Information System (INIS)

Copley, J.R.D.; Mildner, D.F.R.

1992-01-01

This paper reports that the spatial intensity distribution of neutrons emerging from a curved guide is far from uniform, particularly at short wavelengths, and curved guides are sometimes followed by a straight section of guide to make the intensity distribution more uniform. The behavior of neutrons within curved-straight neutron guide systems is examined using both ray-tracing and analytical approaches to the problem. The intensity distribution within the straight guide tends to wash from one side of the guide to the other. The amplitude of this transverse wave decreases with increasing guide length, and the characteristic length of the wave decreases with increasing neutron wavelength

Roundness and straightness measurement of ceramic beam ducts for the 3 GeV-synchrotron

Energy Technology Data Exchange (ETDEWEB)

Nishizawa, Daiji; Kinsho, Michikazu; Kanazawa, Kenichiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kubo, Tomio; Sato, Yoshihiro; Saito, Yoshio [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

2001-12-01

Large aperture ({phi}200 - {phi}250) cylindrical beam ducts consisting of alumina ceramics will be used in the 3 GeV-synchrotron of High Intensity Proton Accelerator Facility. In particular, bending magnet sections require the large length ({approx}3500 mm) ceramic beam duct connecting several unit ducts whose length is around 500-1000 mm by metallizing and glazing. Therefore it is very important to evaluate roundness and straightness of ceramic ducts because we have to compensate contact area large and have to minimize misalignment of ducts connected. We developed an apparatus for measuring roundness and straightness, and we completed data analysis method using general application software Excel as well as measuring method. Then we have taken data, and have evaluated value of roundness and straightness for the first time about 7 pieces (3 kinds) of ceramic beam duct. At last we have found out that unit ceramic ducts can be made after sintering without polishing with roundness several hundred micron ({mu}m) and straightness around 0.2-1 mm, and that straightness has a tendency to become large as duct length increases as well as roundness increases directly proportional to the maximum oblateness. (author)

Gay-Straight Alliance (GSA) Members' Engagement with Sex Education in Canadian High Schools

Science.gov (United States)

Lapointe, Alicia

2014-01-01

This paper offers an examination of gay-straight alliance (GSA) members' engagement with sex education, sexual health, and prejudice and discrimination in Canadian public high schools. It explores how five students' (four straight and one gay-identifying) participation in GSAs served as a springboard for learning about and challenging stereotypes;…

Methods of reconstruction of multi-particle events in the new coordinate-tracking setup

Science.gov (United States)

Vorobyev, V. S.; Shutenko, V. V.; Zadeba, E. A.

2018-01-01

At the Unique Scientific Facility NEVOD (MEPhI), a large coordinate-tracking detector based on drift chambers for investigations of muon bundles generated by ultrahigh energy primary cosmic rays is being developed. One of the main characteristics of the bundle is muon multiplicity. Three methods of reconstruction of multiple events were investigated: the sequential search method, method of finding the straight line and method of histograms. The last method determines the number of tracks with the same zenith angle in the event. It is most suitable for the determination of muon multiplicity: because of a large distance to the point of generation of muons, their trajectories are quasiparallel. The paper presents results of application of three reconstruction methods to data from the experiment, and also first results of the detector operation.

A Dynamic Bayesian Observer Model Reveals Origins of Bias in Visual Path Integration.

Science.gov (United States)

Lakshminarasimhan, Kaushik J; Petsalis, Marina; Park, Hyeshin; DeAngelis, Gregory C; Pitkow, Xaq; Angelaki, Dora E

2018-06-20

Path integration is a strategy by which animals track their position by integrating their self-motion velocity. To identify the computational origins of bias in visual path integration, we asked human subjects to navigate in a virtual environment using optic flow and found that they generally traveled beyond the goal location. Such a behavior could stem from leaky integration of unbiased self-motion velocity estimates or from a prior expectation favoring slower speeds that causes velocity underestimation. Testing both alternatives using a probabilistic framework that maximizes expected reward, we found that subjects' biases were better explained by a slow-speed prior than imperfect integration. When subjects integrate paths over long periods, this framework intriguingly predicts a distance-dependent bias reversal due to buildup of uncertainty, which we also confirmed experimentally. These results suggest that visual path integration in noisy environments is limited largely by biases in processing optic flow rather than by leaky integration. Copyright © 2018 Elsevier Inc. All rights reserved.

Fission track dating and thermal history of Habahe rock body in Altai

International Nuclear Information System (INIS)

Liu Shunsheng; Tan Kaixuan

2002-01-01

The fission track ages (FTA) of several apatite and zircon samples from Habahe rock body in Altai were determined. The FTA of apatites were 51.1-76.9 Ma, and FTA of zircons were 141-149 Ma. Modelling of the palaeo-temperature evolution [T(t)-path] of rock body relies on confined track length measurements and the annealing equations of Laslett et al. (1987). The thermal and uplift history of this region was discussed

The path integral formulation of fractional Brownian motion for the general Hurst exponent

International Nuclear Information System (INIS)

Calvo, I; Sanchez, R

2008-01-01

In 1995, Sebastian (1995 J. Phys. A: Math. Gen. 28 4305) gave a path integral computation of the propagator of subdiffusive fractional Brownian motion (fBm), i.e. fBm with a Hurst or self-similarity exponent H element of (0, 1/2). The extension of Sebastian's calculation to superdiffusion, H element of (1/2, 1], becomes however quite involved due to the appearance of additional boundary conditions on fractional derivatives of the path. In this communication, we address the construction of the path integral representation in a different fashion, which allows us to treat both subdiffusion and superdiffusion on an equal footing. The derivation of the propagator of fBm for the general Hurst exponent is then performed in a neat and unified way. (fast track communication)

Path Creation, Path Dependence and Breaking Away from the Path

OpenAIRE

Wang, Jens; Hedman, Jonas; Tuunainen, Virpi Kristiina

2016-01-01

The explanation of how and why firms succeed or fail is a recurrent research challenge. This is particularly important in the context of technological innovations. We focus on the role of historical events and decisions in explaining such success and failure. Using a case study of Nokia, we develop and extend a multi-layer path dependence framework. We identify four layers of path dependence: technical, strategic and leadership, organizational, and external collaboration. We show how path dep...

AUV-Based Plume Tracking: A Simulation Study

Directory of Open Access Journals (Sweden)

Awantha Jayasiri

2016-01-01

Full Text Available This paper presents a simulation study of an autonomous underwater vehicle (AUV navigation system operating in a GPS-denied environment. The AUV navigation method makes use of underwater transponder positioning and requires only one transponder. A multirate unscented Kalman filter is used to determine the AUV orientation and position by fusing high-rate sensor data and low-rate information. The paper also proposes a gradient-based, efficient, and adaptive novel algorithm for plume boundary tracking missions. The algorithm follows a centralized approach and it includes path optimization features based on gradient information. The proposed algorithm is implemented in simulation on the AUV-based navigation system and successful boundary tracking results are obtained.

Gender, Health Behavior, and Intimate Relationships: Lesbian, Gay, and Straight Contexts

OpenAIRE

Reczek, Corinne; Umberson, Debra

2011-01-01

Many studies focus on health behavior within the context of intimate ties. However, this literature is limited by reliance on gender socialization theory and a focus on straight (i.e., heterosexual) marriage. We extend this work with an analysis of relationship dynamics around health behavior in 20 long-term straight marriages as well as 15 gay and 15 lesbian long-term cohabiting partnerships in the United States (N=100 individual in-depth interviews). We develop the concept of “health behavi...

Solid state nuclear track detectors kit for the use in teaching

International Nuclear Information System (INIS)

Khouri, M.T.F.C.; Koskinas, M.F.

1988-11-01

The kit intends to improve the possibilities in performing experiments of Nuclear Physics in Modern Physics laboratories of Physics Course introducing the solid state nuclear track detectors. In these materials the passage of heavily ionizing nuclear particles creates paths (tracks) that may be revealed and made visible in an optical microscope. By the help of the kit several experiments and/or demonstrations may be performed. The kit contains solid state nuclear track detectors unirradiated and irradiated, irradiated etched and unetched sheets: an alpha source of 241 Am and an instrution text with photomicrographs. To use the kit the laboratory must have an ordinary optical microscope. (author) [pt

Inspection Robot Based Mobile Sensing and Power Line Tracking for Smart Grid.

Science.gov (United States)

Byambasuren, Bat-Erdene; Kim, Donghan; Oyun-Erdene, Mandakh; Bold, Chinguun; Yura, Jargalbaatar

2016-02-19

Smart sensing and power line tracking is very important in a smart grid system. Illegal electricity usage can be detected by remote current measurement on overhead power lines using an inspection robot. There is a need for accurate detection methods of illegal electricity usage. Stable and correct power line tracking is a very prominent issue. In order to correctly track and make accurate measurements, the swing path of a power line should be previously fitted and predicted by a mathematical function using an inspection robot. After this, the remote inspection robot can follow the power line and measure the current. This paper presents a new power line tracking method using parabolic and circle fitting algorithms for illegal electricity detection. We demonstrate the effectiveness of the proposed tracking method by simulation and experimental results.

A Mini-Review of Track And Field’s Talent-Identification Models in Iran and Some Designated Countries

OpenAIRE

Ebrahim Ghasemzadeh Mirkolaee; Seyed Mohammad Hossein Razavi; Saeed Amirnejad

2013-01-01

Talent identification and training the athletes of the basic levels in track and field requires codifying a proper model like any other system so that any duplication is prevented as well as knowing the right path. The federation of track and field started to codify the national talent-identification scheme in track and field in 1385. Hence, the present studies track-and-field talent-identification patterns in some designated countries and compare them with the codified pattern in Iran. The r...

Rotational error in path integration: encoding and execution errors in angle reproduction.

Science.gov (United States)

Chrastil, Elizabeth R; Warren, William H

2017-06-01

Path integration is fundamental to human navigation. When a navigator leaves home on a complex outbound path, they are able to keep track of their approximate position and orientation and return to their starting location on a direct homebound path. However, there are several sources of error during path integration. Previous research has focused almost exclusively on encoding error-the error in registering the outbound path in memory. Here, we also consider execution error-the error in the response, such as turning and walking a homebound trajectory. In two experiments conducted in ambulatory virtual environments, we examined the contribution of execution error to the rotational component of path integration using angle reproduction tasks. In the reproduction tasks, participants rotated once and then rotated again to face the original direction, either reproducing the initial turn or turning through the supplementary angle. One outstanding difficulty in disentangling encoding and execution error during a typical angle reproduction task is that as the encoding angle increases, so does the required response angle. In Experiment 1, we dissociated these two variables by asking participants to report each encoding angle using two different responses: by turning to walk on a path parallel to the initial facing direction in the same (reproduction) or opposite (supplementary angle) direction. In Experiment 2, participants reported the encoding angle by turning both rightward and leftward onto a path parallel to the initial facing direction, over a larger range of angles. The results suggest that execution error, not encoding error, is the predominant source of error in angular path integration. These findings also imply that the path integrator uses an intrinsic (action-scaled) rather than an extrinsic (objective) metric.

Synthesis method based on solution regions for planar four bar straight line linkages

International Nuclear Information System (INIS)

Lai Rong, Yin; Cong, Mao; Jian you, Han; Tong, Yang; Juan, Huang

2012-01-01

An analytical method for synthesizing and selecting desired four-bar straight line mechanisms based on solution regions is presented. Given two fixed pivots, the point position and direction of the target straight line, an infinite number of mechanism solutions can be produced by employing this method, both in the general case and all three special cases. Unifying the straight line direction and the displacement from the given point to the instant center into the same form with different angles as parameters, infinite mechanism solutions can be expressed with different solution region charts. The mechanism property graphs have been computed to enable the designers to find out the involved mechanism information more intuitively and avoid aimlessness in selecting optimal mechanisms

A new straight accelerator tube with U diaphragm

International Nuclear Information System (INIS)

Liu Jinhong; Lai Weiquan; Deng Yushen; Zhang Jidong

1994-01-01

After calculating the potential distribution and the particle trajectories in electrostatic accelerator tubes, a new straight tube with U diaphragm to suppress secondary particles is proposed. It's properties are demonstrated by the high voltage tests and the γ-rays measurements in the accelerator

Pattern Classification of Tropical Cyclone Tracks over the Western North Pacific using a Fuzzy Clustering Method

Science.gov (United States)

Kim, H.; Ho, C.; Kim, J.

2008-12-01

This study presents the pattern classification of tropical cyclone (TC) tracks over the western North Pacific (WNP) basin during the typhoon season (June through October) for 1965-2006 (total 42 years) using a fuzzy clustering method. After the fuzzy c-mean clustering algorithm to the TC trajectory interpolated into 20 segments of equivalent length, we divided the whole tracks into 7 patterns. The optimal number of the fuzzy cluster is determined by several validity measures. The classified TC track patterns represent quite different features in the recurving latitudes, genesis locations, and geographical pathways: TCs mainly forming in east-northern part of the WNP and striking Korean and Japan (C1); mainly forming in west-southern part of the WNP, traveling long pathway, and partly striking Japan (C2); mainly striking Taiwan and East China (C3); traveling near the east coast of Japan (C4); traveling the distant ocean east of Japan (C5); moving toward South China and Vietnam straightly (C6); and forming in the South China Sea (C7). Atmospheric environments related to each cluster show physically consistent with each TC track patterns. The straight track pattern is closely linked to a developed anticyclonic circulation to the north of the TC. It implies that this ridge acts as a steering flow forcing TCs to move to the northwest with a more west-oriented track. By contrast, recurving patterns occur commonly under the influence of the strong anomalous westerlies over the TC pathway but there definitely exist characteristic anomalous circulations over the mid- latitudes by pattern. Some clusters are closely related to the well-known large-scale phenomena. The C1 and C2 are highly related to the ENSO phase: The TCs in the C1 (C2) is more active during La Niña (El Niño). The TC activity in the C3 is associated with the WNP summer monsoon. The TCs in the C4 is more (less) vigorous during the easterly (westerly) phase of the stratospheric quasi-biennial oscillation

Morbidity Following Coloanal Anastomosis: A Comparison of Colonic J-Pouch vs Straight Anastomosis.

Science.gov (United States)

Brown, Shaun; Margolin, David A; Altom, Laura K; Green, Heather; Beck, David E; Kann, Brian R; Whitlow, Charles B; Vargas, Herschel David

2018-02-01

Low rectal tumors are often treated with sphincter-preserving resection followed by coloanal anastomosis. The purpose of this study was to compare the short-term complications following straight coloanal anastomosis vs colonic J-pouch anal anastomosis. Patients were identified who underwent proctectomy for rectal neoplasia followed by coloanal anastomosis in the 2008 to 2013 American College of Surgeons National Surgical Quality Improvement Program database. Demographic characteristics and 30-day postoperative complications were compared between groups. A national sample was extracted from the American College of Surgeons National Surgical Quality Improvement Project database. Inpatients following proctectomy and coloanal anastomosis for rectal cancer were selected. Demographic characteristics and 30-day postoperative complications were compared between the 2 groups. One thousand three hundred seventy patients were included, 624 in the straight anastomosis group and 746 in the colonic J-pouch group. Preoperative characteristics were similar between groups, with the exception of preoperative radiation therapy (straight anastomosis 35% vs colonic J-pouch 48%, p = 0.0004). Univariate analysis demonstrated that deep surgical site infection (3.7% vs 1.4%, p = 0.01), septic shock (2.25% vs 0.8%, p = 0.04), and return to the operating room (8.8% vs 5.0%, p = 0.0006) were more frequent in the straight anastomosis group vs the colonic J-pouch group. Major complications were also higher (23% vs 14%, p = 0.0001) and length of stay was longer in the straight anastomosis group vs the colonic J-pouch group (8.9 days vs 8.1 days, p = 0.02). After adjusting for covariates, major complications were less following colonic J-pouch vs straight anastomosis (OR, 0.57; CI, 0.38-0.84; p = 0.005). Subgroup analysis of patients who received preoperative radiation therapy demonstrated no difference in major complications between groups. This study had those limitations inherent to a

Comparison of Genetic Algorithm and Hill Climbing for Shortest Path Optimization Mapping

Directory of Open Access Journals (Sweden)

Fronita Mona

2018-01-01

Full Text Available Traveling Salesman Problem (TSP is an optimization to find the shortest path to reach several destinations in one trip without passing through the same city and back again to the early departure city, the process is applied to the delivery systems. This comparison is done using two methods, namely optimization genetic algorithm and hill climbing. Hill Climbing works by directly selecting a new path that is exchanged with the neighbour’s to get the track distance smaller than the previous track, without testing. Genetic algorithms depend on the input parameters, they are the number of population, the probability of crossover, mutation probability and the number of generations. To simplify the process of determining the shortest path supported by the development of software that uses the google map API. Tests carried out as much as 20 times with the number of city 8, 16, 24 and 32 to see which method is optimal in terms of distance and time computation. Based on experiments conducted with a number of cities 3, 4, 5 and 6 producing the same value and optimal distance for the genetic algorithm and hill climbing, the value of this distance begins to differ with the number of city 7. The overall results shows that these tests, hill climbing are more optimal to number of small cities and the number of cities over 30 optimized using genetic algorithms.

Efficiency and Privacy Enhancement for a Track and Trace System of RFID-Based Supply Chains

Directory of Open Access Journals (Sweden)

Xunjun Chen

2015-06-01

Full Text Available One of the major applications of Radio Frequency Identification (RFID technology is in supply chain management as it promises to provide real-time visibility based on the function of track and trace. However, such an RFID-based track and trace system raises new security and privacy challenges due to the restricted resource of tags. In this paper, we refine three privacy related models (i.e., the privacy, path unlinkability, and tag unlinkability of RFID-based track and trace systems, and clarify the relations among these privacy models. Specifically, we have proven that privacy is equivalent to path unlinkability and tag unlinkability implies privacy. Our results simplify the privacy concept and protocol design for RFID-based track and trace systems. Furthermore, we propose an efficient track and trace scheme, Tracker+, which allows for authentic and private identification of RFID-tagged objects in supply chains. In the Tracker+, no computational ability is required for tags, but only a few bytes of storage (such as EPC Class 1 Gen 2 tags are needed to store the tag state. Indeed, Tracker+ reduces the memory requirements for each tag by one group element compared to the Tracker presented in other literature. Moreover, Tracker+ provides privacy against supply chain inside attacks.

Hierarchical path planning and control of a small fixed-wing UAV: Theory and experimental validation

Science.gov (United States)

Jung, Dongwon

2007-12-01

problem is formulated by setting up geometric linear constraints as well as boundary conditions. Subsequently, we construct B-spline path templates by solving a set of distinct optimization problems. For application in UAV motion planning, the path templates are incorporated to replace parts of the entire path by the smooth B-spline paths. Each path segment is stitched together while preserving continuity to obtain a final smooth reference path to be used for path following control. The path following control for a small fixed-wing UAV to track the prescribed smooth reference path is also addressed. Assuming the UAV is equipped with an autopilot for low level control, we adopt a kinematic error model with respect to the moving Serret-Frenet frame attached to a path for tracking controller design. A kinematic path following control law that commands heading rate is presented. Backstepping is applied to derive the roll angle command by taking into account the approximate closed-loop roll dynamics. A parameter adaptation technique is employed to account for the inaccurate time constant of the closed-loop roll dynamics during actual implementation. Finally, we implement the proposed hierarchical path control of a small UAV on the actual hardware platform, which is based on an 1/5 scale R/C model airframe (Decathlon) and the autopilot hardware and software. Based on the hardware-in-the-loop (HIL) simulation environment, the proposed hierarchical path control algorithm has been validated through on-line, real-time implementation on a small micro-controller. By a seamless integration of the control algorithms for path planning, path smoothing, and path following, it has been demonstrated that the UAV equipped with a small autopilot having limited computational resources manages to accomplish the path control objective to reach the goal while avoiding obstacles with minimal human intervention.

Straight studs from southern pine veneer cores and cordwood

Science.gov (United States)

Peter Koch

1968-01-01

An economically feasible system has been developed for converting southern pine veneer cores into straight 8-foot studs (2). Prototype studs - two per core - were 100 percent SPIB stud grade and better.

Interactive navigation and bronchial tube tracking in virtual bronchoscopy.

Science.gov (United States)

Heng, P A; Fung, P F; Wong, T T; Siu, Y H; Sun, H

1999-01-01

An interactive virtual environment for simulation of bronchoscopy is developed. Medical doctor can safely plan their surgical bronchoscopy using the virtual environment without any invasive diagnosis which may risk the patient's health. The 3D pen input device of the system allows the doctor to navigate and visualize the bronchial tree of the patient naturally and interactively. To navigate the patient's bronchial tree, a vessel tracking process is required. While manual tracking is tedious and labor-intensive, fully automatic tracking may not be reliable. We propose a semi-automatic tracking technique called Intelligent Path Tracker which provides automation and enough user control during the vessel tracking. To support an interactive frame rate, we also introduce a new volume rendering acceleration technique, named as IsoRegion Leaping. The volume rendering is further accelerated by distributed rendering on a TCP/IP-based network of low-cost PCs. With these approaches, a 256 x 256 x 256 volume data of human lung, can be navigated and visualized at a frame rate of over 10 Hz in our virtual bronchoscopy system.

Calculation of gas Bremsstrahlung power from straight sections of storage ring at SSRF

International Nuclear Information System (INIS)

Hua Zhengdong; Xu Xunjiang; Fang Keming; Xu Jiaqiang

2008-01-01

The Shanghai Synchrotron Radiation Facility (SSRF) is a third-generation synchrotron radiation light source with 3.5 GeV in energy, which is composed of the linear accelerator, the booster and the storage ring. The storage ring provides 16 standard straight sections of 6.5 m and 4 long straight sections of 12 meters. Gas Bremsstrahlung (GB) produced by the interaction of the stored beam with the residual gas molecules in straight section, which is so intense and has a very small angular that the GB spectra, the GB power and the GB power distribution should be known. The characters of GB are studied by means of Fluka Monte Carlo code. Our result shows agreement with those obtained by the experiential formulae. (authors)

Inspection Robot Based Mobile Sensing and Power Line Tracking for Smart Grid

Directory of Open Access Journals (Sweden)

Bat-erdene Byambasuren

2016-02-01

Full Text Available Smart sensing and power line tracking is very important in a smart grid system. Illegal electricity usage can be detected by remote current measurement on overhead power lines using an inspection robot. There is a need for accurate detection methods of illegal electricity usage. Stable and correct power line tracking is a very prominent issue. In order to correctly track and make accurate measurements, the swing path of a power line should be previously fitted and predicted by a mathematical function using an inspection robot. After this, the remote inspection robot can follow the power line and measure the current. This paper presents a new power line tracking method using parabolic and circle fitting algorithms for illegal electricity detection. We demonstrate the effectiveness of the proposed tracking method by simulation and experimental results.

School Climate, Individual Support, or Both? Gay-Straight Alliances and the Mental Health of Sexual Minority Youth

Science.gov (United States)

Walls, N. Eugene; Wisneski, Hope; Kane, Sarah

2013-01-01

Using a sample of 284 sexual minority youth and young adults, this paper examines the relationships between mental health variables, the absence or presence of a gay-straight alliance, and membership status in a gay-straight alliance. The results suggest that the presence of a gay-straight alliance in a school or college, rather than actual…

Real-time markerless tracking for augmented reality: the virtual visual servoing framework.

Science.gov (United States)

Comport, Andrew I; Marchand, Eric; Pressigout, Muriel; Chaumette, François

2006-01-01

Tracking is a very important research subject in a real-time augmented reality context. The main requirements for trackers are high accuracy and little latency at a reasonable cost. In order to address these issues, a real-time, robust, and efficient 3D model-based tracking algorithm is proposed for a "video see through" monocular vision system. The tracking of objects in the scene amounts to calculating the pose between the camera and the objects. Virtual objects can then be projected into the scene using the pose. Here, nonlinear pose estimation is formulated by means of a virtual visual servoing approach. In this context, the derivation of point-to-curves interaction matrices are given for different 3D geometrical primitives including straight lines, circles, cylinders, and spheres. A local moving edges tracker is used in order to provide real-time tracking of points normal to the object contours. Robustness is obtained by integrating an M-estimator into the visual control law via an iteratively reweighted least squares implementation. This approach is then extended to address the 3D model-free augmented reality problem. The method presented in this paper has been validated on several complex image sequences including outdoor environments. Results show the method to be robust to occlusion, changes in illumination, and mistracking.

Optical track width measurements below 100 nm using artificial neural networks

Science.gov (United States)

Smith, R. J.; See, C. W.; Somekh, M. G.; Yacoot, A.; Choi, E.

2005-12-01

This paper discusses the feasibility of using artificial neural networks (ANNs), together with a high precision scanning optical profiler, to measure very fine track widths that are considerably below the conventional diffraction limit of a conventional optical microscope. The ANN is trained using optical profiles obtained from tracks of known widths, the network is then assessed by applying it to test profiles. The optical profiler is an ultra-stable common path scanning interferometer, which provides extremely precise surface measurements. Preliminary results, obtained with a 0.3 NA objective lens and a laser wavelength of 633 nm, show that the system is capable of measuring a 50 nm track width, with a standard deviation less than 4 nm.

A Straight-Talk Survival Guide for Colleges

Science.gov (United States)

Facione, Peter A.

2009-01-01

Times are very tough. The great majority of colleges are looking at 2009 and 2010 and beyond, in anticipation of the deepest budget cuts in more than a generation. But as bad as the financial situation may be, colleges can survive if they take swift and strong emergency action. It is time for some straight talk, starting with the realization that…

Excitation of Structures Near Railway Tracks-Analysis of the Wave Propagation Path

DEFF Research Database (Denmark)

Bucinskas, Paulius; Andersen, Lars Vabbersgaard

2017-01-01

High-speed rails are an attractive alternative to other forms of intercity transportation. It is a fast, cost-efficient and environmentally friendly solution, which is being developed in various countries across the world. However, in order to be successful, high-speed rails need to transport...... trains. Unfortunately, the prediction of vibrations in nearby structures is difficult, as wave propagation from the vibration source to the structure is a complex phenomenon. The behaviour of the structure is highly dependent on the path along which the vibrations travel between their source...

A collaborative network middleware project by Lambda Station, TeraPaths, and Phoebus

International Nuclear Information System (INIS)

Bobyshev, A.; Bradley, S.; Crawford, M.; DeMar, P.; Katramatos, D.; Shroff, K.; Swany, M.; Yu, D.

2010-01-01

The TeraPaths, Lambda Station, and Phoebus projects, funded by the US Department of Energy, have successfully developed network middleware services that establish on-demand and manage true end-to-end, Quality-of-Service (QoS) aware, virtual network paths across multiple administrative network domains, select network paths and gracefully reroute traffic over these dynamic paths, and streamline traffic between packet and circuit networks using transparent gateways. These services improve network QoS and performance for applications, playing a critical role in the effective use of emerging dynamic circuit network services. They provide interfaces to applications, such as dCache SRM, translate network service requests into network device configurations, and coordinate with each other to setup up end-to-end network paths. The End Site Control Plane Subsystem (ESCPS) builds upon the success of the three projects by combining their individual capabilities into the next generation of network middleware. ESCPS addresses challenges such as cross-domain control plane signalling and interoperability, authentication and authorization in a Grid environment, topology discovery, and dynamic status tracking. The new network middleware will take full advantage of the perfSONAR monitoring infrastructure and the Inter-Domain Control plane efforts and will be deployed and fully vetted in the Large Hadron Collider data movement environment.

A Novel Real-Time Path Servo Control of a Hardware-in-the-Loop for a Large-Stroke Asymmetric Rod-Less Pneumatic System under Variable Loads

Directory of Open Access Journals (Sweden)

Hao-Ting Lin

2017-06-01

Full Text Available This project aims to develop a novel large stroke asymmetric pneumatic servo system of a hardware-in-the-loop for path tracking control under variable loads based on the MATLAB Simulink real-time system. High pressure compressed air provided by the air compressor is utilized for the pneumatic proportional servo valve to drive the large stroke asymmetric rod-less pneumatic actuator. Due to the pressure differences between two chambers, the pneumatic actuator will operate. The highly nonlinear mathematical models of the large stroke asymmetric pneumatic system were analyzed and developed. The functional approximation technique based on the sliding mode controller (FASC is developed as a controller to solve the uncertain time-varying nonlinear system. The MATLAB Simulink real-time system was a main control unit of a hardware-in-the-loop system proposed to establish driver blocks for analog and digital I/O, a linear encoder, a CPU and a large stroke asymmetric pneumatic rod-less system. By the position sensor, the position signals of the cylinder will be measured immediately. The measured signals will be viewed as the feedback signals of the pneumatic servo system for the study of real-time positioning control and path tracking control. Finally, real-time control of a large stroke asymmetric pneumatic servo system with measuring system, a large stroke asymmetric pneumatic servo system, data acquisition system and the control strategy software will be implemented. Thus, upgrading the high position precision and the trajectory tracking performance of the large stroke asymmetric pneumatic servo system will be realized to promote the high position precision and path tracking capability. Experimental results show that fifth order paths in various strokes and the sine wave path are successfully implemented in the test rig. Also, results of variable loads under the different angle were implemented experimentally.

A Novel Real-Time Path Servo Control of a Hardware-in-the-Loop for a Large-Stroke Asymmetric Rod-Less Pneumatic System under Variable Loads.

Science.gov (United States)

Lin, Hao-Ting

2017-06-04

This project aims to develop a novel large stroke asymmetric pneumatic servo system of a hardware-in-the-loop for path tracking control under variable loads based on the MATLAB Simulink real-time system. High pressure compressed air provided by the air compressor is utilized for the pneumatic proportional servo valve to drive the large stroke asymmetric rod-less pneumatic actuator. Due to the pressure differences between two chambers, the pneumatic actuator will operate. The highly nonlinear mathematical models of the large stroke asymmetric pneumatic system were analyzed and developed. The functional approximation technique based on the sliding mode controller (FASC) is developed as a controller to solve the uncertain time-varying nonlinear system. The MATLAB Simulink real-time system was a main control unit of a hardware-in-the-loop system proposed to establish driver blocks for analog and digital I/O, a linear encoder, a CPU and a large stroke asymmetric pneumatic rod-less system. By the position sensor, the position signals of the cylinder will be measured immediately. The measured signals will be viewed as the feedback signals of the pneumatic servo system for the study of real-time positioning control and path tracking control. Finally, real-time control of a large stroke asymmetric pneumatic servo system with measuring system, a large stroke asymmetric pneumatic servo system, data acquisition system and the control strategy software will be implemented. Thus, upgrading the high position precision and the trajectory tracking performance of the large stroke asymmetric pneumatic servo system will be realized to promote the high position precision and path tracking capability. Experimental results show that fifth order paths in various strokes and the sine wave path are successfully implemented in the test rig. Also, results of variable loads under the different angle were implemented experimentally.

Making a Home in the Taiga: Movements, Paths and Signs among Orochen-Evenki Hunters and Herders of Zabaikal Krai (South East Siberia

Directory of Open Access Journals (Sweden)

Donatas Brandišauskas

2012-06-01

Full Text Available In this article, I will explore interrelations between place making, movement, use of paths and signs among the Orochen of Zabaikal Krai (Province. Although under the Russian Tsars Orochen-Evenki hunters and herders were referred to negatively as wanderers; today my ethnography demonstrates how movements of animals and humans are crucial for the success of their subsistence, place making and worldview. Hence, walking in the taiga is an important skill that is essential to hunting and herding activities when humans strive to identify animals' 'living places' (Orochen bikit by reading their tracks and movements. Humans also leave their own tracks and paths as well as signs communicating with each other while subsisting in remote areas, in this way creating their own living places. Thereby, I show how movements and the use of paths is an important dimension of Orochen-Evenki wellbeing as well as their moral code.

Investigation into the limitations of straightness interferometers using a multisensor-based error separation method

Science.gov (United States)

Weichert, Christoph; Köchert, Paul; Schötka, Eugen; Flügge, Jens; Manske, Eberhard

2018-06-01

The uncertainty of a straightness interferometer is independent of the component used to introduce the divergence angle between the two probing beams, and is limited by three main error sources, which are linked to each other: their resolution, the influence of refractive index gradients and the topography of the straightness reflector. To identify the configuration with minimal uncertainties under laboratory conditions, a fully fibre-coupled heterodyne interferometer was successively equipped with three different wedge prisms, resulting in three different divergence angles (4°, 8° and 20°). To separate the error sources an independent reference with a smaller reproducibility is needed. Therefore, the straightness measurement capability of the Nanometer Comparator, based on a multisensor error separation method, was improved to provide measurements with a reproducibility of 0.2 nm. The comparison results revealed that the influence of the refractive index gradients of air did not increase with interspaces between the probing beams of more than 11.3 mm. Therefore, over a movement range of 220 mm, the lowest uncertainty was achieved with the largest divergence angle. The dominant uncertainty contribution arose from the mirror topography, which was additionally determined with a Fizeau interferometer. The measured topography agreed within  ±1.3 nm with the systematic deviations revealed in the straightness comparison, resulting in an uncertainty contribution of 2.6 nm for the straightness interferometer.

49 CFR 238.119 - Rim-stamped straight-plate wheels.

Science.gov (United States)

2010-10-01

... input to the wheel during braking. (b) A rim-stamped straight-plate wheel shall not be used as a... that is periodically tread-braked for a short duration by automatic circuitry for the sole purpose of...

Path Dependency

OpenAIRE

Mark Setterfield

2015-01-01

Path dependency is defined, and three different specific concepts of path dependency – cumulative causation, lock in, and hysteresis – are analyzed. The relationships between path dependency and equilibrium, and path dependency and fundamental uncertainty are also discussed. Finally, a typology of dynamical systems is developed to clarify these relationships.

Setting the Record Straight on "High-Yield" Strategies

Science.gov (United States)

Marzano, Robert J.

2009-01-01

Widely credited with proposing nine "high-yield" instructional strategies, author Robert J. Marzano sets the record straight about the broader number of strategies identified by the research. He provides a list of 41 strategies and suggests more nuanced ways of using, observing, and evaluating them. (Contains 1 figure.)

Steam cracking of hydrocarbons 3. Straight-run naphtha

NARCIS (Netherlands)

Bajus, M.; Vesely, V.; Leclercq, P.A.; Rijks, J.A.

1980-01-01

Steam cracking of straight-run naphtha from Romashkino crude oil was investigated in quartz and stainless steel reactors with a relatively large ratio of Inner surface to volume. The experiments were performed at atmospheric pressure at 780-800 OC for starting ratios of steam to naphtha between 0.5

Remote removal of an obstruction from FFTF [Fast Flux Test Facility] in-service inspection camera track

International Nuclear Information System (INIS)

Gibbons, P.W.

1990-11-01

Remote techniques and special equipment were used to clear the path of a closed-circuit television camera system that travels on a monorail track around the reactor vessel support arm structure. A tangle of wire-wrapped instrumentation tubing had been inadvertently inserted through a dislocated guide-tube expansion joint and into the camera track area. An externally driven auger device, mounted on the track ahead of the camera to view the procedure, was used to retrieve the tubing. 6 figs

Tracking the Career Paths of Physics Teachers in Texas

Science.gov (United States)

Mount, Jennifer; Marshall, Jill; Fuller, Edward

2013-10-01

In Texas, and some other states, there is a documented shortage of physics teachers, in terms of both number and qualifications. The shortage in Texas is due as much to teachers leaving the field (attrition) as to a lack of teachers entering. There are efforts under way to prepare more and better-qualified physics teachers who will stay in the field longer,2 but increasing the overall supply and retention will not necessarily address localized teacher shortages. To investigate this issue, we obtained a database cataloging every teacher who taught science in Texas public schools from 2003 to 2008, indicating the school where they taught during each of those years, the subjects they taught, and their route to certification. This allowed us to track not only teachers entering and leaving the public school system, but also migration between schools within the system. We found that migration poses a much bigger problem than attrition for some schools. We also found patterns in the movement of physics teachers in Texas that we would not necessarily have predicted and that varied substantially depending on certification.

Manufacture of the straight section chambers for the SPring-8 storage ring

International Nuclear Information System (INIS)

Watanabe, K.; Saeki, H.; Sakaue, H.; Ohkuma, H.; Be, S.H.; Oishi, M.; Tuchiya, M.; Nishidono, T.

1995-01-01

To carry out the performance test of the vacuum system, we manufactured three different straight section chambers prior to the manufacture of the 48 cell full scale vacuum systems. One of three straight section chambers contains only downstream end absorber, while the other two contain a downstream end absorber, upstream end bellows and a photon beam extraction duct. In this paper, the manufacture of these chambers and their assemblies are described in detail. (author). 1 ref., 3 figs., 3 tabs

Construction of a WMR for Trajectory Tracking Control: Experimental Results

Directory of Open Access Journals (Sweden)

R. Silva-Ortigoza

2013-01-01

Full Text Available This paper reports a solution for trajectory tracking control of a differential drive wheeled mobile robot (WMR based on a hierarchical approach. The general design and construction of the WMR are described. The hierarchical controller proposed has two components: a high-level control and a low-level control. The high-level control law is based on an input-output linearization scheme for the robot kinematic model, which provides the desired angular velocity profiles that the WMR has to track in order to achieve the desired position (x*,y* and orientation (φ*. Then, a low-level control law, based on a proportional integral (PI approach, is designed to control the velocity of the WMR wheels to ensure those tracking features. Regarding the trajectories, this paper provides the solution or the following cases: (1 time-varying parametric trajectories such as straight lines and parabolas and (2 smooth curves fitted by cubic splines which are generated by the desired data points x1*,y1*,…,xn*,yn*. A straightforward algorithm is developed for constructing the cubic splines. Finally, this paper includes an experimental validation of the proposed technique by employing a DS1104 dSPACE electronic board along with MATLAB/Simulink software.

FIXTURING DEVICE FOR DRILLING A STRAIGHT SHAFT

Directory of Open Access Journals (Sweden)

SUSAC, Florin

2017-05-01

Full Text Available The paper presents a fixturing device used for machining by drilling a straight shaft. The shaft was manufactured on EMCO CONCEPT TURN 55 CNC. The blank used was a bar with circular cross-section. The orientation and fixing scheme of the part and the orientation elements for fixturing device are presented as they were drawn in Autodesk Inventor and AutoCAD software.

"Appearance potent"? A content analysis of UK gay and straight men's magazines.

Science.gov (United States)

Jankowski, Glen S; Fawkner, Helen; Slater, Amy; Tiggemann, Marika

2014-09-01

With little actual appraisal, a more 'appearance potent' (i.e., a reverence for appearance ideals) subculture has been used to explain gay men's greater body dissatisfaction in comparison to straight men's. This study sought to assess the respective appearance potency of each subculture by a content analysis of 32 issues of the most read gay (Attitude, Gay Times) and straight men's magazines (Men's Health, FHM) in the UK. Images of men and women were coded for their physical characteristics, objectification and nudity, as were the number of appearance adverts and articles. The gay men's magazines featured more images of men that were appearance ideal, nude and sexualized than the straight men's magazines. The converse was true for the images of women and appearance adverts. Although more research is needed to understand the effect of this content on the viewer, the findings are consistent with a more appearance potent gay male subculture. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Fluorescent detection of single tracks of alpha particles using lithium fluoride crystals

International Nuclear Information System (INIS)

Bilski, P.; Marczewska, B.

2017-01-01

Lithium fluoride single crystals were successfully used for fluorescent imaging of single tracks of alpha particles. This was realized with a standard wide-field fluorescent microscope equipped with a 100× objective. Alpha particles create F_2 and F_3"+ color centers in LiF crystals. The subsequent illumination with the blue light (wavelength around 445 nm), excites these centers and produces fluorescence with a broad band peaked at 670 nm. The observed tracks of alpha particles have diameter of about 500 nm. Focusing of the microscope at different depths in a LiF crystal, enables imaging changes of shape and position of tracks, allowing for visualization of their paths. These encouraging results are the first step towards practical application of LiF as fluorescent nuclear track detectors.

Integrals over products of distributions and coordinate independence of zero-temperature path integrals

International Nuclear Information System (INIS)

Kleinert, H.; Chervyakov, A.

2003-01-01

In perturbative calculations of quantum-statistical zero-temperature path integrals in curvilinear coordinates one encounters Feynman diagrams involving multiple temporal integrals over products of distributions, which are mathematically undefined. In addition, there are terms proportional to powers of Dirac δ-functions at the origin coming from the measure of path integration. We give simple rules for integrating products of distributions in such a way that the results ensure coordinate independence of the path integrals. The rules are derived by using equations of motion and partial integration, while keeping track of certain minimal features originating in the unique definition of all singular integrals in 1-ε dimensions. Our rules yield the same results as the much more cumbersome calculations in 1-ε dimensions where the limit ε→0 is taken at the end. They also agree with the rules found in an independent treatment on a finite time interval

Quivers of Bound Path Algebras and Bound Path Coalgebras

Directory of Open Access Journals (Sweden)

Dr. Intan Muchtadi

2010-09-01

Full Text Available bras and coalgebras can be represented as quiver (directed graph, and from quiver we can construct algebras and coalgebras called path algebras and path coalgebras. In this paper we show that the quiver of a bound path coalgebra (resp. algebra is the dual quiver of its bound path algebra (resp. coalgebra.

Standing down Straight: Jump Rhythm Technique's Rhythm-Driven, Community-Directed Approach to Dance Education

Science.gov (United States)

Siegenfeld, Billy

2009-01-01

"Standing down straight" means to stand on two feet with both stability and relaxation. Using standing down straight as the foundation of class work, Jump Rhythm Technique offers a fresh alternative to conventional systems of dance study. It bases its pedagogy on three behaviors: grounding the body so that it can move with power and efficiency,…

Modeling plasma flow in straight and curved solenoids

International Nuclear Information System (INIS)

Boercker, D.B.; Sanders, D.M.; Storer, J.; Falabella, S.

1991-01-01

The ''flux-tube'' model originated by Morozov is a very simple and numerically efficient method for simulating ion motion in plasma filters. In order to test its utility as a design tool, we compare the predictions of the model to recent experimental measurements of plasma flow in both straight and curved solenoids

Novel high accurate sensorless dual-axis solar tracking system controlled by maximum power point tracking unit of photovoltaic systems

International Nuclear Information System (INIS)

Fathabadi, Hassan

2016-01-01

Highlights: • Novel high accurate sensorless dual-axis solar tracker. • It has the advantages of both sensor based and sensorless solar trackers. • It does not have the disadvantages of sensor based and sensorless solar trackers. • Tracking error of only 0.11° that is less than the tracking errors of others. • An increase of 28.8–43.6% depending on the seasons in the energy efficiency. - Abstract: In this study, a novel high accurate sensorless dual-axis solar tracker controlled by the maximum power point tracking unit available in almost all photovoltaic systems is proposed. The maximum power point tracking controller continuously calculates the maximum output power of the photovoltaic module/panel/array, and uses the altitude and azimuth angles deviations to track the sun direction where the greatest value of the maximum output power is extracted. Unlike all other sensorless solar trackers, the proposed solar tracking system is a closed loop system which means it uses the actual direction of the sun at any time to track the sun direction, and this is the contribution of this work. The proposed solar tracker has the advantages of both sensor based and sensorless dual-axis solar trackers, but it does not have their disadvantages. Other sensorless solar trackers all are open loop, i.e., they use offline estimated data about the sun path in the sky obtained from solar map equations, so low exactness, cloudy sky, and requiring new data for new location are their problems. A photovoltaic system has been built, and it is experimentally verified that the proposed solar tracking system tracks the sun direction with the tracking error of 0.11° which is less than the tracking errors of other both sensor based and sensorless solar trackers. An increase of 28.8–43.6% depending on the seasons in the energy efficiency is the main advantage of utilizing the proposed solar tracking system.

Tracking Electromagnetic Energy With SQUIDs

Science.gov (United States)

2005-01-01

A superconducting quantum interference device (SQUID) is a gadget used to measure extremely weak signals, specifically magnetic flux. It can detect subtle changes in energy, up to 100 billion times weaker than the electromagnetic energy required to move a compass needle. SQUIDs are used for a variety of testing procedures where extreme sensitivity is required and where the test instrument need not come into direct contact with the test subject. NASA uses SQUIDs for remote, noncontact sensing in a variety of venues, including monitoring the Earth s magnetic field and tracking brain activity of pilots. Scientists at NASA s Goddard Space Flight Center have been making extensive use of this technology, from astrophysical research, to tracking the navigational paths of bees in flight to determine if they are using internal compasses. These very sensitive measurement devices have a wide variety of uses within NASA and even more uses within the commercial realm.

Straight chiropractic philosophy as a barrier to Medicare compliance: a discussion of 5 incongruent issues.

Science.gov (United States)

Seaman, David R; Soltys, Jonathan R

2013-12-01

The purpose of this commentary is to discuss potential 5 factors within straight chiropractic philosophy and practice that may prevent Medicare compliance. The national Medicare Benefit Policy Manual and the Florida Local Coverage Determination were reviewed to identify documentation and conceptual issues regarding chiropractic practice. Five Medicare positions were contrasted with tenets of straight chiropractic philosophy. Based on Medicare's documentation requirements, Medicare defines subluxation and chiropractic practice from the perspective of treating spinal pain and related functional disability. In contrast, traditional straight chiropractic philosophy is not based on the treatment of spinal pain and disability or other symptomatic presentations. In this context, 5 potential areas of conflict are discussed. The Medicare version of chiropractic practice is not consistent with traditional straight chiropractic philosophy, which may play a role in preventing Medicare compliance. The chiropractic profession may need to consider the fashion in which "philosophy" as it relates to technique and practice is presented to students and doctors to facilitate compliance with the documentation requirements of Medicare.

Tracking strategy for photovoltaic solar systems in high latitudes

International Nuclear Information System (INIS)

Quesada, Guillermo; Guillon, Laura; Rousse, Daniel R.; Mehrtash, Mostafa; Dutil, Yvan; Paradis, Pierre-Luc

2015-01-01

Highlights: • In cloudy conditions tracking the sun is ineffective. • A methodology to estimate a theoretical threshold for solar tracking was developed. • A tracking strategy to maximize electricity production was proposed. - Abstract: Several studies show that from about 20% to 50% more solar energy can be recovered by using photovoltaic systems that track the sun rather than systems set at a fixed angle. For overcast or cloudy days, recent studies propose the use of a set position in which each photovoltaic panel faces toward the zenith (horizontal position). Compared to a panel that follows the sun’s path, this approach claims that a horizontal panel increases the amount of solar radiation captured and subsequently the quantity of electricity produced. The present work assesses a solar tracking photovoltaic panel hourly and seasonally in high latitudes. A theoretical method based on an isotropic sky model was formulated, implemented, and used in a case study analysis of a grid-connected photovoltaic system in Montreal, Canada. The results obtained, based on the definition of a critical hourly global solar radiation, were validated numerically and experimentally. The study confirmed that a zenith-set sun tracking strategy for overcast or mostly cloudy days in summer is not advantageous

Status of PF-ring commissioning after the reconstruction for the straight-sections upgrade

International Nuclear Information System (INIS)

Tanimoto, Yasunori; Miyauchi, Hiroshi; Honda, Tohru; Kobayashi, Yukinori

2006-01-01

The upgrade project of the straight sections at the PF-ring enables the reinforcement of insertion devices and their beamlines. As a main part of this project, a large-scale reconstruction of the storage ring was carried out from March to September in 2005. The lattice configuration was modified to create short straight sections of 1.4 m and to extend the existing straight sections. Optical functions of the short sections were optimized for short-gap mini-pole undulators as X-ray sources. The first mini-pole undulator SGU no.17 has been operated for a protein crystallography. A recommissioning of the ring was conducted for about one month, and user experiments were restarted on 18th October 2005 according to schedule. The recovery of the beam lifetime due to the process of the vacuum scrubbing has been favorably progressed. (author)

[The peculiar morphological features of the imprints of straight and wavy head hair dirtied with blood].

Science.gov (United States)

Leonova, E N; Nagornov, M N; Prokhorenko, A S

2018-01-01

The objective of the present study was to elucidate the specific morphological features of the imprints of blood-soaked straight and wavy head hair. The contact imprints of straight and wavy head hair dirtied with blood were obtained experimentally. The imprints of straight hair were shown to exhibit the elements in the form of the rectilinear and bow-shaped slightly bent stripes. The imprints of wavy hair were shaped as the arches, waves, circles, and a large number of various small elements, such as dashes and commas.

Subjective Straight Ahead Orientation in Microgravity

Science.gov (United States)

Clement, G.; Reschke, M. F.; Wood, S. J.

2015-01-01

This joint ESA NASA study will address adaptive changes in spatial orientation related to the subjective straight ahead and the use of a vibrotactile sensory aid to reduce perceptual errors. The study will be conducted before and after long-duration expeditions to the International Space Station (ISS) to examine how spatial processing of target location is altered following exposure to microgravity. This study addresses the sensorimotor research gap to "determine the changes in sensorimotor function over the course of a mission and during recovery after landing."

The distribution of intergranular gaps along α tracks recorded in ionographic emulsions

International Nuclear Information System (INIS)

Wittendorp-Rechenmann, E.; Senger, B.; Koziel-Vigneron, V.; Rechenmann, R.V.

1990-01-01

Detailed microscopic analyses performed at high statistics (size: 1100) on 8.776 MeV α tracks materialised in nuclear emulsion demonstrated a distribution of intergranular gaps along the primary ion's path that was not only non-random but also fluctuated significantly with the energy of the projectile. The highest and lowest gap frequencies measured correspond to the energy region of 0.7 - 1.5 MeV and 7 MeV, respectively. The gap length distributions followed an exponential law, a known characteristic of the intergranular gaps distributed along the tracks of high energy charged particles. A tentative interpretation of these observations has been undertaken in terms of spatial distributions of δ rays around the incoming ion's path, by applying the Double-Differential Cross-Section Mixed Treatment to the geometrical configuration of the AgBr microcrystals embedded in the gelatin matrix. At this preliminary stage of our modelling, the main experimental data could already be reproduced satisfactorily. (author)

Study on an Undershot Cross-Flow Water Turbine with Straight Blades

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Yasuyuki Nishi

2015-01-01

Full Text Available Small-scale hydroelectric power generation has recently attracted considerable attention. The authors previously proposed an undershot cross-flow water turbine with a very low head suitable for application to open channels. The water turbine was of a cross-flow type and could be used in open channels with the undershot method, remarkably simplifying its design by eliminating guide vanes and the casing. The water turbine was fitted with curved blades (such as the runners of a typical cross-flow water turbine installed in tube channels. However, there was ambiguity as to how the blades’ shape influenced the turbine’s performance and flow field. To resolve this issue, the present study applies straight blades to an undershot cross-flow water turbine and examines the performance and flow field via experiments and numerical analyses. Results reveal that the output power and the turbine efficiency of the Straight Blades runner were greater than those of the Curved Blades runner regardless of the rotational speed. Compared with the Curved Blades runner, the output power and the turbine efficiency of the Straight Blades runner were improved by about 31.7% and about 67.1%, respectively.

Ted Irving and the Arc of APW Paths

Science.gov (United States)

Kent, D. V.

2014-12-01

Ted Irving's last two published papers neatly encapsulate his seminal contributions to the delineation of ever-important apparent polar wander (APW) paths. His final (210th) paper [Creer & Irving, 2012 Earth Sciences History] describes in detail how Ken Creer and he when still graduate students at Cambridge started to generate and assemble paleomagnetic data for the first APW path, for then only the UK; the paper was published 60 years ago and happened to be Ted's first [Creer, Irving & Runcorn, 1954 JGE]. Only 10 years later, there was already a lengthy reference list of paleomagnetic results available from most continents that had been compiled in pole lists he published in GJRAS from 1960 to 1965 and included in an appendix in his landmark book "Paleomagnetism" [Irving, 1964 Wiley] in support of wide ranging discussions of continental drift and related topics in chapters like 'Paleolatitudes and paleomeridians.' A subsequent innovation was calculating running means of poles indexed to a numerical geologic time scale [Irving, 1977 Nature], which with independent tectonic reconstructions as already for Gondwana allowed constructions of more detailed composite APW paths. His 1977 paper also coined Pangea B for an earlier albeit contentious configuration for the supercontinent that refuses to go away. Gliding over much work on APW tracks and hairpins in the Precambrian, we come to Ted's penultimate (209th) paper [Kent & Irving, 2010 JGR] in which individual poles from short-lived large igneous provinces were grouped and most sedimentary poles, many rather venerable, excluded as likely to be biased by variable degrees of inclination error. The leaner composite APW path helped to resurrect the Baja BC scenario of Cordilleran terrane motions virtually stopped in the 1980s by APW path techniques that relied on a few key but alas often badly skewed poles. The new composite APW path also revealed several major features, such as a huge polar shift of 30° in 15 Myr in the

Radiographic comparison of apical root resorption after orthodontic treatment between bidimensional and Roth straight-wire techniques.

Science.gov (United States)

Zawawi, Khalid H; Malki, Ghadah A

2014-10-01

The aim of this study was to compare the amount of root resorption after orthodontic treatment between the bidimensional and the Roth straight-wire techniques. Another objective was to compare the amount of root resorption in the whole sample studied and record the prevalence of root resorption. The sample consisted of 40 patients (age ranged between 11 and 18 years) with Angle Class II division 1 malocclusions, treated nonextraction. Twenty patients were treated with bidimensional technique and 20 with a 0.018-inch Roth straight-wire technique. Root lengths of the maxillary incisors were measured on pre- and post-treatment periapical radiographs. The results demonstrated that the bidimensional and Roth straight-wire groups showed significant root resorption after treatment, 1.11 (0.17) and 0.86 (0.05), respectively, P root shortening between the bidimensional and Roth straight-wire groups, there was no significant difference between the mean change from pre- to post-treatment between bidimensional group (mean = 1.00 ± 1.34) and Roth straight-wire group (mean = 0.88 ± 0.86), P = 0.63. Considering the whole sample, there was no root resoprtion in 32.5% of the analysed teeth. There was only mild resorption in 56.2%, moderate in 8.8% and severe in only 2.5% of the teeth. Treatment with the bidimensional technique did not produce an increase in the amount of root resorption. The prevalence and amount of root resorption was similar between bidimensional and Roth straight-wire techniques.

Cubic systems with invariant affine straight lines of total parallel multiplicity seven

Directory of Open Access Journals (Sweden)

Alexandru Suba

2013-12-01

Full Text Available In this article, we study the planar cubic differential systems with invariant affine straight lines of total parallel multiplicity seven. We classify these system according to their geometric properties encoded in the configurations of invariant straight lines. We show that there are only 17 different topological phase portraits in the Poincar\\'e disc associated to this family of cubic systems up to a reversal of the sense of their orbits, and we provide representatives of every class modulo an affine change of variables and rescaling of the time variable.

Monte Carlo charged-particle tracking and energy deposition on a Lagrangian mesh.

Science.gov (United States)

Yuan, J; Moses, G A; McKenty, P W

2005-10-01

A Monte Carlo algorithm for alpha particle tracking and energy deposition on a cylindrical computational mesh in a Lagrangian hydrodynamics code used for inertial confinement fusion (ICF) simulations is presented. The straight line approximation is used to follow propagation of "Monte Carlo particles" which represent collections of alpha particles generated from thermonuclear deuterium-tritium (DT) reactions. Energy deposition in the plasma is modeled by the continuous slowing down approximation. The scheme addresses various aspects arising in the coupling of Monte Carlo tracking with Lagrangian hydrodynamics; such as non-orthogonal severely distorted mesh cells, particle relocation on the moving mesh and particle relocation after rezoning. A comparison with the flux-limited multi-group diffusion transport method is presented for a polar direct drive target design for the National Ignition Facility. Simulations show the Monte Carlo transport method predicts about earlier ignition than predicted by the diffusion method, and generates higher hot spot temperature. Nearly linear speed-up is achieved for multi-processor parallel simulations.

Assessment of the pseudo-tracking approach for the calculation of material acceleration and pressure fields from time-resolved PIV: part I. Error propagation

Science.gov (United States)

van Gent, P. L.; Schrijer, F. F. J.; van Oudheusden, B. W.

2018-04-01

Pseudo-tracking refers to the construction of imaginary particle paths from PIV velocity fields and the subsequent estimation of the particle (material) acceleration. In view of the variety of existing and possible alternative ways to perform the pseudo-tracking method, it is not straightforward to select a suitable combination of numerical procedures for its implementation. To address this situation, this paper extends the theoretical framework for the approach. The developed theory is verified by applying various implementations of pseudo-tracking to a simulated PIV experiment. The findings of the investigations allow us to formulate the following insights and practical recommendations: (1) the velocity errors along the imaginary particle track are primarily a function of velocity measurement errors and spatial velocity gradients; (2) the particle path may best be calculated with second-order accurate numerical procedures while ensuring that the CFL condition is met; (3) least-square fitting of a first-order polynomial is a suitable method to estimate the material acceleration from the track; and (4) a suitable track length may be selected on the basis of the variation in material acceleration with track length.

Dynamic Behavior of a SCARA Robot by using N-E Method for a Straight Line and Simulation of Motion by using Solidworks and Verification by Matlab/Simulink

Directory of Open Access Journals (Sweden)

Fernini Brahim

2014-05-01

Full Text Available SCARA (Selective Compliant Assembly Robot Arm robot of serial architecture is widely used in assembly operations and operations "pick-place", it has been shown that use of robots improves the accuracy of assembly, and saves assembly time and cost as well. The most important condition for the choice of this kind of robot is the dynamic behavior for a given path, no closed solution for the dynamics of this important robot has been reported. This paper presents the study of the kinematics (forward and inverse by using D-H notation and the dynamics of SCARA robot by using N-E methods. A computer code is developed for trajectory generation by using inverse kinematics, and calculates the variations of the torques of the links for a straight line (path rest to rest between two positions for operation "pick-place". SCARA robot is constructed to achieve “pick-place» operation using SolidWorks software. And verification by Matlab/Simulink. The results of simulations were discussed. An agreement between the two softwares is certainly obtained herein

Swan-neck versus straight peritoneal dialysis catheter: Long-term effect on patient and method survival.

Science.gov (United States)

Filiopoulos, V; Biblaki, D; Takouli, L; Dounavis, A; Hadjiyannakos, D; Vlassopoulos, D

2016-09-01

Peritoneal dialysis (PD) is limited mainly by a higher technique failure rate as compared to hemodialysis (HD), catheter malfunction being an important reason. Intra- and extra-peritoneal catheter configuration may be associated with mechanical and infectious complications affecting method survival. We report our experience with two extra-peritoneal catheter configurations: the straight and the swan-neck (SN) catheters. A total of 85 consecutive patients, 58 males and 27 females were included in the study. Among them, 26 were diabetics; 52 were treated with automated PD (APD) and 33 with continuous ambulatory PD (CAPD). Straight catheters were used in 38 patients (straight group) and SN catheters in 47 patients (SN group). Straight catheters were mostly used in the first 6-year period while SN catheters in the last 6-year period. The baseline demographics were similar between the two groups. A significantly higher frequency of APD use was observed in SN group. Technique survival was better with SN versus straight (log-rank test, P = 0.01) while patient and catheter survival were similar. A better technique survival is noted in our group of patients with SN catheters. An additional factor could be the significantly higher frequency of APD use in this group. Changes in PD solutions' composition could also contribute to improvement in technique survival. The outcome for patients and catheter types used was similar.

First straw straightness measurements on a 4-plane end-cap ATLAS TRT wheel

CERN Document Server

Lucotte, A; Mitsou, V A; Mouraviev, S V; Nadtochy, A

2001-01-01

This document reports the first results and their interpretation of the straw straightness measurements that have been performed on the first 4-plane end-cap prototype of the ATLAS TRT. Section 2 presents the experimental setup used for the measurements, as well as a review of the data sample used to perform this study. It also provides a description of the method used to assess straw straightness, which is based on the measurements of the maximal gas gain deviation (``straw eccentricity'') seen along the straw. Section 3 reports the results of straw straightness for the 4-plane module, including corrections due to the gas flow. The effect of energy resolution degradation is also explained and results in terms of wire offset are reported. In Section 4, the straw bending due to an applied lateral deformation is measured, and finally Section 5 reviews the conclusions.

Adaptive DFT-Based Interferometer Fringe Tracking

Science.gov (United States)

Wilson, Edward; Pedretti, Ettore; Bregman, Jesse; Mah, Robert W.; Traub, Wesley A.

2005-12-01

An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA) Observatory at Mount Hopkins, Arizona. The system can minimize the optical path differences (OPDs) for all three baselines of the Michelson stellar interferometer at IOTA. Based on sliding window discrete Fourier-transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on offline data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately [InlineEquation not available: see fulltext.] milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. The adaptive DFT-based tracking algorithm should be applicable to other systems where there is a need to detect or track a signal with an approximately constant-frequency carrier pulse. One example of such an application might be to the field of thin-film measurement by ellipsometry, using a broadband light source and a Fourier-transform spectrometer to detect the resulting fringe patterns.

Adaptive DFT-Based Interferometer Fringe Tracking

Directory of Open Access Journals (Sweden)

Wesley A. Traub

2005-09-01

Full Text Available An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA Observatory at Mount Hopkins, Arizona. The system can minimize the optical path differences (OPDs for all three baselines of the Michelson stellar interferometer at IOTA. Based on sliding window discrete Fourier-transform (DFT calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on offline data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms, using the science camera and piezo scanners to measure and correct the OPDs. The adaptive DFT-based tracking algorithm should be applicable to other systems where there is a need to detect or track a signal with an approximately constant-frequency carrier pulse. One example of such an application might be to the field of thin-film measurement by ellipsometry, using a broadband light source and a Fourier-transform spectrometer to detect the resulting fringe patterns.

Tetrahedron equations and the relativistic S-matrix of straight-strings in 2+1-dimensions

International Nuclear Information System (INIS)

Zamolodchikov, A.B.

1981-01-01

The quantum S-matrix theory of straight-strings (infinite one-dimensioanl objects like straight domain walls) in 2 + 1-dimensions is considered. The S-matrix is supposed to be purely elastic and factorized. The tetrahedron equations (which are the factorization conditions) are investigated for the special two-colour model. The relativistic three-string S-matrix, which apparently satisfies this tetrahedron equation, is proposed. (orig.)

Polygonal Area of Prosthesis Support with Straight and Tilted Dental Implants in Edentulous Maxillae.

Science.gov (United States)

Wentaschek, Stefan; Lehmann, Karl Martin; Scheller, Herbert; Weibrich, Gernot; Behneke, Nikolaus

2016-01-01

The aim of this in vitro study was to assess the increase in the polygonal area of implant-retained prosthesis supports in edentulous maxillae with the use of tilted distal implants compared with the use of straight distal implants, using a variety of implant lengths. A total of 25 DICOM datasets of atrophic edentulous maxillae were provided. Bone augmentations in the molar region had to be avoided. Two straight reference implants were virtually inserted in the anterior region. Two additional implants were placed far distally on both sides (4 groups: [1] straight, 12-mm length; [2] straight, 10 mm; [3] straight, 8 mm; [4] tilted, 12-16 mm). The resulting implant-supported polygon was measured for each of the 4 groups using three-dimensional planning software. The mean sagittal depth of the supported polygon in Group 1 was 9.9 mm (standard deviation [SD] 4.4) on the right and 10.2 mm (SD 4.4) on the left, and it was 33.7 mm (SD 5.8) in width. For Group 2, the mean sagittal depth was 11.5 mm (SD 5.0) on the right and 11.9 mm (SD 4.7) on the left, and the width was 35.2 mm (SD 5.6). The measurements for Group 3 were 13.8 mm (SD 4.9) deep on the right, 13.8 mm (SD 5.1) deep on the left, and 37.0 mm (SD 5.4) in width. For Group 4, the depth was 15.8 mm (SD 4.9) on the right and 16.4 mm (SD 5.8) on the left, and the width was 39.0 mm (SD 5.1). The area of implant-retained prosthesis support can be enlarged by the use of tilted implants (12 to 16 mm in length, 42 to 45 degrees) compared to the use of straight 8-mm implants (resulting increase: about 15%).

Comparison of Axillary Loop and Straight Grafts Patency and Their Complications for Hemodialylis Access

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J KHoshnevis

2011-08-01

Full Text Available Introduction & Objective: Dialysis vascular access complications are important causes of morbidity in chronic hemodialysis patients. The aim of the present study was a comparison of auxillary loop and atraight grafts patency and its complications for hemodialysis access. Materials & Methods: In this cohort study conducted at Shahid Beheshti Medical University, 58 patients who underwent placement of loop or straight access grafts were included in the study. Demographics, primary and secondary patency rates and complications like thrombosis, infection, bleeding, steal syndrome and other complications were compared in these two groups. The collected data was analyzed by the SPSS statistical software using the chi-square test, t-test, and logistic regression. Results: Thrombosis rates were 51.1% and 53.8% in straight and loop groups respectively (P=0.862, steal syndrome rates were 2.2% and 7.7% in straight and loop groups respectively (P=0.341, psudoanevrism were 11.1% and 23.1% in straight and loop groups respectively (P=0.270, bleeding rates were 4.4% and 0% in straight and loop groups respectively (P=0.439, infection rate were 8.9% and 7.7% in straight and loop groups respectively (P=0.892, and primary patency rate after 1 month were 88.9% and 92.3% respectively (P=0.721, and primary patency rate after 24 month were 31% and 55.5% respectively (P=0.058. Secondary patency rate after 3 month were 75.6% and 92.3% respectively (P=0.189, and secondary patency rate after 24 month were 37.9% and 66.7% respectively (P=0.044. Conclusion: PTFE vascular graft seems to be an appropriate vascular access and is a promising alternative when upper extremity arteriovenous fistulas cannot be constructed. Additionally, there was no significant different between two groups for complications and early patency, but late patency was better in loop group. More study is necessary for final judgment.

Robotic Online Path Planning on Point Cloud.

Science.gov (United States)

Liu, Ming

2016-05-01

This paper deals with the path-planning problem for mobile wheeled- or tracked-robot which drive in 2.5-D environments, where the traversable surface is usually considered as a 2-D-manifold embedded in a 3-D ambient space. Specially, we aim at solving the 2.5-D navigation problem using raw point cloud as input. The proposed method is independent of traditional surface parametrization or reconstruction methods, such as a meshing process, which generally has high-computational complexity. Instead, we utilize the output of 3-D tensor voting framework on the raw point clouds. The computation of tensor voting is accelerated by optimized implementation on graphics computation unit. Based on the tensor voting results, a novel local Riemannian metric is defined using the saliency components, which helps the modeling of the latent traversable surface. Using the proposed metric, we prove that the geodesic in the 3-D tensor space leads to rational path-planning results by experiments. Compared to traditional methods, the results reveal the advantages of the proposed method in terms of smoothing the robot maneuver while considering the minimum travel distance.

Feynman's path integrals and Bohm's particle paths

International Nuclear Information System (INIS)

Tumulka, Roderich

2005-01-01

Both Bohmian mechanics, a version of quantum mechanics with trajectories, and Feynman's path integral formalism have something to do with particle paths in space and time. The question thus arises how the two ideas relate to each other. In short, the answer is, path integrals provide a re-formulation of Schroedinger's equation, which is half of the defining equations of Bohmian mechanics. I try to give a clear and concise description of the various aspects of the situation. (letters and comments)

Nonlinear Autoregressive Network with the Use of a Moving Average Method for Forecasting Typhoon Tracks

OpenAIRE

Tienfuan Kerh; Shin-Hung Wu

2017-01-01

Forecasting of a typhoon moving path may help to evaluate the potential negative impacts in the neighbourhood areas along the moving path. This study proposed a work of using both static and dynamic neural network models to link a time series of typhoon track parameters including longitude and latitude of the typhoon central location, cyclonic radius, central wind speed, and typhoon moving speed. Based on the historical records of 100 typhoons, the performances of neural network models are ev...

Computation of Slip analysis to detect adhesion for protection of rail vehicle and derailment

Directory of Open Access Journals (Sweden)

Zulfiqar Ali Soomro

2015-07-01

Full Text Available Adhesion level for the proper running of rail wheelset on track is crucial problem in detecting slippage to avoid accidents. The slippage of rail wheels has been observed applying forward and lateral motions to slip velocity and torsion motion. The longitudinal and lateral forces behavior is watched with respect to traction force to note correlation based on angle of attack. The deriving torque relation with tractive torque is watched to check slippage. Coulomb’s law is applied in terms of tangential forces to normal forces owing to creep co-efficient and friction to know adhesion. Nadal’s limiting ratio is applied to escape from wheel climb and derailment from track depending upon wheel profile and flange on straight path and curves.

Terminal Sliding Mode Tracking Controller Design for Automatic Guided Vehicle

Science.gov (United States)

Chen, Hongbin

2018-03-01

Based on sliding mode variable structure control theory, the path tracking problem of automatic guided vehicle is studied, proposed a controller design method based on the terminal sliding mode. First of all, through analyzing the characteristics of the automatic guided vehicle movement, the kinematics model is presented. Then to improve the traditional expression of terminal sliding mode, design a nonlinear sliding mode which the convergence speed is faster than the former, verified by theoretical analysis, the design of sliding mode is steady and fast convergence in the limited time. Finally combining Lyapunov method to design the tracking control law of automatic guided vehicle, the controller can make the automatic guided vehicle track the desired trajectory in the global sense as well as in finite time. The simulation results verify the correctness and effectiveness of the control law.

Active Disturbance Rejection with Sliding Mode Control Based Course and Path Following for Underactuated Ships

Directory of Open Access Journals (Sweden)

Ronghui Li

2013-01-01

Full Text Available The compound control of active-disturbance-rejection control (ADRC with sliding mode is proposed to improve the performance of the closed-loop system and deal with the constraint condition problem of a surface ship. The advantages of ADRC with sliding mode were verified by ship course control simulations. Meanwhile, to solve the path-following problem of underactuated surface ships with uncertainties of internal dynamic and external disturbances, the ADRC controller with sliding mode is introduced to steer the ship to follow the desired path. In order to overcome the cross-track error caused by wind and current, drift angle is compensated in the controller by designing a coordinate transformation equation. Simulations were performed on a nonlinear kinematics model of a training ship to validate the stability and excellent robustness of the proposed path-following controller.

Accounting for straight parts effects on elbow's flexibilities in a beam type finite element program

International Nuclear Information System (INIS)

Millard, A.

1983-01-01

An extension of Von Karman's theory is applied to the calculations of the flexibility factor of a pipe bend terminated by a straight part or a flange. This analysis is restricted to the linear elastic deformation behaviour under in plane bending. Analytical solutions are given for the propagation of ovalization in the elbow and in the straight part. Considering the response of the piping structures, we note that the ovalization of the piping systems are reduced significantly when the straight parts or flanges effects are included. This results are presented in terms of global as well local flexibility factors. They have been compared to numerical results obtained by shell type finite elements method. A complete piping system is analyzed, for economical reasons, with a beam type approach. Also, we show how it is possible to take into account an elbow's flexibilities the straight parts effects by means of flexibilities factors introduced in a beam type elements. We have implemented this method in the computer program TEDEL. In some specific geometrical features, we compare solutions using shell type elements and our formulation. (orig.)

Accounting for straight parts effects on elbow's flexibilities in a beam type finite element program

International Nuclear Information System (INIS)

Millard, A.; Vaghi, H.; Ricard, A.

1983-08-01

An extension of Von Karman's theory is applied to the calculations of the flexibility factor of a pipe bend terminated by a straight part or a flange. This analysis is restricted to the linear elastic deformation behaviour under in plane bending. Analytical solutions are given for the propagation of ovalization in the elbow and in the straight part. Considering the response of the piping structures, we note that the ovalization of the piping systems are reduced significantly when the straight parts or flanges effects are included. The results are presented in terms of global as well local flexibility factors. They have been compared to numerical results obtained by shell type finite element method. A complete piping system is analyzed, for economical reasons, with a beam type approach. Also, we show how it is possible to take into account on elbow's flexibilities the straight parts effects by means of flexibilities factors introduced in a beam type element. We have implemented this method in the computer program TEDEL. In some specific geometrical features, we compare solutions using shell type elements and our formulation

Multi-Dimensional Path Queries

DEFF Research Database (Denmark)

Bækgaard, Lars

1998-01-01

to create nested path structures. We present an SQL-like query language that is based on path expressions and we show how to use it to express multi-dimensional path queries that are suited for advanced data analysis in decision support environments like data warehousing environments......We present the path-relationship model that supports multi-dimensional data modeling and querying. A path-relationship database is composed of sets of paths and sets of relationships. A path is a sequence of related elements (atoms, paths, and sets of paths). A relationship is a binary path...

Three-Axis Ground Reaction Force Distribution during Straight Walking.

Science.gov (United States)

Hori, Masataka; Nakai, Akihito; Shimoyama, Isao

2017-10-24

We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body's center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.

Straight proximal humeral nails are surrounded by more bone stock in comparison to bent nails in an experimental cadaveric study.

Science.gov (United States)

Günther, Christian Max; Müller, Peter Ernst; Mutschler, Wolf; Sprecher, Christoph Martin; Milz, Stefan; Braunstein, Volker

2014-01-01

In the management of proximal humeral fractures intramedullary implants with bent and straight shape of the proximal part of nail are available. Based on data from previous studies on bone distribution in the humeral head, we hypothesized, that higher densities might exist in the bone stock surrounding straight nails in comparison to their angulated counterparts. With a known positive correlation between bone density and mechanical stability, this could indicate potentially higher rigidity of osteosyntheses done with straight implants. We performed high resolution peripheral quantitative computed tomographies of the potential straight and bent implant bearing regions of 27 cadaveric proximal humeri. The acquired data were analyzed for differences between straight and bent Volumes of Interest as well as intra- and interindividual bone stock distribution. For both straight and bent volumes of interest a considerably declining bone mineral density was found in craniocaudal direction. Mean densities of bent volumes were significantly lower in comparison to their corresponding straight counterparts (p straight shaped implants can be assumed. Since we found a rapid decrease of bone density in cranio-caudal direction, intramedullary implants should be anchored as proximally in the subcortical area as possible to minimize the risk of displacement or cutout. The high correlation between the Volumes of Interest of the corresponding right and left sides could aid in preoperative planning when considering an intra- or extramedullary approach.

Polygonal-path approximations on the path spaces of quantum-mechanical systems: properties of the polygonal paths

International Nuclear Information System (INIS)

Exner, P.; Kolerov, G.I.

1981-01-01

Properties of the subset of polygonal paths in the Hilbert space H of paths referring to a d-dimensional quantum-mechanical system are examined. Using the reproduction kernel technique we prove that each element of H is approximated by polygonal paths uniformly with respect to the ''norm'' of time-interval partitions. This result will be applied in the second part of the present paper to prove consistency of the uniform polygonal-path extension of the Feynman maps [ru

Improved Line Tracking System for Autonomous Navigation of High-Speed Vehicle

Directory of Open Access Journals (Sweden)

Yahya Zare Khafri

2012-07-01

Full Text Available Line tracking navigation is one of the most widely techniques used in the robot navigation. In this paper, a customized line tracking system is proposed for autonomous navigation of high speed vehicles. In the presented system, auxiliary information -in addition to the road path- is added to the tracking lines such as locations of turn and intersections in the real roads. Moreover, the geometric position of line sensors is re-designed enables the high rate sensing with higher reliability. Finally, a light-weight navigation algorithm is proposed allow the high-speed movement using a reasonable processing power. This system is implemented on a MIPS-based embedded processor and experimental results with this embedded system show more than 98% accuracy at 200km/h with a 1GHz processor is viable.

Dynamic response of the train-track-bridge system subjected to derailment impacts

Science.gov (United States)

Ling, Liang; Dhanasekar, Manicka; Thambiratnam, David P.

2018-04-01

Derailments on bridges, although not frequent, when occurs due to a complex dynamic interaction of the train-track-bridge structural system, are very severe. Furthermore, the forced vibration induced by the post-derailment impacts can toss out the derailed wagons from the bridge deck with severe consequences to the traffic underneath and the safety of the occupants of the wagons. This paper presents a study of the train-track-bridge interaction during a heavy freight train crossing a concrete box girder bridge from a normal operation to a derailed state. A numerical model that considers the bridge vibration, train-track interaction and the train post-derailment behaviour is formulated based on a coupled finite-element - multi-body dynamics (FE-MBD) theory. The model is applied to predict the post-derailment behaviour of a freight train composed of one locomotive and several wagons, as well as the dynamic response of a straight single-span simply supported bridge containing ballast track subjected to derailment impacts. For this purpose, a typical derailment scenario of a heavy freight train passing over a severe track geometry defect is introduced. The dynamic derailment behaviour of the heavy freight train and the dynamic responses of the rail bridge are illustrated through numerical examples. The results exhibit the potential for tossing out of the derailed trains from the unstable increase in the yaw angle signature and a lower rate of increase of the bridge deck bending moment compared to the increase in the static axle load of the derailed wheelset.

Observation of anomalons in CR-39 track detectors

International Nuclear Information System (INIS)

Tincknell, M.L.; Price, P.B.

1984-01-01

The authors have observed fragments of 1.85 GeV/nucleon 40 Ar in CR-39 etched track detector and they find anomalously short mean free paths (mfp's) of secondary nuclei with 11 less than or equal to Z less than or equal to 17 in the first 2 cm after their production, at approx.3 standard deviations. This confirms previous reports of this anomalon effect in nuclear emulsion in a new detector with dissimilar potential systematic errors

Force-field compensation in a manual tracking task.

Directory of Open Access Journals (Sweden)

Valentina Squeri

2010-06-01

Full Text Available This study addresses force/movement control in a dynamic "hybrid" task: the master sub-task is continuous manual tracking of a target moving along an eight-shaped Lissajous figure, with the tracking error as the primary performance index; the slave sub-task is compensation of a disturbing curl viscous field, compatibly with the primary performance index. The two sub-tasks are correlated because the lateral force the subject must exert on the eight-shape must be proportional to the longitudinal movement speed in order to perform a good tracking. The results confirm that visuo-manual tracking is characterized by an intermittent control mechanism, in agreement with previous work; the novel finding is that the overall control patterns are not altered by the presence of a large deviating force field, if compared with the undisturbed condition. It is also found that the control of interaction-forces is achieved by a combination of arm stiffness properties and direct force control, as suggested by the systematic lateral deviation of the trajectories from the nominal path and the comparison between perturbed trials and catch trials. The coordination of the two sub-tasks is quickly learnt after the activation of the deviating force field and is achieved by a combination of force and the stiffness components (about 80% vs. 20%, which is a function of the implicit accuracy of the tracking task.

The Dugdale solution for two unequal straight cracks weakening

Indian Academy of Sciences (India)

A crack arrest model is proposed for an infinite elastic perfectly-plastic plate weakened by two unequal, quasi-static, collinear straight cracks. The Dugdale model solution is obtained for the above problem when the developed plastic zones are subjected to normal cohesive quadratically varying yield point stress. Employing ...

Rail Track Detection and Modelling in Mobile Laser Scanner Data

Directory of Open Access Journals (Sweden)

S. Oude Elberink

2013-10-01

Full Text Available We present a method for detecting and modelling rails in mobile laser scanner data. The detection is based on the properties of the rail tracks and contact wires such as relative height, linearity and relative position with respect to other objects. Points classified as rail track are used in a 3D modelling algorithm. The modelling is done by first fitting a parametric model of a rail piece to the points along each track, and estimating the position and orientation parameters of each piece model. For each position and orientation parameter a smooth low-order Fourier curve is interpolated. Using all interpolated parameters a mesh model of the rail is reconstructed. The method is explained using two areas from a dataset acquired by a LYNX mobile mapping system in a mountainous area. Residuals between railway laser points and 3D models are in the range of 2 cm. It is concluded that a curve fitting algorithm is essential to reliably and accurately model the rail tracks by using the knowledge that railways are following a continuous and smooth path.

Multi-physics modeling of single/multiple-track defect mechanisms in electron beam selective melting

International Nuclear Information System (INIS)

Yan, Wentao; Ge, Wenjun; Qian, Ya; Lin, Stephen; Zhou, Bin; Liu, Wing Kam; Lin, Feng; Wagner, Gregory J.

2017-01-01

Metallic powder bed-based additive manufacturing technologies have many promising attributes. The single track acts as one fundamental building unit, which largely influences the final product quality such as the surface roughness and dimensional accuracy. A high-fidelity powder-scale model is developed to predict the detailed formation processes of single/multiple-track defects, including the balling effect, single track nonuniformity and inter-track voids. These processes are difficult to observe in experiments; previous studies have proposed different or even conflicting explanations. Our study clarifies the underlying formation mechanisms, reveals the influence of key factors, and guides the improvement of fabrication quality of single tracks. Additionally, the manufacturing processes of multiple tracks along S/Z-shaped scan paths with various hatching distance are simulated to further understand the defects in complex structures. The simulations demonstrate that the hatching distance should be no larger than the width of the remelted region within the substrate rather than the width of the melted region within the powder layer. Thus, single track simulations can provide valuable insight for complex structures.

COMPARISON OF POSTOP SIA IN MSICS WITH STRAIGHT INCISION VERSUS FROWN INCISION

Directory of Open Access Journals (Sweden)

Shayana Bhumbla

2017-05-01

Full Text Available BACKGROUND Surgically-Induced Astigmatism (SIA is one of the commonest causes of poor postoperative vision even after uneventful cataract surgery. Recent advances have led to a newer concept of “refractive cataract surgery.” The aim of the study is to study the comparison of postop SIA in Manual Small Incision Cataract Surgery (MSICS with straight versus frown incision. MATERIALS AND METHODS 50 patients of cataract were divided into 2 groups (25 each - group A underwent MSICS with 6 mm straight incision, group B underwent MSICS with 6 mm frown incision. BCVA, keratometry readings were recorded with auto kerato-refractometer preop, at 1 week, 1 month, 3 months and SIA was calculated with SIA calculator version 2.1, a free software program. RESULTS Mean SIA in group A and B were - 1.14D versus 0.92D at 1 week; 1.26D versus 0.97D at 1 month; 1.29D versus 0.95D at 3 months. The difference was statistically significant at each follow up visit (p<0.05. CONCLUSION Frown incision gives lesser SIA than straight incision in MSICS.

Inverse modelling of thermal histories with apatite fission tracks

International Nuclear Information System (INIS)

El Lmrani, A.; Zine El Abidine, H.; Limouri, M.; Essaid, A.; POupeau, G.

1998-01-01

The problem of modelling thermal histories lies in the exploration of a time-temperature space, usually so broad, in order to identify the optimal paths. For overcoming this difficulty, many approaches were proposed, using linear and non-linear optimisation algorithms. Generally, these approaches do not take into account the experimental data (fission track age [FTA] and fission track length distribution [FTLD]) to better aim the search strategy. The present work shows that experimental data hold some precious information, for which it should be known how to extract it. In fact, it allows us to tighten the time-temperature space of search, supposed to contain the optimal solutions. A genetic algorithm is also used in this work to perform the search for these optimal solutions. (authors)

Three-dimensional particle tracking velocimetry using dynamic vision sensors

Science.gov (United States)

Borer, D.; Delbruck, T.; Rösgen, T.

2017-12-01

A fast-flow visualization method is presented based on tracking neutrally buoyant soap bubbles with a set of neuromorphic cameras. The "dynamic vision sensors" register only the changes in brightness with very low latency, capturing fast processes at a low data rate. The data consist of a stream of asynchronous events, each encoding the corresponding pixel position, the time instant of the event and the sign of the change in logarithmic intensity. The work uses three such synchronized cameras to perform 3D particle tracking in a medium sized wind tunnel. The data analysis relies on Kalman filters to associate the asynchronous events with individual tracers and to reconstruct the three-dimensional path and velocity based on calibrated sensor information.

Modeling analyses of two-phase flow instabilities for straight and helical tubes in nuclear power plants

International Nuclear Information System (INIS)

Dong, Ruiting; Niu, Fenglei; Zhou, Yuan; Yu, Yu; Guo, Zhangpeng

2016-01-01

Highlights: • Two-phase flow instabilities in straight and helical tubes were studied. • The effects of system pressure, mass flux, inlet subcooling on DWO were studied. • The simulation results are consistent with the experimental results. • The RELAP5 results are consistent with frequency domain method results. - Abstract: The effects of system pressure, mass flux and inlet subcooling on two-phase flow instability for the test section consisted of two heated straight channels or two helical channels are studied by means of RELAP5/MOD3.3 and multi-variable frequency domain control theory. The experimental data in two straight channels are used to verify the RELAP5 and multi-variable frequency domain control theory results. The thermal hydraulic behaviors and parametric effects are simulated and compared with the experimental data. The RELAP5 results show that the flow stability increases with the system pressure, mass velocity, and inlet subcooling at high subcoolings. The frequency domain theory presents the same results as those given by the time domain theory (RELAP5). The effects of system pressure, mass velocity and inlet subcooling are simulated to find the difference between the straight and the helical tube flows. The RELAP5 and the multi-variable frequency domain control theory are used in modeling and simulating density wave oscillation to study their advantages and disadvantages in straight and helical tubes.

Modeling analyses of two-phase flow instabilities for straight and helical tubes in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Dong, Ruiting [Beijing Key Laboratory of Passive Nuclear Power Safety and Technology, North China Electric Power University, Beijing 102206 (China); Niu, Fenglei, E-mail: niufenglei@ncepu.edu.cn [Beijing Key Laboratory of Passive Nuclear Power Safety and Technology, North China Electric Power University, Beijing 102206 (China); Zhou, Yuan [School of Nuclear Science and Engineering, Shanghai Jiaotong University, Shanghai 200240 (China); Yu, Yu; Guo, Zhangpeng [Beijing Key Laboratory of Passive Nuclear Power Safety and Technology, North China Electric Power University, Beijing 102206 (China)

2016-10-15

Highlights: • Two-phase flow instabilities in straight and helical tubes were studied. • The effects of system pressure, mass flux, inlet subcooling on DWO were studied. • The simulation results are consistent with the experimental results. • The RELAP5 results are consistent with frequency domain method results. - Abstract: The effects of system pressure, mass flux and inlet subcooling on two-phase flow instability for the test section consisted of two heated straight channels or two helical channels are studied by means of RELAP5/MOD3.3 and multi-variable frequency domain control theory. The experimental data in two straight channels are used to verify the RELAP5 and multi-variable frequency domain control theory results. The thermal hydraulic behaviors and parametric effects are simulated and compared with the experimental data. The RELAP5 results show that the flow stability increases with the system pressure, mass velocity, and inlet subcooling at high subcoolings. The frequency domain theory presents the same results as those given by the time domain theory (RELAP5). The effects of system pressure, mass velocity and inlet subcooling are simulated to find the difference between the straight and the helical tube flows. The RELAP5 and the multi-variable frequency domain control theory are used in modeling and simulating density wave oscillation to study their advantages and disadvantages in straight and helical tubes.

Tracking in full Monte Carlo detector simulations of 500 GeV e+e- collisions

International Nuclear Information System (INIS)

Ronan, M.T.

2000-01-01

In full Monte Carlo simulation models of future Linear Collider detectors, charged tracks are reconstructed from 3D space points in central tracking detectors. The track reconstruction software is being developed for detailed physics studies that take realistic detector resolution and background modeling into account. At this stage of the analysis, reference tracking efficiency and resolutions for ideal detector conditions are presented. High performance detectors are being designed to carry out precision studies of e + e - annihilation events in the energy range of 500 GeV to 1.5 TeV. Physics processes under study include Higgs mass and branching ratio measurements, measurement of possible manifestations of Supersymmetry (SUSY), precision Electro-Weak (EW) studies and searches for new phenomena beyond their current expectations. The relatively-low background machine environment at future Linear Colliders will allow precise measurements if proper consideration is given to the effects of the backgrounds on these studies. In current North American design studies, full Monte Carlo detector simulation and analysis is being used to allow detector optimization taking into account realistic models of machine backgrounds. In this paper the design of tracking software that is being developed for full detector reconstruction is discussed. In this study, charged tracks are found from simulated space point hits allowing for the straight-forward addition of background hits and for the accounting of missing information. The status of the software development effort is quantified by some reference performance measures, which will be modified by future work to include background effects

A note on frequency distributions of fission tracks in apatite

International Nuclear Information System (INIS)

He, Z.; Lerche, I.

1989-01-01

Two different formulae, both purportedly describing track length reduction in apatite, are converted to forms useful in prediction of track length distributions along sedimentary burial history paths. Using the formalism, track length distribution data from four NW Canning Basin wells are inverted to determine the physical (chemical) parameters associated with the models as well as the heat flux variation with time. For each formula the resulting physical parameters are consistent among the wells tested but differ from laboratory-derived parameter values, and the thermal histories are consistent with those inferred from geological data. Comparison of the two models shows no evidence that one model should be favored over the other based on the data available. It is also shown that the resolution of the parameters is dependent not only on the quantity of the data but also on the ''quality'' -explicitly upon the variation and distribution with depth. (author)

The Effects of Direction of Exertion, Path, and Load Placement in Nursing Cart Pushing and Pulling Tasks: An Electromyographical Study.

Science.gov (United States)

Kao, Huei Chu; Lin, Chiuhsiang Joe; Lee, Yung Hui; Chen, Su Huang

2015-01-01

The purpose of this study was to explore the effects of direction of exertion (DOE) (pushing, pulling), path (walking in a straight line, turning left, walking uphill), and load placement (LP) (the 18 blocks were indicated by X, Y and Z axis; there were 3 levels on the X axis, 2 levels on the Y axis, and 3 levels on the Z axis) on muscle activity and ratings of perceived exertion in nursing cart pushing and pulling tasks. Ten participants who were female students and not experienced nurses were recruited to participate in the experiment. Each participant performed 108 experimental trials in the study, consisting of 2 directions of exertion (push and pull), 3 paths, and 18 load placements (indicated by X, Y and Z axes). A 23kg load was placed into one load placement. The dependent variables were electromyographic (EMG) data of four muscles collected bilaterally as follows: Left (L) and right (R) trapezius (TR), flexor digitorum superficialis (FDS), extensor digitorum (ED), and erector spinae (ES) and subjective ratings of perceived exertion (RPE). Split-split-plot ANOVA was conducted to analyze significant differences between DOE, path, and LP in the EMG and RPE data. Pulling cart tasks produced a significantly higher activation of the muscles (RTR:54.4%, LTR:50.3%, LFDS:57.0%, LED:63.4%, RES:40.7%, LES:36.7%) than pushing cart tasks (RTR:42.4%, LTR:35.1%, LFDS:32.3%, LED:55.1%, RES:33.3%, LES:32.1%). A significantly greater perceived exertion was found in pulling cart tasks than pushing cart tasks. Significantly higher activation of all muscles and perceived exertion were observed for walking uphill than walking in a straight line and turning left. Significantly lower muscle activity of all muscles and subject ratings were observed for the central position on the X axis, the bottom position on the Y axis, and the posterior position on the Z axis. These findings suggest that nursing staff should adopt forward pushing when moving a nursing cart, instead of backward

Pulled Motzkin paths

International Nuclear Information System (INIS)

Janse van Rensburg, E J

2010-01-01

In this paper the models of pulled Dyck paths in Janse van Rensburg (2010 J. Phys. A: Math. Theor. 43 215001) are generalized to pulled Motzkin path models. The generating functions of pulled Motzkin paths are determined in terms of series over trinomial coefficients and the elastic response of a Motzkin path pulled at its endpoint (see Orlandini and Whittington (2004 J. Phys. A: Math. Gen. 37 5305-14)) is shown to be R(f) = 0 for forces pushing the endpoint toward the adsorbing line and R(f) = f(1 + 2cosh f))/(2sinh f) → f as f → ∞, for forces pulling the path away from the X-axis. In addition, the elastic response of a Motzkin path pulled at its midpoint is shown to be R(f) = 0 for forces pushing the midpoint toward the adsorbing line and R(f) = f(1 + 2cosh (f/2))/sinh (f/2) → 2f as f → ∞, for forces pulling the path away from the X-axis. Formal combinatorial identities arising from pulled Motzkin path models are also presented. These identities are the generalization of combinatorial identities obtained in directed paths models to their natural trinomial counterparts.

Pulled Motzkin paths

Energy Technology Data Exchange (ETDEWEB)

Janse van Rensburg, E J, E-mail: rensburg@yorku.c [Department of Mathematics and Statistics, York University, Toronto, ON, M3J 1P3 (Canada)

2010-08-20

In this paper the models of pulled Dyck paths in Janse van Rensburg (2010 J. Phys. A: Math. Theor. 43 215001) are generalized to pulled Motzkin path models. The generating functions of pulled Motzkin paths are determined in terms of series over trinomial coefficients and the elastic response of a Motzkin path pulled at its endpoint (see Orlandini and Whittington (2004 J. Phys. A: Math. Gen. 37 5305-14)) is shown to be R(f) = 0 for forces pushing the endpoint toward the adsorbing line and R(f) = f(1 + 2cosh f))/(2sinh f) {yields} f as f {yields} {infinity}, for forces pulling the path away from the X-axis. In addition, the elastic response of a Motzkin path pulled at its midpoint is shown to be R(f) = 0 for forces pushing the midpoint toward the adsorbing line and R(f) = f(1 + 2cosh (f/2))/sinh (f/2) {yields} 2f as f {yields} {infinity}, for forces pulling the path away from the X-axis. Formal combinatorial identities arising from pulled Motzkin path models are also presented. These identities are the generalization of combinatorial identities obtained in directed paths models to their natural trinomial counterparts.

Pulled Motzkin paths

Science.gov (United States)

Janse van Rensburg, E. J.

2010-08-01

In this paper the models of pulled Dyck paths in Janse van Rensburg (2010 J. Phys. A: Math. Theor. 43 215001) are generalized to pulled Motzkin path models. The generating functions of pulled Motzkin paths are determined in terms of series over trinomial coefficients and the elastic response of a Motzkin path pulled at its endpoint (see Orlandini and Whittington (2004 J. Phys. A: Math. Gen. 37 5305-14)) is shown to be R(f) = 0 for forces pushing the endpoint toward the adsorbing line and R(f) = f(1 + 2cosh f))/(2sinh f) → f as f → ∞, for forces pulling the path away from the X-axis. In addition, the elastic response of a Motzkin path pulled at its midpoint is shown to be R(f) = 0 for forces pushing the midpoint toward the adsorbing line and R(f) = f(1 + 2cosh (f/2))/sinh (f/2) → 2f as f → ∞, for forces pulling the path away from the X-axis. Formal combinatorial identities arising from pulled Motzkin path models are also presented. These identities are the generalization of combinatorial identities obtained in directed paths models to their natural trinomial counterparts.

Side-suspended High- Tc Superconducting Maglev Prototype Vehicle Running at a High Speed in an Evacuated Circular Test Track

International Nuclear Information System (INIS)

Zhou, Dajin; Zhao, Lifeng; Cui, Chenyu; Zhang, Yong; Guo, Jianqiang; Zhao, Yong

2017-01-01

High- T c superconductor (HTS) and permanent magnetic guideway (PMG) based maglev train is intensively studied in China, Japan, Germany and Brazil, mainly through static or vibration test. Amongst these studies, only a few of reports are available for the direct and effective assessment on the dynamic performance of the HTS maglev vehicle by running on a straight or circular PMG track. The highest running speed of these experiments is lower than 50 km/h. In this paper, a side-suspended HTS permanent magnetic guideway maglev system was proposed and constructed in order to increase the running speed in a circular track. By optimizing the arrangement of YBCO bulks besides the PMG, the side-suspended HTS maglev prototype vehicle was successfully running stably at a speed as high as 150 km/h in a circular test track with 6.5 m in diameter, and in an evacuated tube environment, in which the pressure is 5 × 10 3 Pa. (paper)

Side-suspended High-Tc Superconducting Maglev Prototype Vehicle Running at a High Speed in an Evacuated Circular Test Track

Science.gov (United States)

Zhou, Dajin; Zhao, Lifeng; Cui, Chenyu; Zhang, Yong; Guo, Jianqiang; Zhao, Yong

2017-07-01

High-T c superconductor (HTS) and permanent magnetic guideway (PMG) based maglev train is intensively studied in China, Japan, Germany and Brazil, mainly through static or vibration test. Amongst these studies, only a few of reports are available for the direct and effective assessment on the dynamic performance of the HTS maglev vehicle by running on a straight or circular PMG track. The highest running speed of these experiments is lower than 50 km/h. In this paper, a side-suspended HTS permanent magnetic guideway maglev system was proposed and constructed in order to increase the running speed in a circular track. By optimizing the arrangement of YBCO bulks besides the PMG, the side-suspended HTS maglev prototype vehicle was successfully running stably at a speed as high as 150 km/h in a circular test track with 6.5 m in diameter, and in an evacuated tube environment, in which the pressure is 5 × 103 Pa.

Radiologic findings of deep seated cerebral arteriovenous malformation with nonvisualization of straight sinus: focused on angiogram

International Nuclear Information System (INIS)

Won, Jong Boo; Park, Sung Ho; Hong, Jong Won; Kim, Yoo Kyoung; Shin, Mi Jeong; Baik, Seung Kuk; Choi, Han Yong; Kim, Bong Gi

1999-01-01

To analyze the radiologic-especially angiographic-findings of deep seated cerebral arteriovenous malformation(AVM) involving nonvisualized straight sinus. In six patients aged between 15 and 53 years with deep seated cerebral AVM, CT and MR images were retrospectively analyzed with regard to the following features : the presence of straight sinus, the location of AVM, and the occurrence of hemorrhage. Angiograms were analyzed for venous drainage routes of AVM, the appearance of veins, the presence of falcine sinus and venous drainage from normal deep brain parenchyme. In four patients who had undergone intravascular embolization therapy, pre- and post- embolization angiograms were compared. CT and MR images showed neither straight sinus nor thrombosis. AVMs were deeply seated in the brain, and in all cases there was cerebral hemorrhage. Angiograms disclosed that venous drainage of all AVMs occurred via the veins of Galen. In one case, venous flow via the falcine sinus to the superior sagittal sinus was noted, but in others, retrograde flow in the deep venous system was observed. Marked collateral routes followed in response to the obstruction of straight sinus included the basal vein of Rosenthal, the internal occipital, internal cerebral, and cerebellar hemispheric veins (which are Galenic afferents), and the inferior sagittal sinus. In all patients, contralateral routes were partially involved. Venous drainage from normal deep parenchyme through the transcerebral veins to the superficial venous system was noted, and in one case, straight sinus which had been observed on an angiogram five years earlier was no longer present. Angiography offers effective evaluation of the dynamic aspect of venous flow in cases involving deep-seated AVM, and of normal deep parenchyme in cases in which AVM involves nonvisualized straight sinus. Before intravascular treatment of AVM, venous flow must be carefully analyzed

Excessive deformation and failure of straight parts and elbows

International Nuclear Information System (INIS)

Touboul, F.; Acker, D.

1991-01-01

The design rules for LMFBRs must cover the ranges of loading types and geometries wider than PWR Design Codes. Steam pipework does not differ between two reactor systems, but as far as sodium piping is concerned, usual PWR criteria may not be adequate. The LMFBR sodium piping is operated at high temperature and low pressure level. Moreover, these peculiar loadings require the geometrical characteristics completely different in the fact that the piping must be flexible but need not to be thick. For such piping components, the ultimate behavior depends much on the geometry. 170 experimental results on straight parts and 95 results on elbows were investigated. As for elbows, half of the tests were performed under in-plane closing moment. On the analysis of straight pipes and elbows, the experiments and the proposed expressions for the evaluation of collapse and instability moments are described, respectively. The application of the present study to the design rules and the criteria for various loading conditions are reported. It is difficult to experimentally distinguish between plastic instability and buckling. (K.I.)

Strategies for Selecting Routes through Real-World Environments: Relative Topography, Initial Route Straightness, and Cardinal Direction.

Directory of Open Access Journals (Sweden)

Tad T Brunyé

Full Text Available Previous research has demonstrated that route planners use several reliable strategies for selecting between alternate routes. Strategies include selecting straight rather than winding routes leaving an origin, selecting generally south- rather than north-going routes, and selecting routes that avoid traversal of complex topography. The contribution of this paper is characterizing the relative influence and potential interactions of these strategies. We also examine whether individual differences would predict any strategy reliance. Results showed evidence for independent and additive influences of all three strategies, with a strong influence of topography and initial segment straightness, and relatively weak influence of cardinal direction. Additively, routes were also disproportionately selected when they traversed relatively flat regions, had relatively straight initial segments, and went generally south rather than north. Two individual differences, extraversion and sense of direction, predicted the extent of some effects. Under real-world conditions navigators indeed consider a route's initial straightness, cardinal direction, and topography, but these cues differ in relative influence and vary in their application across individuals.

Youth Empowerment and High School Gay-Straight Alliances

OpenAIRE

Russell, Stephen T.; Muraco, Anna; Subramaniam, Aarti; Laub, Carolyn

2009-01-01

In the field of positive youth development programs, “empowerment” is used interchangeably with youth activism, leadership, civic participation and self-efficacy. However, few studies have captured what empowerment means to young people in diverse contexts. This article explores how youth define and experience empowerment in youth-led organizations characterized by social justice goals: high school Gay-Straight Alliances (GSAs). Through focus group interviews, fifteen youth leaders of GSAs fr...

Readout electronics for the SiPM tracking plane in the NEXT-1 prototype

International Nuclear Information System (INIS)

Herrero, V.; Toledo, J.; Català, J.M.; Esteve, R.; Gil, A.; Lorca, D.; Monzó, J.M.; Sanchis, F.; Verdugo, A.

2012-01-01

NEXT is a new experiment to search for neutrinoless double beta decay using a 100 kg radio-pure high-pressure gaseous xenon TPC with electroluminescence readout. A large-scale prototype with a SiPM tracking plane has been built. The primary electron paths can be reconstructed from time-resolved measurements of the light that arrives to the SiPM plane. Our approach is to measure how many photons have reached each SiPM sensor each microsecond with a gated integrator. We have designed and tested a 16-channel front-end board that includes the analog paths and a digital section. Each analog path consists of three different stages: a transimpedance amplifier, a gated integrator and an offset and gain control stage. Measurements show good linearity and the ability to detect single photoelectrons.

Readout electronics for the SiPM tracking plane in the NEXT-1 prototype

Energy Technology Data Exchange (ETDEWEB)

Herrero, V. [Instituto de Instrumentacion para Imagen Molecular I3M (Centro mixto CSIC-Universitat Politecnica de Valencia-CIEMAT), 46022 Valencia (Spain); Toledo, J., E-mail: jtoledo@eln.upv.es [Instituto de Instrumentacion para Imagen Molecular I3M (Centro mixto CSIC-Universitat Politecnica de Valencia-CIEMAT), 46022 Valencia (Spain); Catala, J.M.; Esteve, R. [Instituto de Instrumentacion para Imagen Molecular I3M (Centro mixto CSIC-Universitat Politecnica de Valencia-CIEMAT), 46022 Valencia (Spain); Gil, A.; Lorca, D. [Instituto de Fisica Corpuscular (CSIC-Universidad de Valencia), 46980 Valencia (Spain); Monzo, J.M.; Sanchis, F. [Instituto de Instrumentacion para Imagen Molecular I3M (Centro mixto CSIC-Universitat Politecnica de Valencia-CIEMAT), 46022 Valencia (Spain); Verdugo, A. [CIEMAT-Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain)

2012-12-11

NEXT is a new experiment to search for neutrinoless double beta decay using a 100 kg radio-pure high-pressure gaseous xenon TPC with electroluminescence readout. A large-scale prototype with a SiPM tracking plane has been built. The primary electron paths can be reconstructed from time-resolved measurements of the light that arrives to the SiPM plane. Our approach is to measure how many photons have reached each SiPM sensor each microsecond with a gated integrator. We have designed and tested a 16-channel front-end board that includes the analog paths and a digital section. Each analog path consists of three different stages: a transimpedance amplifier, a gated integrator and an offset and gain control stage. Measurements show good linearity and the ability to detect single photoelectrons.

New airfoil sections for straight bladed turbine

Science.gov (United States)

Boumaza, B.

1987-07-01

A theoretical investigation of aerodynamic performance for vertical axis Darrieus wind turbine with new airfoils sections is carried out. The blade section aerodynamics characteristics are determined from turbomachines cascade model. The model is also adapted to the vertical Darrieus turbine for the performance prediction of the machine. In order to choose appropriate value of zero-lift-drag coefficient in calculation, an analytical expression is introduced as function of chord-radius ratio and Reynolds numbers. New airfoils sections are proposed and analyzed for straight-bladed turbine.

New airfoil sections for straight bladed turbine

International Nuclear Information System (INIS)

Boumaza, B.

1987-07-01

A theoretical investigation of aerodynamic performance for vertical axis Darrieus wind turbine with new airfoils sections is carried out. The blade section aerodynamics characteristics are determined from turbomachines cascade model. The model is also adapted to the vertical Darrieus turbine for the performance prediction of the machine. In order to choose appropriate value of zero-lift-drag coefficient in calculation, an analytical expression is introduced as function of chord-radius ratio and Reynolds numbers. New airfoils sections are proposed and analyzed for straight-bladed turbine

Straight Vegetable Oil as a Diesel Fuel?

Energy Technology Data Exchange (ETDEWEB)

None

2014-01-01

Biodiesel, a renewable fuel produced from animal fats or vegetable oils, is popular among many vehicle owners and fleet managers seeking to reduce emissions and support U.S. energy security. Questions sometimes arise about the viability of fueling vehicles with straight vegetable oil (SVO), or waste oils from cooking and other processes, without intermediate processing. But SVO and waste oils differ from biodiesel (and conventional diesel) in some important ways and are generally not considered acceptable vehicle fuels for large-scale or long-term use.

Path Expressions

Science.gov (United States)

1975-06-01

Traditionally, synchronization of concurrent processes is coded in line by operations on semaphores or similar objects. Path expressions move the...discussion about a variety of synchronization primitives . An analysis of their relative power is found in [3]. Path expressions do not introduce yet...another synchronization primitive . A path expression relates to such primitives as a for- or while-statement of an ALGOL-like language relates to a JUMP

27-GAUGE VITRECTOMY WOUND INTEGRITY: A Randomized Pilot Study Comparing Angled Versus Straight Entry in Fluid-Filled Vitrectomized Eyes.

Science.gov (United States)

Khan, M Ali; Durrani, Alia K; Hsu, Jason; Regillo, Carl D

2018-04-01

To compare clinical outcomes using angled versus straight trocar insertion during 27-gauge pars plana vitrectomy for epiretinal membrane. Pilot randomized controlled trial. Thirty eyes of 30 patients undergoing 27-gauge pars plana vitrectomy with membrane peeling for epiretinal membrane were randomized 1:1 to receive angled or straight trocar insertion. Intraocular pressure (IOP) and postoperative wound-related complications were compared. Fifteen eyes were randomized to each the angled and straight incision groups. No significant difference in phakic status (P = 0.71) or preoperative IOP (15.1 ± 3.4 vs. 14.6 ± 3.0 mmHg, P = 0.67) existed between groups. On postoperative Day 1, eyes in the straight group had lower IOP compared with the angled group (11.8 ± 3.9 vs. 15.3 ± 5.2 mmHg, P = 0.04) and a relative decrease in IOP compared with preoperative values (11.8 ± 3.9 vs. 15.1 ± 3.4 mmHg, P straight group) and serous choroidal detachment (1 eye, angled group). Eyes with straight incisions had transiently lower IOP on postoperative Day 1, possibly suggestive of subclinical wound leak in the very early postoperative period. Overall, rates of hypotony and sclerotomy-related complications were similarly low between wound construction strategies.

Effect of the track potential on the motion and energy flow of secondary electrons created from heavy-ion irradiation

Science.gov (United States)

Moribayashi, Kengo

2018-05-01

Using simulations, we have evaluated the effect of the track potential on the motion and energy flow of secondary electrons, with the goal of determining the spatial distribution of energy deposition due to irradiation with heavy ions. We have simulated this effect as a function of the mean path τ between the incident ion-impact-ionization events at ion energies Eion. Here, the track potential is the potential formed from electric field near this incident ion path. The simulations indicate that this effect is mainly determined by τ and hardly depends on Eion. To understand heavy ion beam science more deeply and to reduce the time required by simulations, we have proposed simple approximation methods that almost reproduce the simulation results here.

Linear Motion Systems. A Modular Approach for Improved Straightness Performance

NARCIS (Netherlands)

Nijsse, G.J.P.

2001-01-01

This thesis deals with straight motion systems. A modular approach has been applied in order to find ways to improve the performance. The main performance parameters that are considered are position accuracy, repeatability and, to a lesser extent, cost. Because of the increasing requirements to

The Roman Road System in the Golan: Highways, Paths and Tracks in Quotidian Life

Directory of Open Access Journals (Sweden)

Pažout Adam

2017-12-01

Full Text Available Roman Imperial Roads (highways built, maintained and organized by the Roman army and provincial authorities were studied in the Golan Heights since Schumacher’s surveys in the 1880s. However, most of these were obliterated by building and agricultural activity since the beginning of the 20th century. Local ancient road system, linking individual communities and their agricultural land was never studied, since it barely leaves a trace in archaeological record. This paper presents reconstruction of inter-provincial highways passing through the southern Golan Heights, and local road system in GIS using cumulative focal mobility network (CFMN analysis. The CFMN provides outline of natural corridors of movement in the region. From CFMN it is possible to extract path with higher mobility potential which will be tested against present evidence for Roman Imperial Highways, since it is assumed that corridors with high mobility potential would be suitable place for construction of (inter-provincial road. Path with lower mobility potential might indicate local road system, so it would be possible to connect agricultural communities with the land they exploited; which in turn may have implications for site prediction and site-catchment analysis exploring quotidian movement of people and goods in the landscape. Two case studies in this respect are presented: the city of Hippos and settlement of es-Safuriyye.

Insurance-markets Equilibrium with Sequential Non-convex Straight-time and Over-time Labor Supply

OpenAIRE

Vasilev, Aleksandar

2016-01-01

This note describes the lottery- and insurance-market equilibrium in an economy with non-convex straight-time and overtime employment. In contrast to Hansen and Sargent (1988), the overtime-decision is a sequential one. This requires two separate insurance market to operate, one for straight-time work, and one for overtime. In addi- tion, given that the labor choice for regular and overtime hours is made in succession, the insurance market for overtime needs to open once the insurance market ...

Different tracks for pathology informatics fellowship training: Experiences of and input from trainees in a large multisite fellowship program

Directory of Open Access Journals (Sweden)

Bruce P Levy

2012-01-01

Full Text Available Background: Pathology Informatics is a new field; a field that is still defining itself even as it begins the formalization, accreditation, and board certification process. At the same time, Pathology itself is changing in a variety of ways that impact informatics, including subspecialization and an increased use of data analysis. In this paper, we examine how these changes impact both the structure of Pathology Informatics fellowship programs and the fellows′ goals within those programs. Materials and Methods: As part of our regular program review process, the fellows evaluated the value and effectiveness of our existing fellowship tracks (Research Informatics, Clinical Two-year Focused Informatics, Clinical One-year Focused Informatics, and Clinical 1 + 1 Subspecialty Pathology and Informatics. They compared their education, informatics background, and anticipated career paths and analyzed them for correlations between those parameters and the fellowship track chosen. All current and past fellows of the program were actively involved with the project. Results: Fellows′ anticipated career paths correlated very well with the specific tracks in the program. A small set of fellows (Clinical - one or two year - Focused Informatics tracks anticipated clinical careers primarily focused in informatics (Director of Informatics. The majority of the fellows, however, anticipated a career practicing in a Pathology subspecialty, using their informatics training to enhance that practice (Clinical 1 + 1 Subspecialty Pathology and Informatics Track. Significantly, all fellows on this track reported they would not have considered a Clinical Two-year Focused Informatics track if it was the only track offered. The Research and the Clinical One-year Focused Informatics tracks each displayed unique value for different situations. Conclusions: It seems a "one size fits all" fellowship structure does not fit the needs of the majority of potential Pathology

Rats track odour trails accurately using a multi-layered strategy with near-optimal sampling.

Science.gov (United States)

Khan, Adil Ghani; Sarangi, Manaswini; Bhalla, Upinder Singh

2012-02-28

Tracking odour trails is a crucial behaviour for many animals, often leading to food, mates or away from danger. It is an excellent example of active sampling, where the animal itself controls how to sense the environment. Here we show that rats can track odour trails accurately with near-optimal sampling. We trained rats to follow odour trails drawn on paper spooled through a treadmill. By recording local field potentials (LFPs) from the olfactory bulb, and sniffing rates, we find that sniffing but not LFPs differ between tracking and non-tracking conditions. Rats can track odours within ~1 cm, and this accuracy is degraded when one nostril is closed. Moreover, they show path prediction on encountering a fork, wide 'casting' sweeps on encountering a gap and detection of reappearance of the trail in 1-2 sniffs. We suggest that rats use a multi-layered strategy, and achieve efficient sampling and high accuracy in this complex task.

Modifications in straight wire treatment.

Science.gov (United States)

Cardona, Alvin

2010-01-01

Orthodontic treatments have been modified with each new generation of clinicians. Today the emphasis is on facial esthetics and healthy temporomandibular joints. With orthopedic treatment, we can develop dental arches to get the necessary space to align the teeth and we can reach adequate function and esthetics, all within relatively good stability. By combining two-phase treatment with low friction fixed orthodontics and super elastic wires we produce light but continuous forces and we can provide better treatment than before. These types of forces cause physiological and functional orthopedic orthodontic reactions. The purpose of this article is to demonstrate our fixed orthopedic and orthodontic approach called "Modified Straight Wire" or "Physiologic Arch Technique." This technique is very successful with our patients because it can exert slow and continuous forces with minimal patient cooperation.

Coupling Between Doppler Radar Signatures and Tornado Damage Tracks

Science.gov (United States)

Jedlovec, Gary J.; Molthan, Andrew L.; Carey, Lawrence; Carcione, Brian; Smith, Matthew; Schultz, Elise V.; Schultz, Christopher; Lafontaine, Frank

2011-01-01

On April 27, 2011, the southeastern United States was raked with several episodes of severe weather. Numerous tornadoes caused extensive damage, and tragically, the deaths of over 300 people. In Alabama alone, there were 61 confirmed tornados, 4 of them produced EF5 damage, and several were on the ground an hour or more with continuous damage tracks exceeding 80km. The use of Doppler radars covering the region provided reflectivity and velocity signatures that allowed forecasters to monitors the severe storms from beginning to end issuing hundreds of severe weather warnings throughout the day. Meteorologists from the the NWS performed extensive surveys to assess the intensity, duration, and ground track of tornadoes reported during the event. Survey activities included site visits to the affected locations, analysis of radar and satellite data, aerial surveys, and interviews with eyewitnesses. Satellite data from NASA's MODIS and ASTER instruments played a helpful role in determining the location of tornado damage paths and in the assessment. High resolution multispectral and temporal composites helped forecasters corroborate their damage assessments, determine starting and ending points for tornado touchdowns, and helped to provide forecasters with a better big-picture view of the damage region. The imagery also helped to separate damage from the April 27th tornados from severe weather that occurred earlier that month. In a post analysis of the outbreak, tornado damage path signatures observed in the NASA satellite data have been correlated to "debris ball" signatures in the NWS Doppler radars and a special ARMOR dual-polarization radar operated by the University of Alabama Huntsville during the event. The Doppler radar data indicates a circular enhanced reflectivity signal and rotational couplet in the radial velocity likely associated with the tornado that is spatially correlated with the damage tracks in the observed satellite data. An algorithm to detect and

Comparison of conventional straight and swan-neck straight catheters inserted by percutaneous method for continuous ambulatory peritoneal dialysis: a single-center study.

Science.gov (United States)

Singh, Shivendra; Prakash, Jai; Singh, R G; Dole, P K; Pant, Pragya

2015-10-01

To evaluate the incidence of mechanical and infectious complications of conventional straight catheter (SC) versus swan-neck straight catheter (SNSC) implanted by percutaneous method. We retrospectively analyzed 45 catheter insertions being done by percutaneous method from January 1, 2011, to May 31, 2014. SC was inserted in 24 patients, and SNSC was inserted in 21 patients. Baseline characteristics for the two groups were similar with respect to age, sex and diabetic nephropathy as the cause for end-stage renal disease. Incidence of mechanical and infectious complications in SNSC group was found to be low as compared to the SC group and was statistically significant (1 in 11.6 patient months vs. 1 in 14.4 patient months, p = 0.02). Catheter migration was found to be the most common mechanical complication (20 %), and peritonitis was found to be the most common infectious complication in conventional SC group (27 episodes in 420 patient months vs. 11 episodes in 333 patient months, p = 0.03). The incidence of exit site and tunnel infection rates revealed no difference between the groups. SNSC insertion by percutaneous method is associated with low mechanical and infectious complications.

Zero-Slack, Noncritical Paths

Science.gov (United States)

Simons, Jacob V., Jr.

2017-01-01

The critical path method/program evaluation and review technique method of project scheduling is based on the importance of managing a project's critical path(s). Although a critical path is the longest path through a network, its location in large projects is facilitated by the computation of activity slack. However, logical fallacies in…

Efficacy of Reciproc(®) and Profile(®) Instruments in the Removal of Gutta-Percha from Straight and Curved Root Canals ex Vivo.

Science.gov (United States)

Marfisi, Karem; Mercadé, Montserrat; Plotino, Gianluca; Clavel, Tatiana; Duran-Sindreu, Fernando; Roig, Miguel

2015-01-01

To compare the efficacy of Reciproc(®) (VDW GmbH) and ProFile(®) (Dentsply Maillefer) instruments at removing gutta-percha from straight and curved root canals ex vivo filled using the cold lateral condensation and GuttaMaster(®) (VDW GmbH) techniques. Forty mesial roots of mandibular molars with two curved canals and 80 single-rooted teeth with straight root canals, a total of 160 root canals, were randomly assigned to eight groups (canals per group = 20) according to filling technique, retreatment instrument and root canal curvature as follows: Group I, cold lateral condensation/ProFile(®)/straight; Group II, cold lateral condensation/ProFile(®)/curved; Group III, cold lateral condensation/Reciproc(®)/straight; Group IV, cold lateral condensation/Reciproc(®)/curved; Group V, GuttaMaster(®)/ProFile(®)/straight; Group VI, GuttaMaster(®)/ProFile(®)/curved; Group VII, GuttaMaster(®)/Reciproc(®)/straight; and Group VIII, GuttaMaster(®)/Reciproc(®)/curved. The following data were recorded: procedural errors, retreatment duration and canal wall cleanliness. Means and standard deviations were calculated and analysed using the Kruskal-Wallis test, one-way analysis of variance and Tukey's test (P straight (P = 0.0001) and curved (P = 0.0003) root canals. Reciproc(®) were statistically more effective than ProFile(®) instruments in removing GuttaMaster(®) from straight root canals (P = 0.021). Regardless of filling technique or retreatment instrument, gutta-percha was removed more rapidly from curved than from straight root canals (P = 0.0001). Neither system completely removed filling material from the root canals. Compared with ProFile(®) instruments, Reciproc(®) instruments removed GuttaMaster(®) filling material from straight and curved root canals more rapidly.

Computer Tomography 3-D Imaging of the Metal Deformation Flow Path in Friction Stir Welding

Science.gov (United States)

Schneider, Judy; Beshears, Ronald; Nunes, Arthur C., Jr.

2004-01-01

In friction stir welding, a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. This solid-state technique has been successfully used in the joining of materials that are difficult to fusion weld such as aluminum alloys. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path is required. Marker studies are the principal method of studying the metal deformation flow path around the FSW pin tool. In our study, we have used computed tomography (CT) scans to reveal the flow pattern of a lead wire embedded in a FSW weld seam. At the welding temperature of aluminum, the lead becomes molten and thus tracks the aluminum deformation flow paths in a unique 3-dimensional manner. CT scanning is a convenient and comprehensive way of collecting and displaying tracer data. It marks an advance over previous more tedious and ambiguous radiographic/metallographic data collection methods.

Identifying and tracking plumes affected by an ocean breeze in support of emergency preparedness

International Nuclear Information System (INIS)

Schwartz, P.E.

1989-01-01

To better support emergency preparedness, General Public Utilities (GPU) Nuclear has investigated the frequency of occurrence of the mesoscale ocean breeze at the Oyster Creek Nuclear Generating Station (OCNGS). Through the analysis of the horizontal wind direction and temperature patterns, simple identification of the ocean breeze along with a plume tracking procedure has been developed and incorporated into the site's emergency plant to better safeguard the public with sophisticated protective action measures in case of a nonroutine release. The ocean breeze will frequently produce wind trajectory fields within the plant's emergency planning zone that are different from the normal gradient wind flow. This could greatly alter proper protective action measures since most utilities employ straight-line trajectory air dispersion models. Knowledge of the existence of the ocean breeze and the location of the ocean breeze front become important in the results generated from the straight-line Gaussian dose calculation methodology and in the further development of a more complex dose assessment model. This paper describes the verification and existence of the sea breeze phenomenon and the incorporation of its effects into the OCNGS emergency plan

Tracking Boulders

Science.gov (United States)

2006-01-01

13 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a trough in the Sirenum Fossae region. On the floor and walls of the trough, large -- truck- to house-sized -- boulders are observed at rest. However, there is evidence in this image for the potential for mobility. In the central portion of the south (bottom) wall, a faint line of depressions extends from near the middle of the wall, down to the rippled trough floor, ending very near one of the many boulders in the area. This line of depressions is a boulder track; it indicates the path followed by the boulder as it trundled downslope and eventually came to rest on the trough floor. Because it is on Mars, even when the boulder is sitting still, this once-rolling stone gathers no moss. Location near: 29.4oS, 146.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

Methodologies for tracking learning paths in the Making a filmmaker research study of young Nordic filmmakers

DEFF Research Database (Denmark)

Frølunde, Lisbeth; Lindstrand, Fredrik; Öhman-Gullberg, Lisa

The aim of this paper is twofold. On the one hand, to present an outline of the ongoing research study Making a filmmaker, which examines how young Nordic filmmakers create their own learning paths along formal and/or informal contexts. Our focus in this paper is especially directed towards issues...

Synthesis and characterization of straight and stacked-sheet AlN nanowires with high purity

International Nuclear Information System (INIS)

Lei, M.; Yang, H.; Li, P.G.; Tang, W.H.

2008-01-01

Large-scale AlN nanowires with hexagonal crystal structure were synthesized by the direct nitridation method at high temperatures. The experimental results indicate that these single-crystalline AlN nanowires have high purity and consist of straight and stacked-sheet nanowires. It is found that straight AlN nanowire grows along [1, 1, -2, 0] direction, whereas the stacked-sheet nanowire with hexagonal cross section is along [0 0 0 1] direction. It is thought that vapor-solid (VS) mechanism should be responsible for the growth of AlN nanowires

Path Creation, Path Dependence and Breaking Away from the Path: Re-Examining the Case of Nokia

OpenAIRE

Wang, Jens; Hedman, Jonas; Tuunainen, Virpi Kristiina

2016-01-01

The explanation of how and why firms succeed or fail is a recurrent research challenge. This is particularly important in the context of technological innovations. We focus on the role of historical events and decisions in explaining such success and failure. Using a case study of Nokia, we develop and extend a multi-layer path dependence framework. We identify four layers of path dependence: technical, strategic and leadership, organizational, and external collaboration. We show how path dep...

Sub-0.1 μm optical track width measurement

Science.gov (United States)

Smith, Richard J.; See, Chung W.; Somekh, Mike G.; Yacoot, Andrew

2005-08-01

In this paper, we will describe a technique that combines a common path scanning optical interferometer with artificial neural networks (ANN), to perform track width measurements that are significantly beyond the capability of conventional optical systems. Artificial neural networks have been used for many different applications. In the present case, ANNs are trained using profiles of known samples obtained from the scanning interferometer. They are then applied to tracks that have not previously been exposed to the networks. This paper will discuss the impacts of various ANN configurations, and the processing of the input signal on the training of the network. The profiles of the samples, which are used as the inputs to the ANNs, are obtained with a common path scanning optical interferometer. It provides extremely repeatable measurements, with very high signal to noise ratio, both are essential for the working of the ANNs. The characteristics of the system will be described. A number of samples with line widths ranging from 60nm-3μm have been measured to test the system. The system can measure line widths down to 60nm with a standard deviation of 3nm using optical wavelength of 633nm and a system numerical aperture of 0.3. These results will be presented in detail along with a discussion of the potential of this technique.

Path-dependent functions

International Nuclear Information System (INIS)

Khrapko, R.I.

1985-01-01

A uniform description of various path-dependent functions is presented with the help of expansion of the type of the Taylor series. So called ''path-integrals'' and ''path-tensor'' are introduced which are systems of many-component quantities whose values are defined for arbitrary paths in coordinated region of space in such a way that they contain a complete information on the path. These constructions are considered as elementary path-dependent functions and are used instead of power monomials in the usual Taylor series. Coefficients of such an expansion are interpreted as partial derivatives dependent on the order of the differentiations or else as nonstandard cavariant derivatives called two-point derivatives. Some examples of pathdependent functions are presented.Space curvature tensor is considered whose geometrica properties are determined by the (non-transitive) translator of parallel transport of a general type. Covariant operation leading to the ''extension'' of tensor fiels is pointed out

Demographic Trends and Advocacy Experiences of Gay-Straight Alliance Advisors

Science.gov (United States)

Graybill, Emily C.; Varjas, Kris; Meyers, Joel; Dever, Bridget V.; Greenberg, Daphne; Roach, Andrew T.; Morillas, Catalina

2015-01-01

Using an ecological model, the individual-, school-, and sociocultural-level characteristics that affect gay-straight alliance (GSA) advisors were examined in the current study. The formation of GSAs has been one way that schools have sought to improve the school climate for lesbian, gay, bisexual, and transgender (LGBT) youth. Limited information…

Controllable synthesis of helical, straight, hollow and nitrogen-doped carbon nanofibers and their magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Li, Xun [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructure, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Xu, Zheng, E-mail: zhengxu@nju.edu.cn [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructure, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

2012-12-15

Graphical abstract: The helical, straight and hollow carbon nanofibers can be selectively synthesized by adjusting either the reaction temperature or feed gas composition. Display Omitted Highlights: ► CNFs were synthesized via pyrolysis of acetylene on copper NPs. ► The helical, straight, hollow and N-doped CNFs can be selectively synthesized. ► The growth mechanism of different types of CNFs was proposed. -- Abstract: Carbon nanofibers (CNFs) with various morphologies were synthesized by catalytic pyrolysis of acetylene on copper nanoparticles which were generated from the in situ decomposition of copper acetylacetonate. The morphology of the pristine and acid-washed CNFs was investigated by field emission scanning electron microscope and high-resolution transmission electron microscope. Helical, straight and hollow CNFs can be selectively synthesized by adjusting either the reaction temperature or feed gas composition. The growth mechanism for these three types of CNFs was proposed.

Head and pelvic movement asymmetry during lungeing in horses with symmetrical movement on the straight.

Science.gov (United States)

Rhodin, M; Roepstorff, L; French, A; Keegan, K G; Pfau, T; Egenvall, A

2016-05-01

Lungeing is commonly used as part of standard lameness examinations in horses. Knowledge of how lungeing influences motion symmetry in sound horses is needed. The aim of this study was to objectively evaluate the symmetry of vertical head and pelvic motion during lungeing in a large number of horses with symmetric motion during straight line evaluation. Cross-sectional prospective study. A pool of 201 riding horses, all functioning well and considered sound by their owners, were evaluated in trot on a straight line and during lungeing to the left and right. From this pool, horses with symmetric vertical head and pelvic movement during the straight line trot (n = 94) were retained for analysis. Vertical head and pelvic movements were measured with body mounted uniaxial accelerometers. Differences between vertical maximum and minimum head (HDmax, HDmin) and pelvic (PDmax, PDmin) heights between left and right forelimb and hindlimb stances were compared between straight line trot and lungeing in either direction. Vertical head and pelvic movements during lungeing were more asymmetric than during trot on a straight line. Common asymmetric patterns seen in the head were more upward movement during push-off of the outside forelimb and less downward movement during impact of the inside limb. Common asymmetric patterns seen in the pelvis were less upward movement during push-off of the outside hindlimb and less downward movement of the pelvis during impact of the inside hindlimb. Asymmetric patterns in one lunge direction were frequently not the same as in the opposite direction. Lungeing induces systematic asymmetries in vertical head and pelvic motion patterns in horses that may not be the same in both directions. These asymmetries may mask or mimic fore- or hindlimb lameness. © 2015 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.

4D tracking with ultra-fast silicon detectors

Science.gov (United States)

F-W Sadrozinski, Hartmut; Seiden, Abraham; Cartiglia, Nicolò

2018-02-01

The evolution of particle detectors has always pushed the technological limit in order to provide enabling technologies to researchers in all fields of science. One archetypal example is the evolution of silicon detectors, from a system with a few channels 30 years ago, to the tens of millions of independent pixels currently used to track charged particles in all major particle physics experiments. Nowadays, silicon detectors are ubiquitous not only in research laboratories but in almost every high-tech apparatus, from portable phones to hospitals. In this contribution, we present a new direction in the evolution of silicon detectors for charge particle tracking, namely the inclusion of very accurate timing information. This enhancement of the present silicon detector paradigm is enabled by the inclusion of controlled low gain in the detector response, therefore increasing the detector output signal sufficiently to make timing measurement possible. After providing a short overview of the advantage of this new technology, we present the necessary conditions that need to be met for both sensor and readout electronics in order to achieve 4D tracking. In the last section, we present the experimental results, demonstrating the validity of our research path.

Leader-Follower Tracking System for Agricultural Vehicles: Fusion of Laser and Odometry Positioning Using Extended Kalman Filter

Directory of Open Access Journals (Sweden)

Zhang Lin Huan

2015-03-01

Full Text Available The aim of this research was to develop a safe human-driven and autonomous leader-follower tracking system for an autonomous tractor. To enable the tracking system, a laser range finder (LRF-based landmark detection system was designed to observe the relative position between a leader and a follower used in agricultural operations. The virtual follower-based formation-tracking algorithm was developed to minimize tracking errors and ensure safety. An extended Kalman filter (EKF was implemented for fusing LRF and odometry position to ensure stability of tracking in noisy farmland conditions. Simulations were conducted for tracking the leader in small and large sinusoidal curved paths. Simulated results verified high accuracy of formation tracking, stable velocity, and regulated steering angle of the follower. The tracking method confirmed the follower could follow the leader with a required formation safely and steadily in noisy conditions. The EKF helped to improve observation accuracy, velocity, and steering angle stability of the follower. As a result of the improved accuracy of observation and motion action, the tracking performance for lateral, longitudinal, and heading were also improved after the EKF was implemented in the tracking system.

STAR reconstruction improvements for tracking with the heavy flavor tracker

Science.gov (United States)

Webb, Jason C.; Lauret, Jérôme; Perevotchikov, Victor; Smirnov, Dmitri; Van Buren, Gene

2017-10-01

The reconstruction and identification of charmed hadron decays provides an important tool for the study of heavy quark behavior in the Quark Gluon Plasma. Such measurements require high resolution to topologically identify decay daughters at vertices displaced demands on track reconstruction software. To enable these measurements at RHIC, the STAR experiment has designed and employed the Heavy Flavor Tracker (HFT). It is composed of silicon-based tracking detectors, providing four layers of high-precision position measurements which are used in combination with hits from the Time Projection Chamber (TPC) to reconstruct track candidates. The STAR integrated tracking software (Sti) has delivered a decade of world-class physics. It was designed to leverage the discrete azimuthal symmetry of the detector and its simple radial ordering of components, permitting a flat representation of the detector geometry in terms of concentric cylinders and planes, and an approximate track propagation code. These design choices reflected a careful balancing of competing priorities, trading precision for speed in track reconstruction. To simplify the task of integrating new detectors, tools were developed to automatically generate the Sti geometry model, tying both reconstruction and simulation to the single source AgML geometry model. The increased precision and complexity of the HFT detector required a careful reassessment of this single geometry path and implementation choices. In this paper we will discuss the test suite and regression tools developed to improve reconstruction with the HFT, our lessons learned in tracking with high precision detectors and the tradeoffs between precision, speed and ease of use which were required.

SU-C-18A-02: Image-Based Camera Tracking: Towards Registration of Endoscopic Video to CT

International Nuclear Information System (INIS)

Ingram, S; Rao, A; Wendt, R; Castillo, R; Court, L; Yang, J; Beadle, B

2014-01-01

Purpose: Endoscopic examinations are routinely performed on head and neck and esophageal cancer patients. However, these images are underutilized for radiation therapy because there is currently no way to register them to a CT of the patient. The purpose of this work is to develop a method to track the motion of an endoscope within a structure using images from standard clinical equipment. This method will be incorporated into a broader endoscopy/CT registration framework. Methods: We developed a software algorithm to track the motion of an endoscope within an arbitrary structure. We computed frame-to-frame rotation and translation of the camera by tracking surface points across the video sequence and utilizing two-camera epipolar geometry. The resulting 3D camera path was used to recover the surrounding structure via triangulation methods. We tested this algorithm on a rigid cylindrical phantom with a pattern spray-painted on the inside. We did not constrain the motion of the endoscope while recording, and we did not constrain our measurements using the known structure of the phantom. Results: Our software algorithm can successfully track the general motion of the endoscope as it moves through the phantom. However, our preliminary data do not show a high degree of accuracy in the triangulation of 3D point locations. More rigorous data will be presented at the annual meeting. Conclusion: Image-based camera tracking is a promising method for endoscopy/CT image registration, and it requires only standard clinical equipment. It is one of two major components needed to achieve endoscopy/CT registration, the second of which is tying the camera path to absolute patient geometry. In addition to this second component, future work will focus on validating our camera tracking algorithm in the presence of clinical imaging features such as patient motion, erratic camera motion, and dynamic scene illumination

An advanced straight tube heat exchanger in which a fluid flows at variable and elevated temperatures

International Nuclear Information System (INIS)

Mauget, C.; Benoit, G.; Stalport, G.

1993-01-01

Straight tube heat exchangers are used as steam generators in nuclear reactors such as in fast neutron nuclear power plants; elevated and highly variable temperatures induce very high thermal expansion constraints in these long straight tubes. In order to avoid the expansion problems, an expansion bellow is disposed between the heat exchanger and the collector tubular plate in such a way that the bundle differential expansions may be absorbed

Comparison of anatomic vs. straight femoral stem design in total hip replacement - femoral canal fill in vivo.

Science.gov (United States)

de Boer, Friso A; Sariali, Elhadi

2017-05-12

The femoral canal fill between an anatomic and a straight prosthesis design in cementless total hip arthroplasty (THA) was compared. We hypothesised that the anatomic SPS stem has higher proximal fill and lesser distal fill than the straight stem. The femoral canal fill was measured on 3 months routine postoperative x-rays at 5 levels of the stem in 50 consecutive patients, aged 35-83 years, who underwent 56 THA procedures by a single surgeon in this hospital. 22 patients received a straight design Ceramconcept Global stem, 34 patients received an anatomic design Symbios SPS stem. Both anteroposterior (AP) and lateral x-rays were combined to suggest a 3-D measurement. On the AP x-rays, the canal fill was significantly higher using the anatomic design stem at the proximal measurement levels, and was significantly higher at the distal levels using the straight stem. With the AP and lateral x-rays combined, the canal fill at the proximal levels was also significantly higher in the anatomic groups, nonsignificantly lower at the central level and significantly lower at the distal levels. In THA surgery, achieving high fill at the metaphysis of the femur and less fill at the diaphysis has been suggested to result in satisfactory outcome and high stability of the prosthesis. This study demonstrated that, compared to straight stem design, an anatomically designed stem has a significantly higher metaphyseal femoral canal fill.

Faller Classification in Older Adults Using Wearable Sensors Based on Turn and Straight-Walking Accelerometer-Based Features.

Science.gov (United States)

Drover, Dylan; Howcroft, Jennifer; Kofman, Jonathan; Lemaire, Edward D

2017-06-07

Faller classification in elderly populations can facilitate preventative care before a fall occurs. A novel wearable-sensor based faller classification method for the elderly was developed using accelerometer-based features from straight walking and turns. Seventy-six older individuals (74.15 ± 7.0 years), categorized as prospective fallers and non-fallers, completed a six-minute walk test with accelerometers attached to their lower legs and pelvis. After segmenting straight and turn sections, cross validation tests were conducted on straight and turn walking features to assess classification performance. The best "classifier model-feature selector" combination used turn data, random forest classifier, and select-5-best feature selector (73.4% accuracy, 60.5% sensitivity, 82.0% specificity, and 0.44 Matthew's Correlation Coefficient (MCC)). Using only the most frequently occurring features, a feature subset (minimum of anterior-posterior ratio of even/odd harmonics for right shank, standard deviation (SD) of anterior left shank acceleration SD, SD of mean anterior left shank acceleration, maximum of medial-lateral first quartile of Fourier transform (FQFFT) for lower back, maximum of anterior-posterior FQFFT for lower back) achieved better classification results, with 77.3% accuracy, 66.1% sensitivity, 84.7% specificity, and 0.52 MCC score. All classification performance metrics improved when turn data was used for faller classification, compared to straight walking data. Combining turn and straight walking features decreased performance metrics compared to turn features for similar classifier model-feature selector combinations.

Bed shear stress distribution in straight channels with arbitrary cross section

DEFF Research Database (Denmark)

Christensen, Henrik Bo; Fredsøe, Jørgen

1998-01-01

The bed shear stress distribution in straight open channels is affected by mechanisms as bed curvature of the cross section profile, shear diffusion, and secondary currents. This paper compares some analytical and numerical methods to estimate the bed shear stress distribution. The methods...

The short straight sections for the LHC

International Nuclear Information System (INIS)

Bergot, J.B.; Coussy, E.; Dambre, P.; Ollivier, Y.; Reynet, D.; Vincent, D.; Rohmig, P.

1999-01-01

In 1995 a close collaboration between CERN, CEA and CNRS has been established for the design, proto-typing and follow-up of industrial series production of a sub-assembly of the Large Hadron Collider (LHC). In this frame, the design office of IPN's Accelerator R and D group has in charge one of these contracts concerning the 386 Short Straight Sections (SSS) and particularly: - the cryostat design; - the study of procedures and tool assembly; - the construction of two prototypes during the year 1999; - the industrialization and the production follow-up for the series SSS. This collaboration will last until the year 2004. (authors)

Radionuclide transport paths in the nearfield - a KBS-3 concept study

International Nuclear Information System (INIS)

Pusch, R.

1990-07-01

The general scope of the study has been to identify and define major paths for radionuclide transport from KBS3 canisters, focusing on the nearfield rock. A primary purpose was to document the hydraulic properties of the 'disturbed zones' around blasted tunnels and it is concluded from compilation of theoretical data and field experiment recording that stress relief and blasting effects combine to form a previous zone that extends to about 1 m from the tunnel periphery. It has an average, isotropic hydraulic conductivity of no less than 10 -8 m/s. A second major purpose of the study was to generalize the structure of granitic rock with respect to water-bearing fractures. Forsmark, Finnsjoen, and Stripa data have been considered and found to support the idea of rather regular 'orthogonal' fracture systems with relatively large spacings. The hydraulically active part of the fractures, which can be characterized by simple statistical distributions of persistence, spacing, and aperture, is formed by channels, which can be taken as plane, straight stripes with constant width and aperture. The width can be assumed on the basis of field observations while the aperture is estimated from the bulk conductivity and the geometry of the fracture network. The major transport paths of the rock have been concretized and combined to form a general simplified model intended for calculation of radionuclide transport through water flow and through diffusion through continuous water passages. This model comprises of a circumscribing pervious zone of 'wall disturbance' around the deposition holes in addition to the fracture channels. (author)

Secondary Flow Phenomena in Rotating Radial Straight Pipes

OpenAIRE

Cheng, K. C.; Wang, Liqiu

1995-01-01

Flow visualization results for secondary flow phenomena near the exit of a rotating radial-axis straight pipe (length ࡁ = 82 cm, inside diameter d = 3.81 cm, ࡁ/d 21.52) are presented to study the stabilizing (relaminarization) and destabilizing (early transition from laminar to turbulent flow) effects of Coriolis forces for Reynolds numbers Re = 500 ∼ 4,500 and rotating speeds n = 0 ∼ 200 rpm. The flow visualization was realised by smoke injection method. The main features of the trans...

Scalar localization by cone-beam computed tomography of cochlear implant carriers: a comparative study between straight and periomodiolar precurved electrode arrays.

Science.gov (United States)

Boyer, Eric; Karkas, Alexandre; Attye, Arnaud; Lefournier, Virginie; Escude, Bernard; Schmerber, Sebastien

2015-03-01

To compare the incidence of dislocation of precurved versus straight flexible cochlear implant electrode arrays using cone-beam computed tomography (CBCT) image analyses. Consecutive nonrandomized case-comparison study. Tertiary referral center. Analyses of patients' CBCT images after cochlear implant surgery. Precurved and straight flexible electrode arrays from two different manufacturers were implanted. A round window insertion was performed in most cases. Two cases necessitated a cochleostomy. The patients' CBCT images were reconstructed in the coronal oblique, sagittal oblique, and axial oblique section. The insertion depth angle and the incidence of dislocation from the scala tympani to the scala vestibuli were determined. The CBCT images and the incidence of dislocation were analyzed in 54 patients (61 electrode arrays). Thirty-one patients were implanted with a precurved perimodiolar electrode array and 30 patients with a straight flexible electrode array. A total of nine (15%) scalar dislocations were observed in both groups. Eight (26%) scalar dislocations were observed in the precurved array group and one (3%) in the straight array group. Dislocation occurred at an insertion depth angle between 170 and 190 degrees in the precurved array group and at approximately 370 degrees in the straight array group. With precurved arrays, dislocation usually occurs in the ascending part of the basal turn of the cochlea. With straight flexible electrode arrays, the incidence of dislocation was lower, and it seems that straight flexible arrays have a higher chance of a confined position within the scala tympani than perimodiolar precurved arrays.

Equilibrium charge distribution on a finite straight one-dimensional wire

Science.gov (United States)

Batle, Josep; Ciftja, Orion; Abdalla, Soliman; Elhoseny, Mohamed; Alkhambashi, Majid; Farouk, Ahmed

2017-09-01

The electrostatic properties of uniformly charged regular bodies are prominently discussed on college-level electromagnetism courses. However, one of the most basic problems of electrostatics that deals with how a continuous charge distribution reaches equilibrium is rarely mentioned at this level. In this work we revisit the problem of equilibrium charge distribution on a straight one-dimensional (1D) wire with finite length. The majority of existing treatments in the literature deal with the 1D wire as a limiting case of a higher-dimensional structure that can be treated analytically for a Coulomb interaction potential between point charges. Surprisingly, different models (for instance, an ellipsoid or a cylinder model) may lead to different results, thus there is even some ambiguity on whether the problem is well-posed. In this work we adopt a different approach where we do not start with any higher-dimensional body that reduces to a 1D wire in the appropriate limit. Instead, our starting point is the obvious one, a finite straight 1D wire that contains charge. However, the new tweak in the model is the assumption that point charges interact with each other via a non-Coulomb power-law interaction potential. This potential is well-behaved, allows exact analytical results and approaches the standard Coulomb interaction potential as a limit. The results originating from this approach suggest that the equilibrium charge distribution for a finite straight 1D wire is a uniform charge density when the power-law interaction potential approaches the Coulomb interaction potential as a suitable limit. We contrast such a finding to results obtained using a different regularised logarithmic interaction potential which allows exact treatment in 1D. The present self-contained material may be of interest to instructors teaching electromagnetism as well as students who will discover that simple-looking problems may sometimes pose important scientific challenges.

Equilibrium charge distribution on a finite straight one-dimensional wire

International Nuclear Information System (INIS)

Batle, Josep; Ciftja, Orion; Abdalla, Soliman; Elhoseny, Mohamed; Farouk, Ahmed; Alkhambashi, Majid

2017-01-01

The electrostatic properties of uniformly charged regular bodies are prominently discussed on college-level electromagnetism courses. However, one of the most basic problems of electrostatics that deals with how a continuous charge distribution reaches equilibrium is rarely mentioned at this level. In this work we revisit the problem of equilibrium charge distribution on a straight one-dimensional (1D) wire with finite length. The majority of existing treatments in the literature deal with the 1D wire as a limiting case of a higher-dimensional structure that can be treated analytically for a Coulomb interaction potential between point charges. Surprisingly, different models (for instance, an ellipsoid or a cylinder model) may lead to different results, thus there is even some ambiguity on whether the problem is well-posed. In this work we adopt a different approach where we do not start with any higher-dimensional body that reduces to a 1D wire in the appropriate limit. Instead, our starting point is the obvious one, a finite straight 1D wire that contains charge. However, the new tweak in the model is the assumption that point charges interact with each other via a non-Coulomb power-law interaction potential. This potential is well-behaved, allows exact analytical results and approaches the standard Coulomb interaction potential as a limit. The results originating from this approach suggest that the equilibrium charge distribution for a finite straight 1D wire is a uniform charge density when the power-law interaction potential approaches the Coulomb interaction potential as a suitable limit. We contrast such a finding to results obtained using a different regularised logarithmic interaction potential which allows exact treatment in 1D. The present self-contained material may be of interest to instructors teaching electromagnetism as well as students who will discover that simple-looking problems may sometimes pose important scientific challenges. (paper)

Path Tortuosity and the Permeability of Roads and Trails to Wolf Movement

Directory of Open Access Journals (Sweden)

Jesse Whittington

2004-06-01

Full Text Available Few studies have examined the effects of human development on fine-scale movement behavior, yet understanding animal movement through increasingly human-dominated landscapes is essential for the persistence of many wild populations, especially wary species. In mountainous areas, roads and trails may be particularly deserving of study because they are concentrated in the valley bottoms where they can impede animal movement both across and between valleys. In this study, we tracked wolf (Canis lupus movement in the snow for two winters in Jasper National Park, Alberta, Canada to examine how wolves navigate through or around human-use features. We quantified the effects of human development and topography on the tortuosity of wolf paths and then tested the permeability of roads, trails, and a railway line to wolf movement by comparing the frequency with which actual wolf paths and a null model of random paths crossed these features. Wolf path tortuosity increased near high-use trails, within areas of high-trail and road density, near predation sites, and in rugged terrain. Wolves crossed all roads, trails, and the railway line 9.7% less often than expected, but avoided crossing high-use roads more than low-use trails. Surprisingly, trails affected movement behavior of wolves equally, if not more, than roads. These results suggest that although roads and trails in this study were not absolute barriers to wolf movement, they altered wolf movements across their territories.

Minimum Time Trajectory Optimization of CNC Machining with Tracking Error Constraints

Directory of Open Access Journals (Sweden)

Qiang Zhang

2014-01-01

Full Text Available An off-line optimization approach of high precision minimum time feedrate for CNC machining is proposed. Besides the ordinary considered velocity, acceleration, and jerk constraints, dynamic performance constraint of each servo drive is also considered in this optimization problem to improve the tracking precision along the optimized feedrate trajectory. Tracking error is applied to indicate the servo dynamic performance of each axis. By using variable substitution, the tracking error constrained minimum time trajectory planning problem is formulated as a nonlinear path constrained optimal control problem. Bang-bang constraints structure of the optimal trajectory is proved in this paper; then a novel constraint handling method is proposed to realize a convex optimization based solution of the nonlinear constrained optimal control problem. A simple ellipse feedrate planning test is presented to demonstrate the effectiveness of the approach. Then the practicability and robustness of the trajectory generated by the proposed approach are demonstrated by a butterfly contour machining example.

Adaptive DIT-Based Fringe Tracking and Prediction at IOTA

Science.gov (United States)

Wilson, Edward; Pedretti, Ettore; Bregman, Jesse; Mah, Robert W.; Traub, Wesley A.

2004-01-01

An automatic fringe tracking system has been developed and implemented at the Infrared Optical Telescope Array (IOTA). In testing during May 2002, the system successfully minimized the optical path differences (OPDs) for all three baselines at IOTA. Based on sliding window discrete Fourier transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on off-line data. Implemented in ANSI C on the 266 MHZ PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. Preliminary analysis on an extension of this algorithm indicates a potential for predictive tracking, although at present, real-time implementation of this extension would require significantly more computational capacity.

MinePath: Mining for Phenotype Differential Sub-paths in Molecular Pathways

Science.gov (United States)

Koumakis, Lefteris; Kartsaki, Evgenia; Chatzimina, Maria; Zervakis, Michalis; Vassou, Despoina; Marias, Kostas; Moustakis, Vassilis; Potamias, George

2016-01-01

Pathway analysis methodologies couple traditional gene expression analysis with knowledge encoded in established molecular pathway networks, offering a promising approach towards the biological interpretation of phenotype differentiating genes. Early pathway analysis methodologies, named as gene set analysis (GSA), view pathways just as plain lists of genes without taking into account either the underlying pathway network topology or the involved gene regulatory relations. These approaches, even if they achieve computational efficiency and simplicity, consider pathways that involve the same genes as equivalent in terms of their gene enrichment characteristics. Most recent pathway analysis approaches take into account the underlying gene regulatory relations by examining their consistency with gene expression profiles and computing a score for each profile. Even with this approach, assessing and scoring single-relations limits the ability to reveal key gene regulation mechanisms hidden in longer pathway sub-paths. We introduce MinePath, a pathway analysis methodology that addresses and overcomes the aforementioned problems. MinePath facilitates the decomposition of pathways into their constituent sub-paths. Decomposition leads to the transformation of single-relations to complex regulation sub-paths. Regulation sub-paths are then matched with gene expression sample profiles in order to evaluate their functional status and to assess phenotype differential power. Assessment of differential power supports the identification of the most discriminant profiles. In addition, MinePath assess the significance of the pathways as a whole, ranking them by their p-values. Comparison results with state-of-the-art pathway analysis systems are indicative for the soundness and reliability of the MinePath approach. In contrast with many pathway analysis tools, MinePath is a web-based system (www.minepath.org) offering dynamic and rich pathway visualization functionality, with the

Novel Straight and Circular Road Driving Control of Electric Power Assisted Wheelchair Based on Fuzzy Algorithm

Science.gov (United States)

Seki, Hirokazu; Tadakuma, Susumu

This paper describes a novel straight and circular road driving control scheme for electric power assisted wheelchairs. “Electric power assisted wheelchair” which assists the driving force by electric motors is expected to be widely used as a mobility support system for elderly people and disabled people, however, the performance of the straight and circular road driving must be further improved because the two wheels drive independently. This paper proposes a novel driving control scheme based on fuzzy algorithm to realize the stable and reliable driving on straight and circular roads. The suitable assisted torque of the right and left wheels is determined by fuzzy algorithm based on the posture angular velocity of the wheelchair and the human input torque proportion of the right and left wheels. Some experiments on the practical roads show the effectiveness of the proposed control system.

Review of the analysis methods of surface crack for straight pipe and elbow

International Nuclear Information System (INIS)

Kim, H. S.; Jang, Y. S.; Jin, T. E.

1999-01-01

The objective of this paper is to find out optimum EPFM analysis methods of straight pipe and elbow by comparison of load-carrying capacities. To do this, analytical and finite element analyses were performed and then these results compared with the ones in the literatures and experimental data to verify the validity of the analysis results. Comparison results showed that NSC method for straight pipe and SC.ELB2 method for elbow were appropriate ones among analytical methods except FEM to predict load-carrying capacities. However, the trend of prediction results scattered according to the analysis conditions such as geometry and material as well as analytical methods, it is necessary for cautious application of the analytical methods

The free energy profile of tubulin straight-bent conformational changes, with implications for microtubule assembly and drug discovery.

Directory of Open Access Journals (Sweden)

Lili X Peng

2014-02-01

Full Text Available αβ-tubulin dimers need to convert between a 'bent' conformation observed for free dimers in solution and a 'straight' conformation required for incorporation into the microtubule lattice. Here, we investigate the free energy landscape of αβ-tubulin using molecular dynamics simulations, emphasizing implications for models of assembly, and modulation of the conformational landscape by colchicine, a tubulin-binding drug that inhibits microtubule polymerization. Specifically, we performed molecular dynamics, potential-of-mean force simulations to obtain the free energy profile for unpolymerized GDP-bound tubulin as a function of the ∼12° intradimer rotation differentiating the straight and bent conformers. Our results predict that the unassembled GDP-tubulin heterodimer exists in a continuum of conformations ranging between straight and bent, but, in agreement with existing structural data, suggests that an intermediate bent state has a lower free energy (by ∼1 kcal/mol and thus dominates in solution. In agreement with predictions of the lattice model of microtubule assembly, lateral binding of two αβ-tubulins strongly shifts the conformational equilibrium towards the straight state, which is then ∼1 kcal/mol lower in free energy than the bent state. Finally, calculations of colchicine binding to a single αβ-tubulin dimer strongly shifts the equilibrium toward the bent states, and disfavors the straight state to the extent that it is no longer thermodynamically populated.

Common-path low-coherence interferometry fiber-optic sensor guided microincision

Science.gov (United States)

Zhang, Kang; Kang, Jin U.

2011-09-01

We propose and demonstrate a common-path low-coherence interferometry (CP-LCI) fiber-optic sensor guided precise microincision. The method tracks the target surface and compensates the tool-to-surface relative motion with better than +/-5 μm resolution using a precision micromotor connected to the tool tip. A single-fiber distance probe integrated microdissector was used to perform an accurate 100 μm incision into the surface of an Intralipid phantom. The CP-LCI guided incision quality in terms of depth was evaluated afterwards using three-dimensional Fourier-domain optical coherence tomography imaging, which showed significant improvement of incision accuracy compared to free-hand-only operations.

Straight and chopped DC performance data for a reliance EV-250AT motor with a General Electric EV-1 controller

Science.gov (United States)

Edie, P. C.

1981-01-01

Straight and chopped DC motor performances for a Reliance EV-250AT motor with an EV-1 controller were examined. Effects of motor temperature and operating voltage are shown. It is found that the maximum motor efficiency is approximately 85% at low operating temperatures in the straight DC mode. Chopper efficiency is 95% under all operating conditions. For equal speeds, the motor operated in the chopped mode develops slightly more torque and draws more current than it does in the straight DC mode.

Eye-Tracking Study on Facial Emotion Recognition Tasks in Individuals with High-Functioning Autism Spectrum Disorders

Science.gov (United States)

Tsang, Vicky

2018-01-01

The eye-tracking experiment was carried out to assess fixation duration and scan paths that individuals with and without high-functioning autism spectrum disorders employed when identifying simple and complex emotions. Participants viewed human photos of facial expressions and decided on the identification of emotion, the negative-positive emotion…

Spatial connectivity in a highly heterogeneous aquifer: From cores to preferential flow paths

Science.gov (United States)

Bianchi, M.; Zheng, C.; Wilson, C.; Tick, G.R.; Liu, Gaisheng; Gorelick, S.M.

2011-01-01

This study investigates connectivity in a small portion of the extremely heterogeneous aquifer at the Macrodispersion Experiment (MADE) site in Columbus, Mississippi. A total of 19 fully penetrating soil cores were collected from a rectangular grid of 4 m by 4 m. Detailed grain size analysis was performed on 5 cm segments of each core, yielding 1740 hydraulic conductivity (K) estimates. Three different geostatistical simulation methods were used to generate 3-D conditional realizations of the K field for the sampled block. Particle tracking calculations showed that the fastest particles, as represented by the first 5% to arrive, converge along preferential flow paths and exit the model domain within preferred areas. These 5% fastest flow paths accounted for about 40% of the flow. The distribution of preferential flow paths and particle exit locations is clearly influenced by the occurrence of clusters formed by interconnected cells with K equal to or greater than the 0.9 decile of the data distribution (10% of the volume). The fraction of particle paths within the high-K clusters ranges from 43% to 69%. In variogram-based K fields, some of the fastest paths are through media with lower K values, suggesting that transport connectivity may not require fully connected zones of relatively homogenous K. The high degree of flow and transport connectivity was confirmed by the values of two groups of connectivity indicators. In particular, the ratio between effective and geometric mean K (on average, about 2) and the ratio between the average arrival time and the arrival time of the fastest particles (on average, about 9) are consistent with flow and advective transport behavior characterized by channeling along preferential flow paths. ?? 2011 by the American Geophysical Union.

Straight spinning cosmic strings in Brans-Dicke gravity

Science.gov (United States)

Dos Santos, S. Mittmann; da Silva, J. M. Hoff; Cindra, J. L.

2018-03-01

An exact solution of straight spinning cosmic strings in Brans-Dicke theory of gravitation is presented. The possibility of the existence of closed time-like curves around these cosmic strings is analyzed. Furthermore, the stability about the formation of the topological defect discussed here is checked. It is shown that the existence of a suitable choice for the integration constants in which closed time-like curves are not allowed. We also study the (im)possibility of using the obtained spacetime in the rotational curves problem.

A fast track path improves access to palliative care for people with learning disabilities.

Science.gov (United States)

Whitington, Jane; Ma, Peng

People with learning disabilities often experience inequalities in accessing general health services. This group, their families and carers need access to effective palliative care when facing a life limiting illness. This article describes the development and implementation of a fast track referral pathway for people with learning disabilities at St Francis Hospice in Essex. Our aim is to share this pathway so others can replicate the collaborative working to improve access to palliative care services for this group.

Transitions in pedestrian fundamental diagrams of straight corridors and T-junctions

International Nuclear Information System (INIS)

Zhang, J; Klingsch, W; Schadschneider, A; Seyfried, A

2011-01-01

Many observations of pedestrian dynamics, including various self-organization phenomena, have been reproduced successfully by different models. But the empirical databases for quantitative calibration are still insufficient, e.g. the fundamental diagram as one of the most important relationships displays non-negligible differences among various studies. To improve this situation, experiments in straight corridors and T-junctions are performed. Four different measurement methods are defined to study their effects on the fundamental diagram. It is shown that they have minor influences for ρ −2 but only the Voronoi method is able to resolve the fine structure of the fundamental diagram. This enhanced measurement method permits us to observe the occurrence of a boundary-induced phase transition. For corridors of different widths we found that the specific flow concept works well for ρ −2 . Moreover, we illustrate the discrepancies between the fundamental diagrams of a T-junction and a straight corridor

Radiation-induced desulfurization of Arabian crude oil and straight-run diesel

International Nuclear Information System (INIS)

Basfar, A.A.; Mohamed, K.A.

2011-01-01

Radiation-induced desulfurization of four types of Arabian crude oils (heavy, medium, light and extra light) and straight-run diesel (SRD) was investigated over the range of 10-200 kGy. Results show that gamma radiation processing at absorbed doses up to 200 kGy without further treatment is not sufficient for desulfurization. However, the combination of gamma-irradiation with other physical/chemical processes (i.e. L/L extraction, adsorption and oxidation) may be capable of removing considerable levels of sulfur compounds in the investigated products. Currently, this approach of combined radiation/physical/chemical processes is under investigation. The findings of these attempts will be reported in the future. - Highlights: → Irradiation effect on desulfurization in Arabian crude oils and straight-run diesel was investigated. → No noticeable changes in sulfur content after irradiation up to 200 kGy were observed. → Stricter regulations on sulfur levels in fuels motivate search for improved desulfurization processes. → Limited investigations on radiation-induced desulfurization of oil products are conducted.

Restoration of lumbopelvic sagittal alignment and its maintenance following transforaminal lumbar interbody fusion (TLIF): comparison between straight type versus curvilinear type cage.

Science.gov (United States)

Kim, Jong-Tae; Shin, Myung-Hoon; Lee, Ho-Jin; Choi, Du-Yong

2015-11-01

To evaluate a radiological and clinical difference between the curvilinear type cages compared to the straight type cages for the restoration of lumbopelvic sagittal alignment and its maintenance after transforaminal lumbar interbody fusion (TLIF) procedure. 68 patients who underwent single-level TLIF using either the straight type or curvilinear type cage were retrospectively reviewed. Assessment of the lumbopelvic parameters and the height of disc space was performed before surgery as well as 2 days, 6 and 12 months after surgery. Clinical outcome was assessed using VAS and ODI. The curvilinear type cages were positioned more anteriorly than the straight type. Restoration of the segmental lordosis (SL) in the curvilinear group was significantly greater than the straight group and at 12 months of follow-up, the straight group showed greater decrease in the disc height than the curvilinear group. The straight group failed to show improvement of lumbar lordosis (LL), while the curvilinear group showed significant restoration of LL and could maintain it to the 6 months of follow-up. In both groups, pelvic tilt was significantly decreased and it lasted to 6 months in the straight group; whereas in the curvilinear group, it was maintained to the last follow-up of 12 months. There were no significant differences between the two groups in mean VAS and ODI score over the follow-up period. This study demonstrates that the curvilinear type cage is superior to the straight type cage in improving the SL and maintaining both the restored lumbopelvic parameters and elevated disc height. These results could be attributable to the anterior position of the curvilinear cage which permits easy restoration of segmental lordosis and less sinking of cages.

Multi-AGV path planning with double-path constraints by using an improved genetic algorithm.

Directory of Open Access Journals (Sweden)

Zengliang Han

Full Text Available This paper investigates an improved genetic algorithm on multiple automated guided vehicle (multi-AGV path planning. The innovations embody in two aspects. First, three-exchange crossover heuristic operators are used to produce more optimal offsprings for getting more information than with the traditional two-exchange crossover heuristic operators in the improved genetic algorithm. Second, double-path constraints of both minimizing the total path distance of all AGVs and minimizing single path distances of each AGV are exerted, gaining the optimal shortest total path distance. The simulation results show that the total path distance of all AGVs and the longest single AGV path distance are shortened by using the improved genetic algorithm.

Multiphase Interface Tracking with Fast Semi-Lagrangian Contouring.

Science.gov (United States)

Li, Xiaosheng; He, Xiaowei; Liu, Xuehui; Zhang, Jian J; Liu, Baoquan; Wu, Enhua

2016-08-01

We propose a semi-Lagrangian method for multiphase interface tracking. In contrast to previous methods, our method maintains an explicit polygonal mesh, which is reconstructed from an unsigned distance function and an indicator function, to track the interface of arbitrary number of phases. The surface mesh is reconstructed at each step using an efficient multiphase polygonization procedure with precomputed stencils while the distance and indicator function are updated with an accurate semi-Lagrangian path tracing from the meshes of the last step. Furthermore, we provide an adaptive data structure, multiphase distance tree, to accelerate the updating of both the distance function and the indicator function. In addition, the adaptive structure also enables us to contour the distance tree accurately with simple bisection techniques. The major advantage of our method is that it can easily handle topological changes without ambiguities and preserve both the sharp features and the volume well. We will evaluate its efficiency, accuracy and robustness in the results part with several examples.

Biomechanical differences in the stem straightening process among Pinus pinaster provenances. A new approach for early selection of stem straightness.

Science.gov (United States)

Sierra-de-Grado, Rosario; Pando, Valentín; Martínez-Zurimendi, Pablo; Peñalvo, Alejandro; Báscones, Esther; Moulia, Bruno

2008-06-01

Stem straightness is an important selection trait in Pinus pinaster Ait. breeding programs. Despite the stability of stem straightness rankings in provenance trials, the efficiency of breeding programs based on a quantitative index of stem straightness remains low. An alternative approach is to analyze biomechanical processes that underlie stem form. The rationale for this selection method is that genetic differences in the biomechanical processes that maintain stem straightness in young plants will continue to control stem form throughout the life of the tree. We analyzed the components contributing most to genetic differences among provenances in stem straightening processes by kinetic analysis and with a biomechanical model defining the interactions between the variables involved (Fournier's model). This framework was tested on three P. pinaster provenances differing in adult stem straightness and growth. One-year-old plants were tilted at 45 degrees, and individual stem positions and sizes were recorded weekly for 5 months. We measured the radial extension of reaction wood and the anatomical features of wood cells in serial stem cross sections. The integral effect of reaction wood on stem leaning was computed with Fournier's model. Responses driven by both primary and secondary growth were involved in the stem straightening process, but secondary-growth-driven responses accounted for most differences among provenances. Plants from the straight-stemmed provenance showed a greater capacity for stem straightening than plants from the sinuous provenances mainly because of (1) more efficient reaction wood (higher maturation strains) and (2) more pronounced secondary-growth-driven autotropic decurving. These two process-based traits are thus good candidates for early selection of stem straightness, but additional tests on a greater number of genotypes over a longer period are required.

The Effect of Adherence to Dietary Tracking on Weight Loss: Using HLM to Model Weight Loss over Time.

Science.gov (United States)

Ingels, John Spencer; Misra, Ranjita; Stewart, Jonathan; Lucke-Wold, Brandon; Shawley-Brzoska, Samantha

2017-01-01

The role of dietary tracking on weight loss remains unexplored despite being part of multiple diabetes and weight management programs. Hence, participants of the Diabetes Prevention and Management (DPM) program (12 months, 22 sessions) tracked their food intake for the duration of the study. A scatterplot of days tracked versus total weight loss revealed a nonlinear relationship. Hence, the number of possible tracking days was divided to create the 3 groups of participants: rare trackers (66% total days tracked). After controlling for initial body mass index, hemoglobin A 1c , and gender, only consistent trackers had significant weight loss (-9.99 pounds), following a linear relationship with consistent loss throughout the year. In addition, the weight loss trend for the rare and inconsistent trackers followed a nonlinear path, with the holidays slowing weight loss and the onset of summer increasing weight loss. These results show the importance of frequent dietary tracking for consistent long-term weight loss success.

Available friction of ladder shoes and slip potential for climbing on a straight ladder.

Science.gov (United States)

Chang, Wen-Ruey; Chang, Chien-Chi; Matz, Simon

2005-07-15

Straight ladder accidents are a major safety problem. As a leading cause of injuries involving straight ladders, slips at the ladder base occur when the required friction exceeds the available friction at the ladder shoe and floor interface. The objectives of this experiment were to measure the available friction at the base of a portable straight ladder in contact with a floor and to estimate the slip potential of the ladder. The results of friction measurements indicated that the measured friction coefficient on the oily surfaces differed among the six commercially available ladder shoes evaluated. A statistical model was used to compare the available friction results from the current study with the friction requirements under different climbing conditions from a previous study based on their stochastic distributions to estimate the slip potential at the base of the ladder. The results showed that different climbing conditions used in the previous study could be supported by available friction on dry surfaces. However, when the ladder was put onto oily surfaces, resulting in a significant reduction in the available friction due to contamination, slip potential was significantly increased.

Effect of Hartmann layer resolution for MHD flow in a straight ...

Indian Academy of Sciences (India)

851–861. c Indian Academy of Sciences. Effect of Hartmann layer resolution for MHD flow in a straight, conducting duct at high Hartmann numbers. SHARANYA SUBRAMANIAN1,∗, P K SWAIN2,. A V DESHPANDE1 and P SATYAMURTHY2. 1Mechanical Engineering Department, Veermata Jijabai Technological Institute,.

Straight A's: Public Education Policy and Progress. Volume 12, Number 2

Science.gov (United States)

Amos, Jason, Ed.

2012-01-01

"Straight A's: Public Education Policy and Progress" is a biweekly newsletter that focuses on education news and events both in Washington, DC and around the country. The following articles are included in this issue: (1) Waiving Away High School Graduation Rate Accountability?: State NCLB Waiver Proposals Threaten to Weaken…

Straight-run vs. sex separate rearing for 2 broiler genetic lines Part 1: Live production parameters, carcass yield, and feeding behavior.

Science.gov (United States)

Da Costa, M J; Zaragoza-Santacruz, S; Frost, T J; Halley, J; Pesti, G M

2017-08-01

The objective of this experiment was to evaluate the effects of raising broilers under sex separate and straight-run conditions for 2 broiler strains. Day-old Ross 308 and Ross 708 chicks (n = 1,344) were separated by sex and placed in 48 pens according to the rearing type: sex separate (28 males or 28 females) or straight-run (14 males + 14 females). There were 3 dietary phases: starter (zero to 17 d), grower (17 to 32 d), and finisher (32 to 48 d). Birds' individual BW and feed intakes were measured at 12, 17, 25, 32, 42, and 48 d to evaluate performance. At 33, 43, and 49 d, 4 birds per pen were sampled for carcass yield evaluation. Additionally, from 06:00 to 06:30, 13:00 to 13:30, and 22:00 to 22:30, video records were taken to assess behavior at 45 days. Data were analyzed as CRD with a 2 × 3 factorial arrangement of treatments over time. Throughout the experiment Ross 308 were heavier than the 708, and after 17 d, male pens had the heavier birds, followed by straight-run and then females. Straight-run pens had higher BW CV in comparison with sex separate pens. Sex separate male BW was negatively impacted from 17 to 32 days. On the other hand, females raised sex separate were heavier than females raised straight-run with lower CV from 25 to 41 days. Post 25 d, FCR was the lowest in male pens whereas feed intake was the highest for these pens after 17 days. Overall, males had total carcass cut-up weights higher than straight-run and females at the 3 processing times. The Ross 708 had higher white meat yields, whereas 308 had higher yields for dark meat. Feeding behavior results were not consistent over time. However, from 13:00 to 13:30, birds in female pens spent more time eating, followed by straight-run and then males. In conclusion, raising females in a straight-run system negatively impacted performance and CV, whereas males benefited from straight-run rearing, with the differences being possibly related to feeder space competition. © 2017

Integral transforms of the quantum mechanical path integral: Hit function and path-averaged potential

Science.gov (United States)

Edwards, James P.; Gerber, Urs; Schubert, Christian; Trejo, Maria Anabel; Weber, Axel

2018-04-01

We introduce two integral transforms of the quantum mechanical transition kernel that represent physical information about the path integral. These transforms can be interpreted as probability distributions on particle trajectories measuring respectively the relative contribution to the path integral from paths crossing a given spatial point (the hit function) and the likelihood of values of the line integral of the potential along a path in the ensemble (the path-averaged potential).

Object tracking using multiple camera video streams

Science.gov (United States)

Mehrubeoglu, Mehrube; Rojas, Diego; McLauchlan, Lifford

2010-05-01

Two synchronized cameras are utilized to obtain independent video streams to detect moving objects from two different viewing angles. The video frames are directly correlated in time. Moving objects in image frames from the two cameras are identified and tagged for tracking. One advantage of such a system involves overcoming effects of occlusions that could result in an object in partial or full view in one camera, when the same object is fully visible in another camera. Object registration is achieved by determining the location of common features in the moving object across simultaneous frames. Perspective differences are adjusted. Combining information from images from multiple cameras increases robustness of the tracking process. Motion tracking is achieved by determining anomalies caused by the objects' movement across frames in time in each and the combined video information. The path of each object is determined heuristically. Accuracy of detection is dependent on the speed of the object as well as variations in direction of motion. Fast cameras increase accuracy but limit the speed and complexity of the algorithm. Such an imaging system has applications in traffic analysis, surveillance and security, as well as object modeling from multi-view images. The system can easily be expanded by increasing the number of cameras such that there is an overlap between the scenes from at least two cameras in proximity. An object can then be tracked long distances or across multiple cameras continuously, applicable, for example, in wireless sensor networks for surveillance or navigation.

Storm-tracks interannual variability and large-scale climate modes

Science.gov (United States)

Liberato, Margarida L. R.; Trigo, Isabel F.; Trigo, Ricardo M.

2013-04-01

In this study we focus on the interannual variability and observed changes in northern hemisphere mid-latitude storm-tracks and relate them to large scale atmospheric circulation variability modes. Extratropical storminess, cyclones dominant paths, frequency and intensity have long been the object of climatological studies. The analysis of storm characteristics and historical trends presented here is based on the cyclone detecting and tracking algorithm first developed for the Mediterranean region (Trigo et al. 1999) and recently extended to a larger Euro-Atlantic region (Trigo 2006). The objective methodology, which identifies and follows individual lows as minima in SLP fields, fulfilling a set of conditions regarding the central pressure and the pressure gradient, is applied to the northern hemisphere 6-hourly geopotential data at 1000 hPa from the 20th Century Reanalyses (20CRv2) project and from reanalyses datasets provided by the European Centre for Medium-Range Weather Forecasts (ECMWF): ERA-40 and ERA Interim reanalyses. First, we assess the interannual variability and cyclone frequency trends for each of the datasets, for the 20th century and for the period between 1958 and 2002 using the highest spatial resolution available (1.125° x 1.125°) from the ERA-40 data. Results show that winter variability of storm paths, cyclone frequency and travel times is in agreement with the reported variability in a number of large-scale climate patterns (including the North Atlantic Oscillation, the East Atlantic Pattern and the Scandinavian Pattern). In addition, three storm-track databases are built spanning the common available extended winter seasons from October 1979 to March 2002. Although relatively short, this common period allows a comparison of systems represented in reanalyses datasets with distinct horizontal resolutions. This exercise is mostly focused on the key areas of cyclogenesis and cyclolysis and main cyclone characteristics over the northern

Questa baseline and pre-mining ground-water quality investigation. 5. Well installation, water-level data, and surface- and ground-water geochemistry in the Straight Creek drainage basin, Red River Valley, New Mexico, 2001-03

Science.gov (United States)

Naus, Cheryl A.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Donohoe, Lisa C.; Hunt, Andrew G.; Paillet, Frederick L.; Morin, Roger H.; Verplanck, Philip L.

2005-01-01

selected samplings. One set of ground-water samples was collected for helium-3/tritium and chlorofluorocarbon (CFC) age dating. Several lines of evidence indicate that surface water is the primary input to the Straight Creek ground-water system. Straight Creek streamflow and water levels in wells closest to the apex of the Straight Creek debris fan and closest to Straight Creek itself appear to respond to the same seasonal inputs. Oxygen and hydrogen isotopic compositions in Straight Creek surface water and ground water are similar, and concentrations of most dissolved constituents in most Straight Creek surface-water and shallow (debris-flow and alluvial) aquifer ground-water samples correlate strongly with sulfate (concentrations decrease linearly with sulfate in a downgradient direction). After infiltration of surface water, dilution along the flow path is the dominant mechanism controlling ground-water chemistry. However, concentrations of some constituents can be higher in ground water than can be accounted for by concentrations in Straight Creek surface water, and additional sources of these constituents must therefore be inferred. Constituents for which concentrations in ground water can be high relative to surface water include calcium, magnesium, strontium, silica, sodium, and potassium in ground water from debris-flow and alluvial aquifers and manganese, calcium, magnesium, strontium, sodium, and potassium in ground water from the bedrock aquifer. All ground water is a calcium sulfate type, often at or near gypsum saturation because of abundant gypsum in the aquifer material developed from co-existing calcite and pyrite mineralization. Calcite dissolution, the major buffering mechanism for bedrock aquifer ground water, also contributes to relatively higher calcium concentrations in some ground water. The main source of the second most abundant cation, magnesium, is probably dissolution of magnesium-rich carbonates or silicates. Strontium may also be

On methodical problems in estimating geological temperature and time from measurements of fission tracks in apatite

International Nuclear Information System (INIS)

Jonckheere, R.

2003-01-01

The results of apatite fission-track modelling are only as accurate as the method, and depend on the assumption that the processes involved in the annealing of fossil tracks over geological times are the same as those responsible for the annealing of induced fission tracks in laboratory experiments. This has hitherto been assumed rather than demonstrated. The present critical discussion identifies a number of methodical problems from an examination of the available data on age standards, borehole samples and samples studied in the framework of geological investigations. These problems are related to low- ( 60 deg. C) annealing on a geological timescale and to the procedures used for calculating temperature-time paths from the fission-track data. It is concluded that it is not established that the relationship between track length and track density and the appearance of unetchable gaps, observed in laboratory annealing experiments on induced tracks, can be extrapolated to the annealing of fossil tracks on a geological timescale. This in turn casts doubt on the central principle of equivalent time. That such uncertainties still exist is in no small part due to an insufficient understanding of the formation, structure and properties of fission tracks at the atomic scale and to a lack of attention to the details of track revelation. The methodical implications of discrepancies between fission track results and the independent geological evidence are rarely considered. This presents a strong case for the re-involvement of track physicists in fundamental fission track research

Object Tracking with LiDAR: Monitoring Taxiing and Landing Aircraft

Directory of Open Access Journals (Sweden)

Zoltan Koppanyi

2018-02-01

Full Text Available Mobile light detection and ranging (LiDAR sensors used in car navigation and robotics, such as the Velodyne’s VLP-16 and HDL-32E, allow for sensing the surroundings of the platform with high temporal resolution to detect obstacles, tracking objects and support path planning. This study investigates the feasibility of using LiDAR sensors for tracking taxiing or landing aircraft close to the ground to improve airport safety. A prototype system was developed and installed at an airfield to capture point clouds to monitor aircraft operations. One of the challenges of accurate object tracking using the Velodyne sensors is the relatively small vertical field of view (30°, 41.3° and angular resolution (1.33°, 2°, resulting in a small number of points of the tracked object. The point density decreases with the object–sensor distance, and is already sparse at a moderate range of 30–40 m. The paper introduces our model-based tracking algorithms, including volume minimization and cube trajectories, to address the optimal estimation of object motion and tracking based on sparse point clouds. Using a network of sensors, multiple tests were conducted at an airport to assess the performance of the demonstration system and the algorithms developed. The investigation was focused on monitoring small aircraft moving on runways and taxiways, and the results indicate less than 0.7 m/s and 17 cm velocity and positioning accuracy achieved, respectively. Overall, based on our findings, this technology is promising not only for aircraft monitoring but for airport applications.

Free-boundary stability of straight stellarators

International Nuclear Information System (INIS)

Barnes, D.C.; Cary, J.R.

1984-02-01

The sharp-boundary model is used to investigate the stability of straight stellarators to free-boundary, long-wavelength modes. To correctly analyze the heliac configuration, previous theory is generalized to the case of arbitrary helical aspect ratio (ratio of plasma radius to periodicity lengths). A simple low-β criterion involving the vacuum field and the normalized axial current is derived and used to investigate a large variety of configurations. The predictions of this low-β theory are verified by numerical minimization of deltaW at arbitrary β. The heliac configuration is found to be remarkably stable, with a critical β of over 15% determined by the lack of equilibrium rather than the onset of instability. In addition, other previously studied systems are found to be stabilized by net axial plasma current

Hand-assisted versus straight laparoscopic sigmoid colectomy on a training simulator: what is the difference? A stepwise comparison of hand-assisted versus straight laparoscopic sigmoid colectomy performance on an augmented reality simulator.

LENUS (Irish Health Repository)

Leblanc, Fabien

2010-12-01

We hypothesized that simulator-generated metrics and intraoperative errors may be able to differentiate the technical differences between hand-assisted laparoscopic (HAL) and straight laparoscopic (SL) approaches.

Ring energy selection and extra long straight sections for the Advanced Photon Source

International Nuclear Information System (INIS)

1987-04-01

Recommended criteria are given for the performance of Advanced Photon Source (APS), taking into consideration undulator tunability criteria and their relationship to the storage ring energy and undulator gap, length of straight sections

MORPION: a fast hardware processor for straight line finding in MWPC

International Nuclear Information System (INIS)

Mur, M.

1980-02-01

A fast hardware processor for straight line finding in MWPC has been built in Saclay and successfully operated in the NA3 experiment at CERN. We give the motivations to build this processor, and describe the hardware implementation of the line finding algorithm. Finally its use and performance in NA3 are described

Magnetic manipulation of particles and cells in ferrofluid flow through straight microchannels using two magnets

Science.gov (United States)

Zeng, Jian

observed particle and cell focusing behaviors with reasonable agreement. Next, a simple magnetic technique to concentrate polystyrene particles and live yeast cells in ferrofluid flow through a straight rectangular microchannel is developed. Concentrating particles to a detectable level is often necessary in many applications. The magnetic field gradient is created by two attracting permanent magnets that are placed on the top and bottom of the planar microfluidic device and held in position by their natural attractive force. The effects of flow speed and magnet-magnet distance are studied and the device was applied for use for concentrating live yeast cells. The magnet-magnet distance is mainly controlled by the thickness of the device substrate and can be made small, providing a locally strengthened magnetic field as well as allowing for the use of dilute ferrofluid in the developed magnetic concentration technique. This advantage not only enables a magnetic/fluorescent label-free handling of diamagnetic particles but also renders such handling biocompatible. Lastly, a device is presented for a size-based continuous separation of particles through a straight rectangular microchannel. Particle separation is critical in many applications involving the sorting of cells. A first magnet is used for focusing the particle mixture into a single stream due to its relative close positioning with respect to the channel, thus creating a greater magnetic field magnitude. Then, a following magnet is used to displace the aligned particles to dissimilar flow paths by placing it farther away compared the first magnet, which provides a weaker magnetic field, therefore more sensitive towards the deflection of particles based on their size. The effects of both flow speed and separator magnet position are examined. The experimental data are found to fit well with analytical model predictions. This is followed by a study replacing the particles which are closely sized to that of live yeast

Path-based Queries on Trajectory Data

DEFF Research Database (Denmark)

Krogh, Benjamin Bjerre; Pelekis, Nikos; Theodoridis, Yannis

2014-01-01

In traffic research, management, and planning a number of path-based analyses are heavily used, e.g., for computing turn-times, evaluating green waves, or studying traffic flow. These analyses require retrieving the trajectories that follow the full path being analyzed. Existing path queries cannot...... sufficiently support such path-based analyses because they retrieve all trajectories that touch any edge in the path. In this paper, we define and formalize the strict path query. This is a novel query type tailored to support path-based analysis, where trajectories must follow all edges in the path...... a specific path by only retrieving data from the first and last edge in the path. To correctly answer strict path queries existing network-constrained trajectory indexes must retrieve data from all edges in the path. An extensive performance study of NETTRA using a very large real-world trajectory data set...

Multi-Objective Climb Path Optimization for Aircraft/Engine Integration Using Particle Swarm Optimization

Directory of Open Access Journals (Sweden)

Aristeidis Antonakis

2017-04-01

Full Text Available In this article, a new multi-objective approach to the aircraft climb path optimization problem, based on the Particle Swarm Optimization algorithm, is introduced to be used for aircraft–engine integration studies. This considers a combination of a simulation with a traditional Energy approach, which incorporates, among others, the use of a proposed path-tracking scheme for guidance in the Altitude–Mach plane. The adoption of population-based solver serves to simplify case setup, allowing for direct interfaces between the optimizer and aircraft/engine performance codes. A two-level optimization scheme is employed and is shown to improve search performance compared to the basic PSO algorithm. The effectiveness of the proposed methodology is demonstrated in a hypothetic engine upgrade scenario for the F-4 aircraft considering the replacement of the aircraft’s J79 engine with the EJ200; a clear advantage of the EJ200-equipped configuration is unveiled, resulting, on average, in 15% faster climbs with 20% less fuel.

From MSM to heteroflexibilities: Non-exclusive straight male identities and their implications for HIV prevention and health promotion.

Science.gov (United States)

Carrillo, Héctor; Hoffman, Amanda

2016-01-01

This article examines the logics of self-identification among men who have same-sex desires and behaviours and consider themselves to be straight. We draw from interviews conducted in the USA with 100 straight-identified men who have same-sex desires and 40 partners of such men. Our data allow us to reject two misconceptions. One is the idea that these men are actually gay or bisexual but refuse to accept those identities. We argue instead that these men see themselves as straight and therefore it is important to understand what specifically they mean by that. The second misconception links straight-identified men who have same-sex desires and behaviours to the racialised discourse of the so-called down low (or 'DL') in the USA. While the DL typically is depicted as involving African American and Latino men, most of our participants are White. Moving beyond these misconceptions, we propose that health educators must acknowledge flexibilities in the definition of heterosexuality and use an expanded definition as a starting point to envision, together with these men, how to more effectively engage them in HIV prevention and health promotion.

Aerodynamic shape optimization of non-straight small wind turbine blades

International Nuclear Information System (INIS)

Shen, Xin; Yang, Hong; Chen, Jinge; Zhu, Xiaocheng; Du, Zhaohui

2016-01-01

Graphical abstract: Small wind turbine blades with 3D stacking lines (sweep and bend) have been considered and analyzed with an optimization code based on the lifting surface method. The results indicated that the power capture and the rotor thrust can be improved with these more complex geometries. The starting behavior of the small wind turbines can be improved by the optimization of the blade chord and twist angle distribution. - Highlights: • The small wind turbine blade was optimized with non-straight shape. • Lifting surface method with free wake was used for aerodyanmic performace evaluation. • The non-straight shape can be used to increase energy production and decrease the thrust. • The energy production should be sacrificed in order to increase the starting behavior. - Abstract: Small wind turbines usually operate in sub-optimal wind conditions in order to satisfy the demand where it is needed. The aerodynamic performance of small horizontal axis wind turbines highly depends on the geometry. In the present study, the geometry of wind turbine blades are optimized not only in terms of the distribution of the chord and twist angle but also with 3-dimensional stacking line. As the blade with 3-dimensional stacking line is given sweep in the plan of rotation and dihedral in the plan containing the blade and rotor axis, the common used blade element momentum method can no longer provide accurate aerodynamic performance solution. A lifting surface method with free wake model is used as the aerodynamic model in the present work. The annual energy production and the starting performance are selected as optimization objective. The starting performance is evaluated based on blade element method. The optimization of the geometry of the non-straight wind turbine blades is carried out by using a micro-genetic algorithm. Results show that the wind turbine blades with properly designed 3-dimensional stacking line can increase the annual energy production and have

Development of a cylindrical tracking detector with multichannel scintillation fibers and pixelated photon detector readout

Energy Technology Data Exchange (ETDEWEB)

Akazawa, Y.; Miwa, K.; Honda, R.; Shiozaki, T.; Chiga, N.

2015-07-01

We are developing a cylindrical tracking detector for a Σp scattering experiment in J-PARC with scintillation fibers and the Pixelated Photon Detector (PPD) readout, which is called as cylindrical fiber tracker (CFT), in order to reconstruct trajectories of charged particles emitted inside CFT. CFT works not only as a tracking detector but also a particle identification detector from energy deposits. A prototype CFT consisting of two straight layers and one spiral layer was constructed. About 1100 scintillation fibers with a diameter of 0.75 mm (Kuraray SCSF-78 M) were used. Each fiber signal was read by Multi-Pixel Photon Counter (MPPC, HPK S10362-11-050P, 1×1 mm{sup 2}, 400 pixels) fiber by fiber. MPPCs were handled with Extended Analogue Silicon Photomultipliers Integrated ReadOut Chip (EASIROC) boards, which were developed for the readout of a large number of MPPCs. The energy resolution of one layer was 28% for a 70 MeV proton where the energy deposit in fibers was 0.7 MeV.

A model expansion criterion for treating surface topography in ray path calculations using the eikonal equation

International Nuclear Information System (INIS)

Ma, Ting; Zhang, Zhongjie

2014-01-01

Irregular surface topography has revolutionized how seismic traveltime is calculated and the data are processed. There are two main schemes for dealing with an irregular surface in the seismic first-arrival traveltime calculation: (1) expanding the model and (2) flattening the surface irregularities. In the first scheme, a notional infill medium is added above the surface to expand the physical space into a regular space, as required by the eikonal equation solver. Here, we evaluate the chosen propagation velocity in the infill medium through ray path tracking with the eikonal equation-solved traveltime field, and observe that the ray paths will be physically unrealistic for some values of this propagation velocity. The choice of a suitable propagation velocity in the infill medium is crucial for seismic processing of irregular topography. Our model expansion criterion for dealing with surface topography in the calculation of traveltime and ray paths using the eikonal equation highlights the importance of both the propagation velocity of the infill physical medium and the topography gradient. (paper)

Next gen PhD a guide to career paths in science

CERN Document Server

Sinche, Melanie V

2016-01-01

For decades, top scientists in colleges and universities pursued a clear path to success: enroll in a prestigious graduate program, conduct research, publish papers, complete the PhD, pursue postdoctoral work. With perseverance and a bit of luck, a tenure-track professorship awaited at the end. In today s academic job market, this scenario represents the exception. As the number of newly conferred science PhDs keeps rising, the number of tenured professorships remains stubbornly stagnant. Only 14 percent of those with PhDs in science occupy tenure-track positions five years after completing their degree. Next Gen PhD provides a frank and up-to-date assessment of the current career landscape facing science PhDs. Nonfaculty careers once considered Plan B are now preferred by the majority of degree holders, says Melanie Sinche. An upper-level science degree is a prized asset in the eyes of many employers, and a majority of science PhDs build rewarding careers both inside and outside the university. A certified ...

Wind tunnel study of helical and straight-bladed vertical-axis wind turbine wakes

Science.gov (United States)

Bagheri, Maryam; Araya, Daniel

2017-11-01

It is hypothesized that blade curvature can serve as a passive means to control fluid entrainment and wake recovery in vertical-axis wind turbine (VAWT) arrays. We test this experimentally in a wind tunnel using two different VAWT configurations, one with straight blades and another with helical blades, keeping all other experimental parameters fixed. A small-scale, commercially available VAWT (15W max power) is used as the baseline wind tunnel model in each case. The commercial VAWT blades are replaced with either straight or helical blades that are 3D-printed extrusions of the same airfoil cross-section. Results from smoke flow visualization, three-component wake velocity measurements, and turbine power data are presented. These results give insight into the potential use of VAWTs with curved blades in utility-scale wind farms.

Development of Intelligent Fuzzy Controller for a Two-Axis Solar Tracking System

Directory of Open Access Journals (Sweden)

Cong-Hui Huang

2016-05-01

Full Text Available This paper proposes the development of a two-axis sun tracking solar energy system using fuzzy logic as intelligent quality policy. To achieve maximum efficiency for solar panels, it is necessary to follow the sun’s path in the sky. Therefore, the architecture for the two-axis sun tracking solar energy system uses software to control the hardware. The hardware comprises (i solar cells; (ii lead-acid batteries; (iii a gear box; (iv a stepping motor; and (v a light detection circuit, while the software comprises (i a detection system; (ii a fuzzy tracking controller; and (iii a database system. A fuzzy logic controller is designed as the software architecture of the system to decide the timing for tracking the sun. The nearest position that results in receiving direct sunlight is obtained from the database. Our system is fully automatic in a changing environment and takes into account meteorological changes and the effects of the external environment arising from a malfunction. This approach reduces the number of starting motors and results in smaller energy loss in cloudy, cloud mask, or unstable weather conditions.

A Novel Randomized Search Technique for Multiple Mobile Robot Paths Planning In Repetitive Dynamic Environment

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Vahid Behravesh

2012-08-01

Full Text Available Presented article is studying the issue of path navigating for numerous robots. Our presented approach is based on both priority and the robust method for path finding in repetitive dynamic. Presented model can be generally implementable and useable: We do not assume any restriction regarding the quantity of levels of freedom for robots, and robots of diverse kinds can be applied at the same time. We proposed a random method and hill-climbing technique in the area based on precedence plans, which is used to determine a solution to a given trajectory planning problem and to make less the extent of total track. Our method plans trajectories for particular robots in the setting-time scope. Therefore, in order to specifying the interval of constant objects similar to other robots and the extent of the tracks which is traversed. For measuring the hazard for robots to conflict with each other it applied a method based on probability of the movements of robots. This algorithm applied to real robots with successful results. The proposed method performed and judged on both real robots and in simulation. We performed sequence of100tests with 8 robots for comparing with coordination method and current performances are effective. However, maximizing the performance is still possible. These performances estimations performed on Windows operating system and 3GHz Intel Pentium IV with and compiles with GCC 3.4. We used our PCGA robot for all experiments.  For a large environment of 19×15m2where we accomplished 40tests, our model is competent to plan high-quality paths in a severely short time (less than a second. Moreover, this article utilized lookup tables to keep expenses the formerly navigated robots made, increasing the number of robots don’t expand computation time.

Straight A's: Public Education Policy and Progress. Volume 12, Number 7

Science.gov (United States)

Amos, Jason, Ed.

2012-01-01

"Straight A's: Public Education Policy and Progress" is a biweekly newsletter that focuses on education news and events both in Washington, DC and around the country. The following articles are included in this issue: (1) Problems Down the Road: House Passes Congressional Budget Resolutions, Sets Overall Spending Cap at $19 Billion Below Senate;…

A Program Review of a Middle School Gay-Straight Alliance Club

Science.gov (United States)

Quasha, Scott; McCabe, Paul C.; Ortiz, Samuel O.

2014-01-01

This program review examined a middle school Gay-Straight Alliance (GSA) club within a northeastern suburban school situated in a large metropolitan area. The GSA was the first in the region to start exclusively in a standalone middle school. The review was accomplished through a staff survey comparing school climates for lesbian, gay, bisexual,…

Straight A's: Public Education Policy and Progress. Volume 6, Number 2

Science.gov (United States)

Amos, Jason, Ed.

2006-01-01

"Straight A's: Public Education Policy and Progress" is a biweekly newsletter that focuses on education news and events both in Washington, DC and around the country. The following articles are included in this issue: (1) State of American Business: U.S. Chamber of Commerce Says U.S. Could Face a "Severe Worker Shortage" Unless…

Parallel Hough Transform-Based Straight Line Detection and Its FPGA Implementation in Embedded Vision

Directory of Open Access Journals (Sweden)

Nam Ling

2013-07-01

Full Text Available Hough Transform has been widely used for straight line detection in low-definition and still images, but it suffers from execution time and resource requirements. Field Programmable Gate Arrays (FPGA provide a competitive alternative for hardware acceleration to reap tremendous computing performance. In this paper, we propose a novel parallel Hough Transform (PHT and FPGA architecture-associated framework for real-time straight line detection in high-definition videos. A resource-optimized Canny edge detection method with enhanced non-maximum suppression conditions is presented to suppress most possible false edges and obtain more accurate candidate edge pixels for subsequent accelerated computation. Then, a novel PHT algorithm exploiting spatial angle-level parallelism is proposed to upgrade computational accuracy by improving the minimum computational step. Moreover, the FPGA based multi-level pipelined PHT architecture optimized by spatial parallelism ensures real-time computation for 1,024 × 768 resolution videos without any off-chip memory consumption. This framework is evaluated on ALTERA DE2-115 FPGA evaluation platform at a maximum frequency of 200 MHz, and it can calculate straight line parameters in 15.59 ms on the average for one frame. Qualitative and quantitative evaluation results have validated the system performance regarding data throughput, memory bandwidth, resource, speed and robustness.

Parallel Hough Transform-based straight line detection and its FPGA implementation in embedded vision.

Science.gov (United States)

Lu, Xiaofeng; Song, Li; Shen, Sumin; He, Kang; Yu, Songyu; Ling, Nam

2013-07-17

Hough Transform has been widely used for straight line detection in low-definition and still images, but it suffers from execution time and resource requirements. Field Programmable Gate Arrays (FPGA) provide a competitive alternative for hardware acceleration to reap tremendous computing performance. In this paper, we propose a novel parallel Hough Transform (PHT) and FPGA architecture-associated framework for real-time straight line detection in high-definition videos. A resource-optimized Canny edge detection method with enhanced non-maximum suppression conditions is presented to suppress most possible false edges and obtain more accurate candidate edge pixels for subsequent accelerated computation. Then, a novel PHT algorithm exploiting spatial angle-level parallelism is proposed to upgrade computational accuracy by improving the minimum computational step. Moreover, the FPGA based multi-level pipelined PHT architecture optimized by spatial parallelism ensures real-time computation for 1,024 × 768 resolution videos without any off-chip memory consumption. This framework is evaluated on ALTERA DE2-115 FPGA evaluation platform at a maximum frequency of 200 MHz, and it can calculate straight line parameters in 15.59 ms on the average for one frame. Qualitative and quantitative evaluation results have validated the system performance regarding data throughput, memory bandwidth, resource, speed and robustness.

Symplectic tracking using point magnets in the presence of a longitudinal magnetic field

International Nuclear Information System (INIS)

Parzen, G.

1993-09-01

In the absence of a longitudinal magnetic field, symplectic tracking can be achieved by replacing the magnets by a series of point magnets and drift spaces. To treat the case when a longitudinal magnetic field is also present, this procedure is modified in this paper by replacing the drift space by a solenoidal drift, which is defined as the motion of a particle in a uniform longitudinal magnetic field. A symplectic integrator can be obtained by subdividing each magnet into pieces and replacing each magnet piece by point magnets, with only transverse fields, and solenoidal drift spaces. The reference orbit used here is made up of arcs of circles and straight lines which join smoothly with each other. For this choice of reference orbit, the required results are obtained to track particles, which are the transfer functions, and the transfer time for the different elements. It is shown that these results provide a symplectic integrator, and they are exact in the sense that as the number of magnet pieces is increased, the particle motion will converge to the particle motion of the exact equations of motion

Design of Test Tracks for Odometry Calibration of Wheeled Mobile Robots

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Changbae Jung

2011-09-01

Full Text Available Pose estimation for mobile robots depends basically on accurate odometry information. Odometry from the wheel's encoder is widely used for simple and inexpensive implementation. As the travel distance increases, odometry suffers from kinematic modeling errors regarding the wheels. Therefore, in order to improve the odometry accuracy, it is necessary that systematic errors be calibrated. The UMBmark test is a practical and useful scheme for calibrating the systematic errors of two-wheeled mobile robots. However, the square path track size used in the test has not been validated. A consideration of the calibration equations, experimental conditions, and modeling errors is essential to improve the calibration accuracy. In this paper, we analyze the effect on calibration performance of the approximation errors of calibration equations and nonsystematic errors under experimental conditions. Then, we propose a test track size for improving the accuracy of odometry calibration. From simulation and experimental results, we show that the proposed test track size significantly improves the calibration accuracy of odometry under a normal range of kinematic modeling errors for robots.

Optimization of Straight Cylindrical Turning Using Artificial Bee Colony (ABC) Algorithm

Science.gov (United States)

Prasanth, Rajanampalli Seshasai Srinivasa; Hans Raj, Kandikonda

2017-04-01

Artificial bee colony (ABC) algorithm, that mimics the intelligent foraging behavior of honey bees, is increasingly gaining acceptance in the field of process optimization, as it is capable of handling nonlinearity, complexity and uncertainty. Straight cylindrical turning is a complex and nonlinear machining process which involves the selection of appropriate cutting parameters that affect the quality of the workpiece. This paper presents the estimation of optimal cutting parameters of the straight cylindrical turning process using the ABC algorithm. The ABC algorithm is first tested on four benchmark problems of numerical optimization and its performance is compared with genetic algorithm (GA) and ant colony optimization (ACO) algorithm. Results indicate that, the rate of convergence of ABC algorithm is better than GA and ACO. Then, the ABC algorithm is used to predict optimal cutting parameters such as cutting speed, feed rate, depth of cut and tool nose radius to achieve good surface finish. Results indicate that, the ABC algorithm estimated a comparable surface finish when compared with real coded genetic algorithm and differential evolution algorithm.

Tracking fuzzy borders using geodesic curves with application to liver segmentation on planning CT

International Nuclear Information System (INIS)

Yuan, Yading; Chao, Ming; Sheu, Ren-Dih; Rosenzweig, Kenneth; Lo, Yeh-Chi

2015-01-01

Purpose: This work aims to develop a robust and efficient method to track the fuzzy borders between liver and the abutted organs where automatic liver segmentation usually suffers, and to investigate its applications in automatic liver segmentation on noncontrast-enhanced planning computed tomography (CT) images. Methods: In order to track the fuzzy liver–chestwall and liver–heart borders where oversegmentation is often found, a starting point and an ending point were first identified on the coronal view images; the fuzzy border was then determined as a geodesic curve constructed by minimizing the gradient-weighted path length between these two points near the fuzzy border. The minimization of path length was numerically solved by fast-marching method. The resultant fuzzy borders were incorporated into the authors’ automatic segmentation scheme, in which the liver was initially estimated by a patient-specific adaptive thresholding and then refined by a geodesic active contour model. By using planning CT images of 15 liver patients treated with stereotactic body radiation therapy, the liver contours extracted by the proposed computerized scheme were compared with those manually delineated by a radiation oncologist. Results: The proposed automatic liver segmentation method yielded an average Dice similarity coefficient of 0.930 ± 0.015, whereas it was 0.912 ± 0.020 if the fuzzy border tracking was not used. The application of fuzzy border tracking was found to significantly improve the segmentation performance. The mean liver volume obtained by the proposed method was 1727 cm 3 , whereas it was 1719 cm 3 for manual-outlined volumes. The computer-generated liver volumes achieved excellent agreement with manual-outlined volumes with correlation coefficient of 0.98. Conclusions: The proposed method was shown to provide accurate segmentation for liver in the planning CT images where contrast agent is not applied. The authors’ results also clearly demonstrated

Discovery Mondays "Controlling the accelerators: tracking the protons"

CERN Multimedia

2007-01-01

Le Centre de contrôle des accélérateurs du CERN.Like a train of particles that picks up speed every time it passes a set of points, by the time they collide the protons and ions in the LHC will have followed their path through the six stages of the CERN accelerator complex, picking up speed at each stage. Operating the controls of this huge complex designed to accelerate the infinitesimally small are its peerless controllers. From the CERN Control Centre, they will be on duty day and night to accelerate the "wagon-loads" of particles, ensuring that they stay on track and lining them up for head-on collisions. At the next Discovery Monday you will discover the path taken by the particles through the accelerator chain. You will gain an insight into the complex work performed by those controlling the particles and learn more about the CERN accelerator complex and its Control Centre. Hop on board for a speed-of-light tour of the C...

Improved Leg Tracking Considering Gait Phase and Spline-Based Interpolation during Turning Motion in Walk Tests

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Ayanori Yorozu

2015-09-01

Full Text Available Falling is a common problem in the growing elderly population, and fall-risk assessment systems are needed for community-based fall prevention programs. In particular, the timed up and go test (TUG is the clinical test most often used to evaluate elderly individual ambulatory ability in many clinical institutions or local communities. This study presents an improved leg tracking method using a laser range sensor (LRS for a gait measurement system to evaluate the motor function in walk tests, such as the TUG. The system tracks both legs and measures the trajectory of both legs. However, both legs might be close to each other, and one leg might be hidden from the sensor. This is especially the case during the turning motion in the TUG, where the time that a leg is hidden from the LRS is longer than that during straight walking and the moving direction rapidly changes. These situations are likely to lead to false tracking and deteriorate the measurement accuracy of the leg positions. To solve these problems, a novel data association considering gait phase and a Catmull–Rom spline-based interpolation during the occlusion are proposed. From the experimental results with young people, we confirm   that the proposed methods can reduce the chances of false tracking. In addition, we verify the measurement accuracy of the leg trajectory compared to a three-dimensional motion analysis system (VICON.

Straight A's: Public Education Policy and Progress. Volume 12, Number 9

Science.gov (United States)

Amos, Jason, Ed.

2012-01-01

"Straight A's: Public Education Policy and Progress" is a biweekly newsletter that focuses on education news and events both in Washington, DC and around the country. The following articles are included in this issue: (1) You Take the High Road and I'll Take the Low Road: As Appropriations Process Begins, Different Spending Approaches Likely to…

Path integration quantization

International Nuclear Information System (INIS)

DeWitt-Morette, C.

1983-01-01

Much is expected of path integration as a quantization procedure. Much more is possible if one recognizes that path integration is at the crossroad of stochastic and differential calculus and uses the full power of both stochastic and differential calculus in setting up and computing path integrals. In contrast to differential calculus, stochastic calculus has only comparatively recently become an instrument of thought. It has nevertheless already been used in a variety of challenging problems, for instance in the quantization problem. The author presents some applications of the stochastic scheme. (Auth.)

Pulse shape simulation for drift chambers with long drift paths

Energy Technology Data Exchange (ETDEWEB)

Mayer, H J

1987-09-15

A detailed Monte Carlo program for the simulation of drift chamber pulse shapes is described. It has been applied to the case of a jet chamber with drift paths up to 24 cm. Results on pulse shapes and corresponding spatial and double hit resolution are discussed and compared to recent measurements of the OPAL central detector jet chamber full size prototype and to measurements of a small 20-wire prototype, which was designed to study the pulse shapes generated by tracks in a magnetic field. Simulated pulse shapes and spatial resolutions agree well with the experimental data. Clustering, saturation and wire crosstalk are shown to be necessary ingredients in the simulation. A deterioration in resolution due to the influence of crosstalk signals is correctly reproduced, as well as the cancellation of this effect by a hardwired first and second neighbour crosstalk compensation. The simulation correctly describes the asymmetry in spatial resolution observed for tracks with positive or negative inclination against the wire plane when a magnetic field is present. The effect of saturation on double hit resolution is found to be small. The magnetic field is predicted to improve the double hit resolution.

Pulse shape simulation for drift chambers with long drift paths

International Nuclear Information System (INIS)

Mayer, H.J.

1987-01-01

A detailed Monte Carlo program for the simulation of drift chamber pulse shapes is described. It has been applied to the case of a jet chamber with drift paths up to 24 cm. Results on pulse shapes and corresponding spatial and double hit resolution are discussed and compared to recent measurements of the OPAL central detector jet chamber full size prototype and to measurements of a small 20-wire prototype, which was designed to study the pulse shapes generated by tracks in a magnetic field. Simulated pulse shapes and spatial resolutions agree well with the experimental data. Clustering, saturation and wire crosstalk are shown to be necessary ingredients in the simulation. A deterioration in resolution due to the influence of crosstalk signals is correctly reproduced, as well as the cancellation of this effect by a hardwired first and second neighbour crosstalk compensation. The simulation correctly describes the asymmetry in spatial resolution observed for tracks with positive or negative inclination against the wire plane when a magnetic field is present. The effect of saturation on double hit resolution is found to be small. The magnetic field is predicted to improve the double hit resolution. (orig.)

Study of Model Predictive Control for Path-Following Autonomous Ground Vehicle Control under Crosswind Effect

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Fitri Yakub

2016-01-01

Full Text Available We present a comparative study of model predictive control approaches of two-wheel steering, four-wheel steering, and a combination of two-wheel steering with direct yaw moment control manoeuvres for path-following control in autonomous car vehicle dynamics systems. Single-track mode, based on a linearized vehicle and tire model, is used. Based on a given trajectory, we drove the vehicle at low and high forward speeds and on low and high road friction surfaces for a double-lane change scenario in order to follow the desired trajectory as close as possible while rejecting the effects of wind gusts. We compared the controller based on both simple and complex bicycle models without and with the roll vehicle dynamics for different types of model predictive control manoeuvres. The simulation result showed that the model predictive control gave a better performance in terms of robustness for both forward speeds and road surface variation in autonomous path-following control. It also demonstrated that model predictive control is useful to maintain vehicle stability along the desired path and has an ability to eliminate the crosswind effect.