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Tracking
Kinds of Tracking Terms modified by Tracking Selected AbstractsASSESSING LAND USE IMPACTS ON WATER QUALITY USING MICROBIAL SOURCE TRACKING,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2004Sharon C. Long ABSTRACT: A renewed emphasis on source water protection and watershed management has resulted from recent amendments and initiatives under the Safe Drinking Water Act and the Clean Water Act. Knowledge of the impact of land use choices on source water quality is critical for efforts to properly manage activities within a watershed. This study evaluated qualitative relationships between land use and source water quality and the quantitative impact of season and rainfall events on water quality parameters. High levels of specific conductance tended to be associated with dense residential development, while organic carbon was elevated at several forested sites. Turbidity was generally higher in more urbanized areas. Source tracking indicators were detected in samples where land use types would predict their presence. Coliform levels were statistically different at the 95 percent confidence levels for winter versus summer conditions and dry versus wet weather conditions. Other water quality parameters that varied with season were organic carbon, turbidity, dissolved oxygen, and specific conductance. These results indicate that land use management can be effective for mitigating impacts to a water body; however, year- round, comprehensive data are necessary to thoroughly evaluate the water quality at a particular site. [source] INCREASING THE PRECISION OF THEODOLITE TRACKING: MODIFIED TECHNIQUE TO CALCULATE THE ALTITUDE OF LAND-BASED OBSERVATION SITESMARINE MAMMAL SCIENCE, Issue 4 2004H. Bailey [source] Simulation of Accuracy Performance for Wireless Sensor-Based Construction Asset TrackingCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2009Miros, aw J. Skibniewski In particular, identifying the location of distributed mobile entities throughout wireless communications becomes the primary task to realize the remote tracking and monitoring of the construction assets. Even though several alternative solutions have been introduced by utilizing recent technologies, such as radio frequency identification (RFID) and the global positioning system (GPS), they could not provide a solid direction to accurate and scalable tracking frameworks in large-scale construction domains due to limited capability and inflexible networking architectures. This article introduces a new tracking architecture using wireless sensor modules and shows an accuracy performance using a numerical simulation approach based on the time-of-flight method. By combining radio frequency (RF) and ultrasound (US) signals, the simulation results showed an enhanced accuracy performance over the utilization of an RF signal only. The proposed approach can provide potential guidelines for further exploration of hardware/software design and for experimental analysis to implement the framework of tracking construction assets. [source] Aortic Valve Closure: Relation to Tissue Velocities by Doppler and Speckle Tracking in Patients with Infarction and at High Heart RatesECHOCARDIOGRAPHY, Issue 4 2010Ph.D., Svein A. Aase M.Sc. Aim: To resolve the event in tissue Doppler (TDI)- and speckle tracking-based velocity/time curves that most accurately represent aortic valve closure (AVC) in infarcted ventricles and at high heart rates. Methods: We studied the timing of AVC in 13 patients with myocardial infarction and in 8 patients at peak dobutamine stress echo. An acquisition setup for recording alternating B-mode and TDI image frames was used to achieve the same frame rate in both cases (mean 136.7 frames per second [FPS] for infarcted ventricles, mean 136.9 FPS for high heart rates). The reference method was visual assessment of AVC in the high frame rate narrow sector B-mode images of the aortic valve. Results: The initial negative velocities after ejection in the velocity/time curves occurred before AVC, 44.9 ± 21.0 msec before the reference in the high heart rate material, and 25.2 ± 15.2 msec before the reference in the infarction material. Using this time point as a marker for AVC may cause inaccuracies when estimating end-systolic strain. A more accurate but still a practical marker for AVC was the time point of zero crossing after the initial negative velocities after ejection, 5.4 ± 15.3 msec before the reference in high heart rates and 8.2 ± 12.9 msec after the reference in the infarction material. Conclusion: The suggested marker of AVC at high heart rate and in infarcted ventricles was the time point of zero crossing after the initial negative velocities after ejection in velocity/time curves. (Echocardiography 2010;27:363-369) [source] Effect of Preload on Left Ventricular Longitudinal Strain by 2D Speckle TrackingECHOCARDIOGRAPHY, Issue 8 2008Jin-Oh Choi M.D. Background: Peak systolic longitudinal strain (PSLS) obtained using the 2D speckle tracking method is a novel indicator of the long-axis function of the left ventricle (LV). We used the 2D strain profile to examine the effect of preload reduction by hemodialysis (HD) on LV PSLS in patients with end-stage renal disease (ESRD). Method and results: Twenty-nine pairs of echocardiographic evaluations were obtained before and after dialysis. Global LV PSLS was ,18.4 ± 2.9%, at baseline and decreased to ,16.9 ± 3.2% after HD (P < 0.001). Segmental analysis showed that the decrease in PSLS after dialysis was most prominent in mid-LV segments (,17.1 ± 3.5% vs. ,15.4 ± 3.4%, P < 0.001). Conclusion: PSLS obtained from the 2D strain profile is a reliable parameter that may be useful for evaluating LV systolic long-axis function. However, PSLS should be applied cautiously in ESRD patients because it could be affected by dialysis. [source] Evaluation of the Left Ventricular Function with Tissue Tracking and Tissue Doppler Echocardiography in Pediatric Malignancy Survivors after Anthracycline TherapyECHOCARDIOGRAPHY, Issue 8 2008it Karakurt M.D. Although the anthracyclines have gained widespread use in the treatment of childhood hematological malignancies and solid tumors, cardiotoxicity is the major limiting factor in the use of anthracyclines. The aim of this study was to assess the mitral annular displacement by tissue tracking in pediatric malignancy survivors who had been treated with anthracycline groups chemotheraphy and compare with the tissue Doppler and conventional two dimensional measurements and Doppler indices. In this study, 32 pediatric malignancy survivors and 22 healthy children were assessed with 2D, colour-coded echocardiography. Left ventricular ejection fraction, fractional shortening, stroke volume, cardiac output, cardiac index and diastolic functions were measured. All subjects were assessed with tissue Doppler echocardiography, mitral annular displacements, and also with tissue tracking method. We detected that peak velocity of the early rapid filling on tissue Doppler (E,) was lower (p < 0.05) and the ratio of early peak velocity of rapid filling on pulse Doppler to tissue Doppler (E/E,) values were statistically higher in patient group than control group (p < 0.05). Myocardial performance index values were also higher in patient group than the control group (p < 0.01). It appears that MPI is a useful echocardiograghic method than tissue tracking of mitral annular displacement in patients with pediatric cancer survivors who had subclinical diastolic dysfunction. [source] Tracking the origins of the bilaterian Hox patterning system: insights from the acoel flatworm Symsagittifera roscoffensisEVOLUTION AND DEVELOPMENT, Issue 5 2009Eduardo Moreno SUMMARY Genes of the Hox cluster encode for transcriptional regulators that show collinear expression along the anteroposterior (AP) body axis in all bilateral animals. However, it is still unclear when in the evolutionary history of bilaterians the Hox system first conferred positional identity along the AP-axis. Recent molecular phylogenies have convincingly shown that the acoel flatworms, traditionally classified within the Platyhelminthes, are the sister group of the remaining Bilateria, branching out before the common ancestor of protostomes, and deuterostomes (the so-called PDA). This key phylogenetic position offers the opportunity to search for the presence and early role of Hox cluster genes to pattern the AP axis in acoels. Here, we report on the cloning, genomic arrangement, and expression domains of Hox genes in Symsagittifera roscoffensis. Three Hox genes were detected: one from each of the major groups of Hox genes, which are anterior, central, and posterior. In bacterial artificial chromosome cloning, sequencing, and chromosomal fluorescence in situ hybridization, Hox genes were not observed as being clustered in a unique genomic region. Nevertheless, despite its dispersion within the genome, Hox genes are expressed in nested domains along the AP axis in the juvenile worm. The basic set of Hox genes in acoels and their coarse nested spatial deployment might be the first indicators of the role of Hox genes in the evolution of bilateral symmetry and AP positional identity from a hypothetical radial ancestor. [source] Tracking ,Same,Sex Love' from Antiquity to the Present in South AsiaGENDER & HISTORY, Issue 1 2002Rosemary Marangoly George This essay focuses on the anthology Same,Sex Love in India: Readings from Literature and History (2000), edited by Ruth Vanita and Saleem Kidwai. Unlike many other recently published, celebratory ,gay anthologies', this book contributes to ongoing scholarly work on specific same,sex erotic practices and relations in historical and cultural context. We examine issues relevant to this anthology and other such projects: the use of ,love' and ,same,sex' as (stable) signifiers over centuries; the validity of interpreting social reality through literary texts from the period; the difficulties of locating ,love' in severely hierarchical, even slave,owning, societies; and the implications of using such anthologies in the classroom. [source] Comparing effects of methylphenidate, sertraline and placebo on neuropsychiatric sequelae in patients with traumatic brain injuryHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 2 2005Hoon Lee Abstract Background This study aimed to investigate the effects of methylphenidate and sertraline compared with placebo on various neuropsychiatric sequelae associated with traumatic brain injury (TBI). Methods This was a 4 week, double-blind, parallel-group trial. Thirty patients with mild to moderate degrees of TBI were randomly allocated to one of three treatment groups (n,=,10 in each group) with matching age, gender and education, i.e. methylphenidate (starting at 5,mg/day and increasing to 20,mg/day in a week), sertraline (starting at 25,mg/day and increasing to 100,mg/day in a week) or placebo. At the baseline and at the 4 week endpoint, the following assessments were administered: subjective (Beck Depression Inventory) and objective (Hamilton Depression Rating Scale) measures of depression; Rivermead Postconcussion Symptoms Questionnaire for postconcussional symptoms; SmithKline Beecham Quality of Life Scale for quality of life; seven performance tests (Critical Flicker Fusion, Choice Reaction Time, Continuous Tracking, Mental Arithmetic, Short-Term memory, Digit Symbol Substitution and Mini-Mental State Examination); subjective measures of sleep (Leeds Sleep Evaluation Questionnaire) and daytime sleepiness (Epworth Sleepiness Scale). All adverse events during the study period were recorded and their relationships to the drugs were assessed. Results Neuropsychiatric sequelae seemed to take a natural recovery course in patients with traumatic brain injury. Methylphenidate had significant effects on depressive symptoms compared with the placebo, without hindering the natural recovery process of cognitive function. Although sertraline also had significant effects on depressive symptoms compared with the placebo, it did not improve many tests on cognitive performances. Daytime sleepiness was reduced by methylphenidate, while it was not by sertraline. Conclusions Methylphenidate and sertraline had similar effects on depressive symptoms. However, methylphenidate seemed to be more beneficial in improving cognitive function and maintaining daytime alertness. Methylphenidate also offered a better tolerability than sertraline. Copyright © 2005 John Wiley & Sons, Ltd. [source] Tracking the Euro's ProgressINTERNATIONAL FINANCE, Issue 3 2000Menzie D. Chinn The evolution of the euro since its inception has appeared inexplicable. This paper develops a monetary model of the euro/US dollar exchange rate to track the progress of the currency, both before and after Stage 3 EMU. The relationship between the exchange rate, money stocks, GDP, interest and inflation rates, and prices is identified. The observed patterns of behaviour during the 1990s are used to predict the euro's value up to mid-2000; a consistent finding is that the euro is over-predicted by 23,30%. This finding is robust to the use of alternative sample periods and alternative estimation methodologies, as long as each of the variables is treated as endogenous. This monetary model does not give much weight to factors such as productivity. However, the past evolution of European exchange rates suggests that productivity trends are indeed important. Some estimates suggest that an annual one percentage point in the intercountry differential in tradable-nontradable productivity causes a 0.85'1.7% real appreciation of a currency. [source] Numerical algorithms for modelling electrodeposition: Tracking the deposition front under forced convection from megasonic agitationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3 2010Michael Hughes Abstract Electrodeposition is a widely used technique for the fabrication of high aspect ratio microstructures. In recent years, much research has been focused within this area aiming to understand the physics behind the filling of high aspect ratio vias and trenches on substrates and in particular how they can be made without the formation of voids in the deposited material. This paper reports on the fundamental work towards the advancement of numerical algorithms that can predict the electrodeposition process in micron scaled features. Two different numerical approaches have been developed, which capture the motion of the deposition interface and 2-D simulations are presented for both methods under two deposition regimes: those where surface kinetics is governed by Ohm's law and the Butler,Volmer equation, respectively. In the last part of this paper the modelling of acoustic forces and their subsequent impact on the deposition profile through convection is examined. Copyright © 2009 John Wiley & Sons, Ltd. [source] Adaptive critic design using non-linear network structuresINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 6 2003Ognjen Kuljaca Abstract A neural net (NN)/fuzzy logic (FL) adaptive critic controller is described. This structure takes advantage of the decision-making properties of a FL system to critique and tune a NN action-generating network. The stability of the proposed structure is proven. NN and fuzzy weight tuning algorithms are given that do not require complicated initialization procedures or any off-line learning phase. Tracking and bounded NN weights and control signals are guaranteed. The adaptive fuzzy critic controller given here is a model-free controller' in the sense that it works for any system in a prescribed class without the need for extensive modeling and preliminary analysis to find a regression matrix'. There is no linearity in the parameter (LIP) requirement. Copyright © 2003 John Wiley & Sons, Ltd. [source] Effectiveness and acceptability of non-pharmacological interventions to reduce wandering in dementia: a systematic reviewINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 1 2007L. Robinson Abstract Background Wandering occurs in 15,60% of people with dementia. Psychosocial interventions rather than pharmacological methods are recommended, but evidence for their effectiveness is limited and there are ethical concerns associated with some non-pharmacological approaches, such as electronic tracking devices. Objective To determine the clinical and cost effectiveness and acceptability of non-pharmacological interventions to reduce wandering in dementia. Design A systematic review to evaluate effectiveness of the interventions and to assess acceptability and ethical issues associated with their use. The search and review strategy, data extraction and analysis followed recommended guidance. Papers of relevance to effectiveness, acceptability and ethical issues were sought. Results (i) Clinical effectiveness. Eleven studies, including eight randomised controlled trials, of a variety of interventions, met the inclusion criteria. There was no robust evidence to recommend any intervention, although there was some weak evidence for exercise. No relevant studies to determine cost effectiveness met the inclusion criteria. (ii) Acceptability/ethical issues. None of the acceptability papers reported directly the views of people with dementia. Exercise and music therapy were the most acceptable interventions and raised no ethical concerns. Tracking and tagging devices were acceptable to carers but generated considerable ethical debate. Physical restraints were considered unacceptable. Conclusions In order to reduce unsafe wandering high quality research is needed to determine the effectiveness of non-pharmacological interventions that are practically and ethically acceptable to users. It is important to establish the views of people with dementia on the acceptability of such interventions prior to evaluating their effectiveness through complex randomised controlled trials. Copyright © 2006 John Wiley & Sons, Ltd. [source] Tracking of multiple target types with a single neural extended Kalman filterINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 5 2010Kathleen A. Kramer The neural extended Kalman filter is an adaptive state estimation routine that can be used in target-tracking systems to aid in the tracking through maneuvers without prior knowledge of the targets' dynamics. Within the neural extended Kalman filter, a neural network is trained using a Kalman filter training paradigm that is driven by the same residual as the state estimator. The difference between the a priori model used in the prediction steps of the estimator and the actual target dynamics is approximated. An important benefit of the technique is its versatility because little if any a priori knowledge of the target dynamics is needed. This allows the technique to be used in a generic tracking system that will encounter various classes of targets. In this paper, the neural extended Kalman filter is applied simultaneously to three separate classes of targets, each with different maneuver capabilities. The results show that the approach is well suited for use within a tracking system with multiple possible or unknown target characteristics. © 2010 Wiley Periodicals, Inc. [source] Tracking a partially occluded target with a cluster of Kalman filtersINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 6 2002Dae-Sik Jang Tracking moving objects is one of the most important techniques in motion analysis and understanding, and it has many difficult problems to solve. Estimating and identifying moving objects, when the background and moving objects vary dynamically, are especially difficult. It is possible under such a complex environment that targets might disappear totally or partially due to occlusion by other objects. The Kalman filter has been used to estimate motion information and use the information in predicting the appearance of targets in succeeding frames. In this article, we propose another version of the Kalman filter, to be called the structural Kalman filter, which can successfully accomplish its role of estimating motion information under such a deteriorating condition as occlusion. Experimental results show that the suggested approach is very effective in estimating and tracking non-rigid moving objects reliably. © 2002 Wiley Periodicals, Inc. [source] Tracking for nonlinear plants with multiple unknown time-varying state delays using sliding mode with adaptationINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 13 2010Boris Mirkin Abstract In this paper, we develop a sliding mode model reference adaptive control (MRAC) scheme for a class of nonlinear dynamic systems with multiple time-varying state delays, which is robust with respect to unknown plant delays, to a nonlinear perturbation, and to an external disturbance with unknown bounds. An appropriate Lyapunov,Krasovskii-type functional is introduced to design the adaptation algorithms, and to prove stability. Copyright © 2009 John Wiley & Sons, Ltd. [source] Characterizing violence in health care in British ColumbiaJOURNAL OF ADVANCED NURSING, Issue 8 2009Rakel N. Kling Abstract Title.,Characterizing violence in health care in British Columbia. Background., The high rate of violence in the healthcare sector supports the need for greater surveillance efforts. Aim., The purpose of this study was to use a province-wide workplace incident reporting system to calculate rates and identify risk factors for violence in the British Columbia healthcare industry by occupational groups, including nursing. Methods., Data were extracted for a 1-year period (2004,2005) from the Workplace Health Indicator Tracking and Evaluation database for all employee reports of violence incidents for four of the six British Columbia health authorities. Risk factors for violence were identified through comparisons of incident rates (number of incidents/100,000 worked hours) by work characteristics, including nursing occupations and work units, and by regression models adjusted for demographic factors. Results., Across health authorities, three groups at particularly high risk for violence were identified: very small healthcare facilities [rate ratios (RR) = 6·58, 95% CI =3·49, 12·41], the care aide occupation (RR = 10·05, 95% CI = 6·72, 15·05), and paediatric departments in acute care hospitals (RR = 2·22, 95% CI = 1·05, 4·67). Conclusions., The three high-risk groups warrant targeted prevention or intervention efforts be implemented. The identification of high-risk groups supports the importance of a province-wide surveillance system for public health planning. [source] Long Term Tracking of Methicillin-Resistant Staphylococcus Aureus in a Large Skilled Nursing FacilityJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 11 2004Paul J. Drinka MD No abstract is available for this article. [source] Overwinter survival of stocked age-0 lake sturgeonJOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2009J. A. Crossman Summary Knowledge of age-specific survivorship is critical when developing management prescriptions for imperiled species such as the lake sturgeon (Acipenser fulvescens). Management has focused on population restoration through hatchery supplementation, largely in the absence of data about relationships between hatchery rearing conditions, size/age at release, and estimates of overwinter survival for stocked age-0 lake sturgeon. Young of the year lake sturgeon were reared from egg to age 3 months in two separate hatchery environments: a streamside hatchery on the natal Upper Black River, Michigan, and a traditional hatchery environment. From age 3 to 6 months all fish were reared in the traditional hatchery. Fish (n = 20) originating from each rearing environment were surgically implanted with ultrasonic transmitters at 6 months of age (mean total length: 31.4 cm; mean weight: 106.4 g) and released into Black Lake in December 2005. Tracking using manual and automated hydrophones was conducted during April and May 2006 to estimate overwinter survival and to test for differences in survival of fish reared in different hatchery environments. Eighteen fish (45%) were detected, 16 (40%) of which survived the winter (range of distance traveled between observations of surviving fish was 0.09,0.55 km). The remaining fish were not detected. No significant differences in survival were documented due to rearing environment or size at release. This study represents the first quantified estimate of overwinter survival for stocked age-0 lake sturgeon. The minimum estimate of 40% survival through the first winter is encouraging for hatchery programs, and will aid in the development of management prescriptions for this species. [source] The shifting trajectory of growth in femur length during gestationJOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2010Åshild Bjørnerem Abstract Bone size is a determinant of bone strength and tracks in its percentile of origin during childhood and adolescence. We hypothesized that the ranking of an individual's femur length (FL) is established in early gestation and tracks thereafter. Fetal FL was measured serially using 2D ultrasound in 625 Norwegian fetuses. Tracking was assessed using Pearson correlation, a generalized estimating equation model, and by calculating the proportion of fetuses whose FL remained within the same quartile. Baseline FL Z -score (weeks 10 to 19) and later measurements correlated, but more weakly as gestation advanced: r,=,0.59 (weeks 20 to 26); r,=,0.45 (weeks 27 to 33); and r,=,0.32 (weeks 34 to 39) (p,<,0.001). Tracking within the same quartile throughout gestation occurred in 13% of fetuses. Of the 87% deviating, 21% returned to the quartile of origin, so 34% began and ended in the same quartile, 38% deviated by one quartile, and 28% deviated by two or more quartiles by the end of gestation. A standard deviation higher baseline FL Z -score, placental weight (150,g), maternal height (5,cm), and weight (10,kg), was associated with a 0.25, 0.15, 0.10, and 0.05 SD higher FL Z -score at the end of gestation, respectively (p ranging from <0.001 to 0.02). Tracking within the same percentile throughout the whole of gestation, as suggest by growth charts, is uncommon. Deviation from tracking is more common and is the result of changes in growth velocity within and between fetuses and is partly influenced by maternal, fetal, and placental factors. © 2010 American Society for Bone and Mineral Research [source] Catheter Ablation of Common-Type Atrial Flutter Guided by Three-Dimensional Right Atrial Geometry Reconstruction and Catheter Tracking Using Cutaneous Patches:JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2004A Randomized Prospective Study Introduction: EnSite® NavXÔ (NavX) is a novel mapping and navigation system that allows visualization of conventional catheters for diagnostic and ablative purposes and uses them to create a three-dimensional (3D) geometry of the heart. NavX is particularly suitable for ablation procedures utilizing an anatomic approach, as in the setting of common-type atrial flutter (AFL). The aim of this study was to compare NavX-guided and conventional ablation procedures for AFL. Methods and Results: Forty consecutive patients (32 male, 59 ± 12 years) with documented AFL were randomized to undergo fluoroscopy-guided (group I, 20 patients) or NavX-guided (group II, 20 patients) ablation, including 3D isthmus reconstruction. The same catheter setup was used in both groups. The endpoint of bidirectional isthmus block was obtained in all patients. Compared to conventional approaches, NavX-guided procedures significantly reduced fluoroscopy time (5.1 ± 1.4 min vs 20 ± 11 min, P < 0.01) and total x-ray exposure (5.1 ± 3.1 Gycm2 vs 24.9 ± 1.6 Gycm2, P < 0.01). Isthmus geometry reconstruction could be performed in all patients of group II. In 4 patients (20%) of group II, anatomic isthmus variations were detected by NavX. No significant differences in radiofrequency current applications and procedural times were found between the two groups. Conclusion: NavX technology allows geometry reconstruction of the cavotricuspid isthmus. NavX-guided ablation of AFL reduces total x-ray exposure compared to the fluoroscopy-guided approach but does not prolong procedure time. [source] Optimal Representative Blocks for the Efficient Tracking of a Moving ObjectJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2004SangJoo Kim Optimal representative blocks are proposed for an efficient tracking of a moving object and it is verified experimentally by using a mobile robot with a pan-tilt camera. The key idea comes from the fact that when the image size of a moving object is shrunk in an image frame according to the distance between the camera of mobile robot and the moving object, the tracking performance of a moving object can be improved by shrinking the size of representative blocks according to the object image size. Motion estimation using edge detection (ED) and block-matching algorithm (BMA) are often used in the case of moving object tracking by vision sensors. However, these methods often miss the real-time vision data since these schemes suffer from the heavy computational load. To overcome this problem and to improve the tracking performance, the optimal representative block that can reduce a lot of data to be computed is defined and optimized by changing the size of the representative block according to the size of object in the image frame. The proposed algorithm is verified experimentally by using a mobile robot with a two degree-of-freedom active camera. © 2004 Wiley Periodicals, Inc. [source] A Flexible Software Architecture for Hybrid TrackingJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 2 2004Miguel Ribo Fusion of vision-based and inertial pose estimation has many high-potential applications in navigation, robotics, and augmented reality. Our research aims at the development of a fully mobile, completely self-contained tracking system, that is able to estimate sensor motion from known 3D scene structure. This requires a highly modular and scalable software architecture for algorithm design and testing. As the main contribution of this paper, we discuss the design of our hybrid tracker and emphasize important features: scalability, code reusability, and testing facilities. In addition, we present a mobile augmented reality application, and several first experiments with a fully mobile vision-inertial sensor head. Our hybrid tracking system is not only capable of real-time performance, but can also be used for offline analysis of tracker performance, comparison with ground truth, and evaluation of several pose estimation and information fusion algorithms. © 2004 Wiley Periodicals, Inc. [source] Predictability of FTY720 efficacy in experimental autoimmune encephalomyelitis by in vivo macrophage tracking: Clinical implications for ultrasmall superparamagnetic iron oxide-enhanced magnetic resonance imagingJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2004Martin Rausch PhD Abstract Purpose To examine the efficacy of FTY720 as a new agent to reduce inflammatory activity in an animal model of multiple sclerosis (MS) by in vivo macrophage tracking. Material and Methods FTY720 was used for treatment of rats in a model of chronic relapsing experimental autoimmune encephalomyelitis (EAE) at an oral dose of 0.3 mg/kg/day. Magnetic resonance imaging (MRI) based on in vivo tracking of macrophages labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, immunohistological staining (IHC), and neurological readouts was used to study the burden of disease in treated and untreated animals. Results While untreated animals showed severe paralysis of the hind paws, intense accumulation of macrophages in brain tissue, and areas of blood-brain barrier (BBB) disruption, FTY720-treated animals displayed no signs of inflammatory activity or neurological impairment. These observations were made for both acute phase and first relapse. Conclusion Tracking of macrophages by MRI provides direct evidence of the immunomodulatory efficacy of FTY720 in the EAE model and correlates well with neurological symptoms and histology. J. Magn. Reson. Imaging 2004;20:16,24. © 2004 Wiley-Liss, Inc. [source] Transcallosal White Matter Degradation Detected With Quantitative Fiber Tracking in Alcoholic Men and Women: Selective Relations to Dissociable FunctionsALCOHOLISM, Issue 7 2010Adolf Pfefferbaum Introduction:, Excessive alcohol consumption can adversely affect white matter fibers and disrupt transmission of neuronal signals. Here, we examined six anatomically defined transcallosal white matter fiber bundles and asked whether any bundle was specifically vulnerable to alcohol, what aspect of white matter integrity was most affected, whether women were more vulnerable than men, and whether evidence of compromise in specific bundles was associated with deficits in balance, sustained attention, associative learning, and psychomotor function, commonly affected in alcoholics. Methods:, Diffusion tensor imaging quantitative fiber tracking assessed integrity of six transcallosal white matter bundles in 87 alcoholics (59 men, 28 women) and 88 healthy controls (42 men, 46 women). Measures included orientational diffusion coherence (fractional anisotropy, FA) and magnitude of diffusion, quantified separately for axial (longitudinal; ,L) and radial (transverse; ,T) diffusivity. The Digit Symbol Test and a test of ataxia were also administered. Results:, Alcoholism negatively affected callosal FA and ,T of all but the sensory-motor bundle. Women showed no evidence for greater vulnerability to alcohol than men. Multiple regression analyses confirmed a double dissociation: higher diffusivity in sensory-motor and parietal bundles was associated with poorer balance but not psychomotor speed, whereas higher diffusivity in prefrontal and temporal bundles was associated with slower psychomotor speed but not balance. Conclusions:, This study revealed stronger alcohol effects for FA and radial diffusivity than axial diffusivity, suggesting myelin degradation, but no evidence for greater vulnerability to alcohol in women than men. The presence of brain-behavior relationships provides support for the role of alcoholism-related commissural white matter degradation as a substrate of cognitive and motor impairment. Identification of a double dissociation provides further support for the role of selective white matter integrity in specific domains of performance. [source] Meteoroid structure from radar head echoesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2007M. D. Campbell-Brown ABSTRACT The Advanced Research Project Agency (ARPA) Long Range Tracking and Instrumentation Radar has recorded thousands of head echoes from small meteoroids, which include detailed trajectory information as well as ionization measurements. In total, 25 complete ionization curves have been matched using a detailed model of meteoroid ablation, though the solutions are not necessarily unique. While measurements of the spread along the trajectory of the echoes indicate that most meteors in this size range do not have large separations among fragments, the ionization curves are consistent with fragmenting bodies in the most cases. Very precise radar measurements of meteors can be a valuable source of data on the chemical and physical properties of small meteoroids. [source] Visual Tracking and LIDAR Relative Positioning for Automated Launch and Recovery of an Unmanned Rotorcraft from Ships at SeaNAVAL ENGINEERS JOURNAL, Issue 2 2009MATT GARRATT Sensors and systems for a fully autonomous unmanned helicopter have been developed with the aim of completely automating the landing and launch of a small-unmanned helicopter from the deck of a ship. For our scheme, we have combined a laser rangefinder (LRF) system with a visual tracking sensor to construct a low-cost guidance system. Our novel LRF system determines both the distance to and the orientation of the deck in one cycle. We have constructed an optical sensor to complement the laser system, comprising a digital camera interfaced to a Field Programmable Gate Array (FPGA), which enables the entire target tracking computation to be achieved in a very small self-contained form factor. A narrowband light source on the deck is detected by the digital camera and tracked by an algorithm implemented on the FPGA to provide a relative bearing to the deck from the helicopter. By combining the optical sensor bearing with the information from the laser system, an accurate estimate of the helicopter position relative to the deck can be found. [source] Magnet Tracking: a new tool for in vivo studies of the rat gastrointestinal motilityNEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2006R. Guignet Abstract, Digestive motility was studied in the rat using a miniaturized version of the Magnet Tracking system which monitored the progression of a small magnetic pill through the entire digestive tract. The dynamics of movement was followed and three-dimensional (3-D) images of digestive tract were generated. After a retention period in the stomach and rapid passage through duodenum, the magnet progressed along the small intestine with gradually decreasing speed and longer stationary periods. It remained in the caecum for variable intervals. In the colon, periods of progress alternated with long quiescent periods. Gastric activity oscillated at 5,6 min,1. In the small intestine, two frequency domains coexisted, showing independent modulations and proximo-distal gradients (40 to >32 and 28 to >20 min,1). Caecal oscillations were of 1.5 min,1. The data allowed the magnet location and calculation of gastric and small intestinal transit times (58 ± 36 and 83 ± 14 min respectively), both significantly prolonged by oleate administration (243 ± 130 and 170 ± 45 min respectively). Magnet Tracking is a non-invasive tool to study the in vivo spatial and temporal organization of gastrointestinal motility in the rat. [source] Online Production Tracking Through Author ServicesNEUROMODULATION, Issue 4 2006Elliot Krames MD Editor-in-Chief [source] Online Production Tracking Through Author ServicesPAIN MEDICINE, Issue 5 2006Article first published online: 27 SEP 200 No abstract is available for this article. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||