			Home About us Contact

Tracking System (tracking + system)

Distribution by Scientific Domains

Medical Sciences	53%
Engineering	26%
Information Science and Computing	10%
2 Other Domains	11%

Selected Abstracts

An automated tracking system to measure the dynamic properties of vesicles in living cells

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2007
Tien-Chuan Ku
Abstract Recent technological improvements have made it possible to examine the dynamics of individual vesicles at a very high temporal and spatial resolution. Quantification of the dynamic properties of secretory vesicles is labor-intensive and therefore it is crucial to develop software to automate the process of analyzing vesicle dynamics. Dual-threshold and binary image conversion were applied to enhance images and define the areas of objects of interest that were to be tracked. The movements, changes in fluorescence intensity, and changes in the area of each tracked object were measured using a new software system named the Protein Tracking system (PTrack). Simulations revealed that the system accurately recognized tracked objects and measured their dynamic properties. Comparison of the results from tracking real time-lapsed images manually with those automatically obtained using PTrack revealed similar patterns for changes in fluorescence intensity and a high accuracy (<89%). According to tracking results, PTrack can distinguish different vesicular organelles that are similar in shape, based on their unique dynamic properties. In conclusion, the novel tracking system, PTrack, should facilitate automated quantification of the dynamic properties of vesicles that are important when classifying vesicular protein locations. Microsc. Res. Tech. 2007. © 2006 Wiley-Liss, Inc. [source]

Magnet Tracking: a new tool for in vivo studies of the rat gastrointestinal motility

NEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2006
R. 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]

New centralized automatic vehicle location communications software system under GIS environment

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2005
Omar Al-Bayari
Abstract Recent advances in wireless communications and networks have integrated relatively new technologies such as Global Positioning System (GPS), to the popular Global System for Mobile Communication (GSM), second generation cellular systems and the Geographic Information Systems (GIS) technologies. Automatic Vehicle Location (AVL) is based on a combination of GPS, GIS and telecommunication technologies. Automatic Vehicle Tracking systems are more and more used for different purposes, especially those related to tracking one vehicle or a fleet of vehicles. In this work, we introduce a new AVL system, which is based and developed under GIS software environment. The centralized software at the control station offers a new technology of transferring the intelligence of tracking system from the car unit, into the control office PC software. Centralized software will reduce the programming efforts in the car unit and will offer better fleet management. Moreover, the core of our system is based on the objects or the controllers of the GIS software, which reduces dramatically the overall system cost. Our system provides an easy access to change the functions of the system, with great possibility to satisfy the local needs. The design of our software will be presented with an explanation of the new supporting technologies that were to create the system. Finally, our software system has been validated using data from local road networks. Copyright © 2005 John Wiley & Sons, Ltd. [source]

The Effects of a Physician Slowdown on Emergency Department Volume and Treatment

ACADEMIC EMERGENCY MEDICINE, Issue 11 2006
Brian Walsh MD
Objectives In February 2003, many physicians in New Jersey participated in a work slowdown to publicize large increases in malpractice premiums and generate support for legislative reform. It was anticipated that the community physician slowdown (hereafter referred to as "slowdown") would increase emergency department (ED) visits. The authors' goal was to help others prepare for anticipated increases in ED volumes by describing the preparatory staffing changes made and quantifying increases in ED volume. Methods This was a retrospective cohort study performed at a New Jersey suburban teaching hospital with 70,000 annual visits. Consecutive patients seen by emergency physicians were enrolled. The authors extracted patient visit data from the computerized tracking system and analyzed hours worked by personnel, patient volumes, admission rates, and patient throughput times. Variables from each day of the slowdown with baseline values for the same day of the week for the four weeks before and after the slowdown were compared. A Bonferroni correction was used, with p < 0.01 considered statistically significant. Results Total patient volume increased 79% from baseline (95% confidence interval [CI] = 20% to 137%). Pediatric volume increased 223% (95% CI = 171% to 274%). Overall admission rate decreased 29% compared with baseline (95% CI = 8% to 51%). Patient throughput times did not change significantly. Similar results for these variables were found for the second through fourth days of the slowdown. Conclusions Emergency department visits, especially pediatric visits, increased markedly during the community physician slowdown. Anticipatory increases in staffing effectively prevented increased throughput times. [source]

Interventions to improve adherence to medication in people with type 2 diabetes mellitus: the role of nurses

EUROPEAN DIABETES NURSING, Issue 2 2006
Deputy Director, H Hearnshaw BSc, PhD Reader in Primary Care
Abstract Summary Nurses now provide the majority of education and support for people with diabetes both in community and hospital settings. However, there are very few studies on nurse-led interventions to improve adherence to medication, a crucial element of the self-management of diabetes. The four studies reviewed formed a subgroup of a Cochrane review on interventions to improve adherence to medication in people with type 2 diabetes. Search terms were ,type 2 diabetes mellitus' and ,compliance' or ,adherence'. Studies were included if they assessed adherence to medical treatment specifically, rather than other aspects of self-management. Out of the 21 studies selected for review, four described an intervention delivered by a nurse. All four studies were from the USA and used an intervention delivered by telephone. Different interventions (two educational programmes, one automated telephone management system, one tracking system for health service and medication use) were backed up by a scripted nurse call. While patients in two studies reported improvements in self-care behaviour, only one measured a significant improvement in blood glucose control. Although some studies asked patients to report on their adherence to medication taking, responses from patients were not explicitly presented. The studies reviewed show the potential for generating evidence for the effectiveness of nurse-led diabetes management programmes. Further high-quality studies into this area are desperately needed, and they should consider new ways of evaluating complex interventions to generate more evidence. Copyright © 2006 FEND. [source]

New centralized automatic vehicle location communications software system under GIS environment

Video tracking system optimization using evolution strategies

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 2 2007
Jesús García
Abstract A video-based tracking system for airport surveillance, composed by modules performing vision tasks at different levels, is adapted for operational conditions by means of Evolution Strategies (ES). An optimization procedure has been carried out considering different scenes composed of representative trajectories, supported by a global evaluation metric proposed to quantify the system performance. The generalization problem (the search of appropriate solutions for general situations, avoiding over-adaptation to particular conditions) is approached considering evaluation of ES-individuals over combinations of trajectories to build the fitness function. In this way, the optimization procedure covers sets of trajectories representing different types of problems. Besides, alternative operators for aggregating partial evaluations have been analysed. Results show how the optimization strategy provides a sensitive tuning of performance related to input parameters at different levels, and how the combination of different situations improves the generalization capability of the trained system. The global performance final system after optimization is also compared with representative algorithms in the state of the art of visual tracking. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 75,90, 2007 [source]

Tracking of multiple target types with a single neural extended Kalman filter

INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 5 2010
Kathleen 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]

Visual servoing of an autonomous helicopter in urban areas using feature tracking

JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3-4 2006
Luis Mejías
We present the design and implementation of a vision-based feature tracking system for an autonomous helicopter. Visual sensing is used for estimating the position and velocity of features in the image plane (urban features like windows) in order to generate velocity references for the flight control. These visual-based references are then combined with GPS-positioning references to navigate towards these features and then track them. We present results from experimental flight trials, performed in two UAV systems and under different conditions, that show the feasibility and robustness of our approach. © 2006 Wiley Periodicals, Inc. [source]

A Flexible Software Architecture for Hybrid Tracking

JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 2 2004
Miguel 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]

Impact implantation of a transmitter on Sarpa salpa behaviour: study with a computerized video tracking system

JOURNAL OF FISH BIOLOGY, Issue 2 2005
C. Jadot
Two transmitter masses (2 and 6% of the fish's mass) were selected to examine the interference of tags with the behaviour of Sarpa salpa using a computerized video tracking system based on digital imaging techniques. The study demonstrated that light transmitters had no effect on the behavioural variables studied, and a substantial bias in behaviour is introduced if heavier (6%) tags are used. [source]

Utility of Infectious Disease Coding Sheets for Surveillance in a State Medical Examiner's Office,

JOURNAL OF FORENSIC SCIENCES, Issue 4 2008
Ph.D., Sarah L. Lathrop D.V.M.
Abstract:, Medical examiners are often first to recognize unusual occurrences of fatal infectious diseases. Recognition of these deaths allows public health officials to institute appropriate public health measures. Therefore, we developed a simple method of identifying and tracking infectious disease deaths in a statewide medical examiner's office. One-page infectious disease forms were completed for 1566/1949 autopsies (80%) performed at the New Mexico Office of the Medical Investigator in 2004. In 241 cases one infectious disease was identified at autopsy and 58 cases had two infectious diseases. Fourteen of the infectious-diseases caused deaths involved diseases that are notifiable conditions in New Mexico. Pneumonia was the most commonly reported infectious process (47 deaths) followed by sepsis (25 deaths). Tracking infectious disease deaths highlighted the importance of recognizing these deaths, although hand-written entries were unstandardized. Preferably, a tracking system would be built into electronic databases at medical examiner and coroner's offices, expediting the identification of these diseases and contact of public health agencies. [source]

Markers of Overcrowding in a Pediatric Emergency Department

ACADEMIC EMERGENCY MEDICINE, Issue 2 2010
Antonia S. Stang MD
Abstract Objectives:, The objective of this study was to identify markers of overcrowding in pediatric emergency departments (PEDs) according to expert opinion and then to use statistical methods to further explore the underlying construct of overcrowding. Methods:, A cross-sectional survey of all PED directors (n = 12) and pediatric emergency medicine fellowship program directors (n = 10) across Canada was conducted to elicit expert opinion on relevant markers of emergency department (ED) crowding. The list of markers was reduced to those specific to the ED for which data could be extracted from one tertiary care PED from an existing computerized patient tracking system. Data representing 2,190 consecutive shifts and 138,361 patient visits were collected between April 2005 and March 2007. Common factor analysis (CFA) was used to determine the underlying factors that best represented overcrowding as determined by markers identified by experts in pediatric emergency medicine Results:, The main markers of overcrowding identified by the survey included measures of patient volume (25%), ED operational processes (55%), and delays in transferring patients to inpatient beds (13%). Data collected on 41 markers were retained for the CFA. The results of the CFA indicated that the largest portion of variation in the data (48%) was accounted for by markers describing patient volumes and flow through the ED. Measures of admission delays accounted for a smaller proportion of variability (9%). Conclusions:, The results suggest that for this tertiary PED, markers of ED operational processes and patient volume may be more relevant for determination of overcrowding than markers reflecting delays in transferring patients to inpatient beds. This study provides a foundation for further research on markers of overcrowding specific to the pediatric setting. ACADEMIC EMERGENCY MEDICINE 2010; 17:151,156 © 2010 by the Society for Academic Emergency Medicine [source]

An automated tracking system to measure the dynamic properties of vesicles in living cells

Validation for tremor quantification of an electromagnetic tracking device

MOVEMENT DISORDERS, Issue 2 2001
Padraig E. O'Suilleabhain MB
Abstract An electromagnetic tracking system was used to record arm motion in subjects with Parkinson's disease (n = 23), essential tremor (n = 28) or without neurological disease (n = 4). Tremor magnitude was calculated by averaging the three-dimensional displacement of individual tremor bursts. Tremor magnitude calculated in this manner was quite closely correlated with a clinician's estimate (r = 0.88 and 0.86 for Parkinsonian and essential tremors, respectively) and was reproducible (r = 0.93 for repeated recordings). The accuracy of the device and algorithm was confirmed by mechanically generating oscillations of known magnitudes and frequencies. This device is adaptable for quantifying different types of tremors and its accuracy is easy to verify. Because position rather than acceleration is tracked, tremor amplitude can be stated in readily comprehensible units. © 2001 Movement Disorder Society. [source]

A frequency domain technique for maintaining resonance condition during sine dwell vibration testing of packages

PACKAGING TECHNOLOGY AND SCIENCE, Issue 6 2000
Vincent Rouillard
Abstract When a package undergoes progressive damage during a sine dwell vertical vibration test, its dynamic characteristics, such as stiffness and damping, will change. This will result in variation of its resonance frequency during a test. This paper demonstrates that tracking the resonance by feedback control of the excitation frequency during resonance dwell tests is essential. Furthermore, this paper shows the differences in the results obtained from dwell tests with uncontrolled and controlled excitation frequencies. A computer-based resonance tracking system was developed and used together with a commercial vibration table to experimentally verify the benefits of such a technique. Copyright,©,2000 John Wiley & Sons, Ltd. [source]

Pesticide illness among flight attendants due to aircraft disinsection,

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 5 2007
Patrice M. Sutton MPH
Abstract Background Aircraft "disinsection" is the application of pesticides inside an aircraft to kill insects that may be on board. Over a 1-year period, California's tracking system received 17 reports of illness involving flight attendants exposed to pesticides following disinsection. Methods Interviews, work process observations, and a records review were conducted. Illness reports were evaluated according to the case definition established by the National Institute for Occupational Safety and Health. Results Twelve cases met the definition for work-related pesticide illness. Eleven cases were attributed to the "Residual" method of disinsection, i.e., application of a solution of permethrin (2.2% w/w), solvents (0.8%), and a surfactant (1.4%); the method of disinsection could not be determined for one case. Conclusions The aerosol application of a pesticide in the confined space of an aircraft cabin poses a hazard to flight attendants. Nontoxic alternative methods, such as air curtains, should be used to minimize disease vector importation via aircraft cabins. Employers should mitigate flight attendant pesticide exposure in the interim. Am. J. Ind. Med. 50:345,356, 2007. © 2007 Wiley-Liss, Inc. [source]

Virtobot,a multi-functional robotic system for 3D surface scanning and automatic post mortem biopsy

THE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 1 2010
Lars Christian Ebert
Abstract Background The Virtopsy project, a multi-disciplinary project that involves forensic science, diagnostic imaging, computer science, automation technology, telematics and biomechanics, aims to develop new techniques to improve the outcome of forensic investigations. This paper presents a new approach in the field of minimally invasive virtual autopsy for a versatile robotic system that is able to perform three-dimensional (3D) surface scans as well as post mortem image-guided soft tissue biopsies. Methods The system consists of an industrial six-axis robot with additional extensions (i.e. a linear axis to increase working space, a tool-changing system and a dedicated safety system), a multi-slice CT scanner with equipment for angiography, a digital photogrammetry and 3D optical surface-scanning system, a 3D tracking system, and a biopsy end effector for automatic needle placement. A wax phantom was developed for biopsy accuracy tests. Results Surface scanning times were significantly reduced (scanning times cut in half, calibration three times faster). The biopsy module worked with an accuracy of 3.2 mm. Discussion Using the Virtobot, the surface-scanning procedure could be standardized and accelerated. The biopsy module is accurate enough for use in biopsies in a forensic setting. Conclusion The Virtobot can be utilized for several independent tasks in the field of forensic medicine, and is sufficiently versatile to be adapted to different tasks in the future. Copyright © 2009 John Wiley & Sons, Ltd. [source]

MMP-Dependent Migration of Extrapulmonary Myofibroblast Progenitors Contributing to Posttransplant Airway Fibrosis in the Lung

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 5 2009
M. Sato
Myofibroblasts play a central role in fibroproliferative airway remodeling in obliterative bronchiolitis (OB) after lung transplantation. The purpose of the study is to elucidate the mechanisms whereby matrix metalloproteinases (MMPs) contribute to myofibroblast-mediated allograft airway fibrosis. In an intrapulmonary tracheal transplant model of OB, broad-spectrum MMP inhibitors, SC080 and MMI270 reduced the number of myofibroblasts at day 28 without changing differentiation, proliferation or apoptosis of myofibroblasts or fibroblasts. Next, myofibroblasts in allograft airway fibrosis were demonstrated to be almost exclusively of extrapulmonary origin by analyzing RT1An positive myofibroblasts in an animal model combining orthotopic lung transplantation (from Lewis (RT1Al) to F1 (Brown,Norway (RT1An) × Lewis)) and intrapulmonary tracheal transplantation (from a Wister,Furth rat (RT1Au) into the transplanted Lewis-derived lung). Using peripheral blood mononuclear cells (PBMCs) that can differentiate into ,-SMA positive myofibroblasts in vitro, we demonstrated their contribution to the myofibroblast population of allograft airway fibrosis in vivo using a fluorescence-labeling cell tracking system. Moreover, PBMC-derived fibroblast-like cells expressed high levels of MMP-9 and MMP-12 and their migration was inhibited by MMP inhibitors in a wound healing assay. In conclusion, MMP-dependent migration of PBMC-derived myofibroblast precursors is an important contributing mechanism to the development of allograft airway fibrosis. [source]

Visual Tracking For References Generated By A Stochastic Model

ASIAN JOURNAL OF CONTROL, Issue 3 2003
T. Kamiya
ABSTRACT This paper describes a visual tracking system for an unknown reference signal. A time-varying reference signal is realized as a random process generated by an auto-regressive (AR) model, which is identifed by a recursive algorithm. Based on the obtained AR model, the future value of reference signal is predicted. We propose a new visual tracking system using generalized minimum variance control (GMVC) and illustrate its properties through experiments. [source]

Competency Testing Using a Novel Eye Tracking Device

ACADEMIC EMERGENCY MEDICINE, Issue 2009
Paul Wetzel
Assessment and evaluation metrics currently rely upon interpretation of observed performance or end points by an ,expert' observer. Such metrics are subject to bias since they rely upon the traditional medical education model of ,see one, do one, teach one'. The Institute of Medicine's Report and the Flexner Report have demanded improvements in education metrics as a means to improve patient safety. Additionally, advancements in adult learning methods are challenging traditional medical education measures. Educators are faced with the daunting task of developing rubrics for competency testing that are currently limited by judgment and interpretation bias. Medical education is demanding learner-centered metrics to reflect quantitative and qualitative measures to document competency. Using a novel eye tracking system, educators now have the ability to know how their learners think. The system can track the focus of the learner during task performance. The eye tracking system demonstrates a learner-centered measuring tool capable of identifying deficiencies in task performance. The device achieves the goal of timely and direct feedback of performance metrics based on the learner's perspective. Employment of the eye tracking system in simulation education may identify mastery and retention deficits before compliance and quality improvement issues develop into patient safety concerns. [source]

Image-guided surgery of liver metastases by three-dimensional ultrasound-based optoelectronic navigation

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 7 2007
S. Beller
Background: Vessel-oriented surgery and tumour-free resection margins are essential for resection of liver metastases to preserve liver parenchyma and improve oncological outcome. Preoperative three-dimensional models reconstructed from imaging data could facilitate surgical planning with the use of navigation technology. Methods: Thirty-three patients with central and/or impalpable liver metastases were scheduled for navigated hepatic resection. Intraoperative three-dimensional ultrasonography and an infrared-based optical tracking system were used for data registration and image-guided surgery. Postoperative three-dimensional data were compared with the preoperative virtual surgical plan to assess the accuracy of navigation, and clinical results were compared with those of a matched control group of 32 patients. Results: Navigation was successful in 32 of 33 patients. Realization of the preoperative plan and R0 resection was achieved in 30 of these 32 patients. The median discrepancy between the planned and actual vascular dissection level was 6 (range 0,11) mm. There was a reduced rate of R1 resection in the navigated group compared with the control group (two versus four patients), and more parenchyma was preserved. Conclusion: Three-dimensional ultrasound-based optoelectronic navigation technology improves intraoperative orientation and enables parenchyma-preserving surgery with high precision. Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source]

Methamphetamine-related Emergency Department Utilization and Cost

ACADEMIC EMERGENCY MEDICINE, Issue 1 2008
Robert G. Hendrickson MD
Abstract Objective:, To quantify the frequency, cost, and characteristics associated with emergency department (ED) visits that are related to methamphetamine use. Methods:, This was a prospective observational study. The authors performed a training program for ED clinicians on the acute and chronic effects of methamphetamine and the signs of methamphetamine abuse. A standardized two question survey was administered to clinicians concerning the relationship between the ED visit and the patient's methamphetamine use. The survey was embedded in the patient tracking system and was required for all ED patients before disposition. Survey results were merged with administrative data on demographics, diagnosis, disposition, and charges. Univariate analyses were used to determine patient characteristics associated with methamphetamine-related ED visits. Results:, The authors examined 15,038 ED visits over a 20-week period from February 2006 to June 2006. There were a total of 353 methamphetamine-related visits, for an average of 17.65 visits per week (2.4% of all visits). Hospital charges for methamphetamine-related ED visits averaged $133,181 per week, for an estimated total of $6.9 M in annual charges. Methamphetamine-related ED patients were more likely to be male (odds ratio [OR] 1.6, 95% confidence interval [CI] = 1.30 to 2.01), white (OR 1.8, 95% CI = 1.38 to 2.29), and uninsured (OR 3.2, 95% CI = 2.21 to 4.69). The top four medical conditions associated with methamphetamine-related visits were mental health (18.7%), trauma (18.4%), skin infections (11.1%), and dental diagnoses (9.6%). Conclusions:, Methamphetamine abuse accounts for a modest but substantial proportion of ED utilization and hospital cost. Methamphetamine-related ED visits are most commonly related to mental illness, trauma, skin, and dental-related problems. [source]

Reliability factors in business software: volatility, requirements and end-users

INFORMATION SYSTEMS JOURNAL, Issue 3 2002
Paul L Bowen
Abstract. Many business-oriented software applications are subject to frequent changes in requirements. This paper shows that, ceteris paribus, increases in the volatility of system requirements decrease the reliability of software. Further, systems that exhibit high volatility during the development phase are likely to have lower reliability during their operational phase. In addition to the typically higher volatility of requirements, end-users who specify the requirements of business-oriented systems are usually less technically oriented than people who specify the requirements of compilers, radar tracking systems or medical equipment. Hence, the characteristics of software reliability problems for business-oriented systems are likely to differ significantly from those of more technically oriented systems. [source]

Comparison of potential solar electricity output from fixed-inclined and two-axis tracking photovoltaic modules in Europe

PROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 1 2008
Thomas Huld
Abstract We present an approach to determine the potential energy gains of flat plate non-concentrating photovoltaic systems for the case of two-axis tracking and two inclination angles with fixed orientation (assuming biannual adjustment) compared to the configuration of single fixed optimum angle. The calculation is based on the Photovoltaic Geographic Information System (PVGIS), which integrates modelling tools with the pan-European solar radiation database. The results indicate that in the case of a PV system with two seasonal inclination angles, the maximum yearly gains, compared to the single fixed optimum angle, do not exceed 60,70,kWh per kWp in the Mediterranean region, while in the Baltic and North Sea regions this configuration gives less than 20,kWh extra. For the case of two-axis tracking, the relative energy gain compared to single fixed optimum angle is highest in the Northern latitudes but the absolute gain is much higher in the South. Typical yearly gains in Portugal and the Mediterranean region are in the range of 400,600,kWh per kWp. The smallest absolute increase is found in the Northwest and Central Europe including the British Isles, where it is lower than 250,kWh per kWp. For crystalline silicon we also investigate the effects of temperature and shallow-angle reflectivity on the comparison between fixed and tracking systems. While both effects reduce the overall energy output, the temperature degradation is stronger for tracking systems while the reflectivity reduces output more for fixed systems. The combined effect is almost equal for fixed and two-axis tracking systems. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Computer-aided navigation for arthroscopic hip surgery using encoder linkages for position tracking,

THE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 3 2006
Emily Monahan
Abstract Background While arthroscopic surgery has many advantages over traditional surgery, this minimally invasive technique is not often applied to the hip joint. Two main reasons for this are the complexity of navigating within the joint and the difficulty of correctly placing portal incisions without damaging critical neurovascular structures. This paper proposes a computer-aided navigation system to address the challenges of arthroscopic hip surgery. Methods Unlike conventional arthroscopic methods, our system uses a hyper-redundant encoder linkage to track surgical instruments, thus eliminating the occlusion and distortion problems associated with standard optical and electromagnetic tracking systems. The encoder linkage position information is used to generate a computer display of patient anatomy. Results The tracking error from the encoder linkage was evaluated to be within an acceptable range for this tracking prototype, and the new computer-aided approach to arthroscopic hip surgery was applied to a prototype system for concept verification. Conclusion This navigation system for arthroscopic hip surgery can be used as a tool to address the challenges of joint navigation and portal placement in arthroscopic hip surgery by visually supplementing the limiting view from the arthroscope. The introduction of a tracking linkage shows significant potential as an alternative to other tracking systems. Positive feedback about the completed demo system was obtained from surgeons who perform arthroscopic proceduces. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Multi-sensor track-to-track fusion via linear minimum variance sense estimators

ASIAN JOURNAL OF CONTROL, Issue 3 2008
Li-Wei Fong
Abstract An integrated approach that consists of sensor-based filtering algorithms, local processors, and a global processor is employed to describe the distributed fusion problem when several sensors execute surveillance over a certain area. For the sensor tracking systems, each filtering algorithm utilized in the reference Cartesian coordinate system is presented for target tracking, with the radar measuring range, bearing, and elevation angle in the spherical coordinate system (SCS). For the local processors, each track-to-track fusion algorithm is used to merge two tracks representing the same target. The number of 2-combinations of a set with N distinct sensors is considered for central track fusion. For the global processor, the data fusion algorithms, simplified maximum likelihood (SML) estimator and covariance matching method (CMM), based on linear minimum variance (LMV) estimation fusion theory, are developed for use in a centralized track-to-track fusion situation. The resulting global fusers can be implemented in a parallel structure to facilitate estimation fusion calculation. Simulation results show that the proposed SML estimator has a more robust capability of improving tracking accuracy than the CMM and the LMV estimators. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]