Tracking Performance Of System Research Articles

Accuracy and stability of deep inspiration breath hold in gated breast radiotherapy – A comparison of two tracking and guidance systems

PurposeTo characterize reproducibility of patient breath-hold positioning and compare tracking system performance for Deep Inspiration Breath Hold (DIBH) gated left breast radiotherapy. Methods29 consecutive left breast DIBH patients (655 fractions) were treated under the guidance of Calypso surface beacons with audio-feedback and 35 consecutive patients (631 fractions) were treated using C-RAD Catalyst HD surface imaging with audiovisual feedback. The Calypso system tracks a centroid determined by two radio-frequency transponders, with a manually enforced institutional tolerance, while the surface image based CatalystHD system utilizes real-time biometric feedback to track a pre-selected point with an institutional tolerance enforced by the Elekta Response gating interface. DIBH motion data from Calypso was extracted to obtain the displacement of breath hold marker in ant/post direction from a set-zero reference point. Ant/post point displacement data from CatalystHD was interpreted by computing the difference between raw tracking points and the center of individual gating windows. Mean overall errors were compared using Welsh’s unequal variance t-test. Wilcoxon rank sum test were used for statistical analysis with P < 0.05 considered significant. ResultsMean overall error for Calypso and CatalystHD were 0.33 ± 1.17 mm and 0.22 ± 0.43 mm, respectively, with t-test comparison P-value < 0.034. Absolute errors for Calypso and CatalystHD were 0.95 ± 0.75 mm and 0.38 ± 0.30 mm, respectively, with Wilcoxon rank sum test P-value <2×10-16. Average standard deviation per fraction was found to be 0.74 ± 0.44 mm for Calypso patients versus 0.54 ± 0.22 mm for CatalystHD. ConclusionReduced error distribution widths in overall positioning, deviation of position, and per fraction deviation suggest that the use of functionalities available in CatalystHD such as audiovisual biofeedback and patient surface matching improves accuracy and stability during DIBH gated left breast radiotherapy.

Performance evaluation of standalone double axis solar tracking system with maximum light detection MLD for telecommunication towers in Malaysia

This paper is performed to investigate the performance of ‎dual-axis solar tracking system with maximum light detection for off-grid telecommunication towers under weather conditions in Malaysia. The studied system consists of High-efficiency heterojunction intrinsic thin (HIT) film solar modules ‎coupled with state-of-the-art dual-axis maximum light detection (MLD) solar ‎tracking system. The ‎investigation method is based on the analyzed the daily actual data record for both the average power output of ‎the photovoltaic system and the ‎state of charge of batteries in four months ‎under different weather conditions as a function of time. Based on the results obtained ‎the use of HIT solar modules with MLD dual ‎axis solar tracking system has high performance effective under ‎Malaysian weather.‎ The study also presented the detailed investigated system description.

A Filtered Sun Sensor for Solar Tracking in HCPV and CSP Systems

Tracking systems with stringent performance are required to take advantage of solar energy produced through the use of high concentration photovolatics and concentrating solar power technologies. Closed-loop tracking systems use measurements provided by a sun sensor, which picks up direct and diffuse sunlight. High levels of diffuse sunlight produce increased levels of measurement noise at the output of the sensor, which in turn limits the maximal achievable gains in the closed-loop controller and consequently the tracking performance deteriorates. The goal of this paper is to present the advantages of equipping a four-quadrant photodiode sun sensor with infrared and linear polarizing optical filters. Experimental results show that these filters reduce the effect of diffuse radiation and allow increasing the performance of sun tracking systems regardless of the type of controller used in the solar tracker. Tracking experiments are presented under indoor and outdoor conditions employing algorithms currently used in solar trackers, including proportional-integral (PI), and proportional-integral-derivative (PID) controllers, and a recently proposed cascade control law. In all the cases, the best performance is obtained with the sun sensor equipped with an infrared filter. Experiments show that an infrared optical filter reduces the filtered mean squared tracking error up to 75% under artificial light conditions and 90% under direct sunlight.

Design and Performance Evaluation of a Dual-Axis Solar Tracking System for Rural Applications

Most rural dwellers in developing countries do not have access to adequate and regular supply of energy and most of these estimated two billion people are poor with no sustainable means of livelihood and therefore rely on wood fuel for their cooking and heating needs. And due to lack of energy, including electricity, socio-economic development is either absent or at abysmally low level. To foster rural development and improved living conditions among this populace, there is need for a reliable, low cost and environmentally risk-free source of energy. This work designed, implemented and evaluated the performance of a dual axis solar tracking system (DATS) using light dependent resistor (LDR) sensors, direct current (DC) motors and microcontroller to make it capable of uninterruptible electricity supply for rural applications. Results of the experiment show that the proposed system is more cost-effective and produces 31.4 % more energy than the single axis tracking system (SATS) and 67.9 % more than the fixed PV panel system (FPPS). Owing to the unique design of the proposed tracking system, solar energy can be tracked and stored continuously so that there is adequate electricity for the consuming population at all times. Though tested on a rural community in Abia State, Nigeria, the proposed system can be adapted to rural communities anywhere in the world.&#x0D;

A Verification on Detection Performance of the Re-entry Capsule Tracking System by Marine Radar

A Verification on Detection Performance of the Re-entry Capsule Tracking System by Marine Radar

Tracking system performance of the BM@N experiment

The Baryonic Matter at Nuclotron (BM@N) experiment represents the first phase of the Nuclotron-based Ion Collider Facility (NICA), a mega-science project at the Joint Institute for Nuclear Research. It is a fixed target experiment built for studying nuclear matter in conditions of extreme density and temperature. The tracking system of the BM@N experiment consists of three main detector systems: Multiwire Proportional Chambers situated before the magnet, Gas Electron Multipliers placed inside the magnet and Drift Chambers placed after the magnet. These systems provide the reconstruction of charged particles’ trajectories and their momentum in the magnetic field. This information is further used by Time of Flight detectors for the particle identification procedure. The system’s performance is reviewed and the spatial resolutions along with efficiencies of the detectors are estimated using the data collected in the recent physics runs of the Nuclotron.

An Integrated Object Tracking and Covert Visual MIMO Communication Service for Museum Security System Using Single Vision Sensor

This paper explores the spatial coverage potential of a vision sensor to implement a dual service for a museum security system. Services include object monitoring and invisible visual Multiple-Input and Multiple-Output (MIMO) communication. For object monitoring, the Kalman filter algorithm is used. To implement a secret visual MIMO communication, an Adaptive Row-Column (ARC)-based LSB substitution technique is used along with the Integer Wavelet Transform method. These proposed services are implemented using existing electronic visual displays and surveillance cameras. Experiments are carried out using a sample object and four stego images. The performance of the object tracking system is measured in terms of accuracy by comparing the actual and estimated position of an object. Similarly, the performance of the covert visual MIMO system is measured at two different stages. On the transmitter side, differences between the cover and stego-images are used to measure imperceptibility. Likewise, at the receiver, differences between the original and the reconstructed data images are used to measure the accuracy. Results illustrate that the proposed system has improved imperceptibility, accuracy, and robustness, as compared to existing techniques.

The tracking system for the IDEA detector at future lepton colliders

While most requirements for detectors at the International Linear Collider (ILC) are very similar to those for the future circular e + e − -colliders FCC–ee ( e + e − Future Circular Collider at CERN) or CEPC (Circular Electron–Positron Collider at IHEP, China), the luminosity is expected to be one or two orders of magnitude larger, with a much shorter bunch spacing, placing severe constraints on the tracking system, favouring an intrinsically fast main tracker to fully exploit the cleanliness of the e + e − environment. Moreover, limits on the maximum magnetic field of the tracker solenoid represent a problem for a large volume TPC, because of the resolution degradation, and for a Si tracker, since it would require a larger radius. The proposed ultra-light He based Drift Chamber is 4 m long, starting at a radius of ∼ 30 c m and extending up to 2 m , with ≲ 1 . 5 c m drift cells, arranged in a fully stereo configuration ( ( 50 – 250 ) m r a d ) and instrumented with readout electronics implementing the Cluster Counting/Timing technique. The total material budget is approximately 0 . 016 X 0 for tracks in the barrel region and 0 . 05 X 0 for forward tracks, providing a momentum resolution of ∼ 5 × 1 0 − 4 for < 10 G e V ∕ c and of < 4 × 1 0 − 3 for 100 G e V ∕ c tracks. Moreover, the use of the Cluster Counting technique will allow for a particle identification (PID) resolution < 3 % , a factor two better than the resolution attainable with dE/dx technique. We will illustrate the tracking system performance obtained with detailed simulations. The hardware features and the construction procedures of the proposed Drift Chamber, making use of the assembly technique developed for MEG2, will also be presented. • Drift chamber proposal for the next generation of electron–positron accelerators. • Ultra-light helium based, fully stereo (no axial layers) drift chamber. • High spatial resolution obtained thanks to the cluster timing technique. • High particle identification capabilities thanks to the cluster counting technique.

Performance Evaluation Strategies for Eye Gaze Estimation Systems with Quantitative Metrics and Visualizations.

An eye tracker’s accuracy and system behavior play critical roles in determining the reliability and usability of eye gaze data obtained from them. However, in contemporary eye gaze research, there exists a lot of ambiguity in the definitions of gaze estimation accuracy parameters and lack of well-defined methods for evaluating the performance of eye tracking systems. In this paper, a set of fully defined evaluation metrics are therefore developed and presented for complete performance characterization of generic commercial eye trackers, when they operate under varying conditions on desktop or mobile platforms. In addition, some useful visualization methods are implemented, which will help in studying the performance and data quality of eye trackers irrespective of their design principles and application areas. Also the concept of a graphical user interface software named GazeVisual v1.1 is proposed that would integrate all these methods and enable general users to effortlessly access the described metrics, generate visualizations and extract valuable information from their own gaze datasets. We intend to present these tools as open resources in future to the eye gaze research community for use and further advancement, as a contribution towards standardization of gaze research outputs and analysis.

A Modified Disturbance Observer Structure Based on Acceleration Measurement for Disturbance Suppression in Tracking Control System

The micro-electro-mechanical system (MEMS) accelerometer is widely adopted in many engineering control systems due to its extraordinary performance with high bandwidth, small size and low weight. However, massive drift caused by its insensitively at low frequency is the main factor which limits its performance. It leads to integral saturation when the feedforward method is used and hinders the improvement of disturbance suppression ability at low frequency, which is a significant factor for evaluating the closed-loop performance of a high-precision tracking system. To solve this problem, a modified disturbance observer structure and its corresponding new controller, which can improve disturbance suppression performance at low frequency by effectively rejecting more drift and weakening the occurrence possibility of integral saturation when drift exists, are proposed. Detailed analyses and a series of comparative experimental results verify that the proposed method can effectively enhance disturbance suppression performance at low frequency.

Production and integration of the ATLAS Insertable B-Layer

During the shutdown of the CERN Large Hadron Collider in 2013-2014, an additional pixel layer was installed between the existing Pixel detector of the ATLAS experiment and a new, smaller radius beam pipe. The motivation for this new pixel layer, the Insertable B-Layer (IBL), was to maintain or improve the robustness and performance of the ATLAS tracking system, given the higher instantaneous and integrated luminosities realised following the shutdown. Because of the extreme radiation and collision rate environment, several new radiation-tolerant sensor and electronic technologies were utilised for this layer. This paper reports on the IBL construction and integration prior to its operation in the ATLAS detector.

Improved kernelized correlation filter algorithm and application in the optoelectronic tracking system

In order to improve the tracking accuracy and real-time performance of the optoelectronic tracking system, an improved kernelized correlation filter approach is developed to obtain precise tracking of a maneuvering object. The proposed strategy contains merits of adaptive threshold approach, kernelized correlation filter method, and Kalman filter algorithm. The adaptive threshold approach can choose the suitable threshold in accordance with the size of the target in the image to improve the tracking performance of the kernelized correlation filter method. When the change between previous position and current position is larger than the distance threshold, Kalman filter algorithm is used to predict the target position for tracking. The tracking accuracy of the proposed algorithm is improved by updating the prediction of the target position with a trusted algorithm. The experimental results on comparison with some state-of-the-art trackers, such as kernelized correlation filter; Tracking-Learning-Detection; scale adaptive with multiple features; minimum output sum of squared error; and dual correlation filter, demonstrate that the proposed approach has the effectiveness of tracking accuracy and real-time performance in tracking the maneuvering object.

Stochastic convergence analysis of cubature Kalman filter with intermittent observations

The stochastic convergence of the cubature Kalman filter with intermittent observations (CKFI) for general nonlinear stochastic systems is investigated. The Bernoulli distributed random variable is employed to describe the phenomenon of intermittent observations. According to the cubature sample principle, the estimation error and the error covariance matrix (ECM) of CKFI are derived by Taylor series expansion, respectively. Afterwards, it is theoretically proved that the ECM will be bounded if the observation arrival probability exceeds a critical minimum observation arrival probability. Meanwhile, under proper assumption corresponding with real engineering situations, the stochastic stability of the estimation error can be guaranteed when the initial estimation error and the stochastic noise terms are sufficiently small. The theoretical conclusions are verified by numerical simulations for two illustrative examples; also by evaluating the tracking performance of the optical-electric target tracking system implemented by CKFI and unscented Kalman filter with intermittent observations (UKFI) separately, it is demonstrated that the proposed CKFI slightly outperforms the UKFI with respect to tracking accuracy as well as real time performance.

Study of the GEM detector performance in BM@N experiment

BM@N is the fixed target experiment at the accelerator complex NICA-Nuclotron aimed to study nuclear matter in the relativistic heavy ion collisions. Triple-GEM detectors were identified as appropriate for the BM@N tracking system located inside the analyzing magnet. Seven GEM chambers are integrated into the BM@N experimental setup and data acquisition system. GEM construction, main characteristics and first obtained results of the GEM tracking system performance in the technical run with the deuteron beam are shortly reviewed.

BioCreative VI Precision Medicine Track system performance is constrained by entity recognition and variations in corpus characteristics.

Precision medicine aims to provide personalized treatments based on individual patient profiles. One critical step towards precision medicine is leveraging knowledge derived from biomedical publications—a tremendous literature resource presenting the latest scientific discoveries on genes, mutations and diseases. Biomedical natural language processing (BioNLP) plays a vital role in supporting automation of this process. BioCreative VI Track 4 brings community effort to the task of automatically identifying and extracting protein–protein interactions (PPi) affected by mutations (PPIm), important in the precision medicine context for capturing individual genotype variation related to disease.We present the READ-BioMed team’s approach to identifying PPIm-related publications and to extracting specific PPIm information from those publications in the context of the BioCreative VI PPIm track. We observe that current BioNLP tools are insufficient to recognise entities for these two tasks; the best existing mutation recognition tool achieves only 55% recall in the document triage training set, while relation extraction performance is limited by the low recall performance of gene entity recognition. We develop the models accordingly: for document triage, we develop term lists capturing interactions and mutations to complement BioNLP tools, and select effective features via a feature contribution study, whereas an ensemble of BioNLP tools is employed for relation extraction.Our best document triage model achieves an F-score of 66.77% while our best model for relation extraction achieved an F-score of 35.09% over the final (updated post-task) test set. Impacting the document triage task, the characteristics of mutations are statistically different in the training and testing sets. While a vital new direction for biomedical text mining research, this early attempt to tackle the problem of identifying genetic variation of substantial biological significance highlights the importance of representative training data and the cascading impact of tool limitations in a modular system.

Real-time multi-scale parallel compressive tracking

Robust visual tracking is a challenging problem because the appearance of a target may rapidly change due to significant variations in the object’s motion and the surrounding illumination. In this paper, a novel robust visual tracking algorithm is proposed based on an existing compressive tracking method. The proposed algorithm adopts multiple naive Bayes classifiers, each trained under a different scale condition, to realize online parallel multi-scale classification. Further, each classifier was initialized by randomly generating different types of Haar-like features. By doing so, the robustness of the feature classification can be improved to obtain more accurate tracking results. To enhance the real-time performance of the visual tracking system, the formula of the naive Bayes classifier is studied and simplified to speed up the processing speed of parallel multi-scale feature classification. After acceleration via formula simplification and parallel implementation, the proposed visual tracking algorithm can reach a tracking performance of approximately 45 frames per second (fps) when dealing with images of 642 × 352 pixels on a popular Intel Core i5-3230M platform. The experimental results show that the proposed algorithm outperforms state-of-the-art visual tracking methods on challenging videos in terms of success rate, tracking accuracy, and visual comparison.

GEM tracking system of the BM@N experiment

BM@N (Baryonic Matter at the Nuclotron) is the fixed target experiment aimed to study nuclear matter in the relativistic heavy ion collisions at the Nuclotron accelerator in JINR. Detectors based on Gas Electron multipliers (GEM) have been identified as appropriate for the BM@N tracking system, which is located inside the BM@N analyzing magnet. The structure of the GEM detectors and the results of study of their characteristics are presented. The GEM detectors are integrated into the BM@N experimental setup and data acquisition system. The performance of the GEM tracking system in the first technical run with the deuteron beam is shortly reviewed.

An Experimental Performance Evaluation of a Cold-Region Photovoltaic System With Tracking

A grid-connected dual-axis tracking photovoltaic (PV) system was installed in the Upper Midwest of the U.S., defined as a cold region, and then evaluated and monitored for a 1 year period. This system serves as a real-world application of PV for electricity generation in a region long overlooked for PV research studies. Additionally, the system provides an opportunity for research, demonstration, and education of dual-axis tracking PV, again not commonly studied in cold regions. In this regard, experimental data for the system were collected and analyzed over a 1year period. During the year of operation, the PV system collected a total of 2173 kWh/m2, which equates to 5.95 kWh/m2 on average per day, of solar insolation and generated a total of 1815 kWh, which equates to an energy to rated power ratio of 1779 kWh/kWp of usable AC electrical energy. The system operated at an annual average conversion efficiency and performance ratio of 11% and 0.82%, respectively, while the annual-average conversion efficiency of the inverter was 92%. The tracking system performance is also compared to a stationary PV system, which is located in close proximity to the tracking PV system. The tracking system's conversion efficiency was 0.3% higher than the stationary system while the energy generation per capacity was 40% higher although the PV module conversion efficiencies were not significantly different for the two systems.

Error-Based Observer of a Charge Couple Device Tracking Loop for Fast Steering Mirror.

The charge couple device (CCD) tracking loop of a fast steering mirror (FSM) is usually used to stabilize line of sight (LOS). High closed-loop bandwidth facilitates good performance. However, low-rate sample and time delay of the CCD greatly limit the high control bandwidth. This paper proposes an error-based observer (EBO) to improve the low-frequency performance of the CCD tracking system. The basic idea is by combining LOS error from the CCD and the controller output to produce the high-gain observer, forwarding into the originally closed-loop control system. This proposed EBO can improve the system both in target tracking and disturbance suppression due to LOS error from the CCD’s sensing of the two signals. From a practical engineering view, the closed-loop stability and robustness of the EBO system are investigated on the condition of gain margin and phase margin of the open-loop transfer function. Two simulations of CCD experiments are provided to verify the benefits of the proposed algorithm.

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

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.