Active Tracking Research Articles

α-Band activity tracks a two-dimensional spotlight of attention during spatial working memory maintenance.

Covert spatial attention is thought to facilitate the maintenance of locations in working memory, and EEG α-band activity (8-12 Hz) is proposed to track the focus of covert attention. Recent work has shown that multivariate patterns of α-band activity track the polar angle of remembered locations relative to fixation. However, a defining feature of covert spatial attention is that it facilitates processing in a specific region of the visual field, and prior work has not determined whether patterns of α-band activity track the two-dimensional (2-D) coordinates of remembered stimuli within a visual hemifield or are instead maximally sensitive to the polar angle of remembered locations around fixation. Here, we used a lateralized spatial estimation task, in which observers remembered the location of one or two target dots presented to one side of fixation, to test this question. By applying a linear discriminant classifier to the topography of α-band activity, we found that we were able to decode the location of remembered stimuli. Critically, model comparison revealed that the pattern of classifier choices observed across remembered positions was best explained by a model assuming that α-band activity tracks the 2-D coordinates of remembered locations rather than a model assuming that α-band activity tracks the polar angle of remembered locations relative to fixation. These results support the hypothesis that this α-band activity is involved in the spotlight of attention, and arises from mid- to lower-level visual areas involved in maintaining spatial locations in working memory.NEW & NOTEWORTHY A substantial body of work has shown that patterns of EEG α-band activity track the angular coordinates of attended and remembered stimuli around fixation, but whether these patterns track the two-dimensional coordinates of stimuli presented within a visual hemifield remains an open question. Here, we demonstrate that α-band activity tracks the two-dimensional coordinates of remembered stimuli within a hemifield, showing that α-band activity reflects a spotlight of attention focused on locations maintained in working memory.

Untethering Single Molecule Spectroscopy with 3D-SMART

Measuring the behavior of single molecules enables the discovery of states and dynamics obscured by bulk measurements. However, molecules in solution rapidly diffuse in three dimensions, precluding long-duration and high-temporal resolution measurement. To overcome this hurdle, we have developed 3D single-molecule active real-time tracking (3D-SMART) which enables active feedback tracking of rapidly diffusing and lowly emitting fluorescent particles. 3D-SMART uses a 3D flying laser focus to tag each arriving photon with 3D position information and a piezoelectric nanopositioner to lock the diffusing object in the objective focal volume, at diffusive speeds exceeding 10 μm2/sec and emission rates of 10 kHz or less. Here we demonstrate the application of 3D-SMART to a range targets, from single virus-like particles and quantum dots in water, all the way down to single fluorophores in viscous solution. This new single molecule tracking can be applied to continuously monitor single proteins and nucleic acids, including real-time measurement of transcription on a freely diffusing, single-dye labelled DNA strand. 3D-SMART represents a critical step towards the untethering of single molecule spectroscopy.

Synchronous 3D Tracking and Imaging at Multiple Scales to Overcome Spatiotemporal Disparity

Single particle tracking methods have been used to dissect the viral infection process step-by-step and elucidate new quantitative understanding of the interactions and dynamics between virus and host. The process begins when a virus diffusing rapidly through solution impacts and binds to the cell. The disparate spatial scales between the virus and a host cell make capturing these moments of transition between fast, 3D viral diffusion and cell-bound interaction an impossible imaging challenge that no single microscope is built to task for. Instead, tradeoffs are required between imaging the narrow field of view required to target-lock a solution-phase virus or imaging the larger cellular environment, temporally limited to confined viral dynamics inside cells after binding. In this work, we introduce the 3D Tracking and Imaging, (3D-TrIm) microscope which merges the best of both worlds; allowing for large-scale, 3D multiphoton volumes to be simultaneously acquired and co-localized with single-particle trajectories obtained via active feedback tracking capable of target-locking freely-diffusive virus-scale particles. This feat is accomplished by the integration of 3D-Dynamic Photon Localization Tracking (3D-DyPLoT), and the 3D Fast Acquisition Scan via z-Translating Raster (3D-FASTR) point-scan imaging pattern. Both microscopes utilize dynamic 3D laser scan patterns to survey two disparate fields of view, coupled through the same objective lens and piezoelectric stage which serves as the reference spatial coordinate system and allows point-scanned multiphoton voxels to be rapidly localized without motion smearing. The ability to quickly and simultaneously image surrounding 3D cellular regions during tracking can provide new insight into the nature of viral activities spanning the range of spatiotemporal regimes in the infection process. Such activities can yield new insight into the critical moments of the process missed by only having access to single spatiotemporal imaging regimes and modalities.

A Mobile Health Platform for Self-Management of Pediatric Cystic Fibrosis: Qualitative Study of Adaptation to Stakeholder Needs and Integration in Clinical Settings.

BackgroundCystic fibrosis (CF) is an inherited chronic condition that requires extensive daily care and quarterly clinic visits with a multidisciplinary care team. The limited exchange of information outside of the quarterly clinic visits impedes optimal disease self-management, patient engagement, and shared decision making.ObjectiveThe aim of this study is to adapt a mobile health (mHealth) app originally developed in Sweden to the needs of patients, families, and health care providers in a CF center in the United States and to test it as a platform for sharing patient-generated health data with the CF health care team.MethodsFocus groups with health care providers of patients with CF, adolescents with CF, and caregivers of children with CF were conducted to determine what modifications were necessary. Focus group data were analyzed using a thematic analysis, and emergent themes were ranked according to desirability and technical feasibility. The mHealth platform was then modified to meet the identified needs and preferences, and the flow of patient-generated health data to a secure Research Electronic Data Capture database was tested. Protocols for data management and clinical follow-up were also developed.ResultsA total of 5 focus groups with 21 participants were conducted. Recommended modifications pertained to all functionalities of the mHealth platform, including tracking of symptoms, treatments, and activities of daily care; creating and organizing medication lists and setting up reminders; generating reports for the health care team; language and presentation; sharing and privacy; and settings and accounts. Overall, health care providers recommended changes to align the mHealth platform with US standards of care, people with CF and their caregivers requested more tracking functionalities, and both groups suggested the inclusion of a mental health tracker as well as more detailed response options and precise language. Beta testers of the modified platform reported issues related to translatability to US environment and various bugs.ConclusionsThis study demonstrated the importance of identifying the needs and preferences of target users and stakeholders before adopting existing mHealth solutions. All relevant perspectives, including those of clinicians, patients, and caregivers, should be thoroughly considered to meet both end users’ needs and evidence-based practice recommendations.

A Web Platform (MOSAICO) to Design, Perform, and Assess Collaborative Clinical Scenarios for Medical Students: Viewpoint.

BackgroundThe collaborative clinical simulation (CCS) model is a structured method for the development and assessment of clinical competencies through small groups working collaboratively in simulated environments. From 2016 onward, the CCS model has been applied successfully among undergraduate and graduate medical students from the Universidad de Talca, Chile; the Universität de Barcelona, Spain; and the Universidad de Vic-Manresa, Spain. All the templates for building the clinical cases and the assessment instruments with CCS were printed on paper. Considering the large number of CCS sessions and the number of participating students that are required throughout the medical degree curriculum, it is impossible to keep an organized record when the instruments are printed on paper. Moreover, with the COVID-19 pandemic, web platforms have become important as safe training environments for students and medical faculties; this new educational environment should include the consolidation and adaptation of didactic sessions that create and use available virtual cases and use different web platforms.ObjectiveThe goal of this study is to describe the design and development of a web platform that was created to strengthen the CCS model.MethodsThe design of the web platform aimed to support each phase of the CCS by incorporating functional requirements (ie, features that the web platform will be able to perform) and nonfunctional requirements (ie, how the web platform should behave) that are needed to run collaborative sessions. The software was developed under the Model-View-Controller architecture to separate the views from the data model and the business logic.ResultsMOSAICO is a web platform used to design, perform, and assess collaborative clinical scenarios for medical students. MOSAICO has four modules: educational design, students’ collaborative design, collaborative simulation, and collaborative debriefing. The web platform has three different user profiles: academic simulation unit, teacher, and student. These users interact under different roles in collaborative simulations. MOSAICO enables a collaborative environment, which is connected via the internet, to design clinical scenarios guided by the teacher and enables the use of all data generated to be discussed in the debriefing session with the teacher as a guide. The web platform is running at the Universidad de Talca in Chile and is supporting collaborative simulation activities via the internet for two medical courses: (1) Semiology for third-year students (70 students in total) and (2) Medical Genetics for fifth-year students (30 students in total).ConclusionsMOSAICO is applicable within the CCS model and is used frequently in different simulation sessions at the Universidad de Talca, where medical students can work collaboratively via the internet. MOSAICO simplifies the application and reuse of clinical simulation scenarios, allowing its use in multiple simulation centers. Moreover, its applications in different courses (ie, a large part of the medical curriculum) support the automatic tracking of simulation activities and their assessment.

An Approximate Formula linking Active Share And Tracking Error

The concept of Active Share in portfolio management has gained widespread acceptance since it was proposed in 2009 by Cremers and Petajisto (2009). An explicit relationship between Active Share and the other popular measure of relative risk, Tracking Error, was proposed by Stowe in 2014 but necessitates the full knowledge of all the weights of the portfolio and of the complete covariance matrix of the assets. I derive an approximation in a simple setup where the exact weights are unknown, the pairwise correlation between the returns of the assets is fixed, and the volatility of the assets is described by its mean and variance. This approximation is really a “toy model” and works for the purpose of understanding changes in Tracking error stemming from changes in a portfolio, and to show what the drivers of the link between Active Share and Tracking error are. Using the approximation and the Fundamental Law of Active Management, I compute the total expected return and variance of a fund with a given active share in our setup. A full derivation of the main results is provided in the appendix.

The origins and development of speech envelope tracking during the first months of life

When humans listen to speech, their neural activity tracks the slow amplitude fluctuations of the speech signal over time, known as the speech envelope. Studies suggest that the quality of this tracking is related to the quality of speech comprehension. However, a critical unanswered question is how envelope tracking arises and what role it plays in language development. Relatedly, its causal role in comprehension remains unclear, as some studies have found it to be present even for unintelligible speech. Using electroencephalography, we investigated whether the neural activity of newborns and 6-month-olds is able to track the speech envelope of familiar and unfamiliar languages in order to explore the developmental origins and functional role of envelope tracking. Our results show that amplitude and phase tracking take place at birth for familiar and unfamiliar languages alike, i.e. independently of prenatal experience. However, by 6 months language familiarity modulates the ability to track the amplitude of the speech envelope, while phase tracking continues to be universal. Our findings support the hypothesis that amplitude and phase tracking could represent two different neural mechanisms of oscillatory synchronisation and may thus play different roles in speech perception.

The Overview of the Conservation and Renewal of the Industrial Belgian Heritage as a Vector for Cultural Regeneration

Industrial heritage reflects the development track of human production activities and witnessed the rise and fall of industrial civilization. As one of the earliest countries in the world to start the Industrial Revolution, Belgium has a rich industrial history. Over the past years, a set of industrial heritage renewal projects have emerged in Belgium in the process of urban regeneration. In this paper, we introduce the basic contents of the related terms of industrial heritage, examine the overall situation of protection and renewal in Belgium. The industrial heritage in Belgium shows its regional characteristics, each region has its representative industrial heritage types. In the Walloon region, it is the heavy industry. In Flanders, it is the textile industry. In Brussels, it is the service industry. The kinds of industrial heritages in Belgium are coordinate with each other. Industrial heritage tourism is developed, especially on eco-tourism, experience tourism. The industrial heritage in transportation and mining are the representative industrial heritages in Belgium. There are a set of numbers industrial heritages are still in running based on a successful reconstruction into industrial tourism projects. Due to the advanced experience in dealing with industrial heritage, the industrial heritage and the city live together harmoniously.

Active illumination uniformity with narrow spectrum laser based on ladderlike phase modulation

<sec>Active illumination is a crucial technology for active imaging, active tracking and aiming system. But the atmosphere turbulence distributed over the entire path causes the intensity to fluctuate, which reduces the illumination uniformity seriously. Therefore, it is desirable to find ways to reduce the intensity fluctuation and improve the uniformity of active illumination. It has been revealed that one can improve illumination uniformity by using multi-beam laser illuminator. Another effective approach is partially coherent beam illumination.</sec><sec>In this paper, a novel method is suggested to improve the illumination uniformity. Phase disturbance is induced by a ladder-like phase modulator (LPM) and the transmitting field of narrow spectrum laser is confused, and thus the atmosphere turbulence will be compensated and the illumination uniformity will be improved. The physical models of narrow spectrum laser phase modulation and atmosphere propagation are deduced, and the expression of the facular distribution is obtained. The active-illumination experimental setup with a laser propagation distance of 1.8 km through horizontal atmosphere is established. Based on the facular distribution of illumination laser at 1.8 km, the uniformity and stabilization are achieved. The experimental results indicate that the illumination uniformity and stabilization are both improved. The spatial and central time scintillation indexes are improved from 0.73 to 0.33 and from 0.38 to 0.14, respectively.</sec>

Active tracking during neoadjuvant therapy to improve outcomes of borderline arterial and locally advanced pancreatic cancer

Active tracking during neoadjuvant therapy to improve outcomes of borderline arterial and locally advanced pancreatic cancer

Waterdrop Removal From Hot-Rolled Steel Strip Surfaces Based on Progressive Recurrent Generative Adversarial Networks

Automated visual inspection (AVI) instrument of surface defects for hot-rolled steel strips is conventionally installed closely before the terminal crimping machine, where the adjacent upstream process is laminar spray cooling. Waterdrops, spreading more or less over the steel strip surface, often trigger false alarms, which is a quite common problem in AVI. Stimulated by the idea of image rain removal in visual enhancement field, this article considers the surface waterdrops, pseudodefects in essence, as a conceptual “rain-like layer.” A targeted method, namely progressive recurrent generative adversarial network (PReGAN), is designed for active waterdrop tracking and fine-grained image inpainting. Meanwhile, a steel surface database (2400 raw images with the resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1000\times1000$ </tex-math></inline-formula> ) captured from actual hot-rolling line is constructed for the first time for open evaluation of waterdrop removal. The experimental results indicate that images enhanced by the PReGAN perform the most informative and spotless, with 52.2073 peak signal-to-noise ratio (PSNR) and 0.9502 structural similarity (SSIM) index, when compared with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">four</i> prestigious networks. Assisted by the PReGAN, the false alarms are proved to be reduced at least a half during the application tests using <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">four</i> traditional simple detection methods.

Моделирование системы управления рысканием ветротурбины

Owing to its being an important component of renewable energy, wind energy is a kind of power generation method with the most mature, highly developed technologies and broad commercial prospects. The stable and efficient conversion of wind energy by wind turbines depends not only on the reliability of the wind power generation equipment itself, but also on the wind turbine control system, which, in turn, contributes to long-term safe and reliable operation of the wind farm fleet. It is exactly the wind turbine control system that is the main subject of this study. The key to efficient and stable operation of the entire wind energy conversion system is the control technology, which includes yaw control, pitch angle control, and maximum power point tracking control. The active yaw control system is one of the important components of a horizontal axis wind turbine's control system. To eliminate the uncertainty of wind direction influence on the turbine power output, a composite yaw control system has been checked. By using an active yaw system and maximum power point tracking system, the turbine position and its rotation speed are adjusted to enable the wind turbine to accurately track the wind direction and capture the wind energy to the fullest extent.

A Novel Enhanced Active Power Control Maximum Power Point Tracking Algorithm for Photovoltaic Grid Tied Systems

The PV systems connected to the grid will be a very significant renewable energy source in the power systems. Numerous researchers believe that in approaching years major amount of ene ...

An Underwater Micro Cable-Driven Pan-Tilt Binocular Vision System With Spherical Refraction Calibration

To improve the operation performance of underwater robots, a novel micro cable-driven pan-tilt camera system is developed, which can play an important role in underwater environmental perception and visual measurement. The designed camera system encompasses three parts: a miniature mechanical structure, a real-time target tracking and location module, and an underwater spherical refraction calibration module. Originally, a cable-driven model is adopted to establish a micro and flexible pan-tilt structure, for which the corresponding active target tracking and location algorithms are proposed. More importantly, for eliminating the measurement error caused by the underwater spherical refraction, an advanced nondominated sorting genetic algorithm (NSGA-II)-based underwater calibration algorithm is presented with the aid of the comprehensive geometric spherical refraction model. By integrating the flexible pan-tilt camera and the proposed calibration algorithm, the performance of underwater environmental perception and visual measurement can be greatly improved. Finally, extensive experiments in air and underwater scenarios are conducted. According to the utilized evaluation index, the deviation of target tracking and underwater location errors can be maintained within 0.06 rad and 21 mm, respectively. The proposed vision system sheds light on precise perception and interaction tasks of underwater vehicles.

Model Predictive Fault-Tolerant Tracking Control for PDF Control Systems With Packet Losses

In this article, a fault-tolerant tracking control strategy is investigated for nonlinear probability density function (PDF) control systems with the actuator fault, uncertainties, unknown disturbance, and random packet losses. The control input signal dropout and measurement signal dropouts are described as the independent Bernoulli distribution. An adaptive fault diagnosis (FD) observer based on the Lyapunov function is given to simultaneously estimate the fault, disturbance, and state with packet losses. Different from the traditional robust fault-tolerant control (FTC), a new active fault-tolerant tracking controller is designed based on the model predictive control framework, which has better adaptive fault-tolerant performance. Finally, the validity of the proposed FTC method has been proved by a simulation study of a papermaking process.

Low-Frequency Entrainment to Visual Motion Underlies Sign Language Comprehension.

When people listen to speech, neural activity tracks the entropy fluctuation in the acoustic envelope of the signal. This signal-based entrainment has been shown to be the basis of speech parsing and comprehension. In this electroencephalography (EEG) study, we compute sign language users’ cortical tracking of changes in visual dynamics of the communicative signal in the time-direct videos of sign language, and their time-reversed counterparts, and assess the relative contribution of response frequencies between.2 and 12.4 Hz to comprehension using a machine learning approach to brain state classification. Lower frequencies of EEG response (.2–4 Hz) yield 100% classification accuracy, while information about cortical tracking of the visual envelope in higher frequencies is less informative. This suggests that signers rely on lower visual frequency data, such as envelope of visual signal, for sign language comprehension. In the context of real-time language processing, given the speed of comprehension responses, this suggests that fluent signers employ a predictive processing heuristic based on sign language knowledge.

Bone Mineral Density in Adolescent Boys: Cross-Sectional Observational Study.

Physical inactivity of children can be a precursor of reduced bone mineral density, considered to be a typical problem only in old age. The aim of this study was to evaluate bone mineral density in 96 Polish boys aged 14–17 years with varied physical activity (swimmers, track and field athletes, non-athletes) and the effect of bone composition, birth weight and breastfeeding during infancy on bone parameters. Anthropometric and body composition measurements were performed according to the kinanthropometric standards. Bone parameters of the forearm were measured by means of dual-energy X-ray absorptiometry. Data on the infant’s birth weight and the length of breastfeeding were collected during direct interviews with mothers. The strongest links with bone parameters were found for the type of physical activity and birth weight. Regardless of birth weight, track and field athletes had the most advantageous bone parameters (mainly sT-score prox values). Swimmers with normal or low birth weight had less favourable sT-score prox values than non-athletes. The type of physical activity proved to be an important determinant of bone parameters. Childhood and adolescence are important periods of bone development and increasing the content of bone mineral components, and the bone status in later years of life depends to a large extent on this period. The perinatal period, especially the correct birth weight of the child, not only has a significant effect on general health, but also on bone status.

Qualitative Phytochemical Analysis and Antibacterial Potential of Chromolena Odorata Leaves as affected by Soxhlet and Maceration Extraction

The project is to design an active solar tracking system which able to track the sunlight with the aid of light dependent resistor (LDR) as input sensor to read the intensity of sunlight. The solar tracking system uses platform as a base and it is moved by a servo motor as the platform needs to be moved towards the sunlight to get the optimum light. The solar tracking system is programmed by using microcontroller Arduino Uno as a main controller. After the setup of the hardware and program, the tracking motion of the tracking system has been implemented to track the sun based on sunlight direction. In this work, it is designed that the motion of the tracking system is depends on the value read by LDR. As a conclusion, the solar tracking system can increase the solar panels efficiency by keeping the solar panels perpendicular with sun’s position.

Analysis on medical observation of 1 665 close contacts of COVID-19 cases

Objective: To understand the identification and medical observation of close contacts of COVID-19 cases in a city and provide scientific basis for the adjustment of the epidemic prevention and control strategies. Methods: Descriptive epidemiological methods were used to analyze the general characteristics of all the close contacts of COVID-19 cases in a city. Throat swabs were collected from the close contacts for real-time fluorescent RT-PCR. The confirmed cases were diagnosed according to diagnosis and treatment of COVID-19 (trial version 5). Results: Among the 1 665 close contacts of COVID-19 cases in a city, 10 were diagnosed as COVID-19 cases during the medical observation period, accounting for 30.30% of all the confirmed cases in a city, most of them were close relatives of the confirmed cases. The longest contact time with the confirmed cases was 8 days and the shortest was 0 days. Ten COVID-19 cases in close contacts constituted to six family clusters. Conclusions: In COVID-19 prevention and control in a city, the active tracking of the transmission chains of the confirmed cases and timely identification of the close contacts were conducted. The people who had close contacts with the confirmed COVID-19 cases within 14 days before onset were all placed under medical observation, which played a key role in the effective prevention and control of COVID-19 epidemic in a city. Nearly one third of COVID-19 cases occurred during the medical observation period, so the infection sources were effectively controlled and transmission routes were effectively blocked, which greatly facilitated the prevention of the clusters of COVID-19 cases.

COVID‐19 and Fiji: A Case Study

<scp>COVID</scp>‐19 and Fiji: A Case Study