Movement Scenarios Research Articles

Improvement in diagnostic quality of structural and angiographic MRI of the brain using motion correction with interleaved, volumetric navigators.

IntroductionSubject movements lead to severe artifacts in magnetic resonance (MR) brain imaging. In this study we evaluate the diagnostic image quality in T1-weighted, T2-weighted, and time-of-flight angiographic MR sequences when using a flexible, navigator-based prospective motion correction system (iMOCO).MethodsFive healthy volunteers were scanned during different movement scenarios with and without (+/-) iMOCO activated. An experienced neuroradiologist graded images for image quality criteria (grey-white-matter discrimination, basal ganglia, and small structure and vessel delineation), and general image quality on a four-grade scale.ResultsIn scans with deliberate motion, there was a significant improvement in the image quality with iMOCO compared to the scans without iMOCO in both general image impression (T1 p<0.01, T2 p<0.01, TOF p = 0.03) and in anatomical grading (T1 p<0.01, T2 p<0.01, TOF p = 0.01). Subjective image quality was considered non-diagnostic in 91% of the scans with motion -iMOCO, but only in 4% of the scans with motion +iMOCO. iMOCO performed best in the T1-weighted sequence and least well in the angiography sequence. iMOCO was not shown to have any negative effect on diagnostic image quality, as no significant difference in diagnostic quality was seen between scans -iMOCO and +iMOCO with no deliberate movement.ConclusionThe evaluation showed that iMOCO enables substantial improvements in image quality in scans affected by subject movement, recovering important diagnostic information in an otherwise unusable scan.

Multimedia data fusion method based on wireless sensor network in intelligent transportation system

In order to realize the ubiquitous perception of urban traffic system integration, a universal technology architecture supporting multiple heterogeneous access, universalization and tailoring is needed to realize the interconnection and interoperability of perception systems in different application scenarios. Based on the analysis of typical application scenarios in traffic field and the performance characteristics of wireless and wired sensor networks, a method of bandwidth allocation for network resources in urban traffic application environment is proposed in this paper, especially in the scenario of high-speed train movement, in order to improve the transmission efficiency of wireless sensor networks. An information matching method for sensor networks is proposed. The correlation among multi-sensors is used to fuse the monitoring information in the coverage area of the sensing system, which is helpful to improve the resolution and accuracy of the system. The theory is applied to vehicle type recognition in traffic flow detection. The simulation results show that the proposed data fusion scheme has obvious advantages over the similar LEACH protocol in terms of energy consumption and fusion accuracy of common nodes.

Molecular analysis of an ancient Thule population at Nuvuk, Point Barrow, Alaska.

The North American archaeological record supports a Holocene origin of Arctic Indigenous peoples. Although the Paleo-Inuit were present for millennia, archaeological and genetic studies suggest that modern peoples descend from a second, more recent tradition known as the Neo-Inuit. Origins of the Neo-Inuit and their relations to the earlier and later Indigenous peoples are an area of active study. Here, we genetically analyze the maternal lineages present at Nuvuk, once the northernmost community in Alaska and located in a region identified as a possible origin point of the Neo-Inuit Thule. The cemetery at Nuvuk contains human remains representing a nearly one thousand year uninterrupted occupation from early Thule to post-contact Iñupiat. We selected 44 individuals from Nuvuk with calibrated dates between 981 AD and 1885 AD for molecular analysis. We amplified and sequenced the hypervariable segment I of the mitogenome. We compared the Nuvuk data with previously published sequences from 68 modern and ancient communities from across Asia and North America. Phylogeographic analyses suggest possible scenarios of Holocene Arctic and sub-Arctic population movements. We successfully retrieved sequence data from 39 individuals. Haplogroup frequencies in Nuvuk were typed as 66.7% A2b1, 25.6% A2a, and 7.7% D4b1a2a1a. These results suggest that the population at Nuvuk was closest to the ancient Thule and modern Inuit of Canada, and to the Siberian Naukan people. We confirm that haplogroups A2a, A2b1, D2a, and D4b1a2a1a appear at high frequency in Arctic and sub-Arctic populations of North America and Chukotka. Sister clades D2b and D4b1a2a1b are present in Asian and Eastern European populations. The ancient mitochondrial sequences from Nuvuk confirm the link between the North Slope and the Thule who later spread east, and the maternal discontinuity between the Neo-Inuit and Paleo-Inuit. We suggest haplogroups A2a, A2b, and D4b1a2a1a are linked to the ancestors of the Thule in eastern Beringia, whereas the D2 and D4b1a2a1 clades appear to have Asian Holocene origins. Further Siberian and Alaskan genomes are necessary to clarify these population migrations beyond a simple two-wave scenario of Neo-Inuit and Paleo-Inuit.

Commuting Tillage Operations of HRP under Hydraulic Cylinder Movements on Plough-breast Performance

Hydraulic Cylinder (HC) is used for the commuting tillage of Horizontally Reversible Plough (HRP). Although the commuting behaviors are demonstrated not to affect basic beam of HRP, whether it has adverse effects on the essential engaging components of HRP, i.e. moldboard is unknown. This study addressed the estimation of the HC movements on the mouldboard, and particularly on the plough-shank of the plough-breast. A combined finite element analysis (FEA), multi-body dynamics analysis (MDA), and scanning electron microscope (SEM) based measurements was applied for five different HC movement scenarios and two actual HRP tilling conditions at the maximum operation depth, i.e. 0.36m. The results demonstrate that the HC movements produce both the maximum stress & strain and the most severe abrasion wear at the plough-shank, but they have no significantly adverse effects on the service life of the plough-breast. The current HC absolutely favors the actual HRP tillage.

Suction Stability Management in SMILE: Development of a Decision Tree for Managing Eye Movements and Suction Loss.

To develop a comprehensive protocol for suction stability management during small incision lenticule extraction (SMILE). This was a retrospective video review of all SMILE cases where suction loss occurred or eye movement was noted in the medical record. The different types of eye movement were collated. A suction stability grading scale was derived to represent the magnitude of eye movements. A decision tree protocol was developed to define the management in each scenario depending on the suction stability grading and the femtosecond laser cutting progress. Eight types of eye movement were identified: fixation light tracking, Bell's reflex, saccades, oscillations, anxiety/uncooperative patient, nociceptive reflex movement, false suction, and nystagmus. Type I eye movements were defined as small movements that shift the corneal position by a clinically negligible amount. The surgeon may want to pause the femtosecond laser cutting, regain control of the patient, then continue. Type II eye movements were defined as large movements that shift the corneal position by a clinically relevant amount, in which case the surgeon may choose to release suction (ie, a surgeon-initiated suction loss). Type III eye movements were defined as those with sufficient force to break suction (ie, a patient-generated suction loss). A comprehensive decision tree was developed to cover all possible eye movement and suction loss scenarios. Example scenarios outside the preprogrammed machine restart treatment module include converting to laser in situ keratomileusis (LASIK) if there was tracking of the interface and restarting SMILE with a thinner cap if the original cap thickness was 135 μm or greater. With appropriate management, it is possible for the SMILE procedure to be completed on the same day by either continuing with SMILE or converting to LASIK depending on the progress of the femtosecond laser cutting. [J Refract Surg. 2018;34(12):809-816.].

Detecting Stepping-Stones for Connectivity Planning in Local-Regional Scale

Habitat detection for local and regional connectivity planning is essential for the conservation of biodiversity, especially in a variety of different types of land use, such as in the Atlantic Forest. This article presents a model based on the use of landscape metrics and features of the physical environment, with procedures based on AHP, use of matrix cost and spatial analysis for the selection of forest fragments that can act as stepping stones. This modeling can be performed for different scenarios of species movement in the landscape, and the planning can be directed according to a management proposal in relation to the behavior of the target species to be conserved.

Mapping deformations and inferring movements of masonry arch bridges using point cloud data

Many historic masonry arch bridges experience damage due to support movements during their lifetime. This damage may influence the performance of the bridge and reduce its load carrying capacity. This paper proposes a new method to quantify past support movements by investigating distortions in bridge geometry. In this method, the bridge geometry is recorded in point cloud format and segmented into different structural components (e.g. 3D piers and barrels or 2D pier and barrel cross-sections). The geometry of each component is investigated further by fitting primitive shapes (e.g. 3D planes and cylinders or 2D lines and arcs) which represent the design intent. The discrepancy between these fitted shapes and the point clouds reveals a characteristic distortion signature. This signature is compared with theoretical distortion traces, which are obtained from kinematical analyses of the arch subjected to a range of support movements. The most likely support movement scenarios identified from these comparisons are then validated with visual indications of damage, such as crack location and size, and other geometric quantities, such as the change of the bedding joint elevations along the bridge. The proposed technique is applied to two masonry rail viaducts in the UK, which demonstrate different evidence of damage. Using the proposed method, past support movements of both bridges, which led to the observed damage, are inferred.

The Topology of the Leg Joints of the Beetle Pachnoda marginata (Scarabaeidae, Cetoniinae) and Its Implication for the Tribological Properties.

Locomotion of walking insects is exceptionally efficient. The function of their leg joints in different movement scenarios depends on their kinematics and contacting conditions between moving parts. The kinematics was previously studied in some insects, but contact mechanics within the joints remains largely unknown. In order to understand the complex topology of the contacting surfaces of the leg joints in the Congo rose beetle Pachnoda marginata peregrina (Scarabaeidae, Cetoniinae), we have investigated the shape, the waviness, and the roughness of the joint base and its counter body by applying confocal laser scanning microscopy and white light interferometry. Additionally, we performed nanoindentation tests on the contacting joint surfaces, in order to analyze material properties (elasticity modulus and hardness) of the joint cuticle. We found two topological design principles of the contact surfaces that might be considered as adaptations for reducing frictional drag during leg movements. First, the contact pairs of all leg joints studied consist of convex and concave counterparts. Second, there is a smooth and a rough surface in contact in which microprotuberances are present on the rough surface. These principles might be potentially interesting for technical implications, to design bioinspired joints with both reduced friction and wear rate.

Fully Rollable Lead-Free Poly(vinylidene fluoride)-Niobate-Based Nanogenerator with Ultra-Flexible Nano-Network Electrodes.

A fully rollable nanocomposite-based nanogenerator (NCG) is developed by integrating a lead-free piezoelectric hybrid layer with a type of nanofiber-supported silver nanowire (AgNW) network as electrodes. The thin-film nanocomposite is composed of electroactive polyvinylidene fluoride (PVDF) polymer matrix and compositionally modified potassium sodium niobate-based nanoparticles (NPs) with a high piezoelectric coefficient ( d33) of 53 pm/V, which is revealed by the piezoresponse force microscopy measurements. Under periodical agitation at a compressive force of 50 N and 1 Hz, the NCG can steadily render high electric output up to an open-circuit voltage of 18 V and a short-circuit current of 2.6 μA. Of particular importance is the decent rollability of the NCG, as indicated by the negligible decay in the electric output after it being repeatedly rolled around a gel pen for 200 cycles. Besides, the biocompatible NCG can potentially be used to scavenge biomechanical energy from low-frequency human motions, as demonstrated by the scenarios of walking and elbow joint movement. These results rationally expand the feasibility of the developed NCG toward applications in lightweight, diminutive, and multifunctional rollable or wearable electronic devices.

Understanding industrial robot programming by aid of a virtual reality environment

This paper reports on the construction of a virtual environment on top of a commercially available authoring platform that simulates an industrial robotic arm in pick-and-place movement scenarios. The user interface constructed follows in functionality the well-known teach pendants but exploits just a normal PC keyboard. However, both forward and inverse kinematics is served allowing the user to command movements in either the joint or the tool coordinate system. Perception pertaining to picking and placing movements and in particular the subtle docking positions was enhanced by adding so-called perceptual aids consisting of auxiliary objects with collision detection capabilities. The application was put to test by a group of practitioner-trainees who reported favourably, using a structured questionnaire, on its merits in enhancing their understanding of the robot’s capabilities, its kinematics, as well as the task performance strategy. Thus, confidence is increased regarding the ability of Virtual Reality – based platforms to contribute to successful training regarding programming and manipulation of industrial equipment.

Wearable Heading Estimation for Motion Tracking in Health Care by Adaptive Fusion of Visual-Inertial Measurements.

The increasing demand for health informatics has become a far-reaching trend in the ageing society. The utilization of wearable sensors enables monitoring senior people daily activities in free-living environments, conveniently and effectively. Among the primary health-care sensing categories, the wearable visual-inertial modality for human motion tracking gradually exerts promising potentials. In this paper, we present a novel wearable heading estimation strategy to track the movements of human limbs. It adaptively fuses inertial measurements with visual features following locality constraints. Body movements are classified into two types: general motion (which consists of both rotation and translation). or degenerate motion (which consists of only rotation). A specific number of feature correspondences between camera frames are adaptively chosen to satisfy both the feature descriptor similarity constraint and the locality constraint. The selected feature correspondences and inertial quaternions are employed to calculate the initial pose, followed by the coarse-to-fine procedure to iteratively remove visual outliers. Eventually, the ultimate heading is optimized using the correct feature matches. The proposed method has been thoroughly evaluated on the straight-line, rotatory and ambulatory movement scenarios. As the system is lightweight and requires small computational resources, it enables effective and unobtrusive human motion monitoring, especially for the senior citizens in the long-term rehabilitation.

Walking the desert, paddling the sea: Comcaac mobility in time

The Comcaac have lived along the central part of the Sonoran coast of Mexico for over a thousand years. These traditionally highly mobile hunters, gatherers, and fishermen of the desert and sea are now mainly settled in two villages with several seasonal exceptions. Past places remain important to the Comcaac, and they recall and remember these places through place-names, storytelling, and other cultural practices that integrate Comcaac historical events and traditions. Enduring cultural knowledge about the land and sea reveals that the Comcaac constructed a complex cultural landscape through their multifaceted mobility patterns during the past that included different people with varying degrees of cultural knowledge and experience.Through materiality theory, a cultural landscape approach and the analytical unit of place, this paper understands mobility as multifaceted, played out by different participants with different motivations. Direct involvement by Comcaac community members in this work expands and refines interpretations about the Comcaac cultural landscape through time using archaeological evidence, oral history, archival documents, and ethnographic information to better understand and explain past mobility patterns. Comcaac patterns of mobility and cultural meanings of places are valuable in understanding broader movement scenarios that may be applicable to a range of cultures.

Testing time-geographic density estimation for home range analysis using an agent-based model of animal movement

ABSTRACTTime-geographic density estimation (TGDE) is a method of movement pattern analysis that generates a continuous intensity surface from a set of tracking data. TGDE has recently been proposed as a method of animal home range estimation, where the goal is to delineate the spatial extents that an animal occupies. This paper tests TGDE’s effectiveness as a home range estimator using simulated movement data. First, an agent-based model is used to simulate tracking data under 16 movement scenarios representing a variety of animal life history traits (habitat preferences, homing behaviour, mobility) and habitat configurations (levels of habitat fragmentation). Second, the accuracy of TGDE is evaluated for four temporal sampling frequencies using three adaptive velocity parameters for 30 sample data sets from each scenario. Third, TGDE accuracy is compared to two other common home range estimation methods, kernel density estimation (KDE) and characteristic hull polygons (CHP). The results demonstrate that TGDE is the most effective at estimating core areas, home ranges and total areas at high sampling frequencies, while CHP performs better at low sampling frequencies. KDE was ineffective across all scenarios explored.

Animal movement affects interpretation of occupancy models from camera‐trap surveys of unmarked animals

AbstractOccupancy models are increasingly applied to data from wildlife camera‐trap (CT) surveys to estimate distribution, habitat use, or relative abundance of unmarked animals. Fundamental to the occupancy modeling framework is the temporal pattern of detections at camera stations, which is influenced by animal population density and the speed and scale of animal movement. How these factors interact withCTsampling designs to affect the interpretation of occupancy parameter estimates is unclear. We developed a simple yet ecologically relevant animal movement simulation to createCTdetections for animal populations varying in movement rate, home range area, and population density. We also variedCTsampling design by the duration of sampling and the density ofCTs in our simulated domain. A single‐species occupancy model was fitted to simulated detection histories, and model‐estimated probabilities of occupancy were compared to the asymptotic proportion of area occupied (PAO), calculated as the union of all simulated home ranges. Occupancy model parameter estimates were sensitive to simulated movement and sampling scenarios. Occupancy models overestimated asymptoticPAOwhen a low population density of simulated animals moved quickly over large home ranges and this positive bias was insensitive to sampling duration. Conversely, asymptoticPAOwas underestimated when simulated animals moved slowly in large‐ or intermediately sized home ranges. This negative bias decreased with increasing sampling duration and a lower density ofCTs. Our results emphasize that the interpretation of occupancy models depends on the underlying processes drivingCTdetections, specifically animal movement and population density, and that model estimates may not reliably reflect variation in these processes. We recommend carefully defining occupancy if it is applied toCTdata in order to better match sampling and analytical frameworks to the ecology of sampled wildlife species.

Factors influencing the sediment delivery ratio of the Three Gorges Reservoir

In recent years, the sediment delivery ratio (SDR) of the Three Gorges reservoir (TGR) has noticeably decreased as a result of the increase in water levels at the dam site and the decrease in inflow of fine particles, thereby resulting in increased reservoir siltation. Therefore, it is vital to research the factors that influence the SDR of the TGR. Factors that could have impact on the SDR were studied using TGR monitoring data. The study indicated that the water level at the dam site and inflow and outflow rates could have contributed to the change in the SDR. A sensitivity analysis of the influencing factors was then carried out using a mathematical model to simulate numerous sediment movement scenarios in the TGR. By changing the input conditions of the model, sufficient results were obtained to enable a sensitivity analysis of each factor. The results showed the flood retention time (FRT)—the ratio of reservoir capacity to average outflow discharge—was the principal factor influencing the SDR. The other factors (inflow sediment concentration, inflow sediment coefficient, inflow sediment gradations, and the shape coefficient of the inflow flood shape coefficient), also had an influence on the SDR. However, under different levels of FRT, their degrees of influence on the SDR were not the same..

Optimal Control of Human Muscle‐Actuated Motion

AbstractThe question how the brain controls locomotion is a highly treated one. This topic is taken up in this study by means of human computational models, simulating the human musculoskeletal system actuated by advanced Hill‐type muscle models. A forward dynamic approach is considered allowing to simulate human motion independently from pre‐measured trajectories and enabling to resemble the control of the central nervous system – the motor command selection. It is suggested that movement paths arise implicitly through optimisation [1,4]. Hence, stimulation patterns passing through activation dynamics are determined by means of constrained optimal control problems with physiologically motivated objective functions. One advantage concerning the implementation within Neweul‐M2 is the possibility to apply well‐elaborated and tested optimisation algorithms available with Matlab to solve optimal control problems, enabling to employ the novel non‐linear model predictive control (NMPC). The introduced framework is applied to treat different biomechanical movement scenarios including reaching scenarios of the arm which are validated against experimental data from [2–4]. (© 2017 Wiley‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Image reconstruction of dynamic infrared single-pixel imaging system

Single-pixel imaging technique has recently received much attention. Most of the current single-pixel imaging is aimed at relatively static targets or the imaging system is fixed, which is limited by the number of measurements received through the single detector. In this paper, we proposed a novel dynamic compressive imaging method to solve the imaging problem, where exists imaging system motion behavior, for the infrared (IR) rosette scanning system. The relationship between adjacent target images and scene is analyzed under different system movement scenarios. These relationships are used to build dynamic compressive imaging models. Simulation results demonstrate that the proposed method can improve the reconstruction quality of IR image and enhance the contrast between the target and the background in the presence of system movement.

Based on Short Motion Paths and Artificial Intelligence Method for Chinese Chess Game

The article develops the decision rules to win each set of the Chinese chess game using evaluation algorithm and artificial intelligence method, and uses the mobile robot to be instead of the chess, and presents the movement scenarios using the shortest motion paths for mobile robots. Player can play the Chinese chess game according to the game rules with the supervised computer. The supervised computer decides the optimal motion path to win the set using artificial intelligence method, and controls mobile robots according to the programmed motion paths of the assigned chesses moving on the platform via wireless RF interface. We uses enhance A* searching algorithm to solve the shortest path problem of the assigned chess, and solve the collision problems of the motion paths for two mobile robots moving on the platform simultaneously. We implement a famous set to be called “wild horses run in farm” using the proposed method. First we use simulation method to display the motion paths of the assigned chesses for the player and the supervised computer. Then the supervised computer implements the simulation results on the chessboard platform using mobile robots. Mobile robots move on the chessboard platform according to the programmed motion paths and is guided to move on the centre line of the corridor, and avoid the obstacles (chesses), and detect the cross point of the platform using three reflective IR modules.

The application of multi-body simulation approach in the kinematic analysis of beetle leg joints

Locomotion of insects is exceptionally efficient and this efficiency is partially due to the kinematics within leg joints, which in different movement scenarios depends on their inner contacting conditions. The investigation of functionality of the leg joints can potentially provide new innovative problem solutions in robotics. The previously published information about the shape of the joints is not sufficient, because without knowledge about the movements of the articulating surfaces within the joint, the kinematics cannot be understood. To understand the joint movements, we have performed motion tracking experiments in the beetle Pachnoda marginata (Scarabaeidae, Cetoniinae) in different locomotory scenarios. We aimed at understanding the range of motion within single leg joints depending on their function in the entire leg movement scenario. For this purpose, we combined the motion analysis of living beetles with the results of the simulation of a multi-body system. The results of the multi-body simulation allowed the kinematic characterization of articulating joints by their degrees of freedom and the identification of the rotation axes. The simulated range of motion predicted by the limitations of the exoskeleton of the joints partially matched those obtained from the motion analysis of the living beetle. We showed that the range of motion of the single leg joints depends strongly on the type of the beetle locomotory scenario. It is also concluded that the simulation of multi-body systems is a powerful tool for the kinematic analysis of insect tribological systems.

Improving ROI detection in photoplethysmographic imaging with thermal cameras.

Photoplethismographic imaging (PPGi) enables the estimation of heart rate without body contact by analyzing the temporal skin color changes from video recordings. Motion artifacts and atypical facial characteristics cause poor signals and currently limit the applicability of PPGi. We have developed a novel algorithm for locating cheek and forehead region of interests (ROI) with the aim to improve PPGi during challenging situations. The proposed approach is based on the fusion of RGB and far-infrared (FIR) video streams where FIR ROI is used as fall-back when RGB alone fails. We validated and compared the algorithm against the detection based on single sources, using videos from 8 subjects with distinctively different face characteristics. The subject performed three scenarios with incremental motion artifact content (head at rest, intensive head movements, speaking). The results showed that combining the two imaging sources increased the detection rate of cheeks from 75% (RGB) to 92% (RGB+FIR) in the challenging intensive head movement scenario. This work demonstrated that FIR imaging is complementary to simple RGB imaging and when combined, adds robustness to the detection of ROI in PPGi applications.