Head Orientation Research Articles

Assessment of body shape variation using Elliptic Fourier descriptors and ellipse fitting estimators and their genetic estimates in the flatfish Senegalese sole

Body shape is an important morphological trait in aquaculture. This study investigates the use of Elliptic Fourier descriptors (EFDs) analysis and ellipse fitting estimators to assess shape variation in Senegalese sole and their genetic variance components. A total of 2271 fish were individually photographed and body contours reconstructed using 20 Elliptic Fourier harmonics. Principal component analysis identified four symmetric components that explained the 68.6% of the total variation. They were mainly related to the adjustment of the body to an ellipse (PC1s and PC3s) and caudal fin morphological features (PC2s, PC3s, PC4s). Moreover, four asymmetric components related to caudal fin (PC1a, PC2a, PC3a) and head orientation (PC4a) that explained 24.5% of the total variation were also found. In addition to EFDs, body perimeter and five ellipse fitting estimators including the maximum body height to caudal peduncle height ratio (MBH/CPH), body aspect ratio (AR), ellipticity (ELL), AR from theoretical ellipse (ARe) and solidity (SOL) were calculated. PC1s was strongly correlated with ARe, AR and ELL (≥0.75), PC2s with SOL (−0.79) and PC3s with AR and ELL (0.48–0.49). Males appeared more elliptic than females as revealed by all ellipse descriptors with a tendency to caudal fins with obtuse angles (PC3a) and heads orientated toward the abdominal cavity (PC4a). Overall, heritabilities for symmetric components were higher than for asymmetric. Heritabilities for body ellipse fitting estimators including PC1s were high or very high with the highest values for AR (0.80) and ARe (0.78) for body and whole-body, respectively. Heritability for MBH/CPH was high (0.51) with low genetic correlation with other morphological traits. Heritabilities for symmetrical and asymmetrical features of caudal fin were moderate or low and indirect selection using other highly correlated traits such as PC2s through SOL and PC3a through PC4a or PC1s would facilitate progress in the selection. Perimeter showed a moderate heritability and it was more genetically correlated with growth than shape-related traits. The data provided represent a valuable tool to assess body shape in sole and in the design of genetic breeding programs in Senegalese sole.

Head Orientation Modulates Vestibular Cerebellar Evoked Potentials (VsCEPs) and Reflexes Produced by Impulsive Mastoid and Midline Skull Stimulation

The cerebellum plays a critical role in the modulation of vestibular reflexes, dependent on input from proprioceptive afferents. The mechanism of this cerebellar control is not well understood. In a sample of 11 healthy human subjects, we investigated the effects of head orientation on ocular, cervical, postural and cerebellar short latency potentials evoked by impulsive stimuli applied at both mastoids and midline skull sites. Subjects were instructed to lean backwards with the head positioned straight ahead or held rotated in different degrees of yaw towards the right and left sides. Impulsive mastoid stimulation, a potent method of utricular stimulation, produced localised vestibular cerebellar evoked potentials (VsCEPs: P12-N17) which were strongly modulated by head orientation. The response was larger on the side opposite to the direction of head rotation and with stimulation on the side of rotation. In contrast, ocular VEMPs (oVEMPs: n10-p16) were present but showed little change with head posture, while cervical VEMPs (cVEMPs: p15-n23) were larger with the head held rotated away from the side of the recording. Postural effects with lateral vestibular stimulation were strongly modulated by head rotation, with more powerful effects occurring bilaterally with stimulation on the side of rotation. The duration of the postural EMG changes was similar to the post-excitation inhibition of the electrocerebellogram (ECeG), consistent with cerebellar participation. We conclude that head rotation selectively affects evoked vestibular reflexes towards different targets, consistent with their physiological roles. Changes in VsCEPs may contribute to the modulation of postural reflexes by the cerebellum.

The Interfacial Dilational Rheology Properties of Betaine Solutions: Effect of Anionic Surfactant and Polymer.

Interfacial dilational rheology is one of the important means to explore the interfacial properties of adsorption films. In this paper, the interfacial rheological properties of the mixed system of sulfobetaine ASB with a linear alkyl group and two anionic surfactants, petroleum sulfonate (PS) and alkyl polyoxyethylene carboxylate (AEC), were investigated by interfacial dilational rheology. The effect of the introduction of polymer hydrophobically modified polyacrylamide (HMPAM) on the interfacial properties of the mixed system was analyzed. In this experiment, the surfactant solution was used as the external phase and n-decane was used as the internal phase. A periodic sinusoidal disturbance of 0.1 Hz was applied to the n-decane droplets, and the changes of parameters such as droplet interfacial tension and interfacial area were monitored in real time with the help of a computer. The results show that the betaine ASB molecule responds to the dilation and compression of the interface through the change of ion head orientation, while the feedback behavior of petroleum sulfonate PS and AEC molecules embedded with oxygen vinyl groups in the molecule is diffusion and exchange between the interface and the bulk phase. Therefore, the interface film formed by ASB alone is higher, and the film formed by PS and AEC molecules alone is relatively lower. After adding two kinds of anionic surfactants to the betaine system, the ionic head of PS or AEC molecules will be attached to the positive center of the hydrophilic group of ASB molecules by electrostatic attraction and no longer adsorb and desorb with the interface deformation. The interfacial rheological properties of the compound system are still dominated by betaine, with higher dilational modulus and lower phase angle. When a small amount of HMPAM is added, or the content of hydrophobic monomer AMPS in the bulk phase is low, the intermolecular interaction at the interface is enhanced, the slow relaxation process is intensified, and the interfacial film strength is increased. As the content of AMPS further increases, hydrophobic blocks and surfactant molecules will form interfacial aggregates similar to mixed micelles at the oil-water interface, which will regulate the properties of the film by affecting the adsorption of surfactants at the interface. As long as the interfacial tension is the same, the properties of the interfacial film are the same. Based on the colloid interface science and the background of enhanced oil recovery, this study provides a reference for the field application of chemical flooding formulations.

Gaze cueing in older and younger adults is elicited by a social robot seen from the back

The ability to follow the gaze of others deteriorates with age. This decline is typically tested with gaze cueing tasks, in which the time it takes to respond to targets on a screen is faster when they are preceded by a facial cue looking in the direction of the target (i.e., gaze cueing effect). It is unclear whether age-related differences in this effect occur with gaze cues other than the eyes, such as head orientation, and how these vary in function of the cue-target timing. Based on the perceived usefulness of social robots to assist older adults, we asked older and young adults to perform a gaze cueing task with the head of a NAO robot as the central cue. Crucially, the head was viewed from the back, and so its eye gaze was conveyed. In a control condition, the head was static and faced away from the participant. The stimulus onset asynchrony (SOA) between cue and target was 340 ms or 1000 ms. Both age groups showed a gaze cueing effect at both SOAs. Older participants showed a reduced facilitation effect (i.e., faster on congruent gazing trials than on neutral trials) at the 340-ms SOA compared to the 1000-ms SOA, and no differences between incongruent trials and neutral trials at the 340-ms SOA. Our results show that a robot with non-visible eyes can elicit gaze cueing effects. Age-related differences in the other effects are discussed regarding differences in processing time.

The effect of listener head orientation on front-to-rear speech intelligibility in an automotive cabin

The listener head orientation significantly affects speech intelligibility (SI) in the small acoustic space of an automobile, owing to near-field binaural listening and special acoustic conditions such as early reflections and seat-back occlusions. However, situations involving a back-row listener and a front-row speaker (i.e., front-to-rear scenarios) have not yet been studied. Such scenarios are dominated by non-uniform early reflections rather than direct sounds, making them distinct from cases considered in previous studies. This study investigates the effect of listener head orientation on SI in front-to-rear scenarios in an automobile, using both the speech transmission index (STI) and subjective experiments. A virtual speaker (i.e., a loudspeaker) is located in the driver’s seat and faces forward. Binaural room impulse responses are measured on a dummy head in the three rear-row seats with different head orientations. Using the binaural room impulse responses, the corresponding STIs are calculated, and the Chinese SI scores are measured virtually via headphones. The results show that the SI variation range for various listener head orientations in front-to-rear scenarios is greatly reduced compared with that in the rear-to-front scenarios considered in previous studies. Overall, the effect of listener head orientation on SI is mostly negligible when a listener in the rear row listens to a speaker in the front, with variations in the SI score of no more than 5%. The present study provides a supplement to previous studies and helps to deepen understanding of the effect of multiple factors on SI in an automotive cabin.

A New Vessel-Based Method to Estimate Automatically the Position of the Nonfunctional Fovea on Altered Retinography From Maculopathies.

The purpose of this study was to validate a new automated method to locate the fovea on normal and pathological fundus images. Compared to the normative anatomic measures (NAMs), our vessel-based fovea localization (VBFL) approach relies on the retina's vessel structure to make predictions. The spatial relationship between the fovea location and vessel characteristics is learnt from healthy fundus images and then used to predict fovea location in new images. We evaluate the VBFL method on three categories of fundus images: healthy images acquired with different head orientations and fixation locations, healthy images with simulated macular lesions, and pathological images from age-related macular degeneration (AMD). For healthy images taken with the head tilted to the side, the NAM estimation error is significantly multiplied by 4, whereas VBFL yields no significant increase, representing a 73% reduction in prediction error. With simulated lesions, VBFL performance decreases significantly as lesion size increases and remains better than NAM until lesion size reaches 200 degrees2. For pathological images, average prediction error was 2.8degrees, with 64% of the images yielding an error of 2.5 degrees or less. VBFL was not robust for images showing darker regions and/or incomplete representation of the optic disk. The vascular structure provides enough information to precisely locate the fovea in fundus images in a way that is robust to head tilt, eccentric fixation location, missing vessels, and actual macular lesions. The VBFL method should allow researchers and clinicians to assess automatically the eccentricity of a newly developed area of fixation in fundus images with macular lesions.

3D dynamic observation of human sperm by parallel phase-shifting digital holographic microscopy based on pixelated polarization

Morphology and motility are essential criteria for assessing sperm viability. However, the human sperm head is small (∼3–4 μm) and requires a relatively high-magnification microscope objective, while the sperm flagella (∼45 μm) are poorly visible with complex 3D properties. Microscopic dynamic observation of intact sperm in 3D is challenging. Conventional inspection methods with a limited depth of field are inadequate for this issue. To provide a solution to this critical need, we develop pixelated polarization-based parallel phase-shifting digital holographic microscopy for the 3D dynamic observation of human sperm. Compared to conventional holographic imaging, this approach can effectively separate the object wavefront and avoid image quality degradation while fully exploiting the spatial bandwidth of the camera. We propose the use of the Stokes parameter reconstruction method to reconstruct the object wavefront and investigate the effect of the sampling interval on the system resolution by spectral analysis. The methodology achieves the retrieval of the 3D trajectory and motion parameters of sperm and reconstructs the sperm head orientation and the thin, highly-dynamic flagellum. The system allows for more comprehensive information on sperm motility and morphology, which is significant for male reproductive research. It also has significant potential for 3D dynamic observation of micro-organisms.

DeepSTI: Towards tensor reconstruction using fewer orientations in susceptibility tensor imaging.

Susceptibility tensor imaging (STI) is an emerging magnetic resonance imaging technique that characterizes the anisotropic tissue magnetic susceptibility with a second-order tensor model. STI has the potential to provide information for both the reconstruction of white matter fiber pathways and detection of myelin changes in the brain at mm resolution or less, which would be of great value for understanding brain structure and function in healthy and diseased brain. However, the application of STI in vivo has been hindered by its cumbersome and time-consuming acquisition requirement of measuring susceptibility induced MR phase changes at multiple head orientations. Usually, sampling at more than six orientations is required to obtain sufficient information for the ill-posed STI dipole inversion. This complexity is enhanced by the limitation in head rotation angles due to physical constraints of the head coil. As a result, STI has not yet been widely applied in human studies in vivo. In this work, we tackle these issues by proposing an image reconstruction algorithm for STI that leverages data-driven priors. Our method, called DeepSTI, learns the data prior implicitly via a deep neural network that approximates the proximal operator of a regularizer function for STI. The dipole inversion problem is then solved iteratively using the learned proximal network. Experimental results using both simulation and in vivo human data demonstrate great improvement over state-of-the-art algorithms in terms of the reconstructed tensor image, principal eigenvector maps and tractography results, while allowing for tensor reconstruction with MR phase measured at much less than six different orientations. Notably, promising reconstruction results are achieved by our method from only one orientation in human in vivo, and we demonstrate a potential application of this technique for estimating lesion susceptibility anisotropy in patients with multiple sclerosis.

CONVOLUTIONAL NEURAL NETWORKS FOR EARLY COMPUTER DIAGNOSIS OF CHILD DYSPLASIA

The problem in ultrasound diagnostics hip dysplasiais the lack of experience of the doctor in case of incorrect orientation of the hip joint andultrasound head. The aim of this study was to evaluate the ability of the convolutional neural network (CNN) to classifyand recognize ultrasound imagingof thehip joint obtained at the correct and incorrect position of the ultrasound sensor head in the computer diagnosisofpediatricdysplasia. CNN's suchas GoogleNet, SqueezeNet, and AlexNet were selected for the study. The most optimal for the task is the useof CNN GoogleNet showed. In this CNN usedtransfer learning. At the same time, fine-tuning of the network and additional training on the databaseof 97 standards of ultrasonic images of the hip jointwere applied. Image type RGB 32 bit, 210 × 300 pixels are used. Fine-tuning has been performedthe lower layers of the structure CNN, in which 5 classesare allocated, respectively 4 classes of hip dysplasia types according to the Graf, and the Type ERROR ultrasound image, where position of the ultrasoundsensor head and of the hip joint in ultrasound diagnostics are incorrect orientation.It was found that the authenticity of training and testing is the highestfor the GoogleNet network:when classified in the training group accuracy is up to 100%, when classified in the test group accuracy–84.5%

Large Variability of Head Angulation During the Epley Maneuver: Use of a Head-Mounted Guidance System with Visual Feedback to Improve Outcomes.

The aim of this study was to show the variability in head angulation during the canalolith repositioning maneuvers to treat benign paroxysmal positional vertigo and to describe a head-mounted benign paroxysmal positional vertigo guidance system to measure the head orientation. A guidance system for benign paroxysmal positional vertigo was developed by NeuroEquilibrium Diagnostic Systems to measure head orientation and provide visual feedback and instructions to examiners during various maneuvers for benign paroxysmal positional vertigo. Twenty-five experienced examiners and 25 healthy volunteers (aged 21-35 years) were recruited. Each examiner applied the Epley maneuver twice in 1 volunteer: without and with the use visual feedback from a guidance system. Head orientation in both procedures was measured and compared. The trained examiners demonstrated a large variability in head orientation during the Epley maneuver, which was reduced by using the benign paroxysmal positional vertigo guidance system. There was a variability of 39-65° in head orientation measured without the guidance system. The use of the guidance system reduced the variation range to a sixfold decrease in variability. There is a large variability in head orientation when performing repositioning maneuvers, which could compromise the efficacy of benign paroxysmal positional vertigo treatment. Treatment for benign paroxysmal positional vertigo can be optimized by reducing this variability with a benign paroxysmal positional vertigo guidance system. It might also be a useful tool for teaching.

Detection of Cyclist’s Crossing Intention Based on Posture Estimation for Autonomous Driving

Improving the safety of bicycle riders is one of the critical issues for autonomous driving. The crossing intention of the cyclist is expected to be predicted from the on-board camera of an autonomous vehicle. In a real traffic situation, a cyclist usually turns his or her head to check the situation of the back of him or her before he or she crosses the road. Therefore, the action of turning head is an important cue to indicate the intention of crossing a road. This research proposes to estimate the cyclist’s intention based on the body and head orientation using deep neural networks. The proposed system first detects the cyclists and extracts the area of the cyclist from RGB images based on a segmentation neural network. After that, the image of each cyclist is processed by a pose estimation neural network to detect each joint of the cyclist. Subsequently, the heat-map image of each joint of the cyclist is imported into a classification neural network to estimate the body and head orientation. The body orientation and head orientation are jointly used for the prediction of the cyclist’s intention. In a separate process, the cyclist’s position is estimated based on the disparity image generated from a stereo camera. Finally, two results, the cyclist’s position and intention, are integrated to predict the trajectory of the cyclist. A series of experiments have been performed and the experimental results demonstrate that the proposed system has a satisfactory performance. In addition, the comparison experiments show that the model with only heat-map images as input has the best accuracy in the body and head orientation estimation.

Eye Facial Gesture System Controller Based on AI ML

Abstract: This paper presents a ground-breaking real-time algorithm for accurately detecting eye blinks in video sequences captured using standard cameras. The algorithm utilizes advanced landmark detectors trained on diverse datasets to ensure robustness against variations in head orientation, illumination, and facial expressions. By employing precise landmark detection techniques, the algorithm estimates the level of eye opening using the eye aspect ratio (EAR) in each frame. An SVM classifier analyses the patterns of EAR values within a short temporal window to identify eye blinks. Comparative evaluations on popular datasets demonstrate the superior performance of the proposed algorithm compared to existing methods. Additionally, the research explores the utilization of eye movements for controlling computer programs, evaluating four distinct approaches in a user-friendly photo viewer. The evaluation process considers various factors such as component sizes, execution time, unintended selections, and gesture repetitions. User experiments reveal that component sizes of 200px provide a convenient and efficient means of application control. The gaze-based method and gestures based on joining points receive positive feedback and exhibit satisfactory performance. This paper contributes significantly to the field of eye-based interaction by introducing an innovative blink detection algorithm and conducting a comprehensive evaluation of eye movement approaches for application control.

Action outcome probability influences the size of the head-fake effect in basketball

Both kinematic and contextual information (e.g., action outcome probability) play a significant role in action anticipation. However, few researchers have examined the reciprocal influence of the two types of information and fewer still have investigated this issue for deceptive actions in sports. In the present study, we investigate the impact of action outcome probability on the processing of deceptive kinematic cues for the head fake in basketball. We manipulated the probability of the action outcome to either pass the ball to the left or to the right side (i.e., 75%, 50%, 25%) and examined how this contextual information affected the influence of head orientation on pass direction judgments. Outcome probability information was either provided explicitly (Experiment 1) or implicitly (Experiment 2). Both experiments indicated an increased head-fake effect with increasing outcome probability. Moreover, the bias to respond in line with the player’s head direction increased linearly with outcome probability. Also, discriminability between deceptive and genuine actions was poorer for high outcome probability (75%) associated with head orientation than for the 25% and 50% values. Last, a stronger response bias toward the higher probability side for deceptive trials than for genuine trials was only significant when the outcome probability information was processed implicitly in Experiment 2. The results of this study fit well with recent literature on contextual information in action prediction and are discussed in light of confirmation bias and signal detection theory.

A Context-Aware, Computer-Vision-Based Approach for the Detection of Taxi Street-Hailing Scenes from Video Streams.

With the increasing deployment of autonomous taxis in different cities around the world, recent studies have stressed the importance of developing new methods, models and tools for intuitive human-autonomous taxis interactions (HATIs). Street hailing is one example, where passengers would hail an autonomous taxi by simply waving a hand, exactly like they do for manned taxis. However, automated taxi street-hailing recognition has been explored to a very limited extent. In order to address this gap, in this paper, we propose a new method for the detection of taxi street hailing based on computer vision techniques. Our method is inspired by a quantitative study that we conducted with 50 experienced taxi drivers in the city of Tunis (Tunisia) in order to understand how they recognize street-hailing cases. Based on the interviews with taxi drivers, we distinguish between explicit and implicit street-hailing cases. Given a traffic scene, explicit street hailing is detected using three elements of visual information: the hailing gesture, the person's relative position to the road and the person's head orientation. Any person who is standing close to the road, looking towards the taxi and making a hailing gesture is automatically recognized as a taxi-hailing passenger. If some elements of the visual information are not detected, we use contextual information (such as space, time and weather) in order to evaluate the existence of implicit street-hailing cases. For example, a person who is standing on the roadside in the heat, looking towards the taxi but not waving his hand is still considered a potential passenger. Hence, the new method that we propose integrates both visual and contextual information in a computer-vision pipeline that we designed to detect taxi street-hailing cases from video streams collected by capturing devices mounted on moving taxis. We tested our pipeline using a dataset that we collected with a taxi on the roads of Tunis. Considering both explicit and implicit hailing scenarios, our method yields satisfactory results in relatively realistic settings, with an accuracy of 80%, a precision of 84% and a recall of 84%.

Miniature camera module with a hollow linear ultrasonic motor-based focus feature

The construction of a miniature camera module that can explore inside limited spaces is of great interest for the design of millimeter-scale devices, such as endoscopes. This article presents a miniature camera module with a focus feature using a hollow linear ultrasonic motor. The hollow stator, which is simplified by the expansion and thickness-shear piezoelectric effects, is suitable for the miniaturization of the camera module because it can contain a lens group. The linear slider, which is thin and cylindrical with a slit, is inserted into the stator’s hole and generates a preload that exploits optimal motor performance measures. The resultant camera module is 4.6 mm × 4.6 mm square, which is the smallest one of camera modules reported to date. The motion of the miniature camera module is demonstrated by the wire-driven mechanism and a visual feedback control system. The orientation of the camera module head is controlled by a wire-driven mechanism until the target object is set in the range of view. The lens group placed inside the slider is controlled by the hollow linear ultrasonic motor in a visual feedback-loop system.

Variational Pose Prediction with Dynamic Sample Selection from Sparse Tracking Signals

AbstractWe propose a learning‐based approach for full‐body pose reconstruction from extremely sparse upper body tracking data, obtained from a virtual reality (VR) device. We leverage a conditional variational autoencoder with gated recurrent units to synthesize plausible and temporally coherent motions from 4‐point tracking (head, hands, and waist positions and orientations). To avoid synthesizing implausible poses, we propose a novel sample selection and interpolation strategy along with an anomaly detection algorithm. Specifically, we monitor the quality of our generated poses using the anomaly detection algorithm and smoothly transition to better samples when the quality falls below a statistically defined threshold. Moreover, we demonstrate that our sample selection and interpolation method can be used for other applications, such as target hitting and collision avoidance, where the generated motions should adhere to the constraints of the virtual environment. Our system is lightweight, operates in real‐time, and is able to produce temporally coherent and realistic motions.

Miniscope-LFOV: A large-field-of-view, single-cell-resolution, miniature microscope for wired and wire-free imaging of neural dynamics in freely behaving animals

Imaging large-population, single-cell fluorescent dynamics in freely behaving animals larger than mice remains a key endeavor of neuroscience. We present a large-field-of-view open-source miniature microscope (MiniLFOV) designed for large-scale (3.6 mm×2.7 mm), cellular resolution neural imaging in freely behaving rats. It has an electrically adjustable working distance of up to 3.5 mm±100 μm, incorporates an absolute head orientation sensor, and weighs only 13.9 g.The MiniLFOV is capable of both deep brain and cortical imaging and has been validated in freely behaving rats by simultaneously imaging >1000 GCaMP7s-expressing neurons in the hippocampal CA1 layer and in head-fixed mice by simultaneously imaging ~2000 neurons in the dorsal cortex through a cranial window. The MiniLFOV also supports optional wire-free operation using a novel, wire-free data acquisition expansion board. We expect that this new open-source implementation of the UCLA Miniscope platform will enable researchers to address novel hypotheses concerning brain function in freely behaving animals.

Robotic Optical Coherence Tomography of Human Subjects with Posture-Invariant Head and Eye Alignment in Six Degrees of Freedom.

Ophthalmic optical coherence tomography (OCT) has achieved remarkable clinical success but remains sequestered in ophthalmology specialty offices. Recently introduced robotic OCT systems seek to expand patient access but fall short of their full potential due to significant imaging workspace and motion planning restrictions. Here, we present a next-generation robotic OCT system capable of imaging in any head orientation or posture that is mechanically reachable. This system overcomes prior restrictions by eliminating fixed-base tracking components, extending robot reach, and planning alignment in six degrees of freedom. With this robotic system, we show repeatable subject imaging independent of posture (standing, seated, reclined, and supine) under widely varying head orientations for multiple human subjects. For each subject, we obtained a consistent view of the retina, including the fovea, retinal vasculature, and edge of the optic nerve head. We believe this robotic approach can extend OCT as an eye disease screening, diagnosis, and monitoring tool to previously unreached patient populations.

Enhancing 360 Video Streaming through Salient Content in Head-Mounted Displays.

Predicting where users will look inside head-mounted displays (HMDs) and fetching only the relevant content is an effective approach for streaming bulky 360 videos over bandwidth-constrained networks. Despite previous efforts, anticipating users' fast and sudden head movements is still difficult because there is a lack of clear understanding of the unique visual attention in 360 videos that dictates the users' head movement in HMDs. This in turn reduces the effectiveness of streaming systems and degrades the users' Quality of Experience. To address this issue, we propose to extract salient cues unique in the 360 video content to capture the attentive behavior of HMD users. Empowered by the newly discovered saliency features, we devise a head-movement prediction algorithm to accurately predict users' head orientations in the near future. A 360 video streaming framework that takes full advantage of the head movement predictor is proposed to enhance the quality of delivered 360 videos. Practical trace-driven results show that the proposed saliency-based 360 video streaming system reduces the stall duration by 65% and the stall count by 46%, while saving 31% more bandwidth than state-of-the-art approaches.

ATP‐induced conformational change of axonemal outer dynein arms revealed by cryo‐electron tomography

Axonemal outer dynein arm (ODA) motors generate force for ciliary beating. We analyzed three states of the ODA during the power stroke cycle using in situ cryo‐electron tomography, subtomogram averaging, and classification. These states of force generation depict the prepower stroke, postpower stroke, and intermediate state conformations. Comparison of these conformations to published in vitro atomic structures of cytoplasmic dynein, ODA, and the Shulin–ODA complex revealed differences in the orientation and position of the dynein head. Our analysis shows that in the absence of ATP, all dynein linkers interact with the AAA3/AAA4 domains, indicating that interactions with the adjacent microtubule doublet B‐tubule direct dynein orientation. For the prepower stroke conformation, there were changes in the tail that is anchored on the A‐tubule. We built models starting with available high‐resolution structures to generate a best‐fitting model structure for the in situ pre‐ and postpower stroke ODA conformations, thereby showing that ODA in a complex with Shulin adopts a similar conformation as the active prepower stroke ODA in the axoneme.