A Unified Representation of Control Logic in Human-Ultrasound Machine Interaction.

Advances in human-computer interaction (HCI) technologies have granted sonographers and radiologists a much improved user experience when operating different ultrasound (US) machines. Continued HCI improvements in US would benefit from a systematic study of the HCI control logic used in this domain. Such a study has not been presented previously and is the subject of this paper. We surveyed sonographers to determine the most frequently used controls in US machines. We standardized the representation of the US machine HCI control logic by using the unified modelling language (UML). We used UML diagrams to analyze the HCI control logic of 10 different cart-based US machines from several major manufacturers, and we discovered that the control logic for the most frequently used functions are identical. While this control logic does not follow an established standard, it has been commonly adopted. Using the UML for the visualization and formulation of control logic, we can target logically optimal interactions (whose operation steps cannot be further reduced), e.g., adjustment of B-mode gain, frequency and depth, and can derive methods to simplify logically sub-optimal interactions, e.g., the pointing and selecting operation, as well as image measurements.Our study provides insights into existing HCI approaches used in US machines and establishes a rigorous UML-based framework for future US machine design to improve interoperability, efficiency and ease-of-use.

Retraction Note: Melting of Pb Nanocrystals Embedded in Al, Si, and Cu Matrices.

An amendment to this paper has been published and can be accessed via the original article.

Hand-eye coordination-based implicit re-calibration method for gaze tracking on ultrasound machines: a statistical approach.

PURPOSE: Eye gaze tracking is proving to be beneficial in many biomedical applications. The performance of systems based on eye gaze tracking is very much dependent on how accurate their calibration is. It has been reported that the gaze tracking accuracy deteriorates cumulatively and significantly with usage time. This impedes the wide use of gaze tracking in user interfaces. METHODS: Explicit re-calibration, typically requiring the user's active attention, is time-consuming and can interfere with the user's main activity. Therefore, we propose an implicit re-calibration method, which can rectify the deterioration of the gaze tracking accuracy without bringing about the user's deliberate attention. We make use of hand-eye coordination, with the reasonable assumption that the eye gaze follows the pointer during a selection task, to acquire additional calibration points during normal usage of a gaze-contingent system. We construct a statistical model for the calibration and the hand-eye coordination and apply the Gaussian process regression framework to perform the re-calibration. RESULTS: To validate our model and method, we performed a user study on ultrasonography tasks on a gaze-contingent interface for ultrasound machines. Results suggest that our method can rectify the tracking accuracy deterioration for [Formula: see text] of all cases where deterioration occurs in our user study. With another benchmark dataset, our method can redress tracking accuracy to a level comparable to the initial calibration in more than [Formula: see text] of the cases. CONCLUSIONS: Our implicit re-calibration method is a practical and convenient fix for tracking accuracy deterioration in gaze-contingent user interfaces, and in particular for gaze-contingent ultrasound machines.

The Neyman Pearson detection of microsaccades with maximum likelihood estimation of parameters.

Despite the fact that the velocity threshold method is widely applied, the detection of microsaccades continues to be a challenging problem, due to gaze-tracking inaccuracy and the transient nature of microsaccades. Important parameters associated with a saccadic event, e.g., saccade duration, amplitude, and maximum velocity, are sometimes imprecisely estimated, which may lead to biases in inferring the roles of microsaccades in perception and cognition. To overcome the biases and have a better detection algorithm for microsaccades, we propose a novel statistical model for the tracked gaze positions during eye fixations. In this model, we incorporate a parametrization that has been previously applied to model saccades, which allows us to veridically capture the velocity profile of saccadic eye movements. Based on our model, we derive the Neyman Pearson Detector (NPD) for saccadic events. Implemented in conjunction with the maximum likelihood estimation method, our NPD can detect a saccadic event and estimate all parameters simultaneously. Because of its adaptive nature and its statistical optimality, our NPD method was able to better detect microsaccades in some datasets when compared with a recently proposed state-of-the-art method based on convolutional neural networks. NPD also yielded comparable performance with a recently developed Bayesian algorithm, with the added benefit of modeling a more biologically veridical velocity profile of the saccade. As opposed to these algorithms, NPD can lend itself better to online saccade detection, and thus has potential for human-computer interaction applications. Our algorithm is publicly available at https://github.com/hz-zhu/NPD-micro-saccade-detection.

A novel gaze-supported multimodal human-computer interaction for ultrasound machines.

PURPOSE: Conventional ultrasound (US) machines employ a physical control panel (PCP) as the primary user interface for machine control. This panel is adjacent to the main machine display that requires the operator's constant attention. The switch of attention to the control panel can lead to interruptions in the flow of the medical examination. Some ultraportable machines also lack many physical controls. Furthermore, the need to both control the US machine and observe the US image may lead the practitioners to adopt unergonomic postures and repetitive motions that can lead to work-related injuries. Therefore, there is a need for a more efficient human-computer interaction method on US machines. METHODS: To tackle some of the limitations with the PCP, we propose to merge the PCP into the main screen of the US machines. We propose to use gaze tracking and a handheld controller so that machine control can be achieved via a multimodal human-computer interaction (HCI) method that does not require one to touch the screen or look away from the US image. As a first step, a pop-up menu and measurement tool were designed on top of the US image based on gaze position for efficient machine control. RESULTS: A comparative study was performed on the BK Medical SonixTOUCH US machine. Participants were asked to complete the task of measuring the area of an ellipse-shaped tumor in a phantom using our gaze-supported HCI method as well as the traditional method. The user study indicates that the task completion time can be reduced by [Formula: see text] when using our gaze-supported HCI, while no extra workload is imposed on the operators. CONCLUSIONS: Our preliminary study suggests that, when combined with a simple handheld controller, eye gaze tracking can be integrated into the US machine HCI for more efficient machine control.

Melting of Pb Nanocrystals Embedded in Al, Si, and Cu Matrices.

Dispersions of nanoscale Pb particles embedded in Si, Al, and Cu matrices have been synthesized by ion implantation and subsequent annealing. The melting transitions of the embedded Pb nanocrystals with epitaxial particle/matrix interfaces were investigated by means of in situ high-temperature X-ray diffraction. Due to different levels of lattice mismatch, the Pb nanoprecipitates experience a different elastic strain in different matrices. Further analysis on the lattice constants of the embedded Pb nanocrystals gives unambiguous evidence of the strain-related pressure effect, which is particle size and matrix dependent, on tuning of the melting behavior of the embedded Pb nanoparticles.

Size evolution of ion beam synthesized Pb nanoparticles in Al.

The size evolution of Pb nanoparticles (NPs) synthesized by ion implantation in an epitaxial Al film has been experimentally investigated. The average radius R of Pb NPs was determined as a function of implantation fluence f. The R(f) data were analyzed using various growth models. Our observations suggest that the size evolution of Pb NPs is controlled by the diffusion-limited growth kinetics (R (2)∝f). With increasing implantation current density, the diffusion coefficient of Pb atoms in Al is evident to be enhanced. By a comparative analysis of the R(f) data, values of the diffusion coefficient of Pb in Al were obtained.

[Measurement of Rho-kinase and CD4+CD25+ regulatory T cells in the peripheral blood in asthmatic patients].

OBJECTIVE: To determine the levels of Rho-kinase and CD4+CD25+ regulatory T cells in patients with asthma, and the relationship between Rho-kinase and CD4+CD25+ regulatory T cells. METHODS: We included 16 patients with moderate to severe asthma in the research group and 14 healthy people as the control group. The levels of Rho-kinase in the 2 groups were measured by ELISA. The level of CD4+CD25+ regulatory T cells in the 2 groups was measured by flow cytometry. The pulmonary function was measured by spirometer. RESULTS: The level of Rho-kinase in the research group was higher than that in the healthy controls (P<0.05). The level of CD4+CD25+ regulatory T cells in the healthy controls was higher than that of the research group (P<0.05). There was no correlation between the level of Rho-kinase in the peripheral blood of the 2 groups and forced expiratiory volume at the first second/ forced vital capacity (FEV1%) (r=-0.491, P>0.05). The level of CD4+CD25+ regulatory T cells in the peripheral blood of the 2 groups showed a positive correlation with FEV1% (r=0.380, P=0.038). There was no correlation between the level of Rho-kinase and the level of CD4+CD25+ regulatory T cells in the peripheral blood of the 2 groups (r=-0.438, P>0.05). CONCLUSION: Rho-kinase and CD4+CD25+ regulatory T cells may play a key role in the pathogenesis of asthma.