Abstract:There are always interferences in environment, especially power-line interferences, when we collect biomedical signals such as electrocardiogram, electromyogram and electroencephalogram. Moreover, the noise amplitude is usually much larger than that of the physiological signals, making the subsequent signal analysis and processing very difficult. The conventional methods are to pass the collected signal through a software filter for reducing the effects of power-frequency interferences. However, it would cause the reduction and distortion of the target signal. In order to solve this problem, this study proposed a novel design of hardware circuit based on the shielding technology, which can intensively inhibit the power-frequency interferences mixed in the original signal in analog front end. The experiments of both electrocardiogram and electromyogram acquisitions carried out on TI ADS1299 platform showed that the power-line interferences could be significantly suppressed when the electrode was electronically shielded. By comparing the conditions when the shielding layer was connected to different driving signals, it was found that the attenuation of the power-frequency interferences could reach as high as 35 dB when the electrode was shielded by signal itself. The shielding technology proposed in this study could be used in a variety of biomedical signal acquisitions to reduce power-frequency interferences at the initial stage, and therefore it could essentially enhance the signal to noise ratio of biomedical signals.

Abstract:Modeling 3D objects with realistic surface appearance is a challenging and time-demanding task. While a rough approximation of the overall object shape can be quickly modeled by an experienced modeler, or retrieved from a shape repository, endowing a 3D shape with realistic surface appearance, consisting of spatially variant fine scale geometric detail and reflectance, can be extremely time consuming. In this paper, a method that allows modelers to quickly extract a non-parametric appearance model from a single photograph and to easily apply it on various 3D shapes was presented. The extraction was assisted by a user-provided proxy, whose geometry roughly approximates that of the object in the image. A novel technique was used to align and deform the proxy shape so as to match the reference object, thereby enabling accurate joint recovery of geometric detail and reflectance. The correlations between the recovered geometry at various scales and the spatially varying appearance constitute a non-parametric model. The extracted appearance model can then be easily applied to the proxy by our normal transfer algorithm, greatly assisting in modeling detailed and realistic 3D models.

Abstract:Magnetic resonance elastography (MRE) can noninvasively quantify tissue elastic properties. There are two kinds of dynamic actuation in MRE, namely harmonic excitation and transient excitation. Due to the complexity of human organs and tissues, the propagation of elastic waves suffers from reflection, diffraction and other interfering effects. In this study, a numerical platform was established to simulate transient MRE. Furthermore, an algorithm of elasticity reconstruction was developed in accordance with time of arrival. A series of numerical experiments were carried out for harmonic and transient MREs. The results show that transient MRE has good anti-interference ability on reflection and diffraction, and the developed algorithm can perform elasticity reconstruction for transient MRE successfully.

Abstract:Conventional depth-camera can provide pixel-wise aligned depth and color images. However, the obtained depth image usually contains a lot of vacant image regions subject to the device resolution and reflectance property of target scene. To solve this problem, a novel depth image completion algorithm was investigated in this paper. To preserve sharp edges in the depth image, an edge mask was first designed. With reference to the edge mask, an improved joint bilateral filtering scheme was proposed. By filtering the depth image in four directions, a Markov random field model was used to combine the filtered depth images into one. Different from conventional filter-based image completion algorithms, the scene occlusion problem is also considered in the proposed algorithm. A variety of depth images are used in the experiment. Comparative results are presented to demonstrate the improvement over some classical methods.

Abstract:The frame rate of ultrasound imaging, which determines the ability of the system to capture moving objects, is a key factor affecting ultrasound imaging applications, such as 3D imaging, cardiac imaging, color Doppler and so on. Traditional ultrasonic imaging method uses delayed focusing to obtain better image, but has low frame rate. At present, both plane wave imaging method and wide beam imaging method can improve the frame rate. Plane wave imaging is a method that simultaneously transmits or receives ultrasonic waves for all the elements. Although the frame rate was significantly increased with plane wave imaging, the improvement of the resolution is still limited, since it is a non-focusing technology. The image quality is moderate especially when less scan angles were employed to maintain a high frame rate. Wide-beam imaging technology could significantly improve the frame rate, uniformity and spatial resolution of the image by using multi-element simultaneous transmit, far point focusing, dynamic aperture apodization and other methods. This paper acquired data using a research ultrasound system (V1, Verasonics, USA), and reconstructed wide beam image with beamforming. Besides, the paper compared wide beam images with plane-wave image and conventional focused image. Results show that the wide beam method has better axial resolution and lateral resolution compared to plane wave imaging and conventional focused imaging. It also can obtain higher frame rate than the focused imaging.

Abstract:Sit-to-walk (STW) motion is one of the most common action in daily life. Falls frequently occur, when there is impaired ability to perform STW movements. In this study, the relationships between dynamical characteristics of STW motion and physical functions of elderly people were investigated. The experiments were conducted in Malianwa community, one of the highest proportion of the elderly population of Beijing. 128 elderly (51 males and 77 females, above 65 years) participated in this experiment. Participants were classified into four groups (normal, mild, moderate and severe group) based on physical function test and were instructed to perform STW motion at comfortable state. The data of ground reaction force (GRF) and moment (GRM) between left and right foot was recorded, and quantified by sample entropy. The results showed that there were statistical differences among sample entropies of GRF or GRM between left and right foot. In addition, a subset of variables was significant difference among four groups. Statistical difference was found for the following variables: sample entropies of medial-lateral, anterior-posterior, and superior-inferior GRF of left foot during walking (LFx, P＝0.049; LFy, P＝0.025; LFz, P＝0.036, respectively); sample entropies of anterior-posterior, and superior-inferior GRF of right foot during walking (RFy, P＝0.043; RFz, P＝0.006, respectively); sample entropies of medial-lateral GRM of right foot during walking (RMx, P＝0.041). Therefore, the data of GRF and GRM between left and right foot should be acquired and analyzed separately.

Abstract:With the advance of urbanization and development of big data, urban traffic forecast has become an essential issue for the Smart City. Many existing traffic prediction models do not fulfill the real-time performance goal in terms of efficiency and accuracy due to the limitation of hardware and software. A highly efficient real-time traffic prediction method using the Spark distributed in-memory computing framework was proposed in this paper. In this method, we estimate the average speed of vehicles on each road segment, and vertical windowed sampling on historical GPS data. Secondly, we use Spark to compute the probability distribution of average speed over each time window. Thirdly, we use Bayesian maximum-a-posteriori estimation to adjust the speed estimate of latest period of time. Experimental results demonstrate that the proposed method can be used for implementing efficient and accurate urban traffic prediction in real time. which reflects the real-time traffic condition. The method works in three steps. Firstly, we perform horizontal

Abstract:In order to improve the response performance of electro-mechanical converter (EMC), a novel EMC device with triple coils was investigated in this paper. Mathematical model of the proposed EMC was firstly established. By applying the Bacterial Foraging Algorithm, an optimal solution for the model can be obtained. Adual-mode controller with Bang-Bang & proportional-integral was designed based on the proposed method. Analytical and simulated results showed that, response time of the triple coil EMC driven by dualmode controller can be reduced from 8.5 ms to 2.5 ms. In comparison with conventional single coil EMC, the ringing and overshoot can be controlled within 5%.

Abstract:Seven main cow milk protein genes, including αs1CN, αs2CN, βCN, κCN, αLa, βLg, and BSA(Bovine Serum Albumin), were expressed in Escherichia coli and three whey proteins were examined by western-blot. As a trial substage, these genes of seven cow milk protiens expressed successfully in E. coli wihout a phenomenon of degradation. The results indicated that it is initial feasible to gain recombinant milk proteins using recombinant E. coli, and this work lays foundations for the production of cow free milk.