Effect of in-app components,medium, and screen size of electronic textbooks on reading performance,behavior, and perception

Although many app-based textbooks are available for students, reading have not been thoroughly outlined. This study aimed to understand how changes from paper to electronic textbooks have affected the academic reading task, investigate student users’ perceptions of in-app components and screen sizes, and identify issues affecting in-app components and task requirements. A mixed factorial design experiment was employed. Results showed that there were no significant changes in comprehension and time spent reading between print text and the iPad. Yet, student highlighting, notetaking, and reading behavior and perception significantly changed based on condition. In addition, students struggled to use in-app components and found them frustrating especially when accounting for sentence splitting. The findings presented can assist in understanding the changes in student reading behavior, which can be used to improve interface design of future e-textbooks.     

Film and television industry cloud exhibition design based on 3D imaging and virtual reality

The three-dimensional virtual scene can provide users with a visual three-dimensional virtual environment, with various multimedia channels such as sound, video, force feedback equipment, etc., to bring users a completely immersive interactive experience. This paper introduces 3D imaging and virtual reality technology in the film and television industry cloud exhibition, and develops a virtual display platform. First of all, this paper divides the registration into two processes: camera calibration and joint calibration of the camera and laser scanner based on the calibration results. Camera calibration can determine the plane model of the calibration board in the camera coordinate system, and the joint calibration uses the RANSAC algorithm to extract the point cloud of the plane model of the calibration board, and then optimizes the distance between the points in the plane model point cloud and the corresponding plane in the camera coordinate system Find the optimal transformation between the two sets of data, and then calculate the registration relationship between the point cloud and the image. Secondly, this article conducts a demand analysis of the film and television industry cloud exhibition platform based on virtual reality technology, including the business goals set by the platform, platform system analysis, overall design, and system operating environment and configuration requirements. This model provides a feasible solution for the visual interaction of the cloud exhibition design of the film and television industry.     

基于阈值和极端随机树的实时跌倒检测方法

针对基于可穿戴设备的跌倒检测存在的实时性与准确性无法兼得的问题,提出一种阈值和极端随机树融合的实时跌倒检测方法。在该方法中,可穿戴设备只需计算阈值量,无需确保跌倒检测的准确率,从而减少了计算量;同时,上位机利用极端随机树算法确保了跌倒检测的准确率。可穿戴设备通过阈值的方法过滤了大部分日常动作,因此减少了上位机检测的动作数据量。这样一来所提方法既满足了跌倒检测的高准确率,又满足了实时性。另外,为了降低跌倒检测的假阳性率,可穿戴设备融合了姿态角度传感器和压力传感器,上位机中加入了反馈机制。当检测结果出现假阳性时,通过上位机将检测错误的样本加入非跌倒数据集中进行再训练,模型经过这样的不断学习会生成适合个人的报警模型,且这种反馈机制为降低跌倒检测的假阳性率提供了新思路。实验结果表明,在1 259个测试样本中,所提方法具有平均99.7%的准确率,最低0.08%的假阳性率。     

AgTaO3 and AgNbO3 thin films by pulsed laser deposition

Silver tantalate AgTaO₃ (ATO) and silver niobate AgNbO₃ (ANO) films have been grown on to the LaAlO₃ (001) and sapphire Al₂O₃ (0112, r-cut) single crystals by pulsed laser deposition technique from stoichiometric ATO and ANO targets. X-ray diffraction study revealed epitaxial quality of ATO and ANO films on the LaAlO₃ (001) whereas on the sapphire r-cut substrate they are preferential (110) and (001) oriented. To characterize microwave films properties in the range from 1 to 40 GHz, coplanar line interdigital capacitors were fabricated by photolithography and lift-off technique. ANO film capacitors show superior properties: frequency dispersion was as low as 13%, voltage tunability (40 V, 200 kV/cm) was about 4.6% at 20 GHz, loss tangent ∼0.106 at 20 GHz, K-factor = tunability / tanδ from 49% @ 10 GHz to 33% at 40 GHz.     

Impact of Pt bottom electrode on the properties of ferroelectric Bi3.25La0.75Ti3O12 capacitors

Lanthanum-modified bismuth titanate (Bi_3.25La_0.75Ti₃O₁₂) (BLT) films have been prepared on platinized silicon substrates using sol–gel method. Highly (001) or (111) oriented platinum layers are used as the bottom electrodes of ferroelectric BLT capacitors to study the effects of Pt orientation on the structural and physical properties of BLT films. X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements demonstrate that the microstructure and morphology of BLT films are not strongly affected by the Pt films. BLT film on highly (111) oriented Pt possesses much higher remanent polarization (∼ 8 μC/cm²) than that on highly (001) oriented Pt although the coercive fields of the two kinds of Bi_3.25La_0.75Ti₃O₁₂ films are almost equal.     

High-power wavelength-tunable cladding-pumped rare-earth-doped silica fiber lasers

We describe the design and performance of cladding-pumped silica fiber lasers with high continuous-wave output powers and broad wavelength tunability in the 1, 1.5, and 2 μm spectral ranges. An ytterbium-doped fiber laser was tuned via wavelength dependent feedback provided by an external cavity containing a diffraction grating from 1027 to 1105 nm at multi-watt power levels. Similarly, high output power and wide wavelength tunability from 1540 to 1600 nm and from 1860 to 2090 nm at multi-watt output power levels has been achieved in Er-Yb co-doped and Tm-doped silica fiber lasers, respectively. A neodymium doped fiber laser was tuned from 1057 to 1118 nm at a lower power level. Limiting factors and the prospects for further improvements in performance are considered.     

Microstructural characterization of donor-doped lead zirconate titanate films prepared by sol–gel processing

Lanthanum and niobium-doped lead zirconate titanate, Pb(Zr,Ti)O₃, (PZT) thin films were prepared on Pt/Ti/SiO₂/Si substrates by sol–gel processing. Films have a Zr/Ti ratio of 52:48 and tetragonal perovskite phase structure. The influence of donor dopants on the morphology, texture and defects of PZT films was studied using X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, breakdown field strength and fatigue. Donor doping of PZT films results in increased breakdown field strength and improved fatigue properties. These originate from (i) the reduction of texture in the [111] and increase in the texture in [100]; (ii) lower porosity, smaller grain size and smoother surfaces; (iii) granular grain structure; and (iv) reduction in the oxygen vacancy concentration in the films.     

基于博弈论和启发式算法的超密集网络边缘计算卸载

超密集网络与边缘计算相结合时,高密度的基站分布可能会对同一用户重复覆盖,该用户选择不同基站进行卸载将会对系统性能产生不同影响,由此引出卸载对象选取问题。同时边缘计算可以将部分任务卸载到边缘服务器进行处理,选择合适的卸载比例能够显著降低所需的时延和能耗,由此引出卸载比例选取问题。提出一种超密集网络环境中基于博弈论和启发式算法的边缘计算卸载策略。针对卸载对象选取问题,根据边缘服务器到用户之间的距离和工作负载定义偏好度指标,各用户根据偏好度进行博弈后选择卸载对象,并对用户进行分组,将原问题分解为若干个并行的子问题。针对卸载比例选取问题,基于萤火虫群优化算法对各用户的卸载比例进行优化,得到适当的卸载比例。与全本地处理（ALP）策略、全卸载策略（AOS）和基于粒子群优化（PSO）算法的卸载策略进行对比,实验结果表明,ALP和AOS策略在总能耗和平均时延上具有一定的局限性,相比基于PSO的卸载策略,所提策略的时延降低22%,能耗降低20%,可以有效减少系统损失。     

Improved SpaceTwist privacy protection method based on anchor optimization algorithm

With location-based services worldwide used,private location data appealed easily in query process which caused serious security problems.So the introduction of SpaceTwist incremental nearest neighbor query algorithm,proposes protection of privacy method combined with improved SpaceTwist location optimization algorithm.The anchor point authentication server added to distributed system structure,user generate a k anonymous area according to their privacy preference and actual environment,using optimization algorithm to generate the anchor point.Forwarding users use the incremental nearest neighbor query throught the anchor point and accurate.Experiments in road network environment with different data sets show that the privacy protection works well in the algorithm,and own high work efficiency.