On stability of distributions of WhatsApp traffic characteristics

This paper deals with the main methods of traffic classification and describes the functional scheme of a test bench and the test procedure. It provides the results of verifying the hypothesis about the stability of distributions of WhatsApp traffic characteristics. The delivered test results in this paper emphasize the influence of certain traffic characteristics on the final traffic distribution form. In addition, the comparison of the results obtained for the entire set of tests and the results received for individual test sets reveals the absence of other critical traffic characteristics significantly influencing the distribution form concluding in the need for further research. The paper concludes that the stability pattern of distributions of WhatsApp traffic characteristics can be obtained and visualized after more critical traffic characteristics are revealed and processed in similar tests. This paper stands as a pioneer research in assessing the traffic analysis and implementing the results in applied science.

Influence of Lightweight Foamed Concrete as Backfill Material on Stress and Deformation of Buttressed Earth-Retaining Wall

Controlling settlement and earth pressure behind retaining wall in soft soil area are ongoing practical problems for the construction and operation of highway, which are mainly caused by the poor nature of soft soil. To reduce the pushing force on retaining wall and subgrade settlement, the authors propose the use of lightweight foamed concrete as subgrade filler behind the buttressed earth-retaining wall. However, the mechanical properties and deformation behavior of the buttressed earth-retaining wall remain unknown when lightweight foamed concrete is used as a backfill behind the wall. To solve this problem, a scale model of the subgrade filled with lightweight foamed concrete behind the buttressed earth-retaining wall is established to determine its stress and deformation characteristics under different factors. Lateral earth pressures and wall displacements at different elevations of the retaining wall model were monitored during the tests. Then, a series of orthogonal experiments are conducted to analyse and compare the effects of overload, density, and replacement thickness of lightweight foamed concrete on the earth pressure and displacement of this retaining wall. The results show that the size of earth pressures at the same position of retaining wall is affected by overload, density, and replacement thickness of lightweight foamed concrete, but its change of distribution form is only related to the replacement thickness of this backfill. Additionally, the primary-secondary relations of different factors’ influence extent on the forces and deformation of the buttressed earth-retaining wall filled with lightweight foamed concrete as backfill are obtained by using range analysis method.

Past, present and future suitable areas for the relict tree Pterocarya fraxinifolia (Juglandaceae): Integrating fossil records, niche modeling, and phylogeography for conservation

Pterocarya fraxinifolia, native to the southern Caucasus and adjacent areas, has been widely introduced in Europe. In this study, we investigate the following: (1) How did its current distribution form? (2) What are the past, current, and future suitable habitats of P. fraxinifolia? (3) What is the best conservation approach? Ecological niche modeling was applied to determine its climatic demands and project the distribution of climatically suitable areas during three periods of past, current, and future (2070) time. Then, an integrated analysis of fossil data was performed. Massive expansion of Pterocarya species between the Miocene and Pliocene facilitated the arrival of P. fraxinifolia to the southern Caucasus. The Last Glacial Maximum played a vital role in its current fragmented spatial distribution in the Euxinian and Hyrcanian regions with lower elevations, and Caucasian and Irano-Turanian regions with higher elevations. Climatic limiting factors were very different across these four regions. Future climate change will create conditions for the expansion of this species in Europe. Human activities significantly decreased the suitable area for P. fraxinifolia, especially in the Euxinian, Hyrcanian, and Irano-Turanian regions. Considering genetic diversity, climate vulnerability, and land utilization, the Euxinian, Hyrcanian, and Irano-Turanian regions have been recognized as conservation priority areas for P. fraxinifolia.

Walking model and planning algorithm of the over-obstacle pipe climbing robot

Effective inspection of pipelines is of significant importance in the industry. In order to reduce human labour, risk and expenses in this area, robots can be applied. The pipe robot should perform not only the linear motion in the axial direction but also the rotary motion in the circumferential direction while working. Meanwhile, in order to achieve reasonable performance and efficiency, these robots should have high enough normal linear motion velocity. They should be able to cross a pipe in one direction to another pipe in a different direction to achieve the over-obstacle function. In this study, a double-joint wheeled robot model is established to fulfil the actions of fast walking, rotation around the pipe and over-obstacle on spatial pipes. Based on the expected position on the pipe for the robot constructed by the proposed model, the precise starting position and control synthesis of the axial and circumferential velocities are initially determined. In order to study the velocity synthesis more accurately, the pipe is unfolded along the axial direction to transform the spatial motion into a plane motion. A novel spatial distribution form of driving wheels is proposed. In addition, based on the initial position of the straight, T-shaped, L-shaped, two-axis ‘+’-shaped and spatial three-axis ‘+’-shaped pipes, the posture adjustment of the robot prior, during and after the over-obstacle is investigated. Furthermore, the corresponding planning algorithms are established.

Localization of Immersed Sources by Modified Convolutional Neural Network: Application to a Deep-Sea Experiment

A modified convolutional neural network (CNN) is proposed to enhance the reliability of source ranging based on acoustic field data received by a vertical array. Compared to the traditional method, the output layer is modified by outputting Gauss regression sequences, expressed using a Gaussian probability distribution form centered on the actual distance. The processed results of deep-sea experimental data confirmed that the ranging performance of the CNN with a Gauss regression output was better than that using single regression and classification outputs. The mean relative error between the predicted distance and the actual value was ~2.77%, and the positioning accuracy with 10% and 5% error was 99.56% and 90.14%, respectively.

STUDY ON STRUCTURAL-ACOUSTIC CHARACTERISTICS OF CYLINDRICAL SHELL BASED ON WAVENUMBER SPECTRUM ANALYSIS METHOD

By the finite element method, the structural vibration response is calculated under the action of the axial exciting force and the moment with different distribution form, and then the transfer function of the mean square normal velocity is analyzed. The wavenumber spectrum analysis method is used to separate and quantify the shell vibration in the wavenumber domain, and then the relation between the structural vibration characteristics and the structural wavelength is summarized. It is concluded that the structural vibration and radiated noise can be reduced under the symmetric action of axial exciting force and the moment. Based on the above conclusion, a symmetrical thrust bearing supporting system is designed and the stiffness of the supporting structure in the axial direction is controlled by selecting suitable size of structural members, therefore, the structural vibration and radiated noise of the submarine is reduced significantly.

Exploring the Variations of Redbed Badlands and Their Driving Forces in the Nanxiong Basin, Southern China: A Geographically Weighted Regression with Gridded Data

At present, most of the international research cases on badlands are based on semiarid regions, while there are few studies on badlands in humid regions. Therefore, the research on badlands in humid regions has strong theoretical and practical significance. By taking the Nanxiong Basin, which is located in the humid regions of southern China as the research object, this paper analyzes the scale and spatial distribution variation characteristics of redbed badlands and builds a set of factors that influence redbed badlands to explore the driving forces influencing the variation of redbed badlands based on remote sensing images of the American KH-4A satellite from 1969 and a Landsat 8 image from 2017. The result shows that the scale of redbed badlands in the Nanxiong Basin had generally decreased from 1969 to 2017. The area of redbed badlands decreased from 1693.97 hm2 in 1969 to 127.4 hm2 in 2017, with a decrease of 92.48%. The spatial distribution of redbed badlands had gradually changed from the contiguous planar distribution form in 1969 to the dispersed island distribution form in 2017, forming four agglomerations. The influence degree of the driving forces for the scale variation of redbed badlands is in the order of lithology > road > aspect > residential locations > slope > water system > vegetation > garden plots. Among these driving forces, except vegetation and garden plots, which have a negative correlation with the variation of redbed badlands, other factors have a positive correlation. Lithology is positively correlated with the variation of redbed badlands and has the strongest influence on the redbed badlands of all the influencing factors. The road factor is second to the lithological factor; the more accessible an area is, the stronger the human influence will be and the more serious the damage to vegetation will be, which easily cause surface vegetation damage, induce land degradation, and form redbed badlands.

Gap formation around 0.5Ωe of whistler-mode waves excited by electron temperature anisotropy

<p>With a 1-D PIC simulation model, we have investigated the gap formation around 0.5Ω<sub>e</sub> of the quasi-parallel whistler-mode waves excited by an electron temperature anisotropy. When the frequencies of excited waves in the linear stage cross 0.5Ω<sub>e</sub>, or when they are slightly larger than 0.5Ω<sub>e </sub>but then drift to lower values, the Landau resonance can make the electron distribution form a beam-like/plateau population. Such an electron distribution only slightly changes the dispersion relation of whistler-mode waves, but can cause severe damping around 0.5Ω<sub>e</sub> via cyclotron resonance. At last, the wave spectrum is separated into two bands with a power gap around 0.5Ω<sub>e</sub>. The condition under different electron temperature anisotropy and plasma beta is also surveyed for such kind of power gap. Besides, when only the waves with frequencies lower than 0.5Ω<sub>e</sub> are excited in the linear stage, a power gap can also be formed due to the wave-wave interactions, i.e., lower band cascade. Our study provides a clue to reveal the well-known 0.5Ω<sub>e</sub> power gap of whistler-mode waves ubiquitously observed in the inner magnetosphere.</p>

Discipline and distinction in the age of the Internet: a sociological study of the fitness practice

This article examines popular fitness sports and home fitness software in China. Drawing on Michel Foucault’s theory of discipline, Norbert Elias’ study on civilization, and Jean Baudrillard’s study on the consumer society, the authors reveal the formation of a new body discipline mechanism against the background of the Internet society and the consumer society. On the one hand, the external disciplinary strategies have been upgraded, including the spatial strategy of liquidity and visibility, the linear and rhythmic time strategy, and the knowledge strategy. On the other hand, different from Foucault’s discussion of discipline, we introduce positive self-discipline. As a unique consumption practice, fitness practices promote a new form of self-discipline among practitioners who also pursue distinctive social positions. The core content of the self-discipline strategy includes code manipulation, time consumption, moral display, and self-writing. In addition, with the continuous infiltration of Internet technologies in daily life, the space-time boundaries of physical discipline gradually blur, whereas the micro-distribution of power changes into a daily distribution form.

Shaking Table Tests on a New Antislide Pile under Earthquakes

A retaining form of a shock-absorbing antislide pile is proposed for slope engineering. A flexible material (shock-absorption layer) is filled in front of an ordinary antislide pile, which is used to absorb a large amount of seismic energy, thereby decreasing the transmission of seismic energy to the antislide pile. The flexible material thus reduces the seismic response, hence improving the aseismic capacity of the antislide pile. To verify the seismic performance of the shock-absorbing antislide pile, a shaking table contrast test was conducted and the results were compared with those from an ordinary antislide pile. The test results show that the flexible material absorbs a portion of the seismic deformation of the slip mass, decreasing the final displacement of the shock-absorbing antislide pile compared to that of the ordinary antislide pile, thereby reducing the sensitivity of the pile body to the displacement. Under the same conditions, the acceleration response of the slope body at the same height is lower for the shock-absorbing antislide pile than that for the ordinary pile, with the seismic performance of the former being superior to that of the latter. Furthermore, the shock-absorbing antislide pile is similar to the ordinary pile in terms of the dynamic earth pressure distribution form of the pile shaft; however, its value is relatively smaller, and the former exhibits better dynamic stress performance than the latter. The test results should prove useful for aseismic design of slopes.