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Inferring Spatial Distribution Patterns in Web Maps for Land Cover Mapping
No full textWeb maps represent an effective source for land cover mapping in capturing human activities. However, due to spatial heterogeneity, previous research has mainly focused on generating land cover maps in partial areas. Inferring spatial distribution patterns in Web maps may provide an alternative perspective on improving map production on a larger scale. This paper represents a novel approach to investigating the spatial distribution in Web maps for land cover mapping. First, linear features from Web maps are utilised to delineate parcels with insufficient Web map data for classification. Then, spatial factors are constructed from point and polygon features to identify the spatial variety of Web maps, with an artificial neural network classifier being adopted to classify land cover automatically. Land cover mapping is finally proposed by combining classified parcels and existing polygon features. The proposed method is applied in Guangzhou, Guangdong Province, using a Web map from AutoNavi. The results show an approximately 88% classification accuracy and an overall mapping accuracy of 85.06%. The results indicate that the proposed approach has the potential to be utilised in land cover mapping, and the constructed spatial factors are effective at characterising land cover information
Water-Based Processing of Fiberboard of Acrylic Resin Composites Reinforced With Cellulose Wood Pulp and Cellulose Nanofibrils
No full textDespite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics, its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character. Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils, and a resin of poly (styrene-methyl-methacrylate-acrylic acid) used as water-based emulsion. Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions. The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension, leading to the co-precipitation of the composite material, which can be easily separated from the water phase. Composites with acrylic polymer/cellulose fibers in the proportions of 75:25, 50:50 and 25:75 wt% were prepared. Composites were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and water absorption tests. SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration, which led to superior mechanical properties. These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials
Evaluation of the Out-of-Plane Shear Properties of Cross-Laminated Timber
No full textThe out-of-plane shear properties of cross-laminated timber (CLT) substantially influence the overall mechanical properties of CLT. Various testing methods and theories related to these properties have recently been developed. The effects of the number of layers (three and five layers) and testing method (short-span three- and four-point bending tests) on the out-of-plane shear properties of CLT were evaluated. The out-of-plane shear strength values were calculated based on different theories for comparison. The failure mode in the short-span four-point bending (FPB) method was mainly the rolling shear (RS) failure in the cross layers, indicating that the FPB method was appropriate to evaluate the RS strength of CLT. The out-of-plane shear capacity obtained using the three-point bending (TPB) method was higher than that tested by the FPB method. The testing methods significantly influenced the out-of-plane shear capacity of the three-layer specimens but not that of the five-layer specimens. With an increase in the number of layers, the out-of-plane shear strength of the specimens decreased by 24%. A linear correlation was found among the shear strength values obtained from different theories
Eigenvalue Analysis of Thin Plate with Complicated Shapes By a Novel Infinite Element Method
Get PDFA novel infinite element method (IEM) is presented for solving plate vibration problems in this paper. In the proposed IEM, the substructure domain is partitioned into multiple layers of geometrically similar finite elements which use only the data of the boundary nodes. A convergence criterion based on the trace of the mass matrix is used to determine the number of layers in the IE model partitioning process. Furthermore, in implementing the Craig-Bampton (CB) reduction method, the inversion of the global stiffness matrix is calculated using only the stiffness matrix of the first element layer. The validity and performance of the proposed method are investigated by means of four illustrative problems. The first example considers the case of a simple clamped rectangular plate. It is observed that the IEM results are consistent with the theoretical results for first six natural frequencies. The second example considers the frequency response of a clamped rectangular plate with a crack. The main feature of IEM is that a very fine and good quality virtual mesh can be created around the crack tip. The third and fourth examples consider the natural frequency of a multiple point supported plate and a perforated plate, respectively. The results are obtained just need to adjust the reference point or boundary nodes. The parametric analyses for various geometric profiles are easy to be conducted using these numerical techniques. In general, the results presented in this study have shown that the proposed method provides a direct, convenient and accurate tool for eigenvalue analysis of thin plate structure with complicated shapes
OpenSees Three-Dimensional Computational Modeling of Ground-Structure Systems and Liquefaction Scenarios
Get PDFThe OpenSees computational platform has allowed unprecedented opportunities for conducting seismic nonlinear soil-structure interaction simulations. On the geotechnical side, capabilities such as coupled solid-fluid formulations and nonlinear incremental-plasticity approaches allow for representation of the involved dynamic/seismic responses. This paper presents recent research that facilitated such endeavors in terms of response of ground-foundation-structure systems using advanced material modeling techniques and high-performance computing resources. Representative numerical results are shown for large-scale soil-structure systems, and ground modification liquefaction countermeasures. In addition, graphical user interface enabling tools for routine usage of such 3D simulation environments are presented, as an important element in support of wider adoption and practical applications. In this context, Performance-Based Earthquake Engineering (PBEE) analysis of bridge-ground systems is highlighted as an important topical applicatio
Reversible Data Hiding Based on Pixel-Value-Ordering and Pixel Block Merging Strategy
Get PDFWith the reversible data hiding method based on pixel-value-ordering, data are embedded through the modification of the maximum and minimum values of a block. A significant relationship exists between the embedding performance and the block size. Traditional pixel-value-ordering methods utilize pixel blocks with a fixed size to embed data; the smaller the pixel blocks, greater is the embedding capacity. However, it tends to result in the deterioration of the quality of the marked image. Herein, a novel reversible data hiding method is proposed by incorporating a block merging strategy into Li et al.’s pixel-value-ordering method, which realizes the dynamic control of block size by considering the image texture. First, the cover image is divided into non-overlapping 2×2 pixel blocks. Subsequently, according to their complexity, similarity and thresholds, these blocks are employed for data embedding through the pixel-value-ordering method directly or after being emerged into 2×4, 4×2, or 4×4 sized blocks. Hence, smaller blocks can be used in the smooth region to create a high embedding capacity and larger blocks in the texture region to maintain a high peak signal-to-noise ratio. Experimental results prove that the proposed method is superior to the other three advanced methods. It achieves a high embedding capacity while maintaining low distortion and improves the embedding performance of the pixel-value-ordering algorithm
The Algorithm of Chemical Species Analysis for <i>Ab Intio</i> Molecular Dynamics Simulations and Its Application
Get PDFIn ab initio molecular dynamics (AIMD) simulations of chemical reactions, it is important but difficult to identify the chemical species in the trajectory automatically and quickly. In this paper, based on the chemical graph theory, an algorithm for molecular species identification, according to the molecular coordinates and empirical bond length database, is presented. As an example, the chemical species in condensed glycine at room temperature are investigated with our algorithm in detail. The chemical species, including canonical and zwitterionic glycine, their protonated and de-protonated states, and the free protons, are all identified, counted and recorded correctly. Potential applications and further development of the algorithm are also discussed
A DPN (Delegated Proof of Node) Mechanism for Secure Data Transmission in IoT Services
Get PDFThe importance of Blockchain and IoT technology have been highlighted in various fields. These are not unaccustomed words anymore in our lives. Although the technologies are in the infancy step and are still many remaining technical challenges, there is no doubt that it will be one of the major parts of the future Internet. The efficiency and security of data transmission scheme have always been major issues in the legacy Internet, and a data transmission scheme for the future Internet, including 5G and IoT environment should also provide and support these issues. Consequently, we propose a new data transmission scheme to successfully support the future Internet environment. The proposed scheme, which is named as S-DTS (Secure Data Transmission Scheme), supports a distributed transmission and decentralized access control. The S-DTS utilizes 4 synchronization zones, which are IoT network zone, aggregation zone, mining zone, and management zone, and these zones are operated by the DPN (Delegated Proof of Node) mechanism. Furthermore, all nodes are categorized to the 3 node groups, LDTG (Low Delay Tolerance Group), MDTG (Medium Delay Tolerance Group), HDTG (High Delay Tolerance Group), to provide an efficient data transmission, and the data in each group will be transmitted in accordance with their own traffic attributes. The evaluation results of this scheme show that it is very suitable for massive IoT environment scenarios, and IoT devices can take advantage of safe and efficient transmission by using the delegated proof of node technique. In addition, the S-DTS might be adaptable for various computing and networking environment with big data, edge cloud and cloud computing, and autonomous networking
Balanced Deep Supervised Hashing
Get PDFRecently, Convolutional Neural Network (CNN) based hashing method has achieved its promising performance for image retrieval task. However, tackling the discrepancy between quantization error minimization and discriminability maximization of network outputs simultaneously still remains unsolved. Motivated by the concern, we propose a novel Balanced Deep Supervised Hashing (BDSH) based on variant posterior probability to learn compact discriminability-preserving binary code for large scale image data. Distinguished from the previous works, BDSH can search an equilibrium point within the discrepancy. Towards the goal, a delicate objective function is utilized to maximize the discriminability of the output space with the variant posterior probability of the pair-wise label. A quantization regularizer is utilized as a relaxation from real-value outputs to the desired discrete values (e.g., -1/+1). Extensive experiments on the benchmark datasets show that our method can yield state-of-the-art image retrieval performance from various perspectives
A Novel Broadband Microstrip Antenna Based on Operation of Multi-Resonant Modes
Get PDFA novel broadband microstrip antenna under operation of TM1/2,0, TM10 and TM12 modes through a shorting wall and slots is proposed in this paper. Initially, an inverted U-shaped slot is adopted around the feeding point, which achieves a good impedance matching on TM10 mode and separates the patch into two parts. Additionally, a shorting wall is added underneath the edge of smaller patch to excite another one-quarter resonant mode, i.e., TM1/2,0 mode of smaller patch close to TM10 mode to expand the impedance bandwidth. Further, the antenna width is enlarged and two symmetrical vertical rectangular slots are cut on the patch to reduce the frequency of TM12 mode to form a broadband. Based on the arrangements above, a wide impedance bandwidth with three minima can finally be achieved. The results show that the impedance bandwidth of proposed antenna for |S11|<-10 dB is extended to 26.5% (23.5-30.67 GHz), which is three times of the conventional antenna at same profile. Moreover, a stable radiation pattern at broadside direction is realized over the operating band