3D Road Network Modeling and Road Structure Recognition in Internet of Vehicles

Internet of Vehicles (IoV) is a new system that enables individual vehicles to connect with nearby vehicles,people, transportation infrastructure, and networks, thereby realizing amore intelligent and efficient transportationsystem. The movement of vehicles and the three-dimensional (3D) nature of the road network cause the topologicalstructure of IoV to have the high space and time complexity.Network modeling and structure recognition for 3Droads can benefit the description of topological changes for IoV. This paper proposes a 3Dgeneral roadmodel basedon discrete points of roads obtained from GIS. First, the constraints imposed by 3D roads on moving vehicles areanalyzed. Then the effects of road curvature radius (Ra), longitudinal slope (Slo), and length (Len) on speed andacceleration are studied. Finally, a general 3D road network model based on road section features is established.This paper also presents intersection and road section recognition methods based on the structural features ofthe 3D road network model and the road features. Real GIS data from a specific region of Beijing is adopted tocreate the simulation scenario, and the simulation results validate the general 3D road network model and therecognitionmethod. Therefore, thiswork makes contributions to the field of intelligent transportation by providinga comprehensive approach tomodeling the 3Droad network and its topological changes in achieving efficient trafficflowand improved road safety.

Synthesis and Crystal Structure of a Novel Three-dimensional Manganese(Ⅱ) Coordination Polymer:[Mn(pdc)]_n (pdc=Pyridine-2,4-dicarboxylate)

A novel manganese（H） coordination polymer [Mn（pdc）]n （pdc = pyridine-2,4- dicarboxylate） has been synthesized under hydrothermal conditions. The crystal is of monoclinic, space group P211n with a = 6.506（4）, b = 9.392（6）, c = 11.217（7） A, β = 105.650（12）°, V= 660.0（7）A3, Z = 4, Mr = 220.04, Dc = 2.215 g/cm3,μ = 1.971 mm-1, F（000） = 436, Rint = 0.0345, R = 0.0360 and wR = 0.0778 for 1259 observed reflections with I 〉 2σ（I）. In the structure, the Mn（Ⅱ） atom is coordinated in a distorted octahedral arrangement by one pyridine N and five carboxylate O atoms from five pdc ligands, each of which coordinates to five Mn atoms to propagate a three-dimensional layered framework.

Novel Poly m eric Transition Metal Co m plexes Having1D Chain and 3D Networks Structures

The syntheses and structures of eleven novel polymeric transition metal complexes having one dimensional chain structures or three dimensional networks are summarized. They are prepared from the controlled assembling reactions in organic solvents and characterized by X ray diffraction analyses. The spectroscopic or magnetic properties of some complexes are studied.

Three-Dimensional Ocean Sensor Networks:A Survey

The past decade has seen a growing interest in ocean sensor networks because of their wide applications in marine research,oceanography,ocean monitoring,offshore exploration,and defense or homeland security.Ocean sensor networks are generally formed with various ocean sensors,autonomous underwater vehicles,surface stations,and research vessels.To make ocean sensor network applications viable,efficient communication among all devices and components is crucial.Due to the unique characteristics of underwater acoustic channels and the complex deployment environment in three dimensional(3D) ocean spaces,new efficient and reliable communication and networking protocols are needed in design of ocean sensor networks.In this paper,we aim to provide an overview of the most recent advances in network design principles for 3D ocean sensor networks,with focuses on deployment,localization,topology design,and position-based routing in 3D ocean spaces.

A Novel Hierarchical Porous 3D Structured Vanadium Nitride/Carbon Membranes for High-performance Supercapacitor Negative Electrodes

Transition-metal nitrides exhibit wide potential windows and good electrochemical performance, but usually experience imbalanced practical applications in the energy storage field due to aggregation, poor circulation stability, and complicated syntheses. In this study, a novel and simple multiphase polymeric strategy was developed to fabricate hybrid vanadium nitride/carbon(VN/C) membranes for supercapacitor negative electrodes, in which VN nanoparticles were uniformly distributed in the hierarchical porous carbon 3D networks. The supercapacitor negative electrode based on VN/C membranes exhibited a high specific capacitance of 392.0 F g^(-1) at 0.5 A g^(-1) and an excellent rate capability with capacitance retention of 50.5% at 30 A g^(-1). For the asymmetric device fabricated using Ni(OH)_2//VN/C membranes, a high energy density of 43.0 Wh kg^(-1) at a power density of800 W kg^(-1) was observed. Moreover, the device also showed good cycling stability of 82.9% at a current density of 1.0 A g^(-1) after 8000 cycles. This work may throw a light on simply the fabrication of other high-performance transition-metal nitridebased supercapacitor or other energy storage devices.

Three-Dimensional Cooperative Localization via Space-Air-Ground Integrated Networks

The space-air-ground integrated network(SAGIN)combines the superiority of the satellite,aerial,and ground communications,which is envisioned to provide high-precision positioning ability as well as seamless connectivity in the 5G and Beyond 5G(B5G)systems.In this paper,we propose a three-dimensional SAGIN localization scheme for ground agents utilizing multi-source information from satellites,base stations and unmanned aerial vehicles(UAVs).Based on the designed scheme,we derive the positioning performance bound and establish a distributed maximum likelihood algorithm to jointly estimate the positions and clock offsets of ground agents.Simulation results demonstrate the validity of the SAGIN localization scheme and reveal the effects of the number of satellites,the number of base stations,the number of UAVs and clock noise on positioning performance.

A study on 3-D velocity structure of crust and upper mantle in Sichuan -Yunnan region, China

Based on the first arrival P and S data of 4 625 regional earthquakes recorded at 174 stations dispersed in the Yunnan and Sichuan Provinces, the 3-D velocity structure of crust and upper mantle in the region is determined, incorporating with previous deep geophysical data. In the upper crust, a positive anomaly velocity zone exists in the Sichuan basin, whereas a negative anomaly velocity zone exists in the western Sichuan plateau. The boundary between the positive and negative anomaly zones is the Longmenshan fault zone. The images of lower crust and upper mantle in the Longmenshan fault, Xianshuihe fault, Honghe fault and others show the characteristic of tectonic boundary, indicating that the faults likely penetrate the Moho discontinuity. The negative velocity anomalies at the depth of 50 km in the Tengchong volcanic area and the Panxi tectonic zone appear to be associated with the temperature and composition variations in the upper mantle. The overall features of the crustal and the upper mantle structures in the SichuanYunnan region are the lower average velocity in both crust and uppermost mantle, the large crustal thickness variations, and the existence of high conductivity layer in the crust or/and upper mantle, and higher geothermal value. All these features are closely related to the collision between the India and the Asia plates. The crustal velocity in the SichuanYunnan rhombic block generally shows normal value or positive anomaly, while the negative anomaly exists in the area along the large strike-slip faults as the block boundary. It is conducive to the crustal block side-pressing out along the faults. In the major seismic zones, the seismicity is relative to the negative anomaly velocity. Most strong earthquakes occurred in the upper-mid crust with positive anomaly or normal velocity, where the negative anomaly zone generally exists below.

A Novel Hydrogen-bonded Three-dimensional Network Complex Containing Nickel

A novel complex, (H 3O) 2[Ni(2,6-pydc) 2]·2H 2O was synthesized in an aqueous solution and characterized by means of single-crystal X-ray diffraction, elemental analyses and IR spectra. The X-ray structural analysis revealed that the novel compound forms three-dimensional(3D) networks by both π-π stacking and hydrogen-bonding interactions. The crystal data for the complex are a=13.853(3) nm, b=9.6892(19) nm, c=13.732(3) nm, α=90.00°, β=115.52(3)°, γ=90.00°, Z=3, R 1=0.0786, wR 2=0.1522.

A 2D Layered Thiostannate: Synthesis and Crystal Structure of [tmdpH_2]Sn_3S_7

A new thiostannate,[tmdpH2]Sn3S7 1（tmdp = 4,4＇-trimethylenedipiperidine）,has been synthesized under solvothermal conditions and characterized by elemental analysis,IR spectroscopy,and single-crystal X-ray diffraction analysis.In 1,the Sn3S4 secondary incomplete cubane-like building units are bridged by μ2-S atoms to form Sn12S12 rings which are then joined parallelly to the [001] plane,giving the final 2D（Sn3S7^2-）n layer of（6,3） network.The layers are stacked along the c axis so that 24-membered ring channels are generated,in which the organic cations are accommodated.The compound crystallizes in monoclinic,space group C2/c,with a=23.052（3）,b=13.4039（12）,c=18.412（2）A,β=120.112（4）°,V=4921.3（9）A^3,C13H28N2S7Sn3,Mr=792.86,Z=8,Dc=2.140 g/cm^3,F（000）=3056,μ=3.619 mm^-1,the final R=0.0488 and wR=0.1125 for 4607 observed reflections with I〉2σ（I）.

Three-Dimensional Dynamic Based Borrowing Scheme for Wireless Cellular Networks

Mobility metrics of wireless networks such as link availability, number of neighboring nodes, link duration, link state, and link stability make it difficult to provide a node with quality of services guarantee. In previous research on Quality of Service (QoS) for cellular networks especially for handling handoff connections, the design was based on a flat 2D hexagon cells. However, in reality Base Station antenna coverage is in a 3D space and there exists a blind spot;the area which is just above and bellow the radiated antenna. In this paper we introduce the concept of Blind Spot (BS) in which there is no signals to initiate a call or accepting a handoff one. In BS, the signal power equal zero. Even if there is enough bandwidth to initiate or accept a handoff call, it will be blocked or dropped respectively. We present an implementation of Static Borrowing Scheme (SBS) and we extend the dynamic-rate based borrowing scheme [1] into 3-Dimentional structure and call it 3-Dimensional Dynamic Based Borrowing Scheme (3D DBBS). The proposed new technique for resource sharing is to ensure the continuity for both originating and handoff connections in 3-D cellular networks based on Dynamic-Based Borrowing Scheme (3D BBS). This technique aims to minimize the blocking probability of the originating calls by minimizing the dropping probability of the handoff requests and maximizing the channel utilization. The results revealed that 3D DBBS outperformed the static based schemes by 5% on average even when the blind spot of the base station antenna is taken into consideration. When moving to a 3D space, the results of the simulation showed the 3D DBBS outperformed the static scheme by 2% on average. As a result, considering nodes in a 3D space will have better QoS guarantee as the blocking and dropping probabilities are decreased. Thus, the bandwidth utilization is increased.

RNA structure prediction:Progress and perspective

Many recent exciting discoveries have revealed the versatility of RNAs and their importance in a variety of cellular functions which are strongly coupled to RNA structures. To understand the functions of RNAs, some structure prediction models have been developed in recent years. In this review, the progress in computational models for RNA structure prediction is introduced and the distinguishing features of many outstanding algorithms are discussed, emphasizing three- dimensional （3D） structure prediction. A promising coarse-grained model for predicting RNA 3D structure, stability and salt effect is also introduced briefly. Finally, we discuss the major challenges in the RNA 3D structure modeling.

Microstructures and properties of Cu/Ag(Invar) composites fabricated by powder metallurgy

The Ag(Invar)composite powder prepared by ball milling was used to fabricate the Cu/Ag(Invar)composites.Microstructures and properties of the composites were studied after sintering and thermo-mechanical treatment.The results indicatethat during ball milling,micro-forging weld and work-hardening fracture result in that the average particle size of the Ag(Invar)powder increases rapidly at first,and then decreases sharply,finally tends to be constant.Compared with the Cu/Invar ones,thesinterability of the composites is greatly improved,resulting in that the pores in them are smaller in amount and size.After thethermo-mechanical treatment,the Cu/Ag(Invar)composites are nearly fully dense with the optimum phase composition and elementdistribution.More importantly,Cu and the Invar alloy in the composites distribute continuously in a three-dimensional(3D)networkstructure.Cu/Invar interface diffusion is effectively inhibited by the Ag barrier layer,leading to a great improvement of themechanical and thermal properties of the Cu/Ag(Invar)composites.

Static dissolution-induced 3D pore network modification and its impact on critical pore attributes of carbonate rocks

To determine the effect of dissolution on pore network development in carbonate rocks, dissolution experiments, X-Ray microtomography, and thin section analysis were conducted on argillaceous limestone and grain limestone samples at different temperatures and constant pH, HCl concentration. The relationship between Ca^(2+) concentration and time was revealed through the experiments; pore size distribution before and after dissolution indicate that there is no correlation between the temperature and pore size variation, but pore size variation in grain limestone is more significant, indicating that the variation is mainly controlled by the heterogeneity of the rock itself(initial porosity and permeability) and the abundance of unstable minerals(related to crystal shape, size and mineral type). At different temperatures, the two kinds of carbonate rocks had very small variation in pore throat radius from 0.003 mm to 0.040 mm, which is 1.3 to 3.5 times more, 1.7 on average of the original pore throat radius. Their pore throat length varied from 0.05 mm to 0.35 mm. The minor changes in the pore throat radius, length and connectivity brought big changes to permeability of up to 1 000×10^(-3) μm^2.

Behavior recognition algorithm based on the improved R3D and LSTM network fusion

Because behavior recognition is based on video frame sequences,this paper proposes a behavior recognition algorithm that combines 3D residual convolutional neural network(R3D)and long short-term memory(LSTM).First,the residual module is extended to three dimensions,which can extract features in the time and space domain at the same time.Second,by changing the size of the pooling layer window the integrity of the time domain features is preserved,at the same time,in order to overcome the difficulty of network training and over-fitting problems,the batch normalization(BN)layer and the dropout layer are added.After that,because the global average pooling layer(GAP)is affected by the size of the feature map,the network cannot be further deepened,so the convolution layer and maxpool layer are added to the R3D network.Finally,because LSTM has the ability to memorize information and can extract more abstract timing features,the LSTM network is introduced into the R3D network.Experimental results show that the R3D+LSTM network achieves 91%recognition rate on the UCF-101 dataset.

A NEW APPROACH TO MANUFACTURING 3D WOVEN PREFORMS USED FOR STRUCTURAL COMPOSITES

The manufacturing of three-dimensional textile preforms used for composites started to re-ceive much attention in the last decade.The major barriers to accelerating the transition from thelamination of two-dimensional fabrics to manufacturing integral three-dimensional near-netshaped textile preforms are high cost and database deficiency.To reduce the cost of weaving three-dimensional preforms,and make full use of the potential of conventional looms,a rig was designedwhich can convert two-dimensional woven fabric to particular three-dimensional preforms wherethe yarn is orientated in the directions of maximum stress.

Synthesis and Structure of Bis[2,6-bis(2-pyridylamino)pyridinium] Tetrachlorocadmiumate(II)

The title compound （H3tpda）2[CdCl4] （H2tpda = 2,6-bis（2-pyridylamino）pyridi-ne） was synthesized by the reaction of CdCl2 with H2tpda in methanol under acidic condition. Singlecrystal X-ray analysis reveals that the compound crystallizes in monoclinic, space group P21/n with a = 13.377（3）, b = 16.978（3）, c = 14.328（3） A, β = 94.75（3）°, V = 3243.1（11） A^3, Z = 4, De = 1.603 g/cm^3,μ = 1.042 mm^-1, F（000） = 1576, C30H28CdCl4N10, Mr = 782.82, T = 291（2） K, R = 0.0433 and wR = 0.0848 for observed 4554 reflections with I 〉 2σ（I）. The cadmium（Ⅱ） atom in the complex anion is tetrahedrally coordinated by four chlorine atoms, whereas, in each [H3tpda]＋ cation, one pyridyl nitrogen is protonated. A 3D network is formed by multiple intermolecular hydrogen bonds between the cations and anions as well as π-π interactions among the pyridyl rings.

A New 3D Supramolecular Network Formed by [Zn_3(2,6-Pyridinedicarboxylate)_3Cl_4]^(4-)and 4-Carboxypyridinium

A new compound [Zn3（C7NO4H3）3Cl4]·[C6NO2H6]4·4H2O （I） has been synthesized and structurally characterized by X-ray crystallography.It crystallizes in monoclinic,space group C2/c with a=16.9018（14）,b=12.6902（10）,c=25.1170（2）,β=90.54°,V=5387.0（8）3,Z=4,Zn3C45H41Cl4N7O24,Mr=1401.76,Dc=1.728 g/cm3,F（000）=2840,μ（MoKa）=1.615 mm-1,the R= 0.0758 and wR=0.2060 for 3468 observed reflections （I 〉 2σ（I））.Analysis of single-crystal X-ray diffraction data shows that compound I displays an interesting example of 3D supramolecular networks with perfect neutral and ionic hydrogen bonding array.

Numerical analysis of the failure process of soil-rock mixtures through computed tomography and PFC3D models

Soil-rock mixture （SRM） is a unique type of geomaterial characterized by a heterogeneous composition and a complicated structure. It is intractable for the continuum-based soil and rock mechanics theories to accurately characterize and predict the SRM＇s mechanical properties. This study reports a novel numerical method incorporating microfocus computed tomography and PFC3D codes to probe the deformation and failure processes of SRM. The three-dimensional （3D） PFC models that represent the SRM＇s complex structures were built. By simulating the entire failure process in PFC3D, the SRM＇s strength, elastic modulus and crack growth were obtained. The influence of rock ratios on the SRM＇s strength, deformation and failure processes, as well as its internal mesoscale mechanism, were analyzed. By comparing simulation results with experimental data, it was verified that the 3D PFC models were in good agreement with SRM＇s real structure and the SRM＇s compression process, deformation and failure patterns; its intrinsic mesomechanism can be effectively analyzed based on such 3D PFC models.

Construction and visualization of 3D vacant place model

The method of building 3D model was discussed at first. Aiming at the feature of mine vacant place,a method to build the 3D vacant place model based on multi TIN (triangular irregular network) was put forward, and the data structure and visualization of vacant place were discussed. Then some crucial technologies of realizing function in 3D-GIS were proposed. In addition,the software about special 3D mapping and assaying was introduced.

3D Modeling and Simulation of Fancy Fabrics in Weft Knitting

Weft knitted fancy fabrics are widely used in knitted garment design. Due to the complexity of the structures, their modeling and simulation needs to be solved in three-dimensional (3D) CAD developments. In this paper, 3D loop geometrical models of weft knitted fancy structures, including tuck stitch, jacquard stitch, transfer stitch and fleecy stitch, were developed based on an improved model of plain loop, and their central axes as some 3D space curves were achieved by using Non-Uniform Rational B-Splines (NURBS). The 3D visual simulation programme was written in C++ programming language using OpenGL, which was a function library of 3D graphics. Some examples of weft knitted fancy fabrics were generated and practical application of 3D simulation was discussed.