Hydrophilic bi-functional B-doped g-C_(3)N_(4) hierarchical architecture for excellent photocatalytic H_(2)O_(2) production and photoelectrochemical water splitting

Graphitic carbon nitride(g-C_(3)N_(4))has attracted great interest in photocatalysis and photoelectrocatalysis.However,their poor hydrophilicity poses a great challenge for their applications in aqueous environment.Here,we demonstrate synthesis of a hydrophilic bi-functional hierarchical architecture by the assembly of B-doped g-C_(3)N_(4)nanoplatelets.Such hierarchical B-doped g-C_(3)N_(4)material enables full utilization of their highly enhanced visible light absorption and photogenerated carrier separation in aqueous medium,leading to an excellent photocatalytic H_(2)O_(2)production rate of 4240.3μM g^(-1)h^(-1),2.84,2.64 and 2.13 times higher than that of the bulk g-C_(3)N_(4),g-C_(3)N_(4)nanoplatelets and bulk B doped g-C_(3)N_(4),respectively.Photoanodes based on these hierarchical architectures can generate an unprecedented photocurrent density of 1.72 m A cm^(-2)at 1.23 V under AM 1.5 G illumination for photoelectrochemical water splitting.This work makes a fundamental improvement towards large-scale exploitation of highly active,hydrophilic and stable metal-free g-C_(3)N_(4)photocatalysts for various practical applications.

QoS-Guaranteed Secure Multicast Routing Protocol for Satellite IP Networks Using Hierarchical Architecture

Most recent satellite network research has focused on providing routing services without considering security. In this paper, for the sake of better global coverage, we introduce a novel triple-layered satellite network architecture including Geostationary Earth Orbit (GEO), Highly Elliptical Orbit (HEO), and Low Earth Orbit (LEO) satellite layers, which provides the near-global coverage with 24 hour uninterrupted over the areas varying from 75° S to 90° N. On the basis of the hierarchical architecture, we propose a QoS-guaranteed secure multicast routing protocol (QGSMRP) for satellite IP networks using the logical location concept to isolate the mobility of LEO and HEO satellites. In QGSMRP, we employ the asymmetric cryptography to secure the control messages via the pairwise key pre-distribution, and present a least cost tree (LCT) strategy to construct the multicast tree under the condition that the QoS constraints are guaranteed, aiming to minimize the tree cost. Simulation results show that the performance benefits of the proposed QGSMRP in terms of the end-to-end tree delay, the tree cost, and the failure ratio of multicasting connections by comparison with the conventional shortest path tree (SPT) strategy.

Hydrothermal Synthesis and Luminescent Properties of Flowerlike Zn_2GeO_4 and Mn^(2+)-Doped Zn_2GeO_4 Hierarchical Architectures

Three-dimensional（3D） flowerlike hierarchical Zn2GeO4 and Mn2＋-doped Zn2GeO4 microstructures have been prepared by a facile hydrothermal approach. X-Ray diffraction（XRD）, field emission scanning electron micro-scopy（FESEM）, transmission electron microscopy（TEM） and photoluminescence（PL） spectrometry were employed to characterize the samples. Such flowerlike hierarchical Zn2GeO4 microstructures with an average diameter of 3―4 μm were found to be constructed by abundant single crystalline nanorods of about 90 nm in diameter. The luminescent properties of Zn2GeO4：xMn phosphors with different contents of Mn2＋ as an activator were investigated. The Mn2＋-doped samples showed green luminescence corresponding to the d-d transition of Mn2＋ under the irradiation of UV light. The red shift（from 531 nm to 538 nm） in λem with increasing Mn2＋ content was observed in the luminescent spectra, which should be attributed to a weak crystal field because of the substitution of Zn2＋ by Mn2＋ at a distorted tetrahedral lattice site.

Design and evaluation of a hierarchical control architecture for an autonomous underwater vehicle

This paper researches on a kind of control architecture for autonomous underwater vehicle (AUV). After describing the hybrid property of the AUV control system, we present the hierarchical AUV control architecture. The architecture is organized in three layers: mission layer, task layer and execution layer. State supervisor and task coordinator are two key modules handling discrete events, so we describe these two modules in detail. Finally, we carried out a series of tests to verify this architecture. The test results show that the AUV can perform autonomous missions effectively and safely. We can conclude the control architecture is valid and practical.

Multi-Layer Tree Hierarchical Architecture Based on Web Service

To solve the problem of the information share and services integration in population information system, we propose a multi-layer tree hierarchical architecture. The command （Web Service Call） is recursively muhicast from top layer of tree to bottom layer of tree and statistical data are gatbered from bottom layer to top layer. We implemented the architecture by using Web Services technology. In our implementation, client program is the requestor of Web Services, and all leaf nodes of the last layer are only the provider of Web Services. For those nodes of intermediate layers, every node is not only the provider of Web Services, but also the dispatcher of Web Services. We take population census as an cxample to describe the working flow of the architecture.

An Energy-aware Hierarchical Architecture Design Scheme

Compared with the flat architecture in the design of sensor networks, the hierarchical architecture gains much attractive for the reason of scalability, management and energy efficiency. In order to distribute the energy evenly, nodes act the cluster head in some orders. The existing approaches don’t pay a critical attention to the overhead during the role rotations. And the duration of a round is a priori, which is very application-specific. An energy-aware hierarchical architecture design scheme is put forward in this paper, namely, Adaptive Minimum Rotational Cost (AMRC) cluster formation scheme. The decision of beginning a new round is made adaptively by the cluster head itself. It combines the dynamic and static advantages in the clustering architecture. The simulation results demonstrate AMRC outperforms some other clustering protocols in many aspects.

Process Mining Discovery Techniques for Software Architecture Lightweight Evaluation Framework

This research recognizes the limitation and challenges of adaptingand applying Process Mining as a powerful tool and technique in theHypothetical Software Architecture (SA) Evaluation Framework with thefeatures and factors of lightweightness. Process mining deals with the largescalecomplexity of security and performance analysis, which are the goalsof SA evaluation frameworks. As a result of these conjectures, all ProcessMining researches in the realm of SA are thoroughly reviewed, and ninechallenges for Process Mining Adaption are recognized. Process mining isembedded in the framework and to boost the quality of the SA model forfurther analysis, the framework nominates architectural discovery algorithmsFlower, Alpha, Integer Linear Programming (ILP), Heuristic, and Inductiveand compares them vs. twelve quality criteria. Finally, the framework’s testingon three case studies approves the feasibility of applying process mining toarchitectural evaluation. The extraction of the SA model is also done by thebest model discovery algorithm, which is selected by intensive benchmarkingin this research. This research presents case studies of SA in service-oriented,Pipe and Filter, and component-based styles, modeled and simulated byHierarchical Colored Petri Net techniques based on the cases’ documentation.Processminingwithin this framework dealswith the system’s log files obtainedfrom SA simulation. Applying process mining is challenging, especially for aSA evaluation framework, as it has not been done yet. The research recognizesthe problems of process mining adaption to a hypothetical lightweightSA evaluation framework and addresses these problems during the solutiondevelopment.

3D Hierarchical Co–Al Layered Double Hydroxides with Long-Term Stabilities and High Rate Performances in Supercapacitors

Three-dimensional(3D) flower-like Co–Al layered double hydroxide(Co–Al-LDH) architectures composed of atomically thin nanosheets were successfully synthesized via a hydrothermal method in a mixed solvent of water and butyl alcohol. Owing to the unique hierarchical structure and modification by butyl alcohol, the electrochemical stability and the charge/mass transport of the Co–Al-LDHs was improved. When used in supercapacitors, the obtained Co–Al-LDHs deliver a high specific capacitance of 838 Fg^(-1) at a current density of 1 Ag^(-1)and excellent rate performance(753 Fg^(-1) at 30 Ag^(-1) and 677 Fg^(-1) at 100 Ag^(-1)), as well as excellent cycling stability with 95% retention of the initial capacitance even after 20,000 cycles at a current density of 5 Ag^(-1). This work provides a promising alternative strategy to enhance the electrochemical properties of supercapacitors.

Domain-Oriented Software Defined Computing Architecture

With the introduction of software defined hardware by DARPA Electronics Resurgence Initiative,software definition will be the basic attribute of information system.Benefiting from boundary certainty and algorithm aggregation of domain applications,domain-oriented computing architecture has become the technical direction that considers the high flexibility and efficiency of information system.Aiming at the characteristics of data-intensive computing in different scenarios such as Internet of Things(IoT),big data,artificial intelligence(AI),this paper presents a domain-oriented software defined computing architecture,discusses the hierarchical interconnection structure,hybrid granularity computing element and its computational kernel extraction method,finally proves the flexibility and high efficiency of this architecture by experimental comparison.

Confinement of sulfur-doped NiO nanoparticles into N-doped carbon nanotube/nanofiber-coupled hierarchical branched superstructures:Electronic modulation by anion doping boosts oxygen evolution electrocatalysis

The search for non-precious and efficient electrocatalysts towards the oxygen evolution reaction(OER)is of vital importance for the future advancement of multifarious renewable energy conversion/storage technologies.Electronic modulation via heteroatom doping is recognized as one of the most forceful leverages to enhance the electrocatalytic activity.Herein,we demonstrate a delicate strategy for the in-situ confinement of S-doped Ni O nanoparticles into N-doped carbon nanotube/nanofiber-coupled hierarchical branched superstructures(labeled as S-Ni O@N-C NT/NFs).The developed strategy simultaneously combines enhanced thermodynamics via electronic regulation with accelerated kinetics via nanoarchitectonics.The S-doping into Ni O lattice and the 1 D/1 D-integrated hierarchical branched carbon substrate confer the resultant S-Ni O@N-C NT/NFs with regulated electronic configuration,enriched oxygen vacancies,convenient mass diffusion pathways and superior architectural robustness.Thereby,the SNi O@N-C NT/NFs display outstanding OER properties with an overpotential of 277 m V at 10 m A cm^(-2)and impressive long-term durability in KOH medium.Density functional theory(DFT)calculations further corroborate that introducing S-dopant significantly enhances the interaction with key oxygenate intermediates and narrow the band gap.More encouragingly,a rechargeable Zn-air battery using an air-cathode of Pt/C+S-Ni O@N-C NT/NFs exhibits a lower charge voltage and preferable cycling stability in comparison with the commercial Pt/C+Ru O_(2)counterpart.This study highlighting the concurrent consideration of electronic regulation,architectural design and nanocarbon hybridization may shed light on the future exploration of economical and efficient electrocatalysts.

Hierarchical Spectrum Sharing Networks

A spectrum heterogeneity analysis in the cognitive radio network is conducted in this paper. Subsequently,a spectrum-heterogeneity-based hierarchical spectrum sharing(HSS) network for cognitive radio is proposed.The corresponding method of classifying available spectrums and communication based on the proposed architecture is also presented. Based on the above network architecture,we propose a reference protocol architecture.Research on these protocol function blocks,such as spectrum sensing,spectrum manager,and so on,is conducted. Numerical results show that HSS can provide a considerable extension to available spectrums so that the spectral utility may be further improved.

Fabrication of Stable Superhydrophobic Cupric Hydroxide Surface with Hierarchical Structure on Copper Substrate

Cupric hydroxide films with a new hierarchical architecture consisting of beautiful nanotubes and nanoflowers were directly fabricated on copper substrate via a solution-immersion process at a constant temperature of 23 ℃. Stable superhydrophobic Cu（OH）2 surface was obtained after Cu（OH）2 films were modified with hydrolyzed 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane （CsH4CI3F13Si, FOTMS）. The surface morphology and composition of the film were studied using scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and X-ray photoelectron spectroscopy （XPS）, respectively. Result shows that the surface of Cu（OH）2 films directly grown on copper substrate was hydrophilic, whereas the modified Cu（OH）2 films exhibited the superhydrophobicity with a water contact angle （CA） of about 160.8°, as well as a small sliding angle （SA） of about 1°. The special hierarchical structure, along with the slow surface energy leads to the high superhydrophobicity of the surface.

Development of covalent-organic frameworks derived hierarchical porous hollow carbon spheres based LiOH composites for thermochemical heat storage

Under the joint assistance of its excellent storage strength, accessible long storage lifespan, and high heat utilization efficiency, salt hydrate-based thermochemical heat storage(THS) materials give renewable energy an important outlet to alleviate the pressure of underutilization. Herein, an activated hollow spherical carbon(AHSC) with hierarchical porous architectures converted from covalent-organic frameworks(COFs) is constructed and utilized as the supporting matrix for Li OH.THS composite material for the first time. The obtained Li/AHSC_(3) composites have distinguished hydration performance while manifesting impressive storage ability up to 1916.4 k J kg^(-1)with low operating temperature stemming from the collective effect of the void spherical framework, multimodal porosity, and high surface area of AHSC3. And the Li/AHSC3-40 composite with evidently progressed thermal conductivity is capable of realizing 94.5% heat preservation after twenty-five adsorption-desorption cycles, exhibiting its eminent cyclability and great heat transfer performance. This study not only brings new hope for overcoming the underutilization of low-grade heat but also may enlighten new ideas for enriching the application scenarios of COFs-derived carbonaceous materials.

A Tile Logic Based Approach for Software Architecture Description Analysis

A main advantage of Architecture Description Languages (ADL) is their aptitude to facilitate formal analysis and verification of complex software architectures. Since some researchers try to extend them by new techniques, we show in this paper how the use of tile logic as extension of rewriting logic can enforce the ability of existing ADL formalisms to cope with hierarchy and composition features which are more and more present in such software architectures. In order to cover ADL key and generic concepts, our approach is explained through LfP (Language for rapid Prototyping) as ADL offering the possibility to specify the hierarchical behaviour of software components. Then, our contribution goal is to exploit a suitable logic that allows reasoning naturally about software system behaviour, possibly hierarchical and modular, in terms of its basic components and their interactions.

A Hierarchal Clustered Based Proactive Caching in NDN-Based Vehicular Network

An Information-Centric Network(ICN)provides a promising paradigm for the upcoming internet architecture,which will struggle with steady growth in data and changes in accessmodels.Various ICN architectures have been designed,including Named Data Networking(NDN),which is designed around content delivery instead of hosts.As data is the central part of the network.Therefore,NDN was developed to get rid of the dependency on IP addresses and provide content effectively.Mobility is one of the major research dimensions for this upcoming internet architecture.Some research has been carried out to solve the mobility issues,but it still has problems like handover delay and packet loss ratio during real-time video streaming in the case of consumer and producer mobility.To solve this issue,an efficient hierarchical Cluster Base Proactive Caching for Device Mobility Management(CB-PC-DMM)in NDN Vehicular Networks(NDN-VN)is proposed,through which the consumer receives the contents proactively after handover during the mobility of the consumer.When a consumer moves to the next destination,a handover interest is sent to the connected router,then the router multicasts the consumer’s desired data packet to the next hop of neighboring routers.Thus,once the handover process is completed,consumers can easily get the content to the newly connected router.A CB-PCDMM in NDN-VN is proposed that improves the packet delivery ratio and reduces the handover delay aswell as cluster overhead.Moreover,the intra and inter-domain handover handling procedures in CB-PC-DMM for NDN-VN have been described.For the validation of our proposed scheme,MATLAB simulations are conducted.The simulation results show that our proposed scheme reduces the handover delay and increases the consumer’s interest satisfaction ratio.The proposed scheme is compared with the existing stateof-the-art schemes,and the total percentage of handover delays is decreased by up to 0.1632%,0.3267%,2.3437%,2.3255%,and 3.7313%at the mobility speeds of 5 m/s,10 m/s,15 m/s,20 m/s,and 25 m/s,and the efficiency of the packet delivery ratio is improved by up to 1.2048%,5.0632%,6.4935%,6.943%,and 8.4507%.Furthermore,the simulation results of our proposed scheme show better efficiency in terms of Packet Delivery Ratio(PDR)from 0.071 to 0.077 and a decrease in the handover delay from 0.1334 to 0.129.

面向未知环境探索的分层架构路径规划算法

为实现无人平台在未知环境下的高效路径探索,该文提出了一种以“感知-规划-控制”分层架构为基础的路径规划算法。在感知层通过Cartographer建图算法实时构建未知环境的二维栅格地图。在规划层,通过Canny边缘检测、基于密度的聚类算法、效能函数评估选择最佳探索目标点,并在规划的效能函数中引入探索方向延续性概念,克服了传统路径规划反复探索已知环境的难题。在控制层,通过概率路线图算法规划从当前位姿到目标点的最短路径,并通过纯跟踪算法和向量直方图算法实现了路径无碰撞跟踪。3种典型环境下的仿真实验表明,所提出的算法在不同环境下均具有较高的探索效率和完成度。

Hierarchical Reinforcement Learning Adversarial Algorithm Against Opponent with Fixed Offensive Strategy

Based on option-critic algorithm,a new adversarial algorithm named deterministic policy network with option architecture is proposed to improve agent's performance against opponent with fixed offensive algorithm.An option network is introduced in upper level design,which can generate activated signal from defensive and of-fensive strategies according to temporary situation.Then the lower level executive layer can figure out interactive action with guidance of activated signal,and the value of both activated signal and interactive action is evaluated by critic structure together.This method could release requirement of semi Markov decision process effectively and eventually simplified network structure by eliminating termination possibility layer.According to the result of experiment,it is proved that new algorithm switches strategy style between offensive and defensive ones neatly and acquires more reward from environment than classical deep deterministic policy gradient algorithm does.

Design,fabrication,and characterization of hierarchical mechanical metamaterials

Natural mechanical materials,such as bamboo and bone,often exhibit superior specific mechanical properties due to their hierarchical porous architectures.Using the principle of hierarchy as inspiration can facilitate the development of hierarchical mechanical metamaterials(HMMs)across multiple length scales via 3D printing.In this work,we propose self-similar HMMs that combine octet-truss(OCT)architecture as the first and second orders,with cubic architecture as the third or more orders.These HMMs were fabricated using stereolithography 3D printing,with the length sizes ranging from approximately 200µm to the centimeter scale.The compressive stress–strain behaviors of HMMs exhibit a zigzag characteristic,and the toughness and energy absorption can be significantly enhanced by the hierarchical architecture.The compressive moduli are comparable to that of natural materials,and the strengths are superior to that of most polymer/metal foams,alumina hollow/carbon lattices,and other natural materials.Furthermore,the flexural stress–strain curves exhibit a nonlinear behavior,which can be attributed to the hierarchical architecture and local damage propagation.The relatively high mechanical properties can be attributed to the synergistic effect of the stretch-dominated OCT architecture and the bending-dominated cube architecture.Lastly,an ultralight HMM-integrated unmanned aerial vehicle(HMM-UAV)was successfully designed and printed.The HMM-UAV is~85%lighter than its bulk counterpart,remarkably extending the flight duration time(~53%).This work not only provides an effective design strategy for HMMs but also further expands the application benchmark of HMMs.

基于SOA理念的新型软件定义汽车电子电气架构

为了适应软件定义汽车发展新趋势,促进汽车电子电气架构变革升级,阐述了软件定义汽车的驱动关键特征,深入研究了未来汽车新型电子电气硬件架构,探讨了面向服务软件架构(Service-Oriented Architecture,SOA)设计理念、分层模型和部署平台。在此基础上,搭建了软件定义汽车整体技术框架,并对未来软件定义汽车开发新流程及应用场景进行了探讨,以期为未来汽车全新电子电气架构设计提供技术参考。