An Experimental Low-Cost, Low-Data-Rate Rapid Structural Assessment Network

In this paper, we present the design, implementation, and experimental evaluation of a wireless sensor network for real-time structural ldquohealthrdquo monitoring. We use simple custom-built gages to detect cracks in critical structural elements. The main data reports require no structural analysis for interpretation, have a low data rate, and are naturally resilient to loss. We show how a variety of low-cost, off-the-shelf data acquisition/communication devices can be used to support remote monitoring by a control center. The heterogeneous hardware is accommodated by the use of open technology standards and a software architecture that is portable, modular, and highly configurable. We present an experimental evaluation of our structural-assessment network done using a full-scale three-story reinforced concrete building that was tested under lateral forces emulating forces induced by earthquakes. Our results show that a set of 12 strategically positioned sensors achieved a 100% detection rate for cracks crossing sensors and a zero false-alarm rate (in the sense that all signals exceeding a preset threshold were traced to cracks exceeding a specified total width).     

Software-Defined Space-Air-Ground Integrated Network Architecture with the Multi-Layer Satellite Backbone Network

Under the background of the rapid development of ground mobile communication, the advantages of high coverage, survivability, and flexibility of satellite communication provide air support to the construction of space information network. According to the requirements of the future space information communication, a software-defined Space-Air-Ground Integrated network architecture was proposed. It consisted of layered structure satellite backbone network, deep space communication network, the stratosphere communication network and the ground network. The SpaceAir-Ground Integrated network was supported by the satellite backbone network. It provided data relay for the missions such as deep space exploration and controlled the deep-space spacecraft when needed. In addition, it safeguarded the anti-destructibility of stratospheric communication and assisted the stratosphere to supplement ground network communication. In this paper, algorithm requirements of the congestion control and routing of satellite backbone protocols for heterogeneous users’ services were proposed. The algorithm requirements of distinguishing different service objects for the deep space communication and stratospheric communication network protocols were described. Considering the realistic demand for the dynamic coverage of the satellite backbone network and node cost, the multi-layer satellite backbone network architecture was constructed. On this basis, the proposed Software-defined Space-Air-Ground Integrated network architecture could be built as a large, scalable and efficient communication network that could be integrated into space, air, and ground.     

Energy-efficient directional routing between partitioned actors in wireless sensor and actor networks

Actor?actor communication is an important part of the functioning of wireless sensor?actor networks and enables the actor nodes to take coordinated action on a given event. Owing to various reasons such as actor mobility and low actor density, the actor network tends to get partitioned. The authors propose to use the underlying sensor nodes, which are more densely deployed, to heal these partitions. In order to maximise the utilisation of the limited energy available with the sensor nodes, a new routing protocol for actor?actor communication using directional antennas on the actor nodes is proposed. The authors contribution is threefold. First, using simulations they show that the problem of partitioning in the actor networks is significant and propose an architecture with directional antennas on actor nodes and sensor bridges to heal these partitions. Second, they identify the routing problem for this architecture based on a theoretical framework and propose centralised as well as distributed solutions to it. Third, they develop a routing protocol based on the distributed solution and show, using network simulations, that the proposed protocol not only heals the network partitions successfully, but also achieves high throughput and fairness across different flows, in addition to maximising the network lifetime.     

Building blocks of e-commerce

This article examines the architecture of e-commerce as a set of layers, each supporting the one above it. The layers have clean interfaces, that is, they can be designed independently. We present an architecture with six layers. The lowest layer consists of a physical communication network such as local area network or public switched telephone networks. The next higher layer is the logical layer which describes the protocol used to interconnect communication systems to create internet, intranet and extranet. The services provided over the internet infrastructure, namely, e-mail, world wide web etc., are described in what is called network services layer. It is essential to ensure security of messages, documents etc., which are transmitted using network services. The messaging layer is thus concerned with encryption methods, both private and public key encryption and their applications. We call the layer above this the middleman service, which is concerned with value-added services offered by intermediaries to enable payment for services received, certify digital signatures, safely transmit documents and provide information on behalf of companies. The topmost layer is the application layer which users see. The major applications are customer-to-business (C2B) e-commerce, business-to-business (B2B) e-commerce, customer-to-consumer (C2C) e-commerce etc. We briefly explain these modes.     

Two-bounce optical arbitrary permutation network

The two-bounce free-space arbitrary interconnection architecture is presented. It results from a series of three-dimensional topological transformations to the Benes network, the minimum rearrangeable nonblocking network. Although functionally equivalent to the Benes network, it requires only two stages of global (spanning multiple chips) optical interconnections. The remaining stages of the modified Benes interconnection network are local and are implemented electronically (on individual chips). The two-bounce network is optimal in the sense that it retains the Benes minimum number of electronic switching resources yet also minimizes the number of optical links needed for global interconnection. Despite the use of higher-order k-shuffle (k > 2) global optical interconnects, the number of 2 x 2 switching elements is identical to the two-shuffle Benes network: there is no need for k x k crossbar switches for local interconnection at each stage. An experimental validation of the two-bounce architecture is presented.     

卫星移动网络总体概念设计仿真

卫星移动网络是以卫星星座为基本物理架构，通过星际的通信链路形成覆盖全球的天基通信网络。它对社会发展、科技进步以及军队的信息化有着重大的推动作用。由于天网的移动性、通信的偶断性、接入的复杂性以及使用的综合性，都为研制提出了重大的挑战。有必要通过总体概念设计仿真，来进一步验证总体需求、总体方案、关键技术指标和研制的约束条件，形成科学的可行性报告。介绍了卫星移动网络的总体概念，设计了针对天网仿真的平台，并用实例获得卫星移动网络总体概念设计的仿真数据。     

A distributed measurement architecture for industrial applications

In this paper, a distributed digital measurement architecture for industrial applications is proposed. The architecture is arranged on three hierarchical communication levels: the fieldbus, the intranet, and the Internet. Particular attention has been paid to the lower level, the field level, implemented using a low-priced smart front-end. It is based on the H8/3048F Hitachi microcontroller and embodies a fieldbus interface (I/F). The same board can be linked to a VXIbus controller by means of a suitable register-based interface. The proposed network can embody a number of analog signal conditioning circuits, processor, and communication capabilities, to meet the industrial needs. We propose two applications of this distributed measurement architecture: the monitoring of power quality in an electrical distribution network and the management of a water distribution system. Experimental results showing the system performance are also included in the paper.     

Control of communication networks: welfare maximization and multipath transfers

We discuss control strategies for communication networks such as the Internet. We advocate the goal of welfare maximization as a paradigm for network resource allocation. We explore the application of this paradigm to the case of parallel network paths. We show that welfare maximization requires active balancing across paths by data sources, and potentially requires implementation of novel transport protocols. However, the only requirement from the underlying 'network layer' is to expose the marginal congestion cost of network paths to the 'transport layer'. We further illustrate the versatility of the corresponding layered architecture by describing transport protocols with the following properties: they welfare maximization, each communication may use an arbitrary collection of paths, where paths may be from an overlay, and paths may be combined in series and parallel. We conclude by commenting on incentives, pricing and open problems.     

Mechanically induced structural changes during dynamic compression of engineered cartilaginous constructs can potentially explain increases in bulk mechanical properties

Several studies on chondrocyte-seeded hydrogels in bioreactor culture report increased mechanical properties of mechanically loaded constructs compared with unloaded free swelling controls despite no significant differences in biochemical composition. One possible explanation is that changes in the collagen architecture of dynamically compressed constructs lead to improved mechanical properties. Collagen molecules are incorporated locally into the extracellular matrix with individual stress-free configurations and orientations. In this study, we computationally investigated possible influences of loading on the collagen architecture in chondrocyte-seeded hydrogels and their resulting mechanical properties. Both the collagen orientation and its stress-free configuration were hypothesized to depend on the local mechanical environment. Reorientation of the collagen network alone in response to dynamic compression leads to a prediction of constructs with lower compressive properties. In contrast, remodelling of the stress-free configuration of the collagen fibres was predicted to result in a more compacted tissue with higher swelling pressures and an altered pre-stressed state within the collagen network. Combining both mechanisms resulted in predictions of construct geometry and mechanical properties in agreement with experimental observations. This study provides support for the hypothesis that structural changes to the collagen network contribute to the enhanced mechanical properties of cartilaginous tissues engineered in bioreactors.     

IoT-based networking for humanoid robots

Abstract

In this paper, a new network communication approach, named real-time network (RTNET), is designed and implemented for humanoid robots. The proposed five network objects – alarm, condition, message, mail, and file are used to represent the task and priority of the communication data. Compared to the existing protocols, the network scheduling mechanism of RTNET arranges, more efficiently, the priority and flow control of the five network communication objects to meet real-time requirements for the limited bandwidth of the local area network. RTNET can be further integrated with other protocols, such as EtherCAT or controller area networks (CAN Bus) for local control systems, e.g. robot arms, to improve the communication mechanism. The RTNET can also be used over Ethernet to connect each subsystem and to exchange information among those systems. Also, an Internet of things (IoT) network structure based on RTNET is proposed in this paper. The information of each subsystems is collected through RTNET and users can access all components in the IoT network. In this paper, the concept of RTNET is presented and RTNET has been implemented on a National Taiwan University (NTU) humanoid robot control system with CAN Bus.     

Blockchain-based ubiquitous manufacturing: a secure and reliable cyber-physical system

With product customisation and emerging business opportunities, small and medium manufacturing enterprises (SMEs) must find ways to collaborate and share competency in a trustable manner to survive a turbulent market. Therefore, service industry turns to the manufacturing industry and SMEs migrate to cloud manufacturing (CM) and ubiquitous manufacturing. However, existing platforms use centralised networking, which suffers from security, scalability and big-data problems. In this paper, we propose a blockchain-based platform as a trustable network to eradicate third-party problems, which can improve the scalability, security and big-data problems for SMEs. Our proposed platform is developed based on a consortium blockchain which provides a peer-to-peer communication network between the end user and the service provider. We improve existing consensus mechanism and communication protocol based on a cyber-physical system (CPS), via an autonomous agent. Firstly, we provide a review of cloud manufacturing, ubiquitous manufacturing and blockchain-based manufacturing approaches by highlighting the main problems. Then, the proposed platform, blockchain ubiquitous manufacturing (BCUM), is explained, based on its architecture, consensus algorithm and CPS, with the help of autonomous agent communication. The proposed platform has been developed for 3D printing companies which are geographically distributed and tested based on network performance and three practical scenarios.     

Investigation of road network features and safety performance

The analysis of road network designs can provide useful information to transportation planners as they seek to improve the safety of road networks. The objectives of this study were to compare and define the effective road network indices and to analyze the relationship between road network structure and traffic safety at the level of the Traffic Analysis Zone (TAZ). One problem in comparing different road networks is establishing criteria that can be used to scale networks in terms of their structures. Based on data from Orange and Hillsborough Counties in Florida, road network structural properties within TAZs were scaled using 3 indices: Closeness Centrality, Betweenness Centrality, and Meshedness Coefficient. The Meshedness Coefficient performed best in capturing the structural features of the road network. Bayesian Conditional Autoregressive (CAR) models were developed to assess the safety of various network configurations as measured by total crashes, crashes on state roads, and crashes on local roads. The models’ results showed that crash frequencies on local roads were closely related to factors within the TAZs (e.g., zonal network structure, TAZ population), while crash frequencies on state roads were closely related to the road and traffic features of state roads. For the safety effects of different networks, the Grid type was associated with the highest frequency of crashes, followed by the Mixed type, the Loops & Lollipops type, and the Sparse type. This study shows that it is possible to develop a quantitative scale for structural properties of a road network, and to use that scale to calculate the relationships between network structural properties and safety.     

A parallel triangular decomposition algorithm on a workstation network with application to structural vibration analysis

This paper presents a parallel triangular decomposition algorithm for banded symmetric matrices and its application to structural vibration analysis, which gives high rates of parallel efficiency on a workstation network. In case of decomposition of a matrix with halfbandwidth 822, the working efficiency rate was 84% using a network of six workstations (SUN SparcStation 20s). The algorithm provides a high rate of working efficiency in parallel environment with local memory, even if the communication time is considerably longer than the operation time. As an application of the algorithm, a finite element (FE) system for structural vibration analysis with the parallel decomposition algorithm was developed on the above workstation network and a model with more than 100,000 degrees of freedom (DOFs) was successfully analyzed by the system. The computation time for the model with 10,752 DOFs and halfbandwidth 822 was 3,661 sec by the present parallel system, whereas the computation time by a single workstation was 14,335 sec.     

一种基于HLA/RTI的卫星组网仿真系统

设计了一种基于HLA/RTI的卫星组网仿真系统,在该系统中卫星节点、星间链路、卫星轨道和通信节点路由被划分为功能独立的联邦成员.这种结构具有良好的可扩展性,可适用于不同的卫星星座结构,同时可以适应不同的路由策略和各类空间通信链路模型.最后通过统计卫星组网网管报文响应时间验证了该仿真系统的可行性.卫星组网仿真系统为卫星组网的其他研究提供了仿真验证平台.     

基于RBF网络的步行式底盘内力计算优化方法

为了确定步行式底盘局部结构在作业时的最大受力状态,提出了一种基于RBF神经网络的两级优化模型求解方法,第一级优化模型用逐步二次规划法找到局部结构在给定位置参数下的最大受力状态,通过正交试验设计,利用RBF网络构造出局部结构界面最大受力状态与位置参数之间的非线性映射关系;第二级优化模型用GA求解RBF网络的最大值,并通过二分法不断缩小位置参数的搜索空间,提高RBF网络的逼近水平。研究表明,计算结果可为步行式底盘设计提供理论依据,该方法是解决复杂结构系统中非线性、多变量优化问题的有效手段。     

Modeling and detecting change in temporal networks via the degree corrected stochastic block model

In many applications, it is of interest to identify anomalous behavior within a dynamic interacting system. Such anomalous interactions are reflected by structural changes in the network representation of the system. We propose and investigate the use of the degree corrected stochastic block model (DCSBM) to model and monitor dynamic networks that undergo a significant structural change. We apply statistical process monitoring techniques to the estimated parameters of the DCSBM to identify significant structural changes in the network. We apply our surveillance strategy to a dynamic US Senate covoting network. We detect significant changes in the political network that reflect both times of cohesion and times of polarization among Republican and Democratic party members. Our analysis demonstrates that the DCSBM monitoring procedure effectively detects local and global structural changes in complex networks, providing useful insights into the modeled system. The DCSBM approach is an example of a general framework that combines parametric random graph models and statistical process monitoring techniques for network surveillance.     

基于申威异构众核处理器架构的模态并行算法

根据国产申威异构众核处理器架构特点,提出了一种结构有限元模态分层通信并行计算方法,对于提高国产申威异构众核分布式存储并行计算机下重大装备系统级模态分析的并行效率具有重要意义.该方法在分层通信策略和加速子空间迭代法的基础上构建了大规模模态分析并行计算体系,不仅实现了计算过程和数据通信的分层,有效提高了通信效率;而且实现了...     

Collaborative agents for production planning and scheduling (CAPPS): a challenge to develop a new software system architecture for manufacturing management in Japan

Considering the frequent changes in market needs, real-time production management will produce huge additional value for manufacturers. As scheduling of shop floor operations is a local and partial decision in enterprises, the distributed local scheduling problems should be integrated at the enterprise level. Since decisions at the shop floor are very valuable, the next generation of production management will be performed as a decentralized system. This paper proposes architecture for scheduling-intensive production management. In the architecture, referred to as collaborative agents for production planning and scheduling, system integration is only achieved by communication among agents, i.e. a system is composed of loose connections between agents. As an implementation method, the paper introduces a standard specification for the communications among agents. The specification is recommended by PSLX, the Japan-based consortium for production planning and scheduling. The paper also shows some emerging business models on scheduling-intensive production management.     

Transactive Demand Response Operation at the Grid Edge using the IEEE 2030.5 Standard

This paper presents a transactive demand response (TDR) scheme for a network of residential customers with generation assets that emphasizes interoperability within a transactive energy architecture. A complete laboratory-based implementation provides the first (to our knowledge) realization of a comprehensive TDR use case that is fully compliant with the Institute of Electrical and Electronics Engineers (IEEE) 2030.5 standard, which addresses interoperability within a cybersecure smart energy profile (SEP) context. Verification is provided by a full system integration with commercial hardware using Internet Protocol (IP)-based (local area network (LAN) and Wi-Fi) communication protocols and transport layer security (TLS) 1.2 cryptographic protocol, and validation is provided by emulation using extensive residential smart meter data. The demand response (DR) scheme is designed to accommodate privacy concerns, allows customers to select their DR compliance level, and provides incentives to maximize their participation. The proposed TDR scheme addresses privacy through the implementation of the SEP 2.0 messaging protocol between a transactive agent (TA) and home energy management system (HEMS) agents. Customer response is handled by a multi-input multi-output (MIMO) fuzzy controller that manages negotiation between the customer agent and the TA. We take a multi-agent system approach to neighborhood coordination, with the TA servicing multiple residences on a common transformer, and use a reward mechanism to maximize customer engagement during the event-based optimization. Based on a set of smart meter data acquired over an extended time period, we engage in multiple TDR scenarios, and demonstrate with a fully-functional IEEE 2030.5-compliant implementation that our scheme can reduce network peak power consumption by 22% under realistic conditions.     

Development of an E-maintenance System for a CNC System

Globalization and rapid growth of network technologies have changed the traditional patterns of device maintenance. E-maintenance has emerged and is widely used in many manufacturing systems. In this paper, a new architecture of an E-maintenance system is proposed, which consists of E-maintenance centre, embedded CNC gateway and CNG terminal. The E-maintenance centre provides the technical support and service for customers based on Internet and communication technologies. The embedded CNC gateway serves as an agent between the public and plant device network, and provides web-based access for the CNC system. A reconfigurable CNC terminal is highly desired in a signal measuring and analysing system, which is built on the top of component and software bus based models. Finally, the E-maintenance system for the CNC machine is implemented and the experiments show that the architecture of an E-maintenance system can effectively reduce the downtime of devices, the responding time of maintenance work, and increase both the quality and the productivity of enterprises.