Efficient Digital Twin Placement for Blockchain-Empowered Wireless Computing Power Network

As an open network architecture,Wireless Computing PowerNetworks(WCPN)pose newchallenges for achieving efficient and secure resource management in networks,because of issues such as insecure communication channels and untrusted device terminals.Blockchain,as a shared,immutable distributed ledger,provides a secure resource management solution for WCPN.However,integrating blockchain into WCPN faces challenges like device heterogeneity,monitoring communication states,and dynamic network nature.Whereas Digital Twins(DT)can accurately maintain digital models of physical entities through real-time data updates and self-learning,enabling continuous optimization of WCPN,improving synchronization performance,ensuring real-time accuracy,and supporting smooth operation of WCPN services.In this paper,we propose a DT for blockchain-empowered WCPN architecture that guarantees real-time data transmission between physical entities and digital models.We adopt an enumeration-based optimal placement algorithm(EOPA)and an improved simulated annealing-based near-optimal placement algorithm(ISAPA)to achieve minimum average DT synchronization latency under the constraint of DT error.Numerical results show that the proposed solution in this paper outperforms benchmarks in terms of average synchronization latency.

Ubiquitous Access Technology for Wireless Digital Home Networks

As an important branch of telecommunication technology, digital home networks have quickly developed in recent years. Although architecture of the digital home network based on telecommunication networks has been standardized in China, only wireless access is defined to be allowable. Therefore, it becomes the focus of further research how to establish a wireless digital home network. This article proposes the concept and shows the architecture of ubiquitous access for wireless digital home networks. Moreover, key technologies for ubiquitous access are discussed here, including cognitive radio, the concept of wireless Mesh, generic link transfer mechanism, Quality of Service (QoS) guarantee mechanism, Electromagnetic Compatibility (EMC) and coexistence of heterogeneous systems.

无线连接，轻松拍摄——Canon DIGITAL IXUS WIRELESS

崇尚自由是现代人的天性，注重生活品质的时尚人士更是如此，越来越多的无线工作方式将人们解放了出来，具有无线功能的时尚数码相机更是将自由和个性进行了充分的融合。

DIGITAL IXUS WIRELESS

Wi—Fi是wireless fidelity（无线保真）的缩写。支持Wi-Fi的产品，可以进行无线连接，实现数据在不同产品中的无线传输。IXUS WIRELESS内置Wi-Fi技术的四大应用。

A study of user experience in Tsinghua Wireless and Mobile Digital Library System(TWIMS)

Tsinghua University Library recently launched Tsinghua Wireless and Mobile Digital Library System(TWIMS) to meet users’ need for wireless access to library services.A survey of user experience about TWIMS was carried out for the purpose of studying its users’ behavior and their level of satisfaction about the system design and its various performance indicators. Based on our research findings, we concluded our research paper with a set of evaluative comments and suggestions. Those remarks are aimed at furthering the TWIMS’ functionality and reconstructing a more sensible questionnaire survey appertaining to the system users’ experience as well in the next phase of our extended research.

幽蓝的无线之风：佳能DIGITAL IXUS WIRELESS数码相机

第一眼看到佳能（Canon）这款DIGITAL IXUS WIRELESS之后感觉毫无特别之处，它和DIGITAL IXUS 55的外观基本一样，但这款机器的内涵在于它支持IEEE802.11b标准的无线传输功能，无需数据线就可以将这款产品和迅驰笔记本或其它无线产品相连。

异彩无线：佳能DIGITAL IXUS WIRELESS数码相机

摆脱线缆的束缚，寻求自由自在的数码空间，一直都是人们在应用消费电子产品时抱有的期望。面对渐渐升温的无线浪潮以及家庭娱乐空间的互动诉求，具备无线能力的数码终端成为了未来家庭用户首选方案。

Data compression of displacement fields in digital image correlation by non-integer quantization

To solve the real-time transmission problem of displacement fields in digital image correlation,two compression coding algorithms based on a discrete cosine transform(DCT)and discrete wavelet transform(DWT)are proposed.Based on the Joint Photographic Experts Group(JPEG)and JPEG 2000 standards,new non-integer and integer quantizations are proposed in the quantization procedure of compression algorithms.Displacement fields from real experiments were used to evaluate the compression ratio and computational time of the algorithm.The results show that the compression ratios of the DCT-based algorithm are mostly below 10%,which are much less than that of the DWT-based algorithm,and the computational speed is also significantly higher than that of the latter.These findings prove the algorithm s effectiveness in real-time displacement field wireless transmission.

Design and Implementation of An Active Multibeam Antenna System with 64 RF Channels and 256 Antenna Elements for Massive MIMO Application in 5G Wireless Communications

This paper focuses on the design and implementation of an active multibeam antenna system for massive MIMO applications in 5G wireless communications.The highly integrated active multibeam antenna system is designed and implemented at 5.8 GHz with 64 RF Channels and 256 antenna elements.The 64-channel highly integrated active multibeam antenna system provides a verification platform for digital beamforming algorithm and massive MIMO channel estimation for next generation wireless communications.

Design of intelligent detecting system based on wireless transmission

An intelligent detecting system based on wireless transmission is designed. Its hardware includes the card reading module, the wireless digital transmission module, the LCD module, the random password keyboard module and a 16×16 lattice word database based on e-Flash MM36SB020. Its software is a communication protocol between the central control computer and the entrance management base station. To resolve the conflicting problems occurred during the data transmission, a method of delaying time at random is proposed.

OvBNN authentication based on cooperative signature for wireless sensor networks

The universality of the application of wireless sensor networks( WSN) makes more attention be paid on the security problem. Node authentication is not only the basis of network security,but also the premise of key management and secure routing protocol. Although the signature mechanism based on symmetric encryption is high in energy efficiency,it is vulnerable to be attacked and there is a time delay during authentication. Traditional public key encryption mechanism with improvement in security brings in complex algorithm and costs much time,which is not suitable for WSN. In this paper,a signature authentication mechanism,an optimized variant Bellare Namprempre Neven( OvBNN) is presented to quickly complete the authentication by mutual cooperation between nodes so as to make the nodes use the intermediate calculation results of their neighbor nodes directly.Simulation results show that the proposed mechanism is superior to traditional authentication mechanisms both in energy consumption and authentication time.

Optimal Territorial Resources Placement for Multipurpose Wireless Services Using Genetic Algorithms

This paper presents a study for finding a solution to the placement of territorial resources for multipurpose wireless services considering also the restrictions imposed by the orography of the territory itself. To solve this problem genetic algorithms are used to identify sites where to place the resources for the optimal coverage of a given area. The used algorithm has demonstrated to be able to find optimal solutions in a variety of considered situations.

A Beamforming Technique Using Rotman Lens Antenna for Wireless Relay Networks

Rotman lens,which is a radio frequency beam-former that consists of multiple input and multiple output beam ports,can be used in industrial,scientific,and medical applications as a beam steering device.The input ports collect the signals to be propagated through the lens cavity toward the output ports before being transmitted by the antenna arrays to the destination in order to enhance the error performance by optimizing the overall signal to noise ratio(SNR).In this article,a low-cost Rotman lens antenna is designed and deployed to enhance the overall performance of the conventional cooperative communication systems without needing any additional power,extra time or frequency slots.In the suggested system,the smart Rotman lens antennas generate a beam steering in the direction of the destination to maximize the received SNR at the destination by applying the proposed optimal beamforming technique.The suggested optimal beamforming technique enjoys high diversity,as well as,low encoding and decoding complexity.Furthermore,we proved the advantages of our suggested strategy through both theoretical results and simulations using Monte Carlo runs.The Monte Carlo simulations show that the suggested strategy enjoys better error performance compared to the current state-of-the-art distributed multiantenna strategies.In addition,the bit error rate(BER)curves drawn from the analytical results are closely matching to those drawn from our conducted Monte Carlo simulations.

Design of on-demand wireless capsule endoscope

An on-demand wireless capsule endoscope with fulldigital and bidirectional communication is presented,aiming at fulfilling the requirements of micromation and micropower consumption of modern wireless endoscope.The proposed multifunctional operation and unique radio transmission system cuts down the power consumption efficiently and on-demand bidirectional communication in vitro improves the detection rate of focus.Meanwhile,gray dilatation is introduced in a bit plane that optimizes the distortion rate in the process of image recording and transmission.

基于LoRa通信的无线发射台信号智能监测技术研究

为实现大面积无线发射台信号覆盖监测,有效地抵御监测过程中多径干扰和频率选择性衰减等干扰因素的影响,研究基于LoRa通信的无线发射台信号智能监测技术。在无线发射台发出信号后,转换成数字信号进行对比,识别出有效发射台信号后,通过级联型LoRa组网方式以及LoRa通信技术,将数据发送到服务器中存储,实现无线发射台信号的传输。利用循环位移因子对基带产生的Chirp信号完成调频扩频调制,扩展信号频谱,增强信号抗干扰能力以及传输可靠性,增强信号监测的效果。实验结果表明:该方法能够在距离LoRa终端设备2.5 km处依旧接收到发射台信号,丢包率为12%,能够准确地监测到无线发射台是否存在发射信号。

数据模型协同驱动的MIMO系统性能预测方法

在具有未知同频干扰和信道状态信息具有不确定性的复杂场景下,现有的多输入多输出系统的性能分析和优化方案通常会退化甚至失效。为了适应这些挑战并更好地完成网络自动调优任务,提出了一个通用的数据模型协同驱动框架,该框架是真实通信系统的数字孪生,系统性能指标由系统参数决定。为了解释所提出的框架是如何工作的,将正则化迫零预编码作为实例。该实例中,首先在模型驱动方面,使用确定性等同理论来获得系统的性能近似结果。但是,该近似结果仅在理想条件下成立,例如系统已知信道状态信息不确定度、无穷天线数和没有任何未知同频干扰。因此在数据驱动方面,使用神经网络以网络参数和近似结果为输入,来进一步推断更准确的系统性能。因为利用了模型数据双驱动方法,轻量级的神经网络具有很好的性能。数据模型双驱动的性能估计器也是该系统的数字孪生。基于该数字孪生,设计了一个信道不确定度估计的流程和算法,以快速感知信道不确定度来支持该系统的自适应优化。该流程中,系统首先以一个初始信道不确定度做信号传输,并获得系统性能指标的检测结果。随后,根据性能估计器,使用梯度投影法,以该检测结果来反推信道不确定度,纠正环境非理想因素。仿真结果验证了所提算法的有效性,该数据模型协同驱动框架对于复杂场景下多输入多输出系统的性能预测具有研究意义。

无线数字新技术及网络数据安全

当前,以第六代移动通信技术(6th-generation mobile communication tenchnology,6G)为代表的无线数字新技术正在塑造着这个信息新时代,在积极发展并应用这些技术的同时,必须高度重视网络数据安全。为此,就网络通信发展态势、6G演进及数据安全、网络数据安全及挑战进行简要评述。

C波段通信相控阵天线设计及关键技术研究

本文主要对应用于微波无线通信的相控阵天线共性技术进行研究,提出了一种收发全数字波束形成的新一代相控阵天线方案,设计了一套C波段256通道的高集成度数字相控阵天线系统。该系统主要由相控阵天线的布阵、数字化射频通道、DBF单元硬件处理平台、波束成形算法等部分组成,经过实验验证达到预期设计指标,具有良好的实用价值。

基于模糊神经网络的数字媒体数据自动化采集系统设计

为了改善数字媒体数据传输效果,确保系统安全、稳定运行,设计基于模糊神经网络的数字媒体数据自动化采集系统。构建数字媒体数据自动化采集系统框架,数据采集层利用数据采集卡获取不同渠道的数字媒体数据,由数据处理层的数据融合模块调用改进模糊神经网络算法完成数字媒体数据的融合处理后,通过数据传输层的分层自组织无线网络将其传输至存储应用层,实现数字媒体数据的存储、查询、显示与输出。实验结果表明:该系统采集的音频信号波形规律、曲线平滑、功率均值波动误差在(0,0.14),满足允许误差范围;数据传输效果优于采用DSR协议的单点传输方式,当数字媒体数据源为3时,平均峰值信噪比指标最高;具有数字媒体数据查询功能。