Cooperative Covert Communication in Multi-Antenna Broadcast Channels

With the gradual popularization of 5G communications,the application of multi-antenna broadcasting technology has become widespread.Therefore,this study aims to investigate the wireless covert communication in the two-user cooperative multi-antenna broadcast channel.We focus on the issue that the deteriorated reliability and undetectability are mainly affected by the transmission power.To tackle this issue,we design a scheme based on beamforming to increase the reliability and undetectability of wireless covert communication in the multi-antenna broadcast channel.We first modeled and analyzed the cooperative multi-antenna broadcasting system,and put forward the target question.Then we use the SCA(successive convex approximation)algorithm to transform the target problem into a series of convex subproblems.Then the convex problems are solved and the covert channel capacity is calculated.In order to verify the effectiveness of the scheme,we conducted simulation verification.The simulation results show that the proposed beamforming scheme can effectively improve the reliability and undetectability of covert communication in multi-antenna broadcast channels.

The National Formation of the Right to Health:Taking Broadcast Gymnastics as an Example

Broadcast gymnastics,which was initiated in 1951,is one of the most widely adopted and popular mass sports activities in China,embodying the country's commitment to shaping the right to health of its citizens.The history and development of broadcast gymnastics are closely tied to the destiny of the nation,reflecting clear national will,and aiming to achieve the goal of“shaping new individuals”.The institutional forms of broadcast gymnastics can be categorized into three stages:“military simulation”,“administrative reinforcement”and“market competition”,each of which aligns with the objectives and needs of different periods.Taking the establishment and promotion of broadcast gymnastics in China as a focal point helps construct a doctrinal framework for the right to health.Based on the purposes and means of health shaping,the implementation of the right to health can be divided into four types:national health projects,citizens'health rights,the social health industry,and civic health consumption.National health projects,facilitated by legislative mechanisms,provide institutional support and supply for citizens'health rights.The right to health,as a social right,has both a subjective rights orientation and an objective value order orientation,thus establishing the individual's subject status in terms of their right to health.Its defense aspect is oriented toward rejecting excessive state intervention,while the benefit aspect directly links to the state's payment measures.The boundaries of state power also need to be defined in the social health industry and civic health consumption.Hence,developing broadcast gymnastics involves adjusting its relationship with the overall objectives of the state and individual citizens'needs.It involves balancing the use of administrative and market methods,continually innovating sports programs that better suit diverse needs,and actively participating in the competition of the fitness market.

基于Broadcast模板的交互系统

本文提出了一种基于Ｂｒｏａｄｃａｓｔ模板开发交互系统的面向对象方法，并分析了此方法所带来的系统结构的清晰性、稳定性及软件部件的可重用性。

广播标记(Broadcast Flag)技术

近来,业界都在讨论广播标记(BroadcastFlag)技术。本文详细介绍了广播标记技术产生的背景、原理与实现,以及争论的焦点问题;最后针对广播标记技术是否可以应用于我国的数字电视领域给出了我们的看法和建议。

使用Broadcast Disks方法分布的空中位图索引

提出一种使用BroadcastDisks算法来分布位图索引的空中索引方法,根据数据项访问概率,使用位图作为数据广播的索引,减少了移动终端等待数据时保持激活状态的时间,达到节能的目的。

High Robust Broadcasting over DTMB-A with Low-rate LDPC Codes

As the 2nd generation digital terrestrial television broadcasting(DTTB)standard,digital terrestrial/television multimedia broadcasting-advanced(DTMB-A)can provide higher spectrum efficiency and transmission reliability by adopting flexible frame structure and advanced forward error correction coding compared with the 1 st generation DTTB systems.In order to increase the flexibility and robustness of the DTTB network,the frequency reuse scheme of factor one(reuse-1)is proposed,where the same RF channel is used by different stations covering the adjacent service areas.However,it demands a very low carrier-tonoise ratio(C/N)threshold below 0 dB at the DTTB physical layer.In this paper,a robust broadcasting technique is proposed based on DTMB-A with newly designed low-rate low density parity check(LDPC)codes.By adopting quasi-cyclic(QC)Raptor-like structure and progressive lifting method,the high performance low-rate LDPC codes are designed supporting multiple code lengths.Both density-evolution analyses and laboratory measurements demonstrate that DTMB-A with low-rate coding can complete the demodulation reliably with the C/N threshold below0 d B,which is one important necessary condition to support frequency reuse-1 scheme.

Godson-T众核体系结构上的Broadcast性能优化

Godson-T是中国科学院计算技术研究所计算机系统结构重点实验室先进微系统组正在研制开发的适合于超深亚微米工艺实现的大规模片上众核系统.Godson-T片上存储的单端口结构节省了芯片面积但制约了共享数据的读取效率.直接在Godson-T上实现传统的Broadcast算法需要大量的同步互斥开销,无法达到很好的性能提升.基于Godson-T体系结构,对数据共享的重要并行算法Broadcast进行优化,提高了Godson-T体系结构下的数据共读的效率.主要采取了以下3项技术:消除大规模的线程同步,建立源地址到目的地址的映射表和用汇编语言实现Broadcast的核心部分.优化后Broadcast在小核数为32时即可达到5.8倍加速比.

New mixed broadcast scheduling approach using neural networks and graph coloring in wireless sensor network

Due to the mutual interference and sharing of wireless links in TDMA wireless sensor networks, conflicts will occur when data messages are transmitting between nodes. The broadcast scheduling problem （BSP） is aimed to schedule each node in different slot of fixed length frame at least once, and the objective of BSP is to seek for the optimal feasible solution, which has the shortest length of frame slots, as well as the maximum node transmission. A two-stage mixed algorithm based on a fuzzy Hopfield neural network is proposed to solve this BSP in wireless sensor network. In the first stage, a modified sequential vertex coloring algorithm is adopted to obtain a minimal TDMA frame length. In the second stage, the fuzzy Hopfleld network is utilized to maximize the channel utilization ratio. Experimental results, obtained from the running on three benchmark graphs, show that the algorithm can achieve better performance with shorter frame length and higher channel utilizing ratio than other exiting BSP solutions.

Cryptanalysis and improvement of quantum broadcast communication and authentication protocol with a quantum one-time pad

The security of quantum broadcast communication（QBC） and authentication protocol based on Greenberger–Horne–Zeilinger（GHZ） state and quantum one-time pad is analyzed. It is shown that there are some security issues in this protocol.Firstly, an external eavesdropper can take the intercept–measure–resend attack strategy to eavesdrop on 0.369 bit of every bit of the identity string of each receiver without being detected. Meanwhile, 0.524 bit of every bit of the secret message can be eavesdropped on without being detected. Secondly, an inner receiver can take the intercept–measure–resend attack strategy to eavesdrop on half of the identity string of the other＇s definitely without being checked. In addition, an alternative attack called the CNOT-operation attack is discussed. As for the multi-party QBC protocol, the attack efficiency increases with the increase of the number of users. Finally, the QBC protocol is improved to a secure one.

Broadcasting with Controlled Redundancy and Improved Localization in Wireless Sensor Networks

Wireless sensor networks （WSNs） consist of sensor nodes that broadcast a message within a network. Efficient broadcasting is a key requirement in sensor networks and has been a focal point of research over the last few years. There are many challenging tasks in the network, including redundancy control and sensor node localization that mainly depend on broadcasting. In this paper, we propose a broadcasting algorithm to control redundancy and improve localization （BACRIL） in WSNs. The proposed algorithm incorporates the benefits of the gossip protocol for optimizing message broadcasting within the network. Simulation results show a controlled level of redundancy, which is up to 57.6% if the number of sensor nodes deployed in a 500 m×500 m area are increased from 50 to 500.

Impact of small-world topologies on broadcasting for wireless sensor networks

Broadcasting is an important operation and been widely used in wireless sensor networks （WSNs）. These networks are power constrained as nodes operate with limited battery power. Wireless sensor networks are spatial graphs that have much more clustered and much high path-length characteristics. After considering energy- efficient broadcasting in such networks, by combining the small-world characteristic of WSNs and the properties of ant algorithm to quickly identify an optimal path, small-world power-aware broadcast algorithm is introduced and evaluated. Given different densities of network, simulation results show that our algorithm significantly improves life of networks and also reduces communication distances and power consumption.

Partially secret broadcasting,partially secret splitting with quantum entanglement

In this paper, we propose a classical secret broadcasting and splitting joint protocol in a quantum scenario. With those genuinely entangled states, the boss can always broadcast some of his secrets and split some others to multi- receivers at the same time. The efficiency of the joint protocol is also compared with that of two separate ones which realise classical secret broadcasting and classical secret splitting respectively, and based on the comparison we can see the promising advantage of our joint protocol is that it can realise the two tasks more efficiently and more conveniently.

The Quality Assessment of Non-Integer-Hour Data in GPS Broadcast Ephemerides and Its Impact on the Accuracy of Real- Time Kinematic Positioning Over the South China Sea

Abnormal effects in GPS broadcast ephemerides can have a significant effect on real-time navigation and positioning solutions that use the orbit and clock error data provided by GPS broadcast ephemerides.This paper describes three types of non-integerhour navigation data in GPS broadcast ephemeris data.Compared with GPST integer hour data,we find that there are two types of data blocks for non-integer-hour navigation containing gross errors with different levels of precision,which is reflected in the user range accuracy(URA)of the broadcast ephemeris.These gross errors can cause large deviations when using the GPS broadcast ephemeris for orbit calculation and lead to a decrease in the kinematic positioning accuracy.An improved weighting method which is based on the consistency relationship between the URA value and the orbital precision is proposed to improve the positioning accuracy by controlling the effect of gross errors in the broadcast ephemerides.The correction algorithm proposed in this paper was applied to real-time kinematic positioning with shipborne GPS data over the South China Sea.The results showed that the proposed positioning algorithm can effectively reduce the effects of gross errors in the broadcast ephemeris,and significantly improve the accuracy of the navigation and positioning.

Scheduling for Uncertain Data Broadcast in Mobile Networks

With the increasing popularity of wireless sensor network and GPS （ global positioning system）, uncertain data as a new type of data brings a new challenge for the traditional data processing methods. Data broadcast is an effective means for data dissemination in mobile networks. In this paper, the def＇mition of the mean uncertainty ratio of data is presented and a broadcasting scheme is proposed for uncertain data dissemination. Simulation results show that the scheme can reduce the uncertainty of the broadcasted uncertain data effectively at the cost of a minor increase in data access time, in the case of no transmission error and presence of transmission errors. As a result, lower uncertainty of data benefits the qualifies of the query results based on the data.

A Preamble-Based Broadcasting Technique for Wireless Ad Hoc Sensor Networks

Broadcasting is a fundamental operation in any wireless networks, more so in wireless ad hoc sensor networks, where each sensor node has limited transmission range as well as battery power. Although broadcasting in wireless ad hoc sensor networks has many advantages but it can cause serious problems like-broadcast storm, which could cause a lot of contention, redundant retransmission, collision and most importantly, drain immense amount of energy from limited battery powered sensor nodes. In this work, our objective is to reduce the number of retransmission and energy consumption of sensor nodes by using the duty cycle property of wireless ad hoc sensor networks. We propose a preamble-based broadcasting technique for wireless ad hoc sensor networks. We show that in dense wireless ad hoc sensor networks a small size preamble can give maximum network-wide data dissemination rather than using the large preamble, which will only consume immense amount of energy during packet reception.

Android中的BroadcastReceiver注册方式研究

在Android整个系统中，Broadcast作为一种机制，在应用程序之间传输信息。而BroadcastReceiver就是对发送出来的Broadcast进行过滤接受并响应的一类组件，也叫作广播接收器，是Android的四大基本组件之一。不过目前对Broadcast-Receiver进行的介绍不是很多，通过对广播接收器的生命周期，广播类型，注册方式等方面进行介绍，并通过两个实例使读者对广播接收器的注册方式有进一步的了解，对两种注册方式有更直面的认识，明白动态注册和静态注册之间的差异和优缺点，对两种基本的注册方法的使用流程更加清晰。

On Neologism in Broadcast News Reporting

Based on the neologism in the broadcast news reporting, this paper will introduce different kinds of the most frequently used words today, including the extended meanings of the conventional words and new words created by word formation.

基于eMBMS的LTE Broadcast技术及应用发展策略

随着移动互联网的快速发展,日益增长的视频业务将对移动运营商的LTE网络产生越来越大的压力。为了应对这一压力,基于eMBMS的LTEBroadcast技术逐渐得到行业的关注。本文分析了LTEBroadcast的产生背景、主要技术方案、应用场景,并对其未来的发展进行了展望。

A Novel Broadcast Encryption Scheme Based on SD Scheme Reconstruction

In this paper,we introduce a novel way to solve thetradeoff problem about communication,storage,computation overhead of broadcast encryptionscheme.We construct a new scheme based on SubsetDifference(SD)scheme,use the concept of RSAaccumulator and the idea of separating the user-sidedevice into different function parts,take advantageof the public device’s functionality,minimize thestorage and computation overhead of the privatedevice,and make the broadcast encryption schememore implementation-oriented.

Broadcast Scheduling Strategy Based on the Priority of Real-Time Data in a Mobile Environment

Data broadcast is an important data dissemination approach in mobile environment. On broadcast channel, scalability and efficiency of data transmission are satisfied. In a mobile environment, there exists a kind of real-time database application in which both the transactions and data can have their timing constraints and priorities of different levels. In order to meet the requirement of real-time data disseminating and retrieving, a broadcast scheduling strategy HPF-ED F (Highest Priority First with Earlier Deadline and Frequency) is proposed under the BoD (Broadcast on Demand) model. Using the strategy, data items are scheduled according to their priority the transaction imposed on them or system set for them. The strategy also considers other characteristics of data items such as deadline and popularity of data. The extensive simulation experiments have been conducted to evaluate the performance of the proposed algorithm. Results show that it can achieve excellent performance compared with existing strategies.