An improved reversible data hiding-based approach for intra-frame error concealment in H.264/AVC

As H.264/AVC video streams are highly compressed, they become sensitive to errors caused by unreliable transmission channels. In order to address this issue, an improved version of Chung et al.’s reversible data hiding-based approach for intra-frame error concealment is proposed for H.264/AVC codec. By using the histogram shifting technique, the original work reversibly embeds the motion vector (MV) of a macroblock (MB) into other MB within the same intra-frame. If an MB is corrupted at the decoder side, the embedded MV can be extracted from the corresponding MB for the recovery of the corrupted MB. However, Chung et al.’s work did not fully exploit the number of coefficients which need to be modified in order to reversibly hiding data, and did not consider many extra nonzero residual blocks produced by data hiding. These two issues could reduce the visual quality of the stego-video. This paper adopts MV data pre-processing, the selection of most suitable embedding region, and the minimum possible amount of histogram modification, which lead to higher PSNR of the stego-video for a given payload. Experimental results further reveal that the proposed method offers stego-video with better visual quality over Chung et al.’s work.     

A Sound Image Externalization Approach for Headphone Reproduction by Simulating Binaural Room Impulse Responses

In this paper, an improved sound image externalization approach is proposed by considering the essential differences between headphone listening and reallife listening to deal with the problem of in-head localization of sound images. Through simulating the virtual sound source in a given enclosure, the proposed externalization approach renders sound images out-of-head by exploiting a Binaural room impulse response （BRIR） simulation approach, which consists of a new hybrid approach for the acoustic Room impulse response （RIR） and the Head-related impulse responses （HRIRs）. The hybrid RIR simulation approach comprises an improved image-source model for the early reflections by integrating the air ab- sorption, and a Feedback delay network （FDN） for the late reflections. Moreover, the HRIRs are further integrated into each sound image in the early reflections to imitate the effect of listener. Psychoacoustic test results demonstrated that the proposed externalization algorithm offered significant out-of-head perception and more natural quality of sound images.     

A source authentication scheme based on message recovery digital signature for multicast

The source authentication is an important issue for the multicast applications because it can let the receiver know whether the multicast message is sent from a legal source or not. However, the previously related schemes did not provide the confidentiality for data packets. In addition, the communication costs of these schemes are still high for real‐time applications in the multicast environments. To solve the aforementioned problems, we propose a new source authentication scheme based on message recovery signature for multicast in this paper. In the proposed scheme, the encrypted data can be embedded in the digital signature, so the communication loads can be greatly reduced. In addition, the digital signature contains the encrypted data, and thus the confidentiality of data packets can be well protected. According to the aforementioned advantages, the proposed scheme is securer and more efficient than the related works for the real‐time applications. Copyright © 2013 John Wiley & Sons, Ltd.     

Transmission Power Control for IEEE 802.15.6 Body Area Networks

Energy consumption is an important issue in body area networks (BANs). In this letter, we propose an energy efficient transmission power control scheme for IEEE 802.15.6 BANs, which can improve energy efficiency by adaptively adjusting the transmit power in an on‐demand way to adapt to varying channel environments. Simulations are performed to evaluate the performance, and it is shown that the proposed power control scheme outperforms traditional ones in terms of energy efficiency without significant reliability degradation.     

一种嵌入式智能家居控制系统的设计

提出智能家居控制系统及其应用意义,采用的是ARM9嵌入式处理器S3C2410进行核心控制电路的设计,完成了主控芯片电路、存储电路以及电源电路。同时LCD接口、USB接口以及无线通信模块等电路作为必不可少的部分,本文也给出了设计方案,另外还专门开发了针对煤气泄漏的报警模块。     

探讨广播电视业务传播中对OTN传输技术的应用

OTN技术具有安全可靠、容易管理以及业务灵活调度等特点。目前,3D电视以及高清电视开始实施互动点播的业务,因此广播电视行业开始传输大速率的广播电视业务。OTN技术具有交叉调动,实现了对不同速率业务的混合传输和灵活调度。     

基站动环监控传输方式研究

高效的基站动力环境集中监控系统可以提高基站通信电源、空调及环境的运行可靠性,而监控系统中监控数据的传输至关重要。文中简要介绍了几种基站的数据传输方式,通过分析对比各自优缺点,探求高效的监控数据传输方式。     

输电线路舞动的研究现状和防治方法

输电线路舞动是影响架空线路安全稳定运行的重要因素之一,为了保证电网的安全稳定运行,有必要深入研究线路舞动的特点。基于大量文献,文中分析总结了导线舞动的形成因素,回顾了舞动的研究理论,列举了舞动的防治方法,针对线路舞动现有研究的不足,指出了今后的研究方向和重点,为正确认识线路舞动理清了思路,有利于线路舞动研究工作的进一步展开。     

提高平行发射方式相干合成效率

从傅里叶变换光学的相关理论出发,提出了一种适合提高平行发射方式下的相干合成效率的方法。并依据激光光学的知识,通过数值模拟计算该方法对激光相干合成效率的影响。以平行发射系统和透镜系统作参考,发现对各光束赋初始相位的方法可以提高平行发射系统的合成效率,并且其极限值为对应透镜系统的合成效率。不同的赋初始相位值对合成效率的影响结果各不相同,通过对比,找到了最好的赋初始相位值方案。     

Explicit Rate Based Transmission Control Scheme in Vehicle-to-lnfrastructure Communication Networks

In Vehicle-to-Infrastructure （V2I） communication networks, mobile users are able to access Internet services, such as video stre- aming, digital map downloading, database acc- ess, online gaming, and even safety services like accident alarm, traffic condition broadcast, etc., through fixed roadside units. However, the dynamics of communication environment and frequent changing topology critically challe- nge the design of an efficient transport layer protocol, which makes it difficult to guarantee diverse Quality of Service （QoS） requirements for various applications. In this paper, we pre- sent a novel transport layer scheme in infra- structure based vehicular networks, and aim to resolve some challenging issues such as sou- rce transfer rate adjustment, congestion avoid- ance, and fairness. By precisely detecting pac- ket losses and identifying various causes of th- ese losses （for example, link disconnection, cha- nnel error, packet collision, buffer overflow）, the proposed scheme adopts different reacting mechanisms to deal with each of the losses. Moreover, it timely monitors the buffer size of the bottleneck Road-Side Unit （RSU）, and dyn- amically makes transfer rate feedbacks to sou- rce nodes to avoid buffer overflow or vacancy. Finally, analysis and simulation results show that the proposed scheme not only successfully reduces packet losses because of buffer over- flow and link disconnection but also improves the utilization efficiency of channel resource.