基于WiFi的电视副机遥控器设计

通过对WiFi无线数据通信系统的分析,探究其在广播电视频道遥控中的运用,针对电视副机不能独立选台的不足,提出了一种基于WiFi的电视副机遥控器方案。方案中手机选台控制软件发送选台控制命令,利用无线的方式传输至控制系统中的WiFi模块,控制系统对数据进行处理后通过遥控器按键拉出引线排传输至遥控器内部实现对主机频道的控制,从而使副机频道随主机的改变而改变。解决了数字电视副机不能独立选台的问题,使用户可以随时随地跨房间自由切换电视节目。     

A novel self-pilot-based transmit-receive architecture for multipath-impaired UWB systems

In the last few years, ultra-wideband (UWB) systems became an appealing technology for wireless communication applications. Unfortunately, when the transmission channel is affected by intersymbol interference (ISI), system performance of UWB systems equipped with receivers based on conventional matched filters presents error-floor phenomena. Aimed by these considerations, in this letter, we present a novel transmit-receive scheme allowing blind channel estimation and minimum mean-square error linear channel equalization. Essentially, the proposed scheme exploits a very short duration of the UWB pulse for achieving reliable blind deconvolution of the received signal. A nice feature of the resulting system is that blind deconvolution of the received signal is achieved without power and throughput losses. Simulation results support the effectiveness of the proposed scheme, and show that it is able to gain about 8 dB over current UWB receivers based on matched filtering on several test channels impaired by ISI.     

Opportunistic Beamforming and Scheduling for OFDMA Systems

Orthogonal frequency-division multiple access (OFDMA) is an attractive technique for exploiting multiuser diversity in the downlink of a cellular system. This paper addresses three problems in multiuser diversity for OFDMA systems. First, we propose a way to significantly reduce the amount of channel state information (CSI) feedback without sacrificing performance too much, by selective and adaptive feedback. Second, we propose a way to increase the cell throughput and fairness by applying an opportunistic beamforming scheme to orthogonal frequency-division multiplexing. This beamforming scheme increases the frequency fading rate, which increases the multiuser diversity effect. Thirdly, we deal with the issue of fairness and quality-of-service (QoS) in opportunistic systems by proposing a modified proportional fair (PF) scheduler for OFDMA. Key features in the scheduler are that it incorporates QoS classes into the PF scheduler and that it has a tunable fairness level. Extensive simulation results are presented to evaluate the performance of the proposed schemes. The opportunistic beamforming scheme performed well in comparison with several other schemes. The modified PF scheduler was able to give users different QoS, based on their requirements, while still exploiting multiuser diversity     

Health monitoring scheme‐based Forster resonance energy transfer nanocommunications in the Internet of Biological Nanothings

In this paper, a health monitoring approach for a targeted drug delivery (TDD) system taking into consideration the binding of drug to a target cell is proposed. The proposed scheme is mainly based on Forster resonance energy transfer (FRET) nanocommunications and the physical phenomenon such as protein–protein interactions in biological systems, in order to propose a molecular communication system with various forms for single and/or multiple ligand–receptor binding. Inspired by classical wireless communication system, the analysis of proposed scheme in terms of bit error rate (BER) and mutual information between the transmitter nanomachine (TN) and receiver nanomachine (RN) is presented. Subsequently, we are able to obtain a closed‐form expression for BER for the proposed scheme. The proposed scheme can be employed in the promising Internet of Biological Nanothings (IoBNT) paradigm. The numerical results reveal that the proposed scheme with multiple donors multiple acceptors system analogous to multiple input multiple output (MIMO) communication system is a superior scheme for transmission therapeutic drug information with achievable BER.     

Design and Implementation of a Latency Efficient Encoder for LTE Systems

The operation time of an encoder is one of the critical implementation issues for satisfying the timing requirements of Long Term Evolution (LTE) systems because the encoder is based on binary operations. In this paper, we propose a design and implementation of a latency efficient encoder for LTE systems. By virtue of 8‐bit parallel processing of the cyclic redundancy checking attachment, code block (CB) segmentation, and a parallel processor, we are able to construct engines for turbo codings and rate matchings of each CB in a parallel fashion. Experimental results illustrate that although the total area and clock period of the proposed scheme are 19% and 6% larger than those of a conventional method based on a serial scheme, respectively, our parallel structure decreases the latency by about 32% to 65% compared with a serial structure. In particular, our approach is more latency efficient when the encoder processes a number of CBs. In addition, we apply the proposed scheme to a real system based on LTE, so that the timing requirement for ACK/NACK transmission is met by employing the encoder based on the parallel structure.     

Comment on “Robust blind image watermarking scheme based on Redundant Discrete Wavelet Transform and Singular Value Decomposition”

It is shown that the robust blind image watermarking scheme based on Redundant Discrete Wavelet Transform and Singular Value Decomposition proposed by Makbol and Khoo in this AEÜ journal has a fundamental flaw in its design that undermines the security of its scheme against the false-positive problem. More crucially, this result therefore invalidates the objective of the scheme that is to achieve ownership protection, so the scheme cannot be used. In more detail, an adversary is able to claim ownership of a watermarked image by extracting his watermark from the image, although his watermark has never been inserted into the image in the first place. We then verified the flaw through experimental results and thus, proved that the Makbol and Khoo scheme was not able to solve the false-positive problem as claimed and should not be used for proof of ownership applications. In discussing ways to mitigate the problem, we investigate an approach that would have worked quite efficiently if Discrete Wavelet Transform was used instead of Redundant Discrete Wavelet Transform.     

基于属性的签密方案

现实生活中存在这样一种情况：具有某些属性的群组中的一个成员，他将上传一些签过名的敏感数据到第三方网站，并希望只能被具有特定属性的群组访问。为满足此需求，文章定义了基于属性的签密方案，其中，文件由属性集标识，私钥由一个访问控制结构产生，用来控制解密权限。最后，给出了方案的正确性证明和安全性分析。     

Multiple-Access Interference Suppression for Interleaved OFDMA System Uplink

In this paper, the issue of multiple-access interference (MAI) suppression for the uplink in an interleaved orthogonal frequency-division multiple-access (OFDMA) system is investigated. In such a system, a carrier frequency offset (CFO) disrupts the orthogonality between the subcarriers and gives rise to MAI among users. Based on the signature vector formulated for each user, we propose a novel detector that performs MAI suppression before CFO compensation and fast Fourier transform (FFT) demodulation. Subspace zero-forcing and minimum mean square error (MMSE) techniques are then developed to suppress MAI. The proposed scheme is shown to become almost MAI free, provided that the CFO estimation is accurate enough. From the obtained simulation results, the proposed scheme is also found to be able to enhance the system performance at low complexity.     

Distributed servers architecture for networked video services

In an on-demand video system, the video repository generally has limited streaming capacities and may be far from the users. In order to achieve higher user capacity and lower network transmission cost, distributed servers architecture can be used, in which multiple local servers are placed close to user pools and, according to their local demands, dynamically cache the contents streamed from the repository. We study a number of caching schemes as applied in the local servers depending on whether the repository is able to multicast movie contents to the local servers or not, and whether the local servers can exchange their cached contents among themselves or not. Our caching schemes keep a circular buffer of data for the movie requested, and hence movies are partially cached. By adjusting the size of the buffer, such caching is able to achieve better tradeoff between network channels and local storage as compared to the traditional caching in which a movie is treated as an entity. For each caching scheme, we study the tradeoff between the local storage and the network channels, and address how the total cost of the system can be minimized by appropriately sizing the buffer. As compared to a number of traditional operations (request batching and multicasting, true-VOD, etc.), we show that distributed servers architecture is able to achieve much lower system cost to offer on-demand video services     

A Simple Adaptive Coding Scheme for Multiuser Interference Suppression in Ultra-Wideband Radio Transmissions

In this letter, we introduce a simple co-decoding scheme for ultra wideband (UWB) impulse radio systems impaired by multiuser interference (MUI). The proposed scheme exhibits an adaptive capability with respect to MUI degrading effects and, depending on the MUI level, it may switch from a hard-detection operating mode to a soft-detection one. So doing, the presented scheme is able to gain resistance against near–far effects. Several numerical tests support the conclusion that the presented scheme outperforms conventional ones currently planned for noise-limited UWB systems up to orders of magnitude in MUI-limited application scenarios.     

Combination of Multiple Measurement Cues for Visual Face Tracking

Visual face tracking is an important building block for all intelligent living and working spaces, as it is able to locate persons without any human intervention or the need for the users to carry sensors on themselves. In this paper we present a novel face tracking system built on a particle filtering framework that facilitates the use of non-linear visual measurements on the facial area. We concentrate on three different such non-linear visual measurement cues, namely object detection, foreground segmentation and colour matching. We derive robust measurement likelihoods under a unified representation scheme and fuse them into our face tracking algorithm. This algorithm is complemented with optimum selection of the particle filter’s object model and a target handling scheme. The resulting face tracking system is extensively evaluated and compared to baseline ones.     

Steganalysis of BCH code based stego schemes

The class of stego systems based on error correcting codes is one of the alternatives to conventional steganographic systems. In the context of code based steganography, the BCH code based stego system offers a very smart solution based on the hardness of syndrome decoding. It has been shown that syndrome decoding problem is able to resist the existing steganalysis attacks. In this paper, we introduce an attack against these systems using a new syndrome decoding method. This scheme also generates a direct estimate of the secret message bit locations by exploiting the embedding patterns. This new attack notably points out that BCH code based stego system with its original parameters do not provide sufficient security.     

基于简化测量的随机数据抖动分离研究

针对通信系统中随机数据的抖动测量,一般都使用数字示波器的眼图功能,对于测量的硬件电路要求较高,要能够对波形进行实时测量.文中基于对抖动类型及其产生因为的分析,提出了一种基于简化测量的抖动分离方案,即只需随机测量波形中某个上升沿-下降沿-上升沿之间的时间间隔,即可获得大部分抖动分量,降低了对硬件电路的要求.     

Stability and Fairness of a Rate Allocation Scheme

In this paper, we analyze quantitatively the stability and equilibrium performance of a rate allocation scheme. This kind of analysis is important because in computer networks where multiple applications compete and share limited amount of system resources, some applications tend to suffer from variations in resource availability, and are desired to adapt their behavior to the resource variations of the network. Also, we analyze the fairness properties of the rate allocation scheme. Fairness guarantees are provided without collecting or analyzing state information on individual flows. The rate allocation scheme is able to provide efficiently and effectively rate guarantees, fairness, responsiveness and robustness without having to incorporate numerous tuning parameters as is normally done in most schemes.     

Region-Level Image Authentication Using Bayesian Structural Content Abstraction

Image authentication (IA) verifies the integrity of image content by detecting malicious modifications. A good IA system should be able to tolerate noncontent-changing operations (NCOs) robustly, and detect content-changing operations (COs) sensitively. Most existing IA methods realize either bit-level or pixel-level authentication; thus, they can tolerate only particular and limited kinds of NCOs. In this paper, we propose an unsupervised region-level IA scheme named Bayesian structural content abstraction (BaSCA), which is capable of tolerating a wide and dynamic range of NCOs and can sensitively detect real COs. We model image structural content using the net-structured Markov Pixon random field (NS-MPRF), from which we derive the size-controllable BaSCA signature. Furthermore, to support dynamic NCO/CO partition, we present an analogous mean-shift algorithm to iteratively optimize the BaSCA signature in the user-defined NCO space. Both theoretical analysis and experimental results demonstrate that our BaSCA scheme has much less false positive and comparable false negative probability, as compared to state-of-the-art IA methods.      

A k‐means clustering‐based security framework for mobile data mining

Data mining is a process of digging data sets from large data‐bases, especially for use to improve the operation efficiency of a company, institution, or an organization. With the increasing cases of cyber and other computer‐related crimes, computer and mobile data security has become a matter of concern, secure, and non‐contaminated data is very important for data mining to improve the performance of a system. This paper proposes a system framework that is able to collect information and then be able to generate alerts in real time. The proposed scheme is then simulated using the K‐means clustering algorithm, which is one of the most popular clustering algorithms to determine the efficiency and the accuracy of the proposed scheme. The paper concludes by proposing further improvements to be undertaken on the proposed system to improve its efficiency and accuracy. Copyright © 2017 John Wiley & Sons, Ltd.     

基于人类视觉系统的各向异性扩散图像平滑方法

本文首先分析了图像处理领域中现存各向异性扩散技术所面临的一些问题,然后根据人类视觉系统的一些特性提出了一个改进的各向异性扩散方法.由于该方法充分利用了可见度函数所提供的信息,它不仅避免了Perona-Malik 以及You-Kaveh方案中对参数选择的困难,而且也克服了Catte方案对观察图像进行预平滑的过程中所面临的问题.实验结果表明,在图像平滑的过程中,该方法在噪声消除和边缘保留方面能获得较好的效果.     

Interactive Broadcasting System for VBR Encoded Videos

Video broadcasting has been proved to be an efficient technique to increase the scalability of a video-on-demand (VoD) system. In this paper, we address the problems in providing interactive functions for VBR encoded videos in a broadcast VoD system. A traffic smoothing scheme is proposed to support the VCR functions in delivering VBR videos over CBR channels by the staggered broadcasting protocol. By introducing a small buffering delay, the customers are able to join back to the broadcasting groups after the interactive functions. A system model is then developed to determine the optimal parameters such that the system can meet the delay requirement as well as provide the expected quality of service to the customers. The results show that the proposed system framework is very efficient in terms of bandwidth requirement and buttering delay to provide interactive VoD services.     

Quantitative analysis of a hybrid replication with forwarding strategy for efficient and uniform location management in mobile wireless networks

A location management scheme in wireless networks must effectively handle both user location update and search operations. Replication and forwarding are two well-known techniques to reduce user search and update costs, respectively, with replication being most effective when the call to mobility ratio (CMR) of the user is high, while forwarding is most effective when the CMR value is low. Thus, based on the user's CMR, the system can adopt a CMR threshold-based scheme such that if the user's CMR is lower than a threshold, then the system applies the forwarding scheme; otherwise, it applies the replication scheme. Applying different location management schemes based on per-user CMR values introduces undesirable high complexity in managing and maintaining location- related information stored in the system as different system support mechanisms must be applied to different users. In this paper, we quantitatively analyze a hybrid replication with forwarding scheme that can be uniformly applied to all users. The most striking feature of the hybrid scheme is that it can determine and apply the optimal number of replicas and forwarding chain length on a per-user basis to minimize the communication cost due to location management operations while still being able to use the same data structure and algorithm to execute location management operations in a uniform way for all users. We develop a stochastic Petri net model to help gather this information and show how the information obtained statically can be used efficiently by the system at runtime to determine the optimal number of replicas and forwarding chain length when given a use user's profile. We show that the proposed hybrid scheme outperforms both pure replication and forwarding schemes, as well as the CMR threshold-based scheme under all CMR values.     

Efficient mobility management for vertical handoff between WWAN and WLAN

As we move toward next-generation all-IP wireless networks, we are facing the integration of heterogeneous networks, such as WWAN and WLAN, where vertical handoff is required. In vertical handoff between WWAN and WLAN, mobile hosts should be able to move freely across different networks while satisfying QoS requirements for a variety of applications. In order to achieve seamless handoff and maintain continuity of connection, we propose a novel mobility. management system that integrates a connection manager to detect network condition changes in a timely and accurate manner, and a virtual connectivity manager that uses an end-to-end principle to maintain a connection without additional network infrastructure support. A prototype system was built to test the effectiveness of the proposed system. Experiments show that seamless roaming between WLAN and WWAN can be achieved, and much better performance can be obtained than with the traditional scheme.