Iterative spatial domain 2-D signal decomposition for effectual image up-scaling

Multimedia Tools and Applications - Image up-scaling employs various polynomial interpolation schemes for their reduced computational complexity and suitability for various real-time applications....     

A high capacity combined reversible watermarking scheme for 2-D CAD engineering graphics

Multimedia Tools and Applications - Compared with the wide research on reversible watermarking scheme for raster image, the research on its counterpart for 2-D CAD engineering graphics lags far...     

Energy efficient heuristic application mapping for 2-D mesh-based network-on-chip

Application mapping in 2-D mesh-based Network-on-Chip (NoC) architecture is an optimization problem in which each application task (e.g., processor or memory units) should be mapped one-to-one onto a network element (switch or router) to optimize performance requirements (e.g., communication energy or communication latency) under certain platform constraints (e.g., bandwidth and/or latency). Network-on-Chip is a scheme that establishes links between limited application-specific components within Multi-Processor System-on-Chip (MPSoC), but it has a vital role to ensure the maximum data transfer rate and reduce total number of physical interconnections. Most of the works on heuristic application mapping for mesh-based NoC design aim to minimize both total communication energy and run-time, however they experience the following issues: (i) relatively high CPU time due to linear search for the task and tile mapping combinations, (ii) consumption of relatively high communication energy due to random tile selection when two or more tiles are equivalent in terms of average weighted distance by their adjacent mapped tasks, and (iii) even after constructive application mapping, some of the tasks consume higher communication energy due to their inappropriate placements. In this paper we present a low time-complexity heuristic mapping algorithm of weighted application graph under permissible bandwidth constraint to minimize communication energy of 2-D mesh-based NoC architecture. The experimental results of multimedia benchmarks, as well as randomly generated samples show the low communication energy as well as time-complexity under bandwidth constraints in comparison to the recent heuristic application mapping approaches. In our approach, the communication energy is also close to the optimal solution obtained by Integer Linear Programming (ILP).     

EP2LBS: efficient privacy-preserving scheme for location-based services

The Journal of Supercomputing - Mobile users frequently change their location and often desire to avail of location-based services (LBS). LBS server provides services to users at the service...     

An efficient task allocation scheme for 2D mesh architectures

Efficient allocation of processors to incoming tasks in parallel computer systems is very important for achieving the desired high performance. It requires recognizing the free available processors with minimum overhead. In this paper, we present an efficient task allocation scheme for 2D mesh architectures. By employing a new approach for searching the mesh, our scheme can find the available submesh without scanning the entire mesh, unlike earlier designs. Comprehensive computer simulation reveals that the average allocation time and waiting delay are much smaller than earlier schemes of comparable performances, irrespective of the size of meshes and distribution of the shape of the incoming tasks     

An efficient authentication scheme for high efficiency video coding/H.265

Multimedia Tools and Applications - In this paper, a semi-fragile authentication scheme for high efficiency video coding is proposed. In this scheme, 4 × 4 intra luma transform blocks of...     

The grid protocol: a high performance scheme for maintainingreplicated data

A new protocol for maintaining replicated data that can provide both high data availability and low response time is presented. In the protocol, the nodes are organized in a logical grid. Existing protocols are designed primarily to achieve high availability by updating a large fraction of the copies, which provides some (although not significant) load sharing. In the new protocol, transaction processing is shared effectively among nodes storing copies of the data, and both the response time experienced by transactions and the system throughput are improved significantly. The authors analyze the availability of the new protocol and use simulation to study the effect of load sharing on the response time of transactions. They also compare the new protocol with a voting-based scheme     

低功耗高性能的分离比较cache方案*

提出了一种基于分离比较cache的设计方法,其技术关键在于设计一个用来存储原标志低四位的全相联cache和分离标志比较器,以确保同时获得高性能和低能量损耗。SPEC95仿真结果表明,分离比较cache能够节省传统四路组相联cache13%的存取时间和45%~60%的能量损耗。     

Hybrid scheme for efficient shape coding

A contour-based scheme for near lossless shape coding is proposed aiming to acquire high coding efficiency. For a given shape image, object contours are firstly extracted and then thinned to be perfect single-pixel width. Next they are transformed into chain-based representation and divided into different chain segments based on link directions. Thirdly, two fundamental coding modes are designed and developed to encode different types of chain segments, where the spatial correlations within object contours are analyzed and exploited to improve the coding efficiency as high as possible. Finally, a fast and efficient mode selection method is introduced to select the one that can produce shorter code length out of the two modes for each chain segment. Experiments are conducted and the results show that the proposed scheme is considerably more efficient than the existing techniques.     

2-D unitary matrix pencil method for efficient direction of arrival estimation

In this study, we extended the one-dimensional (1-D) unitary matrix pencil method (UMP) [N. Yilmazer, J. Koh, T.K. Sarkar, Utilization of a unitary transform for efficient computation in the matrix pencil method to find the direction of arrival, IEEE Trans. Antennas Propagat. 54 (1) (2006) 175–181] to two-dimensional case, where 2-D matrix pencil (MP) method are used to find the 2-D poles corresponding to the direction of arrival (DOA), azimuth and elevation angles, of the far field sources impinging on antenna arrays. This technique uses MP method to compute the DOA of the signals using a very efficient computational procedure in which the complexity of the computation can be reduced significantly by using a unitary matrix transformation. This method applies the technique directly to the data without forming a covariance matrix. Using real computations through the unitary transformation for the 2-D matrix pencil method leads to a very efficient computational methodology for real time implementation on a DSP chip. The numerical simulation results are provided to see the performance of the method.     

Improving risk-adjusted performance in high frequency trading using interval type-2 fuzzy logic

In this paper, we investigate the ability of higher order fuzzy systems to handle increased uncertainty, mostly induced by the market microstructure noise inherent in a high frequency trading (HFT) scenario. Whilst many former studies comparing type-1 and type-2 Fuzzy Logic Systems (FLSs) focus on error reduction or market direction accuracy, our interest is predominantly risk-adjusted performance and more in line with both trading practitioners and upcoming regulatory regimes. We propose an innovative approach to design an interval type-2 model which is based on a generalisation of the popular type-1 ANFIS model. The significance of this work stems from the contributions as a result of introducing type-2 fuzzy sets in intelligent trading algorithms, with the objective to improve the risk-adjusted performance with minimal increase in the design and computational complexity. Overall, the proposed ANFIS/T2 model scores significant performance improvements when compared to both standard ANFIS and Buy-and-Hold methods. As a further step, we identify a relationship between the increased trading performance benefits of the proposed type-2 model and higher levels of microstructure noise. The results resolve a desirable need for practitioners, researchers and regulators in the design of expert and intelligent systems for better management of risk in the field of HFT.     

A flexible nonlinear model predictive control scheme for quality/performance handling in nonlinear SMB chromatography

In this paper, a new state feedback scheme is proposed for the control of simulated moving beds with strongly nonlinear isotherms. The proposed scheme offers a unified framework enabling different performance criteria to be improved according to the active production constraints (achieving low cost, improving efficiency, respecting deadlines) that may unpredictably change during the production batch. The proposed scheme is illustrated through several examples showing the robustness of the closed-loop behavior against parameter uncertainties as well as its reactivity to changes in the active auxiliary criterion.     

2-D canonical correlation analysis based image super-resolution scheme for facial emotion recognition

Multimedia Tools and Applications - In this research work, a new Image super-resolution-based Face Emotion Recognition Model has been introduced. The proposed work includes two major phases: (a)...     

一种面向FPGA异构计算的高效能KV加速器

网络功能虚拟化等新兴应用的蓬勃发展对Key-Value查询的能效提出了更高要求。传统的解决方法要么采用基于软件Hash表,要么采用专用的三态内容可寻址存储器(TCAM)芯片进行加速。其中,软件方法实现成本低,但是在数据冲突较高时会导致查表性能急速下降;硬件TCAM方法具有优良的时间特性,但其价格昂贵、耗能巨大。目前,随着基于现场可编程门阵列FPGA的异构计算技术的高速发展,利用系统已经提供的FPGA资源对基于软件实现的Hash表结构进行加速成为一种性价比更佳的解决方案。探讨如何利用FPGA上的RAM资源来实现一种具有高扩展性和高能效比的TCAM逻辑。与传统的TCAM结构不同,提出的架构支持查表范围的动态缩放,从而可以有效减少查表功耗。为了验证方案的有效性,利用Virtex-7系列FPGA对本文方案进行实现和评估,并与软件查表的性能进行详细比较。实验表明,本文方案吞吐量可达到234 Mpps,查表延迟为25.56ns。相比软件的方法,吞吐量提高780倍,延迟降低240倍。     

一种高性能的二维波达方向估计算法

在二维虚拟ESPRIT算法的基础上,提出了一种高性能的改进算法。改进方法依照子阵数据直接空间平滑的思想对子阵数据进行预处理,用虚拟阵列变换技术实施阵列变换,采用波达方向矩阵法的思路计算二维角度参数。仿真结果表明,相比于空域平滑的DOA矩阵法和空域平滑的二维虚拟ESPRIT算法,该方法在低信噪比情况下对相干信号源具有更好的估计性能,对独立信号源,能够估计出超过子阵阵元数的信号。     

高效查询的XML编码方案

在XML数据查询中,结构连接操作占用了大量时间。针对这个问题,提出一种高效查询的编码方案—LSEQ编码。它将节点路径信息进行分解,避免记录路径的重复信息,减小了编码长度;同时支持节点祖先后代关系,父子关系和兄弟关系的表示。LSEQ编码通过记录非叶节点的路径,在节点查询中避免了结构连接操作,提高了查询效率。实验表明LSEQ编码提高了空间利用率,在查询速度上具有出良好的性能。     

一种有效减少码字长度的两用户合谋安全指纹编码方案

运用级联码的思想提出了一种抗两用户合谋攻击的指纹设计方法和与其对应的跟踪方法。编码算法中内码采用文献[4]构建的一种新的两用户合谋安全码,外码采用q进制随机数,减小了编码的难度。设计了跟踪算法验证了这种编码算法的有效性。该算法在用户数增加、码字长度不变的情况下,仍能有效跟踪到至少一个合谋用户,克服了以往码字过长的缺点。     

Cloud-based efficient scheme for handwritten digit recognition

Multimedia Tools and Applications - Handwritten character recognition has been acknowledged and achieved more prominent attention in pattern recognition research community due to enormous...     

Numerical scheme for efficient colour image denoising

In this paper, we are interested by the enhancement of colour images, where we present a numerical scheme to implement a non-linear diffusion filter. This scheme is developed to denoise colour images corrupted by additive noise. The method is based on harmonic averaging that takes into account correlation between all colour components of the image by using a common gradient magnitude which can be computed by using the Di Zenzo idea, and a marginal gradient magnitude in order to conserve the self behaviour of each colour component. The proposed scheme is an efficient tool at image selective smoothing in presence of strong noise. This analysis shows that our method performs better than some related works, and particularly in avoiding colour artifacts.     

高性能DSP核心电源设计及其纹波电压抑制

针对高性能DSP核心电源的供电需求,给出了以LTM4650作为核心器件的大电流、小纹波、小尺寸电源设计方案。通过对电压纹波产生原因的分析,提出了电压纹波抑制的方法,并经过仿真和实际测试,保证了高性能DSP的正常工作,对于其他数字电源设计有一定参考意义。