基于H.264的SSIM预测模型及其帧层应用

为使H.264帧层码率控制算法得到更好的主观视频质量,提出一种基于结构相似性因子的码率控制算法。提出结构相似性线性预测模型;通过预测模型预测当前帧的结构相似性,由结构相似性定义一个表征帧主观复杂度的结构相似性因子,根据它来分配当前帧的目标比特数。实验结果表明,该算法有效提高了重建视频帧结构相似性,得到了更好的主观视频质量。     

H.264标准中的CAVLC编码算法与FPGA实现

H.264视频编码标准在基本档次和扩展档次采用CAVLC（基于上下文的自适应可变长编码）熵编码方法,但标准并未给出详细的CALVC编码句法。从CALVC的解码原理出发,详细分析了H.264视频编码标准中的CAVLC编码算法,提出了一种应用于H.264标准的快速低功耗CAVLC编码器结构,给出了各个功能模块的详细设计原理与FPGA实现方法,并对较复杂的几个模块进行了算法和结构上的优化,降低了实现的复杂度。FPGA实验验证表明,该方案编码系统时钟可达100 MHz,能满足对高速、实时应用的编码要求。     

支持等式测试的身份基可否认认证加密方案及其在电子投票系统的应用

电子投票系统被认为是现代生活中高效提供政府服务和进一步加强民主活力的方法。但是,现有构建电子投票系统的方法存在以下问题:第一,在面临贿选及胁迫的压力时,选民无法无视外在压力独立投票。其次,审计投票结果的实体可以在审计的同时获知有关投票内容的额外信息。为了解决上述两个问题,我们首次将可否认认证加密技术与身份基等式测试加密技术相结合,提出了一种支持等式测试的身份基可否认认证加密方案。该方案可以在第三方服务器不解密的情况下提供密文可比性,还能保证接收方验证发送方的身份的同时,不能向第三方证明信息来自发送方,从而保护发送方的隐私。该方案利用可否认认证加密技术在技术层面保证了选民独立投票的能力,并额外增加了身份基下的等式测试功能以确保审计机构在逻辑结构上拥有访问权限。在使用本方案的电子投票系统中,审计机构在审计投票结果的同时,不获得有关选票的任何其他信息。我们证明了我们的方案在随机预言模型中是安全的,并且可以在电子投票系统中确保不可胁迫性和可审计性。该方案与已有相关方案相比,在开销和安全性能均有较好表现的同时,实现了更为丰富的功能。此外,我们使用所提出的密码学方案设计了一个安全的电子投票系统,其...     

支持等式测试的身份基可否认认证加密方案及其在电子投票系统的应用CSCD

电子投票系统被认为是现代生活中高效提供政府服务和进一步加强民主活力的方法。但是,现有构建电子投票系统的方法存在以下问题:第一,在面临贿选及胁迫的压力时,选民无法无视外在压力独立投票。其次,审计投票结果的实体可以在审计的同时获知有关投票内容的额外信息。为了解决上述两个问题,我们首次将可否认认证加密技术与身份基等式测试加密技术相结合,提出了一种支持等式测试的身份基可否认认证加密方案。该方案可以在第三方服务器不解密的情况下提供密文可比性,还能保证接收方验证发送方的身份的同时,不能向第三方证明信息来自发送方,从而保护发送方的隐私。该方案利用可否认认证加密技术在技术层面保证了选民独立投票的能力,并额外增加了身份基下的等式测试功能以确保审计机构在逻辑结构上拥有访问权限。在使用本方案的电子投票系统中,审计机构在审计投票结果的同时,不获得有关选票的任何其他信息。我们证明了我们的方案在随机预言模型中是安全的,并且可以在电子投票系统中确保不可胁迫性和可审计性。该方案与已有相关方案相比,在开销和安全性能均有较好表现的同时,实现了更为丰富的功能。此外,我们使用所提出的密码学方案设计了一个安全的电子投票系统,其安全特性可以很好地保护电子投票系统中的选民自由和公平性。     

Distributed optimization for structured programs and its application to energy management in a building district

This paper deals with structured multi-agent optimization problems that involve coupled local and global decision variables. We propose an iterative distributed algorithm that explicitly accounts for this structure, and requires the agents to communicate only their tentative solutions for the global variables throughout iterations. Our approach extends to structured multi-agent optimization a proximal-based distributed methodology that has recently appeared in the literature. Privacy of local information is preserved and communication effort is reduced with respect to alternative distributed solutions where local and global optimization variables are grouped together and treated as a single decision vector. Multi-agent optimization problems with the considered structural properties appear in various contexts. In this paper, we apply our approach to energy management in a district where multiple buildings can communicate over a possibly time-varying network and aim at optimizing the use of shared and local resources. We illustrate the efficacy of the resulting distributed energy management algorithm by means of a detailed simulation study on a cooling problem.     

基于H.264帧间预测解码的研究及高效VLSI实现

在深入研究H.264帧间预测技术的基础上,采用三级流水线实现帧间预测解码的VLSI设计,并详细介绍了基于宏块分割的变块自适应循环控制单元,针对存储器的读写问题提出了一种交织存取方式,针对分像素插值提出了一种基于H.264标准的插值运算电路。通过仿真及在H.264解码器中的实际应用和测试,证明该设计工作稳定,能够满足H.264标准基本框架下4CIF格式图片30fps(帧/秒)实时解码的要求。     

An incremental solution for developing knowledge-based software: its application to an expert system for isokinetics interpretation

Many researchers working in the field of knowledge engineering (KE) are now concerned with identifying a model suitable for developing knowledge-based software and, especially, expert systems (ES). It is important to find a standard model that meets current needs and incorporates techniques successfully implemented in SE (object- or event-orientation, etc.), which are also of keen interest in KE.In this paper, we present an iterative and incremental solution for developing ES, according to which the system domain is derived naturally from the problem domain, thus surmounting the problems now involved in the transition from the conceptual model of the problem to the formal model of the system.As compared with conventional development models, this solution encompasses five main tools, which are:• Use cases with their respective actor interaction diagrams and activity flow diagrams in order to specify the expert system.• The concept dictionary, which allows knowledge engineers to define, bound and select the meaning of each concept used by experts.• The static conceptual model, which provides an overview (concepts and their relations) of the expert system (ES) modelled.• The control and process model, which models the knowledge and metaknowledge used by the expert to attain a goal.• An object-oriented metamodel, which outputs the formal knowledge model, providing an efficient, reusable, extendible and easy-to-implement ES architecture.To demonstrate the robustness of this solution, we describe how it was applied to an ES that interprets the graphs output by an isokinetics machine for a blind person. An isokinetics machine assesses the strength of the muscles of the leg, arm, etc.     

Evaluating software reuse alternatives: a model and its application to an industrial case study

We propose a model that enables software developers to systematically evaluate and compare all possible alternative reuse scenarios. The model supports the clear identification of the basic operations involved and associates a cost component with each basic operation in a focused and precise way. The model is a practical tool that assists developers to weigh and evaluate different reuse scenarios, based on accumulated organizational data, and then to decide which option to select in a given situation. The model is currently being used at six different companies for cost-benefit analysis of alternative reuse scenarios; we give a case study that illustrates how it has been used in practice.     

Technique for authenticating H.264/SVC and its performance evaluation over wireless mobile networks

In this paper, a bit stream-based authentication scheme for H.264/Scalable Video Coding (SVC) is proposed. The proposed scheme seamlessly integrates cryptographic algorithms and Erasure Correction Codes (ECCs) to SVC video streams such that the authenticated streams are format compliant with the SVC specifications and preserve the three-dimensional scalability (i.e., spatial, quality and temporal) of the original streams. We implement our scheme on a smart phone and study its performance over a realistic bursty packet-lossy wireless mobile network. Our analysis and experimental results show that the scheme achieves very high verification rates with lower communication overhead and much smaller decoding delay compared with the existing solutions.     

Motion mapping and mode decision for MPEG-2 to H.264/AVC transcoding

This paper describes novel transcoding techniques aimed for low-complexity MPEG-2 to H.264/AVC transcoding. An important application for this type of conversion is efficient storage of broadcast video in consumer devices. The architecture for such a system is presented, which includes novel motion mapping and mode decision algorithms. For the motion mapping, two algorithms are presented. Both efficiently map incoming MPEG-2 motion vectors to outgoing H.264/AVC motion vectors regardless of the block sizes that the motion vectors correspond to. In addition, the algorithm maps motion vectors to different reference pictures, which is useful for picture type conversion and prediction from multiple reference pictures. We also propose an efficient rate-distortion optimised macroblock coding mode decision algorithm, which first evaluates candidate modes based on a simple cost function so that a reduced set of candidate modes is formed, then based on this reduced set, we evaluate the more complex Lagrangian cost calculation to determine the coding mode. Extensive simulation results show that our proposed transcoder incorporating the proposed algorithms achieves very good rate-distortion performance with low complexity. Compared with the cascaded decoder-encoder solution, the coding efficiency is maintained while the complexity is significantly reduced.

Distributed identification and control of spatially interconnected systems with application to an actuated beam

This paper presents a case study on modelling and control of spatially interconnected systems. Considered is a vibration control problem, with experimental results on a flexible beam that is equipped with an array of piezo sensors and actuators. The sensor–actuator array induces a spatial discretization of the beam into an array of interconnected subsystems. Models are experimentally identified that have the structure of spatially interconnected systems. Based on the identified models, distributed control schemes are designed by solving a linear matrix inequality (LMI) problem that has the size of a single subsystem. Modelling and control is considered for both spatially invariant and spatially varying systems; in the latter case the system is represented as linear parameter-varying (LPV) system that is scheduled not over time but over space. Simulation and experimental closed-loop results demonstrate the practicality and efficiency of the underlying framework.     

H.264中自适应二进制算术编码的IP核设计及其FPGA验证

阐述H.264/AVC二进制算术编码的原理,论述此编码的IP核设计方案及其FPGA验证。整个设计使用VerilogHDL语言描述,在ALDEC的Active_HDL6.2平台上进行时序仿真,在Synplicity的Synplify7.0平台上进行综合。设计充分利用了硬件并行性,并进行关键路径优化和复用器重构算法优化,通过实际验证证明了设计的高效性和可行性。     

Convex optimization with an interpolation-based projection and its application to deep learning

Machine Learning - Convex optimizers have known many applications as differentiable layers within deep neural architectures. One application of these convex layers is to project points into a...     

Wavelet-based multiresolution analysis for data cleaning and its application to water quality management systems

Data cleaning techniques are useful for extracting desirable knowledge or interesting patterns from existing databases in engineering applications. The major problems of conventional techniques (e.g., Fourier Transformation Technique) are that they are (1) more appropriate in linear systems than nonlinear systems, and (2) stringently depend on state space functions. In this study a wavelet-based multiresolution analysis technique (WMAT) is proposed for reducing noises induced by complex uncertainty. The approach is applied to a river water quality simulation system for showing its practicability in data cleaning and parameter estimation. Clean data are prepared through running a Thomas’ river water quality model and polluted data are synthesized by mixing clean data with white Gaussian noises. The results show that WMAT will not distort the clean data, and can effectively reduce the noise in the polluted data. The data denoised by WMAT are furthermore used for estimating the modeling parameters. It is also indicated that the parameters estimated with the denoised data through WMAT are much closer to real values than those (1) with polluted data through WMAT and (2) with data through Fourier analysis technique. It is thus recommended that the prepared data be used for estimating the modeling parameters until being cleaned with WMAT.     

A general methodology for data-based rule building and its application to natural disaster management

Risks derived from natural disasters have a deeper impact than the sole damage suffered by the affected zone and its population. Because disasters can affect geostrategic stability and international safety, developed countries invest a huge amount of funds to manage these risks. A large portion of these funds are channeled through United Nations agencies and international non-governmental organizations (NGOs), which at the same time are carrying out more and more complex operations. For these reasons, technological support for these actors is required, all the more so because the global economic crisis is placing emphasis on the need for efficiency and transparency in the management of (relatively limited) funds. Nevertheless, currently available sophisticated tools for disaster management do not fit well into these contexts because their infrastructure requirements usually exceed the capabilities of such organizations. In this paper, a general methodology for inductive rule building is described and applied to natural-disaster management. The application is a data-based, two-level knowledge decision support system (DSS) prototype which provides damage assessment for multiple disaster scenarios to support humanitarian NGOs involved in response to natural disasters. A validation process is carried out to measure the accuracy of both the methodology and the DSS.     

A software tool for semi-automatic gridification of resource-intensive Java bytecodes and its application to ray tracing and sequence alignment

Computational Grids deliver the necessary computational infrastructure to perform resource-intensive computations such as the ones that solve the problems scientists are facing today. Exploiting Computational Grids comes at the expense of explicitly adapting the ordinary software implementing scientific problems to take advantage of Grid resources, which unavoidably requires knowledge on Grid programming. The recent notion of “gridifying” ordinary applications, which is based on semi-automatically deriving a Grid-aware version from the compiled code of a sequential application, promises users to be relieved from the requirement of manual usage of Grid APIs within their source codes. In this paper, we describe a novel gridification tool that allows users to easily parallelize Java applications on Grids. Extensive experiments with two real-world applications - ray tracing and sequence alignment - suggest that our approach provides a convenient balance between ease of gridification and Grid resource exploitation compared to manually using Grid APIs for gridifying ordinary applications.     

重用运动矢量和预测残差的MPEG-2/H.264空间分辨率转码

本文提出一种新的MPEG-2到H.264的视频转码算法.它通过充分利用MPEG-2解码过程中得到的运动矢量和宏块编码残差等信息,可显著减少H.264编码过程中宏码编码模式确定和运动估计过程的计算复杂度,并得到最终的H.264视频流.几种典型视频测试序列的仿真实验结果表明,本算法对视频质量的损失较小,有稳定的率失真性能,有利于实时转码的实现.     

Mixed H2/H infinity design for a decentralized discrete variable structure control with application to mobile robots.

In this paper, a decentralized discrete variable structure control via mixed H2/H infinity design was developed. In the beginning, the H2-norm of output error and weighted control input was minimized to obtain a control such that smaller energy consumption with bounded tracking error was assured. In addition, a suitable selection of this weighted function (connected with frequency) could reduce the effect of disturbance on the control input. However, an output disturbance caused by the interactions among subsystems, modeling error, and external load deteriorated system performance or even brought about instability. In this situation, the H infinity-norm of weighted sensitivity between output disturbance and output error was minimized to attenuate the effect of output disturbance. Moreover, an appropriate selection of this weighted function (related to frequency) could reject the corresponding output disturbance. No solution of Diophantine equation was required; the computational advantage was especially dominated for low-order system. For further improving system performance, a switching control for every subsystem was designed. The proposed control (mixed H2/H infinity DDVSC) was a three-step design method. The stability of the overall system was verified by Lyapunov stability criterion. The simulations and experiments of mobile robot were carried out to evaluate the usefulness of the proposed method.     

Adaptive critic designs for discrete-time zero-sum games with application to H(infinity) control.

In this correspondence, adaptive critic approximate dynamic programming designs are derived to solve the discrete-time zero-sum game in which the state and action spaces are continuous. This results in a forward-in-time reinforcement learning algorithm that converges to the Nash equilibrium of the corresponding zero-sum game. The results in this correspondence can be thought of as a way to solve the Riccati equation of the well-known discrete-time H(infinity) optimal control problem forward in time. Two schemes are presented, namely: 1) a heuristic dynamic programming and 2) a dual-heuristic dynamic programming, to solve for the value function and the costate of the game, respectively. An H(infinity) autopilot design for an F-16 aircraft is presented to illustrate the results.