For the traditional steganographic method of Jsteg, the emmbedment of secret message is completed by dividing cover-image into nonoverlapping blocks of 8×8 pixels, discrete cosine transform （DCT） transforming, ...For the traditional steganographic method of Jsteg, the emmbedment of secret message is completed by dividing cover-image into nonoverlapping blocks of 8×8 pixels, discrete cosine transform （DCT） transforming, and using the standard 8×8 quantization table to quantize. In this paper, a novel steganographic method based on the JPEG quantization table modification is presented. Instead of dividing cover-image into 8×8 blocks, nonoverlapping blocks of 16×16 pixels is used. Both theoretical anlysis and experiment results show that the new methods has larger steganography capacity and better stego-image quality, compared with the method of Jsteg and Chang＇s展开更多
A new two-stage soft real-time scheduling algorithm based on priority table was proposed for task dispatch and selection in cluster systems with inaccurate parameters. The inaccurate characteristics of the system were...A new two-stage soft real-time scheduling algorithm based on priority table was proposed for task dispatch and selection in cluster systems with inaccurate parameters. The inaccurate characteristics of the system were modeled through probability analysis. By taking into account the multiple important system parameters, including task deadline, priority, session integrity and memory access locality, the algorithm is expected to achieve high quality of service. Lots of simulation results collected under different load conditions demonstrate that the algorithm can not only effectively overcome the inaccuracy of the system state, but also optimize the task rejected ratio, value realized ratio, differentiated service guaranteed ratio, and session integrity ensured ratio with the average improvement of 3.5%, 5.8%, 7.6% and 5. 5%, respectively. Compared with many existing schemes that cannen deal with the inaccurate parameters of the system, the proposed scheme can achieve the best system performance by carefully adjusting scheduling probability. The algorithm is expected to be promising in systems with soft real-time scheduling requirement such as E-commerce applications.展开更多
在智能电网通信架构持续演化的背景下,变电站对信息流控制系统提出高密度并发、精细调度与异常自愈等多重能力要求,推动软件定义网络(Software Defined Network,SDN)技术向变电站场景深入渗透。本研究构建一套基于SDN架构的变电站智能...在智能电网通信架构持续演化的背景下,变电站对信息流控制系统提出高密度并发、精细调度与异常自愈等多重能力要求,推动软件定义网络(Software Defined Network,SDN)技术向变电站场景深入渗透。本研究构建一套基于SDN架构的变电站智能化信息流控制系统,围绕转发结构重构、状态动态建模、资源分配优化与故障联动反馈4个维度展开系统性设计,形成由控制器统一调度、策略解析层动态编排、转发执行层实时响应的分层联控体系。测试结果表明,该系统在多个方面均优于传统架构,可为构建柔性可编程的变电站通信平台提供方法与路径。展开更多
基金Supported by the National Natural Science Foundation of China(50803016)the Fundamental Research Funds for the Central Universities
文摘For the traditional steganographic method of Jsteg, the emmbedment of secret message is completed by dividing cover-image into nonoverlapping blocks of 8×8 pixels, discrete cosine transform （DCT） transforming, and using the standard 8×8 quantization table to quantize. In this paper, a novel steganographic method based on the JPEG quantization table modification is presented. Instead of dividing cover-image into 8×8 blocks, nonoverlapping blocks of 16×16 pixels is used. Both theoretical anlysis and experiment results show that the new methods has larger steganography capacity and better stego-image quality, compared with the method of Jsteg and Chang＇s
基金Project(60573127) supported by the National Natural Science Foundation of China project(05JJ40131) supported by theNatural Science Foundation of Hunan Province
文摘A new two-stage soft real-time scheduling algorithm based on priority table was proposed for task dispatch and selection in cluster systems with inaccurate parameters. The inaccurate characteristics of the system were modeled through probability analysis. By taking into account the multiple important system parameters, including task deadline, priority, session integrity and memory access locality, the algorithm is expected to achieve high quality of service. Lots of simulation results collected under different load conditions demonstrate that the algorithm can not only effectively overcome the inaccuracy of the system state, but also optimize the task rejected ratio, value realized ratio, differentiated service guaranteed ratio, and session integrity ensured ratio with the average improvement of 3.5%, 5.8%, 7.6% and 5. 5%, respectively. Compared with many existing schemes that cannen deal with the inaccurate parameters of the system, the proposed scheme can achieve the best system performance by carefully adjusting scheduling probability. The algorithm is expected to be promising in systems with soft real-time scheduling requirement such as E-commerce applications.
文摘在智能电网通信架构持续演化的背景下,变电站对信息流控制系统提出高密度并发、精细调度与异常自愈等多重能力要求,推动软件定义网络(Software Defined Network,SDN)技术向变电站场景深入渗透。本研究构建一套基于SDN架构的变电站智能化信息流控制系统,围绕转发结构重构、状态动态建模、资源分配优化与故障联动反馈4个维度展开系统性设计,形成由控制器统一调度、策略解析层动态编排、转发执行层实时响应的分层联控体系。测试结果表明,该系统在多个方面均优于传统架构,可为构建柔性可编程的变电站通信平台提供方法与路径。
