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41.
It has recently been shown that authenticated Byzantine agreement,
in which more than a third of the parties are corrupted, cannot be
securely realized under concurrent or parallel (stateless)
composition. This result puts into question any usage of
authenticated Byzantine agreement in a setting where many
executions take place. In particular, this is true for the whole
body of work of secure multi-party protocols in the case that a
third or more of the parties are corrupted. This is because these
protocols strongly rely on the extensive use of a broadcast
channel, which is in turn realized using authenticated Byzantine
agreement. We remark that it was accepted folklore that the use of
a broadcast channel (or authenticated Byzantine agreement) is
actually essential for achieving meaningful secure multi-party
computation whenever a third or more of the parties are corrupted.
In this paper we show that this folklore is false. We present a
mild relaxation of the definition of secure computation allowing
abort. Our new definition captures all the central security issues
of secure computation, including privacy, correctness and
independence of inputs. However, the novelty of the definition is
in decoupling the issue of agreement from these issues. We
then show that this relaxation suffices for achieving secure
computation in a point-to-point network. That is, we show that
secure multi-party computation for this definition can be achieved
for any number of corrupted parties and without a
broadcast channel (or trusted pre-processing phase as required for
running authenticated Byzantine agreement). Furthermore, this is
achieved by just replacing the broadcast channel in known
protocols with a very simple and efficient echo-broadcast
protocol. An important corollary of our result is the ability to
obtain multi-party protocols that remain secure under composition,
without assuming a broadcast channel. 相似文献
42.
用CPLD实现总线扩展 总被引:1,自引:1,他引:0
文中介绍了一种用CPLD实现的总线扩展技术,该设计具有灵活和可编程的特点,并在单片机和DSP外部总线扩展中得到了多次应用。 相似文献
43.
44.
We say that a distribution over {0,1}n is (ε,k)-wise independent if its restriction to every k coordinates results in a distribution that is ε-close to the uniform distribution. A natural question regarding (ε,k)-wise independent distributions is how close they are to some k-wise independent distribution. We show that there exist (ε,k)-wise independent distributions whose statistical distance is at least nO(k)·ε from any k-wise independent distribution. In addition, we show that for any (ε,k)-wise independent distribution there exists some k-wise independent distribution, whose statistical distance is nO(k)·ε. 相似文献
45.
46.
In this study, crisp and fuzzy multiple-goal optimization approaches are respectively introduced to design an optimal biocompatible solvent to a two-stage extractive fermentation with cell recycling for ethanol production. When designing a biocompatible solvent for the extractive fermentation process, many issues, such as extractive efficiency, conversion, amount of solvent utilized and so on, have to be considered. An interactive multiple-goal design procedure is introduced to determine a trade-off result in order to satisfy such contradicted goals. Both approaches could be iterated to solve the interactive multiple-goal design problem in order to yield a trade-off result. However, the crisp optimization design is a tedious task that requires the designer to provide various pairs of the upper bounds for the design problem to obtain the corresponding solution. The fuzzy optimization approach is able to be trade-off several goals simultaneously and to yield the overall satisfactory grade for the product/process design problem. 相似文献
47.
提出了一种采用数字聚焦方法的微电阻率测井仪器设计方案,其主要特点利用DSP集成芯片的数字信号处理优势,实现仪器的控制与测量,并通过软件滤波和聚焦处理获得视电阻率。该设计用超大规模集成电路DSP及软件处理取代了老式微球形聚焦测井仪器复杂的硬件监控、反馈、检波和测量线路,提高了仪器的可靠性和测量精度。对仪器原理进行了较详细的说明,在DSP技术应用于测井井下仪器方面做了有益的探索。 相似文献
48.
小容量机组保护监控一体化 总被引:2,自引:2,他引:0
以数字信号处理器(DSP)和复杂可编程逻辑器件(CPLD)为硬件平台,研制了新一代面向中、小型水电站的综合自动化模块.充分发挥MB40智能可编程逻辑控制器(iPLC)及MB100系列保护测控系统的技术优势,将小型水电站的保护装置做成模块插件,融入监控系统,降低了小型水电站自动化设备的成本,为推出真正意义上的面向小型水电站的"五合一"产品打下坚实的基础. 相似文献
49.
P.-C. Chung Author Vitae C.-L. Huang Author Vitae E.-L. Chen Author Vitae 《Pattern recognition》2007,40(3):1066-1077
Motion vector plays one significant feature in moving object segmentation. However, the motion vector in this application is required to represent the actual motion displacement, rather than regions of visually significant similarity. In this paper, region-based selective optical flow back-projection (RSOFB) which back-projects optical flows in a region to restore the region's motion vector from gradient-based optical flows, is proposed to obtain genuine motion displacement. The back-projection is performed based on minimizing the projection mean square errors of the motion vector on gradient directions. As optical flows of various magnitudes and directions provide various degrees of reliability in the genuine motion restoration, the optical flows to be used in the RSOFB are optimally selected based on their sensitivity to noises and their tendency in causing motion estimation errors. In this paper a deterministic solution is also derived for performing the minimization and obtaining the genuine motion magnitude and motion direction. 相似文献
50.
本文先介绍了TMS320C5000 DSP中的重要存储器概念:存储器空间,装载地址和运行地址。然后在将.const段分配到程序空间的实例中对 这些概念进行具体的阐述,并给出了基于普通C语言编程和基于实时软件基础DSP/BIOS的编程中的详细实现方法。 相似文献