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151.
In this paper, we investigate the dynamic properties of an overlapping generations’ model with capital accumulation and publicly funded inventions under three different expectations: perfect foresight, myopic expectations and adaptive expectations. We show that considering productive public expenditures in the model will increase the dimension of the dynamical system. To study the dynamic behavior of a high-dimensional dynamical system, we focus on the case when the elasticity of publicly funded invention to output is small and approximate the system by using a one-dimensional dynamical system. This approximation method provides an efficient way to rigorously prove the existence of chaos in high-dimensional dynamical systems. We show that when agents are perfectly foresighted, there exists a unique, nontrivial steady state which is a global attractor. Cycles or even chaos may occur under myopic and adaptive expectations when the inter-temporal elasticity of substitution of consumption is large enough. Furthermore, we find that the impact of fiscal policy is sensible to the expectation formation.  相似文献   
152.
移动通信网的公共预警系统研究   总被引:3,自引:1,他引:2  
文中根据公共预警系统的需求提出了几种基于移动通信网络的ETWS的解决方案.基于公共预警系统对速度的需要和优化的信息传送的特征,分析了公共预警系统的各项需求,给出预警通知提供方和移动通信网络的信息交互过程,并基于现有的移动通信网络,提出了带特殊IMSI寻呼的CBS、增强的CBS和E-MBMS三种解决方案.其中,增强的CBS方案更为符合全球的需求.  相似文献   
153.
田宝民 《电子质量》2001,(10):21-22,25
ESAM-嵌入式安全控制模块作为一种完全灵巧的硬件平台,在嵌入式软件的版权保护领域,以发挥重要的作用,作为一种软件保护的硬件解决方法,可以使软件的销售有一量化的标准,将复杂的软件销售变成简单的硬件销售。  相似文献   
154.
Building a quantum key distribution network is crucial for practical quantum cryptography. We present a scheme to build a star topology quantum key distribution network based on wavelength division multiplexing which, with current technology, can connect at least a hundred users. With the scheme, a 4-user demonstration network was built up and key exchanges were performed.  相似文献   
155.
田备 《电声技术》2001,(12):58-58
论述了校园多媒体广播系统中数据通信的又一差错纠错方法--卷积码,其编码器和大数逻辑译码器较简单,纠错性能更好。  相似文献   
156.
随着有线电视的发展,各地方政府都非常关注有线调频广播的发展,为了使所采用的技术方案能在原有有线电视网络基础上发展有线调频广播,做到既经济、先进又安全,广电部门面临着不同的选择,提出一种有线调频广播技术方案供同行参考.  相似文献   
157.
The increasing use of network-connected embedded devices and online transactions creates a growing demand of network security for embedded systems. The security requirements, such as authentication, confidentiality and integrity, always make computationally intensive processes and can easily become the bottleneck of the related applications. In this paper we implement Elliptic Curve Cryptography (ECC) (Miller in Lecture Notes in Computer Science, vol. 218, pp. 417–426, 1985; Koblitz in Math. Comput. 48:203–209, 1987) on an embedded multicore system, and explore the task scheduling methods in different levels. First, we propose an instruction scheduling method that utilizes all the cores to perform one modular operation in parallel. Second, we perform multiple modular operations with multiple cores in parallel. The performance of those two implementations is compared and a scheduling method combining these two types of parallelism is proposed. We discuss the details of our proposed method by using an FPGA implementation of ECC over a prime field.  相似文献   
158.
In quantum key distribution (QKD), there are some security loopholes opened by the gaps between the theoretical model and the practical system, and they may be exploited by eavesdroppers (Eve) to obtain secret key information without being detected. This is an effective quantum hacking strategy that seriously threatens the security of practical QKD systems. In this paper, we propose a new quantum hacking attack on an integrated silicon photonic continuous-variable quantum key distribution (CVQKD) system, which is known as a power analysis attack. This attack can be implemented by analyzing the power originating from the integrated electrical control circuit in state preparation with the help of machine learning, where the state preparation is assumed to be perfect in initial security proofs. Specifically, we describe a possible power model and show a complete attack based on a support vector regression (SVR) algorithm. The simulation results show that the secret key information decreases with the increase of the accuracy of the attack, especially in a situation with less excess noise. In particular, Eve does not have to intrude into the transmitter chip (Alice), and may perform a similar attack in practical chip-based discrete-variable quantum key distribution (DVQKD) systems. To resist this attack, the electrical control circuit should be improved to randomize the corresponding power. In addition, the power can be reduced by utilizing the dynamic voltage and frequency scaling (DVFS) technology.  相似文献   
159.
对大客户的融合通信业务需求特点进行了分析,探讨了相关技术在大客户融合通信接入中的应用场景和发展趋势,并对大客户融合通信业务接入建设模式进行了分析。  相似文献   
160.
Virtualization and distributed parallel architecture are typical cloud computing technologies. In the area of virtualization technology, this article discusses physical resource pooling, resource pool management and use. cluster fault location and maintenance, resource pool grouping, and construction and application of heterogeneous virtualization platforms. In the area of distributed technology, distributed file system and Key/Value storage engine are discussed. A solution is proposed for the host bottleneck problem, and a standard storage interface is proposed for the distributed file system. A directory-based storage scheme for Key/Value storage engine is also proposed.  相似文献   
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