共查询到20条相似文献,搜索用时 15 毫秒
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1971,59(12):1711-1711
A statistical method is used to find the worst case number of switchings per clock pulse of large digital integrated circuits containing n gates to be 2.12√n. This result is useful in designing decoupling capacitors and in measuring the interference generated. 相似文献
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Cloud computing enables the provisioning of resources in a reliable and on-demand manner. With the increasing importance of the network bandwidth in the Cloud environment, the networking related resources need to be optimally allocated together with the traditional Cloud computing resources. In addition, the significant growth of the global data center traffic raises the challenge of supporting demands with large bandwidth requirements for the Cloud provider. In our paper, we consider the network-efficient virtualized cloud infrastructure provisioning problem in IP over elastic optical network (IP-over-EON) based on the data center as a service model. The elastic optical network is adopted to provide spectrum and cost-efficient networking resources for large bandwidth requests in our work. We develop mixed integer linear programming formulations to construct the mathematic model for this problem and propose a cost-optimized heuristic to solve this problem. To investigate the cost and blocking rate for the served demands, different modulation formats are compared in the EON layer, and the sliceable bandwidth-variable transponders and optical traffic grooming technology are considered. The experimental results show that different modulation formats that are adopted in the EON layer will have different impacts on the total cost and demand blocking rate for the same data set size. Also the use of SBVT will reduce the total cost no matter which modulation format is adopted, and the reduction is related to the bandwidth requirement of the demands. 相似文献
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Habal H. Mayaram K. Fiez T.S. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2005,13(3):330-338
A new method is presented to compress switching information in large synchronous digital circuits. This is combined with an efficient generation of digital cell library noise signatures and results in an accurate estimation of the switching noise in digital circuits. It provides a practical approach to generating the digital switching noise for simulating substrate coupling noise in mixed-signal ICs. Nearly two orders of magnitude reduction in the memory and simulation time are achieved using this approach without significant loss of accuracy. 相似文献
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A method for the design of cost-effective one-stage PCM switching networks composed of uniform time-space elements is proposed. These one-stage networks can be used as submodules for multistage networks, having, in many cases, fewer elements than currently known networks. 相似文献
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Digital switching of communication channels is now a practical alternative to analog switching. This application of well-known principles is economically possible due to the availability of low-cost LSI devices and the significant benefits of integrating digital transmission with digital switching. This paper reviews the key elements of a digital switch and summarizes the current debate relating to the design of a local digital switch. 相似文献
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A method for the design of economic and reliable PCM switching networks composed of uniform time-space elements is proposed. The described networks can be used in switching systems containing concentrators connected by an even number of PCM links to a main switching network. 相似文献
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This article proposes a solution for two issues in current communications. Firstly, that IMS suffers from lack of clients. Secondly, that mobile operators want to give the subscriber a possibility to access their VoIP network and efficiently cover special, densely populated areas like airports. To address these problems, we have developed a novel service architecture, which allows 2G subscribers access to a SIP based VoIP network via WiFi complying security standards. User authentication and authorization is based on the EAP-SIM algorithm. Integrity and confidentiality is provided by IPSec connection established using parameters derived from authentication triplets. Consequently, all security-related issues can be performed exclusively using the Subscriber Identity Module (SIM). We have tested and verified the proposed architecture with a mobile phone and have proven the correctness of our approach. The main drawback that remains is the difficulty of IPSec implementation that can be bypassed by a special application. 相似文献
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Jian-Guo Zhang 《Broadcasting, IEEE Transactions on》1999,45(3):283-293
This paper presents the design of a new type of integrated services digital broadcasting (ISDB) systems which use a multirate optical fiber code-division multiplexing (OF-CDM) technique. The proposed system can efficiently multiplex various kinds of digital signals with multiple bit rates. This is feasibly achieved by using strict optical orthogonal codes of both auto- and cross-correlation constraints being “1” in multirate OF-CDM systems. Moreover, the low-cost design of OF-CDM transmitters is presented, and experimental demonstrations are also carried out. The measured results show that a transmission distance up to 13 km can be feasibly accomplished by using the proposed transmitter design and the external optical injection-locking scheme. It is expected that the proposed ISDB systems can be employed to cost-effectively transmit fast ethernet (125 Mbit/s), FDDI (125 Mbit/s), ATM (155 Mbit/s), and ESCON (200 Mbit/s) protocol data. Their potential applications include Internet services and multimedia broadcasting, such as videoconferencing, video on demand, HDTV, distance learning, and World Wide Web 相似文献
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A new type of one-stage switching network comprising digital switching matrices is proposed. In many cases such a network contains fewer matrices than currently known networks. The proposed one-stage networks can be used as submodules for cost-effective multistage networks.<> 相似文献
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Ahmed H.M. Gallon R. Malis Moy J. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1997,85(12):1984-1997
Internet protocol (IP) switching is emerging as a critical technology for improving the speed and scalability of the Internet. This paper discusses IP Navigator, a form of IP switching developed specifically for use in core network backbones, such as Internet service provider networks and major corporate backbones. IP Navigator combines the high speed and quality of service capabilities of asynchronous transfer mode (ATM) with the scalability and flexibility of IP. This paper presents an overview of the techniques that have been developed for operating IP over ATM. We outline the IP Navigator design and compare IP Navigator with other IP switching approaches 相似文献
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QoS provisioning in IEEE 802.11 networks is a nontrivial task due to a certain degree of randomness in the contention-based medium access control protocol. The problem often resides in the fact that flows belonging to the same service class use the same MAC parameters regardless of their respective bit rates. Assigning static MAC parameters confines WLAN deployment possibilities, and often leads to throughput fairness rather than perceived QoS fairness. This creates situations where network resources as well as their potential profitability are underex-ploited. Restricting the volume of traffic load carried by the network is a primordial task in order to preserve QoS performances of active multimedia services. In this article we review existing approaches to deliver QoS to real-time services in order to gain thorough insight into inhibiting factors inherent to contention-based 802.11 networks. The emphasis is put on studying the possible means to sustain QoS guarantees, which is of utmost importance for network operators willing to commit theirs underlying resources through service level agreements. 相似文献
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Methods for the design of cost-effective one-stage PCM switching networks composed of digital switching matrices are proposed. These one-stage networks have, in many cases, a more regular structure and contain fewer elements than networks currently known. The proposed one-stage networks can also be used as submodules for multistage networks.<> 相似文献
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The recent trend toward distributed processing in stored-program-controlled (SPC) switching systems has resulted in increased use of firmware. The impact of firmware on SPC switching system reliability and maintainability, after sale of the product to user companies, can be substantial. The author examines both life cycle practices for firmware and the impact of firmware on switching systems, and he suggests means to lessen this impact. He examines present firmware technologies, which indicate a trend toward electrically erasable/programmable firmware devices; shows the importance of parallel development methodologies for firmware and software; shows the advantages of loose coupling between firmware and software; shows a relationship between the quality of firmware product and the quality of service a telephone company provides; and suggest a classification of firmware devices 相似文献