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1.
使用扩展逻辑效力的逻辑路径尺寸优化方法   总被引:1,自引:0,他引:1  
为解决集成电路物理设计中考虑互连线影响的逻辑路径延迟优化问题,提出一个计入互连线负载的扩展的逻辑效力(ELE),并针对ELE给出一个可同时优化逻辑路径中各个逻辑门尺寸及各段互连线长度的优化流程.ELE在保留原有逻辑效力参数的同时,使用互连寄生参数提取软件获得的Ⅱ型互连线参数,实现对带有互连线负载的逻辑门的传播延迟的描述和估计;逻辑路径优化流程采用效力延迟分配策略作为初始条件来表示各段互连线负载对总效力延迟的影响,将所用目标单元库和制造工艺的物理尺寸信息作为限制条件,以ELE表达式为核心展开优化计算,辅以动态规划办法,无需迭代运算,仅通过一轮计算即可求得全部结果.实验结果表明,该流程计算任务简单,资源耗费少,可以准确、快速地获得所需的逻辑门尺寸和互连线长度;结果清晰合理,与目标单元库和工艺库完全兼容.  相似文献   

2.
IC制造技术先后进入亚微米、VDSM和LIDSM工艺,互连线延迟关注随之逐渐增强.事实上,互连线延迟早已超过了器件延迟,使IC设计重点转移到以互连线设计为核心.在对互连延迟模型、延迟影响因素、互连线延迟优化以及互连线延迟对IC设计的影响作简要分析基础上,给出了有价值的总结.  相似文献   

3.
树状结构多芯片组件互连网络延迟的研究   总被引:1,自引:1,他引:0  
大多芯片组件互连传输线的电路模型中,必须同时考虑线电感和线电阻,因此其互连延迟的研究比传统的PCB和IC互连更具复杂性。研究了具有树状拓扑结构的MCM互连网络的延迟:在明确了MCM互连延迟的独特点后,着重给出了树状结构互连网络冲激响应的矩的求法,从矩与延迟的密切关系中给出了求延迟的一种有效方法。  相似文献   

4.
集成电路设计工艺达到深亚微米领域时,互连线的延迟影响越来越大,已经超过门延迟,成为电路延迟的主要部分。因此,设计前期的互连线延迟的评估已成为集成电路设计中必须解决的问题。目前,已经提出了许多互连延迟的评估分析方法。本文主要介绍采用概率解释算法的原理及具体实现,并比较各自的优缺点。  相似文献   

5.
在系统描述当前各种典型的网关选择策略基础上,第一次给出了MANET与Internet互连的网关选择策略的分类方法,并比较和分析了这些策略的优势与不足;最后结合该领域当前的研究现状,指出MANET与Internet互连的网关选择策略的发展方向。  相似文献   

6.
当前主流高性能互连网络的端口速率已达到100~400 Gbps,其单通道速率已达到25~50 Gbps。在这种高速率的网络上传输数据,前向纠错编码是提高其可靠性的必要技术。以太网国际规范IEEE 802.3采用的前向纠错编码为RS(528,514)和RS(544,514),但是这2种码型难以满足高性能互连网络在低延迟方面的性能需求。首先,分析了RS的编码和译码结构,并定量研究了RS码型参数与编解码延迟之间的关系。接着,提出了一种面向当前高性能互连网络的新型低延迟编码—RS(271,257),并比较了该码型在占用带宽和纠错能力等方面的优缺点。最后,实现了基于RS(271,257)的低延迟网络编码子层,并对其进行了资源消耗评估和延迟性能模拟。综合考虑资源消耗、纠错能力和延迟性能3方面因素,RS(271,257)是一种理想的低延迟前向纠错码型,可满足当前面向HPC的低延迟高性能互连网络的编码子层的设计需求。  相似文献   

7.
复杂的虚拟试验系统往往需要基于异构网络环境互连的方法搭建,以满足不同试验实体问通信的实时性要求.当前,虚拟试验系统中存在大量的网间实体交互感知的需求,而且需求随着试验进程的推进而不同;当系统中网络拓扑固定不变时,必将导致网问信息传输延迟超过试验要求.提出了网间实体感知度的评价指标,通过分析网间信息传输延迟的组成,提出了以改变"实体-网络"对应关系为主要手段的网间实体迁移方法;研究了实体迁移的发起机制和仲裁策略.最后在HLA/RTI与实时网互连环境下验证了方法的正确性.  相似文献   

8.
异构无线网络互连是当前研究的热点,针对异构无线网络互连的通用结构问题,提出了一种基于IP一体化交换机制的互连互通策略,重点研究了互连总体结构、互连核心模块设计等关键技术,并通过对互连策略、IP映射和IP封装技术的性能仿真结果分析,验证了互连互通策略的有效性.  相似文献   

9.
为了避免以太网通信中大量短帧数据包引起通信阻塞问题,LwIP 协议栈采用了 Nagle 算法和延迟 ACK 策略提高以太网通信效率.嵌入式以太网通信以短帧数据包为主,Nagle 算法和延迟 ACK 策略大大降低了通信的实时性,这在单向数据传输的应用中尤为明显.本文将 LwIP协议栈中的延迟 ACK定时器独立出来,并提出了一种基于数据统计的自适应延迟 ACK定时算法,该算法可以根据上位机发送数据包的周期自主修改延迟 ACK 定时器周期.最后设计了通信实时性测试实验,证实了延迟 ACK定时周期可以在1 s 左右跟踪上位机的数据发送周期,自适应的定时周期约为发送周期的80%~100%,且通信延迟小于1 ms,该改进在保证 ARM使用效率的前提下提高了以太网通信的实时性.  相似文献   

10.
通过硬件对归约进行支持是高性能互连网络发展的一种趋势.建立了无冲突和冲突条件下的归约延迟模型,分析了串行轮询、剩余报文集中和先到先服务3种调度策略对归约延迟的影响,表明了剩余报文集中策略能够取得多个归约操作在路由器上平均延迟的最小值.为了准确评测各种调度策略的性能,基于OMNeT++开发了微片级互连网络模拟器.模拟结果表明,先到先服务策略能够取得最优的性能,而在低维度互连网络中,串行轮询策略能取得良好的性价比.  相似文献   

11.
Uncertainty is a characteristic element in the early planning phase of assembly systems. Today, planning methods normally apply precise data and do not take uncertainty into account. In this context, customer demand is one of the most important planning parameters for the design of assembly systems, providing specifications for the quantity of products to be assembled. This parameter is essential for dimensioning assembly systems. However, in the early planning phase it is often based on forecasts and therefore subject to uncertainty. This paper proposes a new method for designing manual assembly systems. For that purpose, interval arithmetic is used to describe customer demand with intervals, which allows the uncertainty of this planning parameter to be taken into account. Results of the proposed method are compared with those of a scenario-based method by means of a practical application example of a self-balanced scooter production. It is shown that interval arithmetic provides additional information indicating robustness of system design.  相似文献   

12.
刘铮  马正新  石荣 《计算机应用研究》2011,28(12):4691-4634
用户分簇是移动自组网通信需要解决的基本问题.从分簇结构与频率规划的角度出发,提出一种基于位置信息的分簇算法.该算法采用估计节点运动速度、引入虚拟网络中心节点、预警簇头失效、均衡簇间负载等方法,达到既形成稳定合理的分簇结构又易于频率规划的目的.仿真结果表明,基于位置信息的分簇算法极大地改善了吞吐量、丢包率及延时等网络性能,可用于多节点、中高速移动环境.  相似文献   

13.
14.
高层次综合中面向功耗优化的方法与技术   总被引:4,自引:0,他引:4  
介绍了高层次综合阶段面向电路功耗的主要优化方法及其研究进展.集成电路设计制造工艺的持续发展使得电路功耗逐步超越了原有的面积、时延等指标,一举成为设计的主导因素.研究表明:集成电路设计层次越高,对电路功耗的优化潜力也就越大,这就要求设计人员在高层次综合阶段即开始考虑对功耗进行有效的降低和优化.对本领域具有代表性的算法进行了系统的描述,并且对这些算法的基本思路进行了相应的分析和总结.  相似文献   

15.
Extensive use of neural network applications prompted researchers to customize a design to speed up their computation based on ASIC implementation. The choice of activation function (AF) in a neural network is an essential requirement. Accurate design architecture of an AF in a digital network faces various challenges as these AF require more hardware resources because of its non-linear nature. This paper proposed an efficient approximation scheme for hyperbolic tangent (tanh) function which purely based on combinational design architecture. The approximation is based on mathematical analysis by considering maximum allowable error in a neural network. The results prove that the proposed combinational design of an AF is efficient in terms of area, power and delay with negligible accuracy loss on MNIST and CIFAR-10 benchmark datasets. Post synthesis results show that the proposed design area is reduced by 66% and delay is reduced by nearly 16% compared to state-of-the-art.  相似文献   

16.
Uncertainty about possible train delays has an impact on train trips, as the exact arrival time is unknown during trip planning. Delays can lead to missing a connecting train at the transfer station, or to coming too late to an appointment at the destination. Facing this uncertainty, the traveler may wish to use an earlier train or a different connection arriving well before the appointment. Currently, train trip planning is based on scheduled times of connections between two stations. Information about approximate delays is only available shortly before train departure. Although several visualization approaches can show temporal uncertainty, we are not aware of any visual design specifically supporting trip planning, which can show delay uncertainty and its impact on the connections. We propose and evaluate a visual design which extends train trip planning with delay uncertainty. It shows the scheduled train connections together with their expected train delays as well as their impacts on both the arrival time, and the potential of missing a transfer. The visualization also includes information about alternative connections in case of these critical transfers. In this way the user is able to judge which train connection is suitable for a trip. We conducted a user study with 76 participants to evaluate our design. We compared it to two alternative presentations that are prominent in Germany. The study showed that our design performs comparably well for tasks concerning train schedules. The additional uncertainty display as well as the visualization of alternative connections was appreciated and well understood. The participants were able to estimate when they would likely arrive at their destination despite possible train delays while they were unable to estimate this with existing presentations. The users would prefer to use the new design for their trip planning.  相似文献   

17.
To meet the competitive demands of modern manufacturing, it is necessary to reduce design times and enrich decision making by integrating process planning into the design activity using Concurrent Engineering principles. Although this is traditionally done through the interaction between designers and process planners, it is perhaps more desirable for a CAD system to have the functionality necessary to automatically advise the designer of the shop floor implications of design decisions. Cutting tool selection is an essential thread linking feature-based design of machined parts to process planning. Thus, the implementation of tooling considerations into design is an important requirement for an integrated CAD/CAPP system. This paper defines an architecture to enable the vertical integration of tooling considerations from early design to process planning and scheduling. The architecture is based on a five-level tool selection procedure which is mapped to a time-phased aggregate, management and detailed process planning framework. This paper draws on literature and the results of an industrial survey to identify the tooling methods suitable for integration within a CAD system and categorises them into the five levels of tool selection. The functions are then placed on a time-dependent framework that covers the progression of a product from design to process planning. The new functionality is being implemented as an object-oriented application called VITool, which is being developed so that it can be fully integrated within an existing CAD system.  相似文献   

18.
This work describes the implementation of an integrated web-based CAD/CAPP/CAM system for the remote design and manufacture of feature-based cylindrical parts. This system, called WebMachining (), was developed in an e-manufacturing context, and the use of features allows the integration among the activities of collaborative design (WebCADbyFeatures), generative process planning (WebCAPP) and manufacturing (WebTurning). Through the WebCADby Features agent-based collaborative design module, cylindrical parts are modeled based on the synthesis of design features, in a Concurrent Engineering context. The WebCAPP generative CAPP module maps design features into machining features (including turning, milling, and drilling), and the mapping considers the setup, geometry, and operation. It uses a data structure similar to STEP-NC, and the generated process plans are nonlinear (i.e. they have alternatives). The WebTurning module performs the remote manufacture of the part, and it is based on a client–server architecture, where: (a) the servers are represented by the programs located at a workstation (Linux platform), which are connected to the machine tool through an Ethernet network interface; (b) the client is represented by a Java Applet. Some examples are provided in this paper, illustrating the remote design, process planning and manufacture of parts in a CNC turning center.  相似文献   

19.
The output stabilization problem for a linear system with an unknown bounded time-varying input delay is considered. The interval observation technique is applied in order to obtain guaranteed interval estimate of the system state. The procedure of the interval observer synthesis uses lower and upper estimates of the unknown delay and requires to solve a special Silvester’s equation. The interval predictor is introduced in order to design a linear stabilizing feedback. The control design procedure is based on Linear Matrix Inequalities (LMI). The theoretical results are supported by numerical simulations and compared with a control design scheme based on a Luenberger-like observer.  相似文献   

20.
The deregulation of the electricity market made the open communication infrastructure an exigent need for future power system. In this scenario dedicated communication links are replaced by shared networks. These shared networks are characterized by random time delay and data loss. The random time delay and data loss may lead to system instability if they are not considered during the controller design stage. Load frequency control systems used to rely on dedicated communication links. To meet future power system challenges these dedicated networks are replaced by open communication links which makes the system stochastic. In this paper, the stochastic stabilization of load frequency control system under networked environment is investigated. The shared network is represented by three states which are governed by Markov chains. A controller synthesis method based on the stochastic stability criteria is presented in the paper. A one-area load frequency control system is chosen as case study. The effectiveness of the proposed method for the controller synthesis is tested through simulation. The derived proportion integration (PI) controller proves to be optimum where it is a compromise between compensating the random time delay effects and degrading the system dynamic performance. The range of the PI controller gains that guarantee the stochastic stability is determined. Also the range of the PI controller gains that achieve the robust stochastic stability is determined where the decay rate is used to measure the robustness of the system.  相似文献   

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