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All analytical and simulation research on ad~hoc wireless networks must necessarily model radio propagation using simplifying assumptions. We provide a comprehensive review of six assumptions that are still part of many ad hoc network simulation studies, despite increasing awareness of the need to represent more realistic features, including hills,(More)
This paper describes the Scalable Simulation Framework (SSF), a discrete event modeling API designed for the construction and simulation of very large networks. SSF can execute detailed simulations of complex topology networks with a million or more concurrent TCP/IP ows. We describe the overall architecture of SSF, the architecture of the network modeling(More)
Robust high-density subthreshold SRAMs are indispensable for emerging ultra-low power applications such as implantable devices, medical instruments, and wireless sensor networks. Conventional 6T SRAMs in the subthreshold region fail to deliver the density and yield requirements due to the reduced static noise margin (SNM), poor writability, limited number(More)
In the scenario of a natural catastrophe or a terrorist attack, a large number of self-organizing, low-cost sensor devices can be deployed over the affected area. Each device equipped with its own power source, sensor, processing unit and low-power radio, can be imbued with the intelligence to seek out its neighbours and join in a wireless network spanning(More)
Computer simulation is the most common approach to studying wireless ad-hoc routing algorithms. The results, however, are only as good as the models the simulation uses. One should not underestimate the importance of <i>validation</i>, as inaccurate models can lead to wrong conclusions. In this paper, we use direct-execution simulation to validate radio(More)
Data centers consume significant amounts of energy. As severs become more energy efficient with various energy saving techniques, the data center network (DCN) has been accounting for 20% or more of the energy consumed by the entire data center. While DCNs are typically provisioned with full bisection bandwidth, DCN traffic demonstrates fluctuating(More)
This paper considers a technique for composing global (barrier-style) and local (channel scanning) synchronization protocols within a single parallel discrete-event simulation. Composition is attractive because it allows one to tailor the synchronization mechanism to the model being simulated. We first motivate the problem by showing the large performance(More)
Rapid growth in wireless communication systems motivates the development of technology supporting the simulation of large-scale wireless systems. However, it is widely recognized that wireless communications do not have substantial "lookahead" needed by conservative synchronization protocols. This paper focuses on identifying and exploiting lookahead for(More)
A voltage scalable 0.26 V, 64 kb 8T SRAM with 512 cells per bitline is implemented in a 130 nm CMOS process. Utilization of the reverse short channel effect in a SRAM cell design improves cell write margin and read performance without the aid of peripheral circuits. A marginal bitline leakage compensation (MBLC) scheme compensates for the bitline leakage(More)
There are at least three major obstacles thwarting wide-spread adoption of parallel discrete-event simulation (a) lack of need, (b) lack of tools, (c) lack of predictability in behavior and performance. The plain truth is that most simulation studies can be adequately done on ordinary serial computers. Parallel simulation tools are products of re-search(More)