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P4 serves as a programming language for configuring flexible and programmable network data planes, facilitating the development of custom protocols and programmable switches, and driving innovation in software-defined networking and network function virtualization. While the Linux container based network emulator, Mininet, coupled with the BMv2 software P4 switch, is widely used for rapid prototyping of P4-based applications, BMv2’s diminished performance raises fidelity concerns under high traffic and large network scenarios. In this paper, we introduce a lightweight virtual time system integrated into Mininet with BMv2 to enhance fidelity and scalability. By applying a time dilation factor (TDF) to interactions between containers and the physical machine, we optimize the emulated P4 network’s perceived speed from the application processes’ perspective. System evaluation demonstrates accurate emulation of significantly larger networks under high loads with minimal system overhead. We showcase our system’s utility through two network applications: an emulation of a TCP SYN flood attack and an ECMP load balancer. Evaluating against a production-grade software switch, Open vSwitch, and a physical testbed, we highlight the virtual time system’s improvement in temporal fidelity despite the observed performance degradation in BMv2 software switches. 

We demonstrate nano-structuring and the reduction of mid-spatial-frequency errors using femtosecond laser figuring and finishing. For the first time, to the best of our knowledge, we have corrected mid-spatial-frequency errors from 17 nm to one nanometer in magnitude. We established a method for creating and predicting periodic nanostructures. This demonstration opens the path of using femtosecond lasers to correct surface errors that inherently result from sub-aperture manufacturing techniques. 

Abstract We consider a class of one-dimensional nonlinear Schrödinger equations of the form $$ \begin{align*} & (i\partial_{t}+\Delta)u = [1+a]|u|^{2} u. \end{align*}$$For suitable localized functions $$a$$, such equations admit a small-data modified scattering theory, which incorporates the standard logarithmic phase correction. In this work, we prove that the small-data modified scattering behavior uniquely determines the inhomogeneity $$a$$.