5,930 research outputs found
Synthesis of Stochastic Flow Networks
A stochastic flow network is a directed graph with incoming edges (inputs)
and outgoing edges (outputs), tokens enter through the input edges, travel
stochastically in the network, and can exit the network through the output
edges. Each node in the network is a splitter, namely, a token can enter a node
through an incoming edge and exit on one of the output edges according to a
predefined probability distribution. Stochastic flow networks can be easily
implemented by DNA-based chemical reactions, with promising applications in
molecular computing and stochastic computing. In this paper, we address a
fundamental synthesis question: Given a finite set of possible splitters and an
arbitrary rational probability distribution, design a stochastic flow network,
such that every token that enters the input edge will exit the outputs with the
prescribed probability distribution.
The problem of probability transformation dates back to von Neumann's 1951
work and was followed, among others, by Knuth and Yao in 1976. Most existing
works have been focusing on the "simulation" of target distributions. In this
paper, we design optimal-sized stochastic flow networks for "synthesizing"
target distributions. It shows that when each splitter has two outgoing edges
and is unbiased, an arbitrary rational probability \frac{a}{b} with a\leq b\leq
2^n can be realized by a stochastic flow network of size n that is optimal.
Compared to the other stochastic systems, feedback (cycles in networks)
strongly improves the expressibility of stochastic flow networks.Comment: 2 columns, 15 page
Fast design optimization of UWB antenna with WLAN Band-Notch
In this paper, a methodology for rapid design optimization of an ultra-wideband ( UWB) monopole antenna with a lower WLAN band-notch is presented. The band-notch is realized using an open loop resonator implemented in the radiation patch of the antenna. Design optimization is a two stage process, with the first stage focused on the design of the antenna itself, and the second stage aiming at identification of the appropriate dimensions of the resonator with the purpose of allocating the band-notch in the desired frequency range. Both optimization stages are realized using surrogate-based optimization involving variable-fidelity electromagnetic ( EM) simulation models as well as an additive response correction ( first stage), and sequential approximate optimization ( second stage). The final antenna design is obtained at the CPU cost corresponding to only 23 high-fidelity EM antenna simulations
Dissipative Quantum Dynamics and Optimal Control using Iterative Time Ordering: An Application to Superconducting Qubits
We combine a quantum dynamical propagator that explicitly accounts for
quantum mechanical time ordering with optimal control theory. After analyzing
its performance with a simple model, we apply it to a superconducting circuit
under so-called Pythagorean control. Breakdown of the rotating-wave
approximation is the main source of the very strong time-dependence in this
example. While the propagator that accounts for the time ordering in an
iterative fashion proves its numerical efficiency for the dynamics of the
superconducting circuit, its performance when combined with optimal control
turns out to be rather sensitive to the strength of the time-dependence. We
discuss the kind of quantum gate operations that the superconducting circuit
can implement including their performance bounds in terms of fidelity and
speed.Comment: 16 pages, 11 figure
Synthesis of Clock Trees with Useful Skew based on Sparse-Graph Algorithms
Computer-aided design (CAD) for very large scale integration (VLSI) involve
Reusing Logic Masking to Facilitate Hardware Trojan Detection
Hardware Trojan (HT) and Integrated Circuit
(IC)/ Intellectual Property (IP) piracy are important threats
which may happen in untrusted fabrication foundries. Modifying
structurally the ICs/IPs design to counter the HT threats has
been proposed, and it is known as Design-For-Hardware-Trust
(DFHT). DFHT methods are used in order to facilitate HT
detection methods. In addition, logic masking methods modify
the IPs/ICs design to harden them against the IP/IC piracy.
These methods modify a circuit such that it does not work
correctly without applying the correct key. In this paper, we
propose DFHT methods leveraging logic masking approach
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