This paper proposes an approach to perform travel demand calibration for high-resolution stochastic traffic simulators. It employs abundant travel times at the path-level, departing from the standard practice of resor...
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ISBN:
(数字)9798331505929
ISBN:
(纸本)9798331505936
This paper proposes an approach to perform travel demand calibration for high-resolution stochastic traffic simulators. It employs abundant travel times at the path-level, departing from the standard practice of resorting to scarce segment-level sensor counts. The proposed approach is shown to tackle high-dimensional instances in a sample-efficient way. For the first time, case studies on 6 metropolitan highway networks are carried out, considering a total of 54 calibration scenarios. This is the first work to show the ability of a calibration algorithm to systematically scale across networks. Compared to the state-of-the-art simultaneous perturbation stochastic approximation (SPSA) algorithm, the proposed approach enhances fit to field data by an average 43.5% with a maximum improvement of 80.0%, and does so within fewer simulation calls.
In this paper, a dual-functionality base station (BS) integrated sensing and communication (ISAC) is exploited to sense one intended target and communicate with multiple users simultaneously. Meanwhile, rate splitting...
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ISBN:
(数字)9798331512880
ISBN:
(纸本)9798331512897
In this paper, a dual-functionality base station (BS) integrated sensing and communication (ISAC) is exploited to sense one intended target and communicate with multiple users simultaneously. Meanwhile, rate splitting multiple access (RSMA) technology is used to improve communication quality. We formalize a problem aimed at maximizing sensing distance by optimizing the beamforming design of the BS and the allocation of common rate portions, where the signal to interference plus noise ratio (SINR) gain constraint of sensing echo signal and the individual communication rate requirements of each user are satisfied. Due to the non-convexity of the formulated problem, a successive convex approximation (SCA)-based algorithm is proposed to tackle it. Simulation results manifest that as the transmit power increases, the achievable sensing distance increases, and as the SINR threshold of the sensing echo signal increases, the achievable sensing distance decrease. Furthermore, it indicates that the RSMA-based protocol offers superior sensing distance gain compared to the SDMA-based protocol. This performance advantage becomes more pronounced when the communication rate threshold is high, resulting in a relatively large performance gap between the two protocols.
Most deterministic multi-objective optimization algorithms assume that the analytical objective functions and multi-objective gradients are available. However, there may be no available or explicit mathematical model ...
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ISBN:
(数字)9798350354409
ISBN:
(纸本)9798350354416
Most deterministic multi-objective optimization algorithms assume that the analytical objective functions and multi-objective gradients are available. However, there may be no available or explicit mathematical model for many real-world optimization problems. These problems are difficult to handle since the evaluations of gradients are inexact or even infeasible, which are termed derivative-free (or zeroth-order) optimization problems. To tackle the issues, a multi-objective derivative-free optimization based on Hessian-aware Gaussian smoothing method is proposed. We evaluate the multi-objective descent direction and produce new candidates for searching the Pareto front. Furthermore, we analyze the corresponding convergence rate of candidates produced by the Hessian-aware Gaussian smoothing method explicitly. Finally, we compared different multi-objective optimization algorithms and illustrated their performance on numerical benchmarks to show the proposed algorithm's effectiveness.
Network slicing is an essential technology in 5G and the forthcoming 6G networks. It aims to embed multiple virtual networks, i.e., network slices, on top of a shared substrate network to meet diverse service requirem...
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ISBN:
(数字)9798350308365
ISBN:
(纸本)9798350308372
Network slicing is an essential technology in 5G and the forthcoming 6G networks. It aims to embed multiple virtual networks, i.e., network slices, on top of a shared substrate network to meet diverse service requirements. While a considerable body of existing research strives to maximize overall profits by meeting the resource demands of the network slices, optimizing their reliability is frequently overlooked. In this paper, we formalize the network slicing problem as a multi-objective optimization problem that aims to maximize total profits and reliability of network slices. To tackle this problem, we propose a new multi-objective optimization approach that improves over the state-of-the-art algorithm, which can achieve good approximate Pareto front results balancing total profits and reliability of network slices. The performance of our proposed method is evaluated on both artificial and real-world network topologies. Experimental results demonstrate the superior performance of our proposed method compared to the baseline algorithm, outperforming the latter in 92% of instances in terms of the Hypervolume (HV) metric.
We address the numerical treatment of source terms in algebraic flux correction schemes for steady convection-diffusion-reaction (CDR) equations. The proposed algorithm constrains a continuous piecewise-linear finite ...
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Neural architecture search (NAS) has emerged as a transformative approach for automating the design of neural networks, demonstrating exceptional performance across a variety of tasks. Numerous NAS methods aim to opti...
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ISBN:
(数字)9798350359312
ISBN:
(纸本)9798350359329
Neural architecture search (NAS) has emerged as a transformative approach for automating the design of neural networks, demonstrating exceptional performance across a variety of tasks. Numerous NAS methods aim to optimize neural architectures within discrete or continuous search spaces, but each method possesses its own inherent limitations. Additionally, the search efficiency is notably impeded by suboptimal encoding methods, presenting an ongoing challenge. In response to these obstacles, this paper introduces a novel approach, evolutionary neural architecture optimization (ENAO), which optimizes architectures in an approximate continuous search space. ENAO begins with training a deep generative model to embed discrete architectures into a condensed latent space, leveraging unsupervised representation learning. Subsequently, evolutionary algorithm is employed to refine neural architectures within this approximate continuous latent space. Empirical comparisons against several NAS benchmarks underscore the effectiveness of the ENAO method. Thanks to its foundation in deep unsupervised representation learning, ENAO demonstrates a distinguished ability to identify high-quality architectures with fewer evaluations and achieve state-of-the-art result in NAS-Bench-201 dataset. Overall, the ENAO method is a promising approach for optimizing neural network architectures in an approximate continuous search space with evolutionary algorithms and may be a useful tool for researchers and practitioners in the field of NAS.
This paper proposes an idea of direction finding using null steering methodology. A reconfigurable intelligent surface (RIS) working at 2.4 GHz is designed and capable of generating as well as steering null when place...
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ISBN:
(数字)9798350367386
ISBN:
(纸本)9798350367393
This paper proposes an idea of direction finding using null steering methodology. A reconfigurable intelligent surface (RIS) working at 2.4 GHz is designed and capable of generating as well as steering null when placed in front of a linearly polarized antenna. This null steering can be used to make an estimate of the direction of waves reaching the receiver. An algorithm has been proposed to mathematically estimate the direction of target. Along with that a comparison between estimated and true direction is presented in a tabular fashion.
Localization of electrons in 1D disordered systems is usually described in the random phase approximation, when distributions of phases φ and θ, entering the transfer matrix, are considered as uniform. In the genera...
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We propose a scalable approximate algorithm for the NP-hard maximum-weight independent set problem. The core of our algorithm is a dual coordinate descent applied to a smoothed LP relaxation of the problem. This techn...
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We investigate application of quantum computing algorithms to classifying network traffic and mitigating denial of service and distributed denial of service attacks. Using actual honeynet data, we compare solutions of...
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ISBN:
(数字)9798331540906
ISBN:
(纸本)9798331540913
We investigate application of quantum computing algorithms to classifying network traffic and mitigating denial of service and distributed denial of service attacks. Using actual honeynet data, we compare solutions of the Max Cut problem using both the quantum approximate optimization algorithm (QAOA) and Variational Quantum Eigensolver (VQE). Experimental results from a 6-qubit quantum computer show that optimal solutions can be found with about 98% accuracy in polynomial execution time. We found that VQE is more accurate than QAOA (compared with classical brute force solutions) but also requires significantly longer execution times. Simulations predict this approach can scale to much larger quantum computing hardware (when available) and may achieve quantum advantage on hardware with 30-35 qubits.
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