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A Novel Load Balancing Scheme for Mobile Edge computing

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arXiv 2021年

作者： Duan, Zhenhua Tian, Cong Zhang, Nan Zhou, Mengchu Yu, Bin Wang, Xiaobing Guo, Jiangen Wu, Ying Institute of Computing Theory and Technology ISN Lab Xidian University Xi’an710071 China Department of Electrical and Computer Engineering New Jersey Institute of Technology NewarkNJ07102 United States

To overcome long propagation delays for data exchange between the remote cloud data center and end devices in Mobile Cloud computing (MCC), Mobile Edge computing (MEC) is emerging to push mobile computing, network control and storage to the network edges. A cloudlet in MEC is a mobility-enhanced small-scale cloud, which contains several MEC servers located in close proximity to mobile devices. The main purpose of a cloudlet is to stably provide services to mobile devices with low latency. When a cloudlet offers hundreds kinds of services to millions of mobile devices, it is critical to balance the loads so as to improve performance. In this paper, we propose a three-layer mobile hybrid hierarchical P2P (MHP2P) model as a cloudlet. MHP2P performs satisfactory service lookup efficiency and system scalability as well as high stability. More importantly, a load balance scheme is provided so that the loads of MHP2P can be well balanced with the increasing of MEC servers and query load. A large number of simulation experiments indicate that the proposed scheme is efficient for enhancing the load balancing performance in MHP2P based MEC systems. Copyright © 2021, The Authors. All rights reserved.

关键词： Mobile edge computing

GNN-Empowered Effective Partial Observation MARL Method for AoI Management in Multi-UAV Network

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arXiv 2024年

作者： Pan, Yuhao Wang, Xiucheng Xu, Zhiyao Cheng, Nan Xu, Wenchao Zhang, Jun-Jie The School of Electronic Engineering Xidian University Xi'An710071 China The State Key Laboratory of ISN School of Telecommunications Engineering Xidian University Xi'An710071 China The School of Artificial Intelligence Xidian University Xi'An710071 China The Department of Computing The Hong Kong Polytechnic University Hong Kong The Northwest Institute of Nuclear Technology Xi'An710024 China

Unmanned Aerial Vehicles (UAVs), due to their low cost and high flexibility, have been widely used in various scenarios to enhance network performance. However, the optimization of UAV trajectories in unknown areas or areas without sufficient prior information, still faces challenges related to poor planning performance and low distributed execution. These challenges arise when UAVs rely solely on their own observation information and the information from other UAVs within their communicable range, without access to global information. To address these challenges, this paper proposes the Qedgix framework, which combines graph neural networks (GNNs) and the QMIX algorithm to achieve distributed optimization of the Age of Information (AoI) for users in unknown scenarios. The framework utilizes GNNs to extract information from UAVs, users within the observable range, and other UAVs within the communicable range, thereby enabling effective UAV trajectory planning. Due to the discretization and temporal features of AoI indicators, the Qedgix framework employs QMIX to optimize distributed partially observable Markov decision processes (Dec-POMDP) based on centralized training and distributed execution (CTDE) with respect to mean AoI values of users. By modeling the UAV network optimization problem in terms of AoI and applying the Kolmogorov-Arnold representation theorem, the Qedgix framework achieves efficient neural network training through parameter sharing based on permutation invariance. Simulation results demonstrate that the proposed algorithm significantly improves convergence speed while reducing the mean AoI values of users. The code is available at https://***/UNIC-Lab/Qedgix. Copyright © 2024, The Authors. All rights reserved.

关键词： Markov processes

Experimental Demonstration of Inequivalent Mutually Unbiased Bases

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Physical Review Letters 2024年第8期132卷 080202-080202页

作者： Wen-Zhe Yan Yunting Li Zhibo Hou Huangjun Zhu Guo-Yong Xiang Chuan-Feng Li Guang-Can Guo CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei 230026 People’s Republic of China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 People’s Republic of China State Key Laboratory of Surface Physics and Department of Physics Fudan University Shanghai 200433 China Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai 200433 China Center for Field Theory and Particle Physics Fudan University Shanghai 200433 China Hefei National Laboratory University of Science and Technology of China Hefei 230088 People’s Republic of China

Quantum measurements based on mutually unbiased bases (MUBs) play crucial roles in foundational studies and quantum information processing. It is known that there exist inequivalent MUBs, but little is known about their operational distinctions, not to say experimental demonstration. In this Letter, by virtue of a simple estimation problem, we experimentally demonstrate the operational distinctions between inequivalent triples of MUBs in dimension 4 based on high-precision photonic systems. The experimental estimation fidelities coincide well with the theoretical predictions with only 0.16% average deviation, which is 25 times less than the difference (4.1%) between the maximum estimation fidelity and the minimum estimation fidelity. Our experiments clearly demonstrate that inequivalent MUBs have different information extraction capabilities and different merits for quantum information processing.

关键词： Quantum foundations Quantum information processing Quantum measurements Quantum optics

Parameterized Inapproximability Hypothesis under ETH

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arXiv 2023年

The Parameterized Inapproximability Hypothesis (PIH) asserts that no fixed parameter tractable (FPT) algorithm can distinguish a satisfiable CSP instance, parameterized by the number of variables, from one where every assignment fails to satisfy an ϵ fraction of constraints for some absolute constant ϵ > 0. PIH plays the role of the PCP theorem in parameterized complexity. However, PIH has only been established under Gap-ETH, a very strong assumption with an inherent gap. In this work, we prove PIH under the Exponential Time Hypothesis (ETH). This is the first proof of PIH from a gap-free assumption. Our proof is self-contained and elementary. We identify an ETH-hard CSP whose variables take vector values, and constraints are either linear or of a special parallel structure. Both kinds of constraints can be checked with constant soundness via a "parallel PCP of proximity" based on the Walsh-Hadamard code. © 2023, CC BY.

关键词： Parameterization

Feasibility Analysis of the Sanchez-Pomraning Method to Treat the Particle Size Distribution in Particle-Dispersed Fuel

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SSRN

SSRN 2024年

作者： Qin, Shuai Zhang, Qian Feng, Xing Liang, Yuechao Laboratory for Advanced Nuclear Energy Theory and Applications Zhejiang Institute of Modern Physics Department of Physics Zhejiang University Zhejiang Hangzhou310027 China Huaneng Shandong Shidao Bay Nuclear Power Co. LTD. Shandong Rongcheng264300 China Laboratory of Digitizing Software for Frontier Equipment National University of Defense Technology Hunan Changsha410073 China National Key Laboratory of Parallel and Distributed Computing National University of Defense Technology Hunan Changsha410073 China

The non-uniform size of particles appears in the particle-dispersed fuel generally, but this phenomenon is usually neglected. This study aims to evaluate the feasibility of the Sanchez-Pomraning method to solve the particle size distribution problem in particle-dispersed fuel. The Pu-rich agglomerate phenomenon in the MOX fuel and manufacturing tolerance in the Fully Ceramic Microencapsulated (FCM) fuel are calculated by ALPHA-DH code, which implements the Sanchez-Pomraning method based on the MOC transport calculation and improved subgroup resonance calculation. Numerical results show that the Sanchez-Pomraning method has the capability to treat the particle size distribution effect accurately, where the differences bwtween the Sanchez-Pomraning method and the Monte Carlo method are generally lower than 160 pcm. For the Pu-rich agglomerate phenomenon, the results show that ignoring the Pu-rich agglomerate effect introduces the reactivity difference of around 600 pcm, and ignoring the size distribution of the Pu agglomerate will cause the reactivity of up to 200 pcm in the extra-high or extra-low Pu enrichment. The more discrete size distribution and the smaller Pu-spots, the more significant influence will occur in the MOX fuel. For the FCM fuel, the influence brought by the TRISO particle size distribution can be ignored when only TRISO particles are filled. However, ignoring the size distribution when TRISO particles and poison particles are both added into the FCM fuel introduces the differences reaching 600-1000 pcm. These results demonstrate the importance of considering the particle size distribution for analyzing the MOX fuel and FCM fuel in practice. And the Sanchez-Pomraning method is reliable to analyze the effect of particle size distribution. © 2024, The Authors. All rights reserved.

关键词： Particle size analysis

Deconfined classical criticality in the anisotropic quantum spin-12 XY model on the square lattice

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arXiv 2024年

作者： Mudry, Christopher Aksoy, Ömer M. Chamon, Claudio Furusaki, Akira Condensed Matter Theory Group PSI Center for Scientific Computing Theory and Data Villigen PSI5232 Switzerland Institut de Physique EPF Lausanne LausanneCH-1015 Switzerland Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Department of Physics Boston University BostonMA02215 United States RIKEN Center for Emergent Matter Science Saitama Wako351-0198 Japan Condensed Matter Theory Laboratory RIKEN Saitama Wako351-0198 Japan

The anisotropic quantum spin-12 XY model on a linear chain was solved by Lieb, Schultz, and Mattis in 1961 [Ann. Phys. 16, 407 (1961)] and shown to display a continuous quantum phase transition at the O(2) symmetric point separating two gapped phases with competing Ising long-range order. For the square lattice, the following is known. The two competing Ising ordered phases extend to finite temperatures, up to a boundary where a transition to the paramagnetic phase occurs, and meet at the O(2) symmetric critical line along the temperature axis that ends at a tricritical point at the Berezinskii-Kosterlitz-Thouless transition temperature where the two competing phases meet the paramagnetic phase. We show that the first-order zero-temperature (quantum) phase transition that separates the competing phases as a function of the anisotropy parameter is smoothed by thermal fluctuations into deconfined classical criticality. © 2024, CC BY.

关键词： Paramagnetism

Generation of spin squeezing via a fully quantum degenerate parametric amplifier

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Physical Review A 2023年第2期107卷 023724-023724页

作者： Yang Liu Jie Song Wei Qin Ye-Hong Chen Yan Xia Fujian Key Laboratory of Quantum Information and Quantum Optics Fuzhou University Fuzhou 350108 China Department of Physics Fuzhou University Fuzhou 350108 China School of Physics Harbin Institute of Technology Harbin 150001 China Theoretical Quantum Physics Laboratory RIKEN Cluster for Pioneering Research Wako-shi Saitama 351-0198 Japan Quantum Information Physics Theory Research Team RIKEN Center for Quantum Computing Wako-shi Saitama 351-0198 Japan

Spin squeezing is one of the most attractive methods for realizing high-precision metrology. In this paper we propose a protocol for generating spin squeezing in an atomic ensemble via a fully quantum degenerate parametric amplifier. We discuss the properties of generating spin squeezing with and without driving the pump cavity. Numerical simulation results show that the generated spin squeezing strength is sizable and is comparable to that obtained using a two-axis twisting model. Moreover, we demonstrate that the protocol is experimentally feasible by introducing the corresponding experimental parameters. Therefore, the proposed protocol provides a promising approach to realize spin squeezing in photon-spin coupling systems.

关键词： Cavity quantum electrodynamics Collective effects in quantum optics Light-matter interaction

Optimal estimation of three parallel spins with genuine and restricted collective measurements

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arXiv 2024年

作者： Yi, Changhao Zhou, Kai Hou, Zhibo Xiang, Guo-Yong Zhu, Huangjun State Key Laboratory of Surface Physics Department of Physics Center for Field Theory and Particle Physics Fudan University Shanghai200433 China Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai200433 China Shanghai Research Center for Quantum Sciences Shanghai201315 China CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei230026 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China

Collective measurements on identical and independent quantum systems are advantageous in information extraction than individual measurements. However, little is known about the distinction between restricted collective measurements and genuine collective measurements in the multipartite setting. In this work we establish a rigorous performance gap based on a simple and old estimation problem, the estimation of a random spin state given three parallel spins. Notably, we derive an analytical formula for the maximum estimation fidelity of biseparable measurements and clarify its fidelity gap from genuine collective measurements. Moreover, we show that this estimation fidelity can be achieved by two- and one-copy measurements assisted by one-way communication in one direction, but not the other way. Our work reveals a rich landscape of multipartite nonclassicality in quantum measurements instead of quantum states and is expected to trigger further studies. Copyright © 2024, The Authors. All rights reserved.

关键词： Spin dynamics

Research on Application of Heterogeneous Resonance Integral for Double Heterogeneous System

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SSRN

SSRN 2024年

作者： Qin, Shuai Zhang, Qian Wang, Kai Huang, Dong Li, Song Liang, Yuechao Laboratory for Advanced Nuclear Energy Theory and Applications Zhejiang Institute of Modern Physics Department of Physics Zhejiang University Zhejiang Hangzhou310027 China Zhejiang Institute of Modern Physics Department of Physics Zhejiang University Zhejiang Hangzhou310027 China School of Nuclear Science and Technology Xi’an Jiaotong University 28 West Xianning Road Shaanxi Xi’an710049 China College of Nuclear Science and Technology Naval University of Engineering Wuhan China Laboratory of Digitizing Software for Frontier Equipment National University of Defense Technology Hunan Changsha410073 China National Key Laboratory of Parallel and Distributed Computing National University of Defense Technology Hunan Changsha410073 China

The Double Heterogeneous (DH) system, where fuel particles are randomly dispersed in the non-fissile matrix, is challenging for the reactor physics calculation. The Sanchez-Pomraning method accurately handles the DH system, but integrating it into existing reactor physics code requires code development. This study adopts the Sanchez-Pomraning coupled Ultra-Fine-Group (SP-UFG) slowing-down calculation to generate the heterogeneous Resonance Integral (RI) for DH system treatment with simple volume homogenization. Fully Ceramic Micro-encapsulated (FCM) fuel pin-cells and plates with varying configurations are calculated for verification. Effective cross-sections (XSs) and keff calculated by the heterogeneous RI are compared with SP-UFG results. Results show that the maximum bias of XSs and keff caused by the XS biases are less than 5% and 200 pcm, respectively. The maximum bias of keff when compared with Monte Carlo calculated results is -213 pcm, demonstrating that only considering the DH effect in the resonance energy region is acceptable. © 2024, The Authors. All rights reserved.

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