397 research outputs found

    NUMERICAL ANALYSIS OF THE EFFECT OF SURCHARGE ON THE MECHANICAL BEHAVIOR OF GEOCELL REINFORCED RETAINING WALL

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    Geocell reinforced retaining structure has been widely used in civil engineering for theprotection of slopes due to its advantages. In this paper, the effects of surcharge on the horizontaldisplacement of the wall back, the size of the sliding wedge and the factor of safety of geocellreinforced retaining wall are numerically analyzed by employing the geotechnical finite elementmethod software Plaxis. The research results show that, when the distance of surcharge from thewall face is small, the maximum and the minimum deformation of the wall back takes place nearthe top of the wall and the wall bottom respectively. After the distance of surcharge from the wallface exceeds about 13% of the wall height, the surcharge has little effect on the horizontaldeformation of the wall back, the size of the sliding wedge and the safety factor of geocellreinforced retaining wall. The horizontal deformation of the wall back gradually increases with theincrease of the length of the surcharge until it reaches a certain value. The effect of the length ofthe surcharge on the failure surface is not significant. Besides, the factor of safety of the wallgradually decreases with the increase of length of the surcharge. However, with the increase of thedistance of the surcharge from the wall face, the influence of the length of the surcharge on thesafety factor gradually becomes small. The study results can supplement theoretical basis for thedesign of geocell reinforced retaining walls in engineering practices

    Retrieving non-linear features from noisy quantum states

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    Accurately estimating high-order moments of quantum states is an elementary precondition for many crucial tasks in quantum computing, such as entanglement spectroscopy, entropy estimation, spectrum estimation and predicting non-linear features from quantum states. But in reality, inevitable quantum noise prevents us from accessing the desired value. In this paper, we address this issue by systematically analyzing the feasibility and efficiency of extracting high-order moments from noisy states. We first show that there exists a quantum protocol capable of accomplishing this task if and only if the underlying noise channel is invertible. We then establish a method for deriving protocols that attain optimal sample complexity using quantum operations and classical post-processing only. Our protocols, in contrast to conventional ones, incur lower overheads and avoid sampling different quantum operations due to a novel technique called observable shift, making the protocols strong candidates for practical usage on current quantum devices. The proposed method also indicates the power of entangled protocols in retrieving high-order information, whereas in the existing methods, entanglement does not help. Our work contributes to a deeper understanding of how quantum noise could affect high-order information extraction and provides guidance on how to tackle it.Comment: 23 pages, 6 figure

    Jet charge identification in ee-Z-qq process at Z pole operation

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    Accurate jet charge identification is essential for precise electroweak and flavor measurements at the high-energy frontier. We propose a novel method called the Leading Particle Jet Charge method (LPJC) to determine the jet charge based on information about the leading charged particle. Tested on Z - bb and Z - cc samples at a center-of-mass energy of 91.2GeV, the LPJC achieves an effective tagging power of 20%/9% for the c/b jet, respectively. Combined with the Weighted Jet Charge method (WJC), we develop a Heavy Flavor Jet Charge method (HFJC), which achieves an effective tagging power of 39%/20% for c/b jet, respectively. This paper also discusses the dependencies between jet charge identification performance and the fragmentation process of heavy flavor jets, and critical detector performances

    Lateglacial and Holocene climate change in the NE Tibetan Plateau : Reconciling divergent proxies of Asian summer monsoon variability

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    The nature of Holocene Asian summer monsoon (ASM) evolution documented by diverse natural archives remains controversial, with a contentious issue being whether or not a strong Asian summer monsoon prevailed during the early Holocene. Here we present sequences of multiple proxies measured in sediment cores from Genggahai Lake in the NE Tibetan Plateau (NETP). The results suggest that a higher lake level and relatively lower terrestrial vegetation cover occurred synchronously during the early Holocene (11.3‚Äď8.6 kyr cal BP), compared with the period from 8.6 to 6.9 kyr cal BP. This finding clearly reflects the existence of different hydroclimatic conditions between the lake and its catchment due to diverse driving mechanisms. The early Holocene high stand of the lake, as demonstrated by the stratigraphic variability of the remains of aquatic biota, may have responded to the strengthened ASM and increased monsoonal precipitation; the relatively low vegetation cover in the marginal region of the Asian monsoon during the early Holocene, and the coeval widespread active sand dune mobility in both the NE Tibetan Plateau and NE China, most likely resulted from a low level of effective moisture due to high evaporation, and hence they cannot be interpreted as evidence of a weak ASM. Our results potentially reconcile the current divergent interpretations of various proxy climate records from the region. Our findings suggest that the ASM evolution was characterized by a consistent pattern across the monsoonal regions, as indicated by the oxygen isotope record of Chinese speleothems.Peer reviewe

    Integration of Self-Adaptive Physical-Layer Key Distribution and Encryption in Optical Coherent Communication

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    We propose and experimentally demonstrate a compatible physical-layer secure optical communication (PLSOC) system that integrates self-adaptive physical-layer key distribution (PLKD) and encryption (PLE) in optical coherent communication. Based on bit error rate difference of QAM signals mapped by asymmetric basis state Y-00 protocol, the secret key can be secretly exchanged over public fiber links without the pre-shared keys. Moreover, we perform a parameter self-adaptive strategy for practical and dynamic PLKD. The security of the key is evaluated in the case of a fiber-tapping attack. A secure hash algorithm, SHA3-512, is used to perform privacy amplification to obtain the virtually secure key. An error-free PLKD rate reaches 39.3 Kbits/s over 300km ultra-low loss fiber. We experimentally enable the integration of the proposed PLKD scheme and quantum noise stream cipher (QNSC) with a single wavelength, same system. Q factor penalty of the integration system compared to the QNSC system is 3.7dB (optical back-to-back) and 4.8dB (300km) respectively. By exploiting a common hardware platform, with the same wavelength, the proposed PLSOC system addresses the problem that PLKD and PLE are separately performed through independent optical fiber links or wavelengths. Since only digital signal processing is used, the scheme does not require extra hardware

    Analysis of labor resources wastage in China’s real estate brokerage: from the perspective of opportunity costs

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    Real estate brokerage has experienced the rapid growth over the past two decades in China, with a significant increase of employees. In particular, in the megacities like Beijing, the growth of employees exceeds the growth of real estate transaction volume. This may lead to the wastage of labor resources. In this regard, the optimal employee size (OES) in China’s real estate brokerage is proposed from the perspective of opportunity costs, which include both under-size and over-size costs. In the proposed OES models, a real estate brokerage firm makes the optimal decisions of number of employees by minimizing expected opportunity costs. In addition, an iterative algorithm is employed to obtain the optimal employee size in different scenarios. The result reveals that high profit gained from the business does attract more employees than what is needed. By addressing various scenarios based on the game model, it is found that asymmetric competition, the increase of market participants, and demand fluctuations also contribute to the labor resources wastage in real estate brokerage industry. The theoretical analysis results are verified by taking Beijing as the case study. Finally, suggestions for reducing labor resources wastage in real estate brokerage of China are provided

    DAG-FL: Direct Acyclic Graph-based Blockchain Empowers On-Device Federated Learning

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    Due to the distributed characteristics of Federated Learning (FL), the vulnerability of global model and coordination of devices are the main obstacle. As a promising solution of decentralization, scalability and security, leveraging blockchain in FL has attracted much attention in recent years. However, the traditional consensus mechanisms designed for blockchain like Proof of Work (PoW) would cause extreme resource consumption, which reduces the efficiency of FL greatly, especially when the participating devices are wireless and resource-limited. In order to address device asynchrony and anomaly detection in FL while avoiding the extra resource consumption caused by blockchain, this paper introduces a framework for empowering FL using Direct Acyclic Graph (DAG)-based blockchain systematically (DAG-FL). Accordingly, DAG-FL is first introduced from a three-layer architecture in details, and then two algorithms DAG-FL Controlling and DAG-FL Updating are designed running on different nodes to elaborate the operation of DAG-FL consensus mechanism. The extensive simulations show that DAG-FL can achieve the better performance in terms of training efficiency and model accuracy compared with the typical existing on-device federated learning systems as the benchmarks
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