分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-06-24
摘要： The W W production is the primary channel to directly probe the triple gauge couplings. We first analyze the e (+) e (-) -> W (+) W (-) process at the future lepton collider, China's proposed Circular Electron-Positron Collider (CEPC). We use the five kinematical angles in this process to constrain the anomalous triple gauge couplings and relevant dimension six operators at the CEPC up to the order of magnitude of 10(-4). The most sensible information is obtained from the distributions of the production scattering angle and the decay azimuthal angles. We also estimate constraints at the 14 TeV LHC, with both 300 fb(-1) and 3000 fb(-1) integrated luminosity from the leading lepton p (T) and azimuthal angle difference Delta I center dot (ll) distributions in the di-lepton channel. The constrain is somewhat weaker, up to the order of magnitude of 10(-3). The limits on the triple gauge couplings are complementary to those on the electroweak precision observables and Higgs couplings. Our results show that the gap between sensitivities of the electroweak and triple gauge boson precision can be significantly decreased to less than one order of magnitude at the 14 TeV LHC, and that both the two sensitivities can be further improved at the CEPC.
分类： 数学 >> 建模与仿真 分类： 语言学及应用语言学 >> 语言学及应用语言学 分类： 计算机科学 >> 自然语言理解与机器翻译 提交时间： 2025-06-03
摘要： Natural language is considered closely intertwined with human cognition, with linguistic structures posited to offer profound insights into the cognitive system. However, as a coding system, natural language encodes diverse objects into unified forms; its prominent formal features capture people’s attention, such as lexical combinatorial rules, which tend to overshadow those form-independent structures. Here, I present knowledge-level, logic-level, task-level, and model-level semantic structures inherent in natural language. These structures are discovered by shifting the research focus from coding forms of natural language to the objects they encode, unveiling different semantic layers integrated within sentences. The cognitive functions of these structures are evident both in themselves and in models developed from them. I therefore introduce four models to demonstrate their capabilities in memorization, reasoning, learning, natural language generation, and understanding. These findings advance our understanding of natural language and provide a framework for investigating the cognitive system’s information processing through structural analysis of natural language.
分类： 统计学 >> 经济统计学 提交时间： 2025-06-23
摘要： 根据国家统计局的数据，截至 2023 年，中国 60 岁及以上老年人口已超过 2.96 亿，占总人口的 21.1%。这一数据凸显了我国人口老龄化问题的严重性。在这种宏观背景下，传统的养老服务模式已经显示出明显的局限性。随着老年人口的持续增加，传统的养老方式正面临前所未有的压力和挑战。这不仅考验着社会福利体系，也迫使我们寻求创新的技术手段和服务模式来填补这一供给缺口。因此，智慧养老产业政策应运而生，它依靠先进的技术手段为老年人提供更高品质的生活。基于此，本文将探讨智慧养老产业政策干预下的“银发经济”，并全面分析这些外部和内部因素对经济增长的影响。本文基于 2008—2023 年中国省级面板数据，通过多维实证方法探讨智能养老政策对中国经济的影响机制，并重点关注资本投资、劳动效率和消费结构带来的中介效应。首先，采用双差法（DID）评价智慧养老试点政策的经济效果，结果表明，该政策的实施使试点地区的GDP增长率平均提高了约1.8个百分点，智慧养老政策对经济增长产生了显著的积极影响。其次，本研究在省级层面检验其机制，并采用中介效应模型发现，智能养老政策通过资本投入、劳动力供给和消费结构 3 条路径促进国内经济发展。当城市老龄化程度较低时，这种效果可能会减弱。最后，采用阈值模型分析智慧养老产业政策的异质性。当该地区人口老龄化，经济快速发展时，政策对经济发展的积极影响更加显著。研究表明，智慧养老产业政策通过促进产业结构升级、倒逼技术创新和需求侧激活的三重机制，有效促进了国民经济增长。建议构建“需求识别—技术赋能—政策协同”的立体化发展体系，针对区域老龄化和区域经济差异实施梯度产业政策。
分类： 计算机科学 >> 自然语言理解与机器翻译 提交时间： 2024-11-25
摘要： Large language models (LLMs) have showcased exceptional capabilities across various natural language processing (NLP) tasks in recent years, such as machine translation, text summarization, and question answering. Despite their impressive performance, the deployment of these models on edge devices, such as mobile phones, IoT devices, and edge computing nodes, is significantly hindered by their substantial computational and memory requirements. This survey provides a comprehensive overview of the state-of-the-art techniques and strategies for enabling efficient inference of LLMs on edge devices. We explore approaches including the development of small language models (SLMs), model compression techniques, inference optimization strategies, and dedicated frameworks for edge deployment. Our goal is to highlight the advancements and ongoing challenges in this field, offering valuable insights for researchers and practitioners striving to bring the power of LLMs to edge environments.
分类： 数学 >> 数学（综合） 分类： 水利工程 >> 水利工程基础学科 提交时间： 2023-04-28
摘要： In this paper, we mainly provide a proper maintenance plan for the Kariba Dam in Africa which falls into disrepair and is facing to collapse. Firstly, we make a threshold analysis of the three options about their costs which include peoples moving, old dams removing, new dams building, later repairing, ecological destruction and their incomes which include generation energy, avoiding of flood disasters loss, providing employment, tourism resources and ecological protection. Then we get the specific relationship between benefits and years with some collected data. Both of the results show that the third option is the best choice from the economic view. And the result is completely as same as the conclusion we get after studying deeply on Option 3. Secondly, we regard water management capabilities as the safety coefficient of dams. We select 30 seed points along the riverbank for preparing the establishment of dams. With flow-between-riverway model, Manning equations, large Cauchy distribute function we get the scores of the seed points. We give an advice that the number of dams should be more and the positions of dams should be well-distributed. Then, we build an assessment model by analytic hierarchy process. We select three factors among all the factors, safety, economy and population. After testing the consistency, we get the weights of each factor: 0.6442, 0.2705, 0.0852. Then we value the factors and get an optimal scheme during the assessment with 0-1 integer programming: the number of dams is 17 and the longitude and latitude of them are shown in Table 17. The sensitivity of the result is tested as well. We also provide some strategies for the managers of ZRA to use. We suggest that they should use the dams normally in general. With the Dam-break model, we find 13 points among 17 points which are shown in Table 20. The dams at the 13 points need to be closed when there is a flood and it is just the opposite when the drought happens. For the extreme water flow, we assume an ideal water flow at first. The extreme water flow has to be adjusted to satisfy the ideal one. As for the restrictions in extreme conditions, the biggest impact happens at the 8th point among the 17 points. If the duration of maximum flow is t0, the drainage time t to make the water flow return to the normal level equals to 4.95t0.
分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-06-18
摘要： With the assistance of a complex singlet, and an effective operator involving CP violations, the dark matter relic abundance and baryon asymmetry of the universe have been addressed simultaneously. We studied the electroweak baryogenesis mechanism systematically. The electroweak phase transition analysis indicates that the strong first order phase transition takes place by one-step or two-step type due to the dynamics of the energy gap between the electroweak vacuum and the vacuum of the complex singlet. The relation between the magnitude of baryon asymmetry of the universe and the phase transition type and strength has been explored in the framework of electroweak baryogenesis.
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-05-31
摘要： The nuclear fuel assembly is the core component of a nuclear reactor. In a pressurized water reactor fuel assembly, the top-connection structure connects the top nozzle to the guide thimble. Its performance reliability is essential for the stability of the nuclear fuel assembly. In this study, an assembly-oriented reliability analysis method for top-connection structures is presented by establishing an assembly-oriented top-connection structure parameter modeling method and a nonlinear contact gap and penetration correction method. A reliability model of the top-connection assembly structure, including multiple stochastic design variables, was constructed, and the overall reliability of the top-connection assembly structure was obtained via a Kriging model and Monte Carlo simulation. The acquired experimental data were consistent with real-world failure conditions, which verified the practicability and feasibility of the reliability analysis method proposed in this study.
分类： 物理学 >> 地球物理学、天文学和天体物理学 提交时间： 2021-06-26
摘要： 本文引入了一个参量n来表征不同惯性系间光速的变化。为了满足众所周知的基本原理，又不违背一些可靠的实验结果，我们应该对n施加一些必要的约束。首先，重要的是，n的引入应该符合以下三个原则:(1)我们可以用一个规定的时钟同步来定义整个空间中的时间;(2)时间是均匀的，空间是各向同性的;(3)所有的惯性系统都是等价的，这是对狭义相对论(SR)思想的继承。在n的一些约束条件下，我们构造了一个满足惯性系对称性的一般坐标变换。近年来，许多理论都表现出对超高能量尺度下洛伦兹不变性的破坏的兴趣，例如量子引力，它暗示粒子的能量有一个有限值(称为普朗克能量)，而不是从洛伦兹模型导出的无限值。因此我们构造一个n的表达式来描述洛伦兹模型的违逆。进一步，通过与著名的彩虹模型比较，我们发现本文推导的“最大能量”与彩虹模型假设的“最大能量”有一定的关系。
分类： 地球科学 >> 地理学 提交时间： 2023-12-20 合作期刊: 《干旱区科学》
摘要： Infiltration is an important part of the hydrological cycle, and it is one of the main abstractions accounted for in the rainfall-runoff modeling. The main purpose of this study is to compare the infiltration models that were used to assess the infiltration rate of the Mitidja Plain in Algeria. Field infiltration tests were conducted at 40 different sites using a double ring infiltrometer. Five statistical comparison criteria including root mean squared error (RMSE), normalized root mean squared error (NRMSE), coefficient of correlation (CC), Nash-Sutcliffe efficiency (NSE), and Kling-Gupta efficiency (KGE) were used to determine the best performing infiltration model and to confirm anomalies between predicted and observed values. Then we evaluated performance of five models (i.e., the Philip model, Kostiakov model, Modified Kostiakov model, Novel model, and Horton model) in simulating the infiltration process based on the adjusted performance parameters cited above. Results indicated that the Novel model had the best simulated water infiltration process in the Mitidja Plain in Algeria. However, the Philip model was the weakest to simulate the infiltration process. The conclusion of this study can be useful for estimating infiltration rate at various sites using a Novel model when measured infiltration data are not available and are useful for planning and managing water resources in the study area.
分类： 地球科学 >> 大气科学 提交时间： 2024-06-21 合作期刊: 《干旱区科学》
摘要： Stable water isotopes are natural tracers quantifying the contribution of moisture recycling to local precipitation, i.e., the moisture recycling ratio, but various isotope-based models usually lead to different results, which affects the accuracy of local moisture recycling. In this study, a total of 18 stations from four typical areas in China were selected to compare the performance of isotope-based linear and Bayesian mixing models and to determine local moisture recycling ratio. Among the three vapor sources including advection, transpiration, and surface evaporation, the advection vapor usually played a dominant role, and the contribution of surface evaporation was less than that of transpiration. When the abnormal values were ignored, the arithmetic averages of differences between isotope-based linear and the Bayesian mixing models were 0.9% for transpiration, 0.2% for surface evaporation, and –1.1% for advection, respectively, and the medians were 0.5%, 0.2%, and –0.8%, respectively. The importance of transpiration was slightly less for most cases when the Bayesian mixing model was applied, and the contribution of advection was relatively larger. The Bayesian mixing model was found to perform better in determining an efficient solution since linear model sometimes resulted in negative contribution ratios. Sensitivity test with two isotope scenarios indicated that the Bayesian model had a relatively low sensitivity to the changes in isotope input, and it was important to accurately estimate the isotopes in precipitation vapor. Generally, the Bayesian mixing model should be recommended instead of a linear model. The findings are useful for understanding the performance of isotope-based linear and Bayesian mixing models under various climate backgrounds.
分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-06-30
摘要： We address the possibility that CP violation in B-s-(B) over bar (s) mixing may help explain the origin of the cosmic baryon asymmetry. We propose a new baryogenesis mechanism-"electroweak beautygenesis"-explicitly showing that these two CP-violating phenomena can be sourced by a common CP phase. As an illustration, we work in the two-Higgs-doublet model. Because the relevant CP phase is flavor off diagonal, this mechanism is less severely constrained by null results of electric dipole moment searches than other scenarios. We show how measurements of flavor observables by the D0, CDF, and LHCb collaborations test this scenario.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-11-10
摘要： The width of three-body single-pion decay process d∗ → NNπ0,± is calculated by using the d∗ wave function obtained from our chiral SU(3) constituent quark model calculation. The effect of the dynamical structure on the width of d∗ is taken into account in both the single ∆∆ channel and cou-pled ∆∆+CC two-channel approximations. Our numerical result shows that in the coupled-channel approximation, namely, the hidden-color configuration being considered, the obtained partial decay width of d∗ → NNπ is about several hundred KeV, while in the single ∆∆ channel it is just about 2 ∼ 3 MeV. We, therefore, conclude that the partial width in the single-pion decay process of d∗ is much smaller than the widths in its double-pion decay processes. Our prediction may provide a criterion for judging different interpretations of the d∗ structure, as different pictures for the d∗ may result quite different partial decay width.
分类： 物理学 >> 核物理学 提交时间： 2016-09-13
摘要： The color connection of the parton system is an important bridge to connect the perturbative process and the hadronization one. The special color connection of four-heavy-quark system in e+e− annihilation, which is the necessary one for the doubly heavy baryon and tetraquark productions is revisited. The hadronization effects, investigated with the help of the Quark Combination Model are compared with the corresponding results employing the Lund String Model in our previous work. The global properties related to a certain color connection are not sensitive to various hadronization models.
分类： 物理学 >> 核物理学 提交时间： 2016-09-13
摘要： The structure and decay properties of d∗ have been detailedly investigated in both the chiral SU(3) quark model and the extended chiral SU(3) quark model that describe the energies of baryon ground states and the nucleon-nucleon (NN) scattering data satisfactorily. By performing a dynamical coupled-channels study of the system of ΔΔ and hidden-color channel (CC) with quantum numbers I(JP)=0(3+) in the framework of the resonating group method (RGM), we find that the d∗ has a mass of about 2.38−2.42 GeV and a root-mean-square radius (RMS) of about 0.76−0.88 fm. The channel wave function is extracted by a projection of the RGM wave function onto the physical basis, and the fraction of CC component in the d∗ is found to be about 66%−68%, which indicates that the d∗ is a hexaquark-dominated exotic state. Based on this scenario the partial decay widths of d∗→dπ0π0 and d∗→dπ+π− are further explicitly evaluated and the total width is then obtained by use of the branching ratios extracted from the measured cross sections of other possible decay channels. Both the mass and the decay width of d∗ calculated in this work are compatible with the data (M≈2380 MeV, Γ≈70 MeV) reported by WASA-at-COSY Collaboration.
分类： 物理学 >> 核物理学 提交时间： 2016-09-12
摘要： We report a measurement of the amplitude ratio rS of B0→D0K∗0 and B0→D0¯K∗0 decays with a Dalitz analysis of D→K0Sπ+π− decays, for the first time using a model-independent method. We set an upper limit rS<0.87 at the 68\% confidence level, using the full data sample of 772×106 BB¯ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB e+e− collider. This result is obtained from observables x−=+0.4+1.0+0.0−0.6−0.1±0.0, y−=−0.6+0.8+0.1−1.0−0.0±0.1, x+=+0.1+0.7+0.0−0.4−0.1±0.1 and y+=+0.3+0.5+0.0−0.8−0.1±0.1, where x±=rScos(δS±ϕ3), y±=rSsin(δS±ϕ3) and ϕ3 (δS) is the weak (strong) phase difference between B0→D0K∗0 and B0→D0¯K∗0.
分类： 物理学 >> 核物理学 提交时间： 2016-09-09
摘要： We report a measurement of the amplitude ratio rS of B0→D0K∗0 and B0→D0¯K∗0 decays with a model-independent Dalitz plot analysis using D→K0Sπ+π− decays. Using the full data sample of 772×106 BB¯ pairs collected at the Υ(4S) resonance with the Belle detector at KEKB accelerator the upper limit is rS<0.87 at the 68 % confidence level. This result is the first measurement of rS with a model-independent Dalitz analysis, and is consistent with results from other analyses. The value of rS indicates the sensitivity of the decay to ϕ3 because the statistical uncertainty is proportional to 1/rS. The rS result is obtained from observables (x±, y±) x−y−x+y+,====+0.4+1.0+0.0−0.6−0.1±0.0−0.6+0.8+0.1−1.0−0.0±0.1+0.1+0.7+0.0−0.4−0.1±0.1+0.3+0.5+0.0−0.8−0.1±0.1 where x±=rScos(δS±ϕ3), y±=rSsin(δS±ϕ3) and ϕ3(δS) are the weak (strong) phase difference between B0→D0K∗0 and B0→D0¯K∗0. The first uncertainty is statistical, the second is the experimental systematic and the third is the systematic due to the uncertainties on ci and si parameters measured by CLEO.
分类： 物理学 >> 基本粒子与场物理学 提交时间： 2016-05-14
摘要： For the experimental search of neutralino dark matter, it is important to know its allowed mass and scattering cross section with the nucleon. In order to figure out how light a neutralino dark matter can be predicted in low energy supersymmetry, we scan over the parameter space of the NMSSM (next-to-minimal supersymmetric model), assuming all the relevant soft mass parameters to be below TeV scale. We find that in the parameter space allowed by current experiments the neutralino dark matter can be as light as a few GeV and its scattering rate off the nucleon can reach the sensitivity of XENON100 and CoGeNT. As a result, a sizable parameter space is excluded by the current XENON100 and CoGeNT data (the plausible CoGeNT dark matter signal can also be explained). The future 6000 kg-days exposure of XENON100 will further explore (but cannot completely cover) the remained parameter space. Moreover, we find that in such a light dark matter scenario a light CP-even or CP-odd Higgs boson must be present to satisfy the measured dark matter relic density. Consequently, the SM-like Higgs boson h(SM) may decay predominantly into a pair of light Higgs bosons or a pair of neutralinos so that the conventional decays like h(SM) -> gamma gamma is much suppressed. (C) 2011 Elsevier B.V. All rights reserved.
分类： 生物学 >> 生态学 提交时间： 2023-06-13 合作期刊: 《干旱区科学》
摘要：The dead fuel moisture content (DFMC) is the key driver leading to fire occurrence. Accurately estimating the DFMC could help identify locations facing fire risks, prioritise areas for fire monitoring, and facilitate timely deployment of fire-suppression resources. In this study, the DFMC and environmental variables, including air temperature, relative humidity, wind speed, solar radiation, rainfall, atmospheric pressure, soil temperature, and soil humidity, were simultaneously measured in a grassland of Ergun City, Inner Mongolia Autonomous Region of China in 2021. We chose three regression models, i.e., random forest (RF) model, extreme gradient boosting (XGB) model, and boosted regression tree (BRT) model, to model the seasonal DFMC according to the data collected. To ensure accuracy, we added time-lag variables of 3 d to the models. The results showed that the RF model had the best fitting effect with an R2 value of 0.847 and a prediction accuracy with a mean absolute error score of 4.764% among the three models. The accuracies of the models in spring and autumn were higher than those in the other two seasons. In addition, different seasons had different key influencing factors, and the degree of influence of these factors on the DFMC changed with time lags. Moreover, time-lag variables within 44 h clearly improved the fitting effect and prediction accuracy, indicating that environmental conditions within approximately 48 h greatly influence the DFMC. This study highlights the importance of considering 48 h time-lagged variables when predicting the DFMC of grassland fuels and mapping grassland fire risks based on the DFMC to help locate high-priority areas for grassland fire monitoring and prevention.
分类： 核科学技术 >> 粒子加速器 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： In this paper, Takagi-Sugeno (T-S) fuzzy control is proposed for stabilizing the output beam of accelerators. To model the nonlinear system, we proposed a hybrid optimization algorithm based on quantum-inspired differential evolution and genetic algorithm. Based on the T-S model identified, the corresponding state-feedback fuzzy controller is designed. The method is applied to the LaB6 electron gun system in the industrial radiation accelerator and the simulation results show its effectiveness.
分类： 地球科学 >> 大气科学 提交时间： 2025-01-14 合作期刊: 《干旱区科学》
摘要： As one of the main characteristics of atmospheric pollutants, PM2.5 severely affects human health and has received widespread attention in recent years. How to predict the variations of PM2.5 concentrations with high accuracy is an important topic. The PM2.5 monitoring stations in Xinjiang Uygur Autonomous Region, China, are unevenly distributed, which makes it challenging to conduct comprehensive analyses and predictions. Therefore, this study primarily addresses the limitations mentioned above and the poor generalization ability of PM2.5 concentration prediction models across different monitoring stations. We chose the northern slope of the Tianshan Mountains as the study area and took the January-December in 2019 as the research period. On the basis of data from 21 PM2.5 monitoring stations as well as meteorological data (temperature, instantaneous wind speed, and pressure), we developed an improved model, namely GCN-TCN-AR (where GCN is the graph convolution network, TCN is the temporal convolutional network, and AR is the autoregression), for predicting PM2.5 concentrations on the northern slope of the Tianshan Mountains. The GCN-TCN-AR model is composed of an improved GCN model, a TCN model, and an AR model. The results revealed that the R2 values predicted by the GCN-TCN-AR model at the four monitoring stations (Urumqi, Wujiaqu, Shihezi, and Changji) were 0.93, 0.91, 0.93, and 0.92, respectively, and the RMSE (root mean square error) values were 6.85, 7.52, 7.01, and 7.28 μg/m³, respectively. The performance of the GCN-TCN-AR model was also compared with the currently neural network models, including the GCN-TCN, GCN, TCN, Support Vector Regression (SVR), and AR. The GCN-TCN-AR outperformed the other current neural network models, with high prediction accuracy and good stability, making it especially suitable for the predictions of PM2.5 concentrations. This study revealed the significant spatiotemporal variations of PM2.5 concentrations. First, the PM2.5 concentrations exhibited clear seasonal fluctuations, with higher levels typically observed in winter and differences presented between months. Second, the spatial distribution analysis revealed that cities such as Urumqi and Wujiaqu have high PM2.5 concentrations, with a noticeable geographical clustering of pollutions. Understanding the variations in PM2.5 concentrations is highly important for the sustainable development of ecological environment in arid areas.
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