XPZLIB:an HDF5-format multi-group cross-section library

A multi-group cross-section library is fundamental for deterministic lattice physics calculations.Most existing multi-group cross-section libraries are customized for particular computer codes,as well as for particular types of nuclear reactors.This paper presents an HDF5-format multi-group cross-section library named XPZLIB.XPZLIB was produced using a selfdeveloped XPZR module integrated into the NJOY2016 code,and an in-house PyNjoy2022 system was developed for autoprocessing.XPZLIB contains detailed data content and well-organized data structures that are user-and developer-friendly.Three typical XPZLIBs with different numbers of energy groups,nuclides,and depletion reaction types were released via the Tsinghua cloud website.Furthermore,the applicability of the released XPZLIBs was investigated using HTGR and PWR lattice calculations,which can provide guidance for applying XPZLIB under different scenarios.

Development of multi-group Monte-Carlo transport and depletion coupling calculation method and verification with metal-fueled fast reactor

The accurate modeling of depletion,intricately tied to the solution of the neutron transport equation,is crucial for the design,analysis,and licensing of nuclear reactors and their fuel cycles.This paper introduces a novel multi-group Monte-Carlo depletion calculation approach.Multi-group cross-sections(MGXS)are derived from both 3D whole-core model and 2D fuel subassembly model using the continuous-energy Monte-Carlo method.Core calculations employ the multi-group Monte-Carlo method,accommodating both homogeneous and specific local heterogeneous geometries.The proposed method has been validated against the MET-1000 metal-fueled fast reactors,using both the OECD/NEA benchmark and a new refueling benchmark introduced in this paper.Our findings suggest that microscopic MGXS,produced via the Monte-Carlo method,are viable for fast reactor depletion analyses.Furthermore,the locally heterogeneous model with angular-dependent MGXS offers robust predictions for core reactivity,control rod value,sodium void value,Doppler constants,power distribution,and concentration levels.

GLOBAL STABILITY OF EXTENDED MULTI-GROUP SIR EPIDEMIC MODELS WITH PATCHES THROUGH MIGRATION AND CROSS PATCH INFECTION

In this article, we establish the global stability of an endemic equilibrium of multi-group SIR epidemic models, which have not only an exchange of individuals between patches through migration but also cross patch infection between different groups. As a result, we partially generalize the recent result in the article [16].

A modified multi-group model of angular and momentum distribution of cosmic ray muons for thickness measurement and material discrimination of slabs

Muon tomography is a capable imaging technique to measure the geometry of high-Z objects. However,most existed algorithms used in muon tomography have obscured the effects of angular distribution and momentum spectra of cosmic ray muons and reduced the spatial resolution. We present a modified multi-group model that takes into account these effects and calibrates the model by the material of lead. Performance tests establish that the model is capable of measuring the thickness of a Pb slab and identifying the material of an unknown slab on a reasonable exposure timescale, in both cases of complete and incomplete angular data. Results show that the modified multi-group model is helpful for improvements in image resolution in real applications.

Global dynamics of a novel multi-group model for computer worms

In this paper, we study worm dynamics in computer networks composed of many autonomous systems. A novel multigroup SIQR （susceptible-infected-quarantined-removed） model is proposed for computer worms by explicitly considering anti-virus measures and the network infrastructure. Then, the basic reproduction number of worm R0 is derived and the global dynamics of the model are established. It is shown that if R0 is less than or equal to 1, the disease-free equilibrium is globally asymptotically stable and the worm dies out eventually, whereas, if R0 is greater than 1, one unique endemic equilibrium exists and it is globally asymptotically stable, thus the worm persists in the network. Finally, numerical simulations are given to illustrate the theoretical results.

Multi-group ant colony algorithm based on simulated annealing method

To overcome the default of single search tendency, the ants in the colony are divided into several sub-groups. The ants in different subgroups have different trail information and expectation coefficients. The simulated annealing method is introduced to the algorithm. Through setting the temperature changing with the iterations, after each turn of tours, the solution set obtained by the ants is taken as the candidate set. The update set is obtained by adding the solutions in the candidate set to the previous update set with the probability determined by the temperature. The solutions in the candidate set are used to update the trail information. In each turn of updating, the current best solution is also used to enhance the trail information on the current best route. The trail information is reset when the algorithm is in stagnation state. The computer experiments demonstrate that the proposed algorithm has higher stability and convergence speed.

DYNAMIC FOR A STOCHASTIC MULTI-GROUP AIDS MODEL WITH SATURATED INCIDENCE RATE

In this paper,a stochastic multi-group AIDS model with saturated incidence rate is studied.We prove that the system is persistent in the mean under some parametric restrictions.We also obtain the sufficient condition for the existence of the ergodic stationary distribution of the system by constructing a suitable Lyapunov function.Our results indicate that the existence of ergodic stationary distribution does not rely on the interior equilibrium of the corresponding deterministic system,which greatly improves upon previous results.

Extinction and Persistent of a Stochastic Multi-group SIR Epidemic Model

We establish a stochastic differential equation epidemic model of multi-group SIR type based on the deterministic multi-group SIR mode. Then, we define the basic reproduction number R0^S and show that it is a sharp threshold for the dynamic of the stochastic multi-group SIR model. More specially, if R0^S 〈 1, then the disease-free equilibrium will be asymptotically stable which means the disease will die out, if R0^S 〉 1, the disease-free equilibrium will unstable, and our model will positively recurrence to a positive domain which implies the persistence of our model. Numerical simulation examples are carried out to substantiate the analytical results.

Estimates of the Fast and Termal Flux in Blanket of Critical Reactors by Using Multi-Group Methods

In this study, based differential equations methods are used to solve equations because these methods are dependent on boundary value data more than other mathematical equations. We have calculated neutron flux, criticality and geometrical eigenvalue by using multi-group method and solving the neutron diffusion equation for finite and infinite cylindrical and spherical reactors in this study. For the calculation of the total neutron flux cross sections, we need the neutron diffusion equation. Thus, we have established the relationship between neuron flow and cross-section of neuron depending on neutron energy. Critical calculations have been made by comparing the results with MNCP (montecarlo n-partical) simulation methods. For necessary computer calculations, the programme, Wolfram-Matematica-7 has been used.

Multi-group pin power reconstruction method based on colorset form functions

A multi-group pin power reconstruction method that fully exploits nodal information obtained from global coarse mesh solution has been developed.It expands the intra-nodal flux distributions into nonseparable semi-analytic basis functions,and a colorset based form function generating method is proposed,which can accurately model the spectral interaction occurring at assembly interface.To demonstrate its accuracy and applicability to realistic problems, the new method is tested against two benchmark problems,including a mixed-oxide fuel problem.The results show that the new method is comparable in accuracy to fine-mesh methods.

农户参与农业废弃物资源化利用行为的影响因素

【目的】农户参与农业废弃物资源化利用对促进绿色乡村建设、实现乡村振兴战略具有重要意义,探究农业废弃物资源化利用的影响因素可针对性提升农户进行农业废弃物资源化利用行为的积极性,为促进其可持续发展提供参考依据。【方法】本研究基于计划行为理论构建农户参与农业废弃物资源化利用认知对其行为响应影响的理论模型,采用500份农户资源化利用行为问卷调查数据,运用结构方程模型进行实证分析,从行为态度、主观规范、知觉行为控制三个维度构建了农业废弃物资源化利用行为的指标体系,并在此基础上进一步考察了农业废弃物资源化利用行为的影响因素。【结果】农户资源化利用认知的行为态度、主观规范和知觉行为控制三个维度均对其行为响应有显著的直接正向影响,同时主观规范和知觉行为控制会通过行为态度的中介作用对行为响应产生间接正向影响;农户资源化利用认知三个维度对其行为响应的综合影响路径系数从大到小依次为知觉行为控制(0.378)、主观规范(0.238)和行为态度(0.182);不同规模、不同地形区域农户的农业废弃物资源化利用认知对行为响应的作用具有异质性,即规模与地形区在其中具有调节作用。【结论】为实现进一步的资源化利用应推进农户参与农业废弃物资源化利用技术培训与指导常态化,强化农户参与农业废弃物资源化利用的行为控制能力,同时加强山区的信息基础设施建设,畅通信息传播,创新媒体手段,推进数字化管理,推进农户参与农业废弃物资源化利用支持政策全覆盖,并对小规模农户实施重点帮扶与支持。

多主体对颠覆性技术采纳行为的动态演化及影响因素——基于演化博弈视角

以参与方有限理性和信息不完全为前提,构建以企业、消费者与政府为核心主体对于颠覆性技术采纳行为的演化博弈模型,从而分析三方对于颠覆性技术采纳的稳定策略,并通过MATLAB进行数值仿真模拟,分析验证该模型具体的演化路径,从而探究三方在颠覆性技术采纳行为博弈过程中决定双方最终策略选择的影响因素。结果表明:(1)企业、消费者与政府等三方主体对颠覆性技术产品的初始态度与接纳倾向会影响的博弈系统的演化路径与结果。(2)对于颠覆性技术企业而言,更高的颠覆性技术产品生产占比有助于缩短颠覆性技术采纳周期,并能提高政府对企业提供扶持的期望;对于政府而言,政府对生产颠覆性技术产品的企业补贴将延长技术采纳周期,同时若政府对生产颠覆性技术产品的企业补贴力度过大将会使政府最终放弃补贴,而政府对购买颠覆性技术产品的消费者补助则在技术采纳过程的前中期进行补助效果明显优于后期补助的效果。

基于精英知识引导的多种群协作粒子群优化算法

目的为了解决粒子群优化(particle swarm optimization,PSO)算法易早熟收敛、后期收敛速度慢、精度低等问题,方法提出一种基于精英知识引导的多种群协作粒子群优化算法(multi-group cooperation particle swarm optimization algorithm,MGCPSO)。首先,采用基于幂函数约束的logistic映射得到分布均匀的初始种群,加快寻优速度并提高找到最优解的概率;其次,在算法执行阶段动态划分多种群,并利用精英知识引导劣势粒子飞行,实现粒子间的信息共享和协同进化,降低粒子在解空间探索的盲目性;最后,综合融入精英知识的反向学习和极值扰动策略对粒子施加变异,帮助粒子扩大搜索区域并加强对最优邻域的精细探索。结果为验证MGCPSO的性能,在30维和100维的基准测试函数上进行了仿真实验研究,结果表明,相比于其他几种改进算法,提出的算法在收敛速度和收敛精度上均有良好表现。结论多种群协作粒子群优化可以有效避免算法早熟收敛和陷入局部最优,同时可以提高算法的全局搜索能力和局部开发能力。

属性权重动态更新的自适应群体共识决策方法

为了提高不确定语言环境下异构多属性群决策的质量、效率及可解释性,提出一种属性权重动态更新的自适应群体共识决策方法。首先,定义不确定语言变量与中间值之间的转换函数,发展多级共识测度,建立计算属性初始权重的双目标优化模型;进而,构建包含群体共识自动达成规则和属性权重动态更新机制的自适应共识模型,实现待调整值的精准定位和自动修改,在优化属性权重的同时进一步提升群体共识水平;然后,对于达成共识的群体决策矩阵,先利用转换函数将中间值转换为不确定语言变量,再使用属性权重和集结算子得到各方案的综合评价结果;最后,通过供应商选择实例和实验比较分析验证所提方法的有效性和可行性。本文研究结果为灵活、高效地求解复杂环境下的多属性群决策问题提供了有效途径。

基于生态安全格局的云南世居民族所在地生态韧性评价研究

云南世居民族所在地是基于传统生态智慧世代延续,以自然系统与社会系统相互嵌套为特点的自然–文化遗产,而现代性和社会经济的快速发展使得世居民族所在地不断被蚕食和消解.研究基于韧性理念,利用多源数据,从稳定性、适宜性、冗余度、多样性4个层面构建云南世居民族所在地生态安全格局和生态韧性耦合框架,对藏、彝、傣族所在地2000—2020年生态韧性进行评价研究.结果表明,近20 a来,世居民族所在地总体生态韧性水平为中等,呈现逐年降低的趋势.高水平韧性区多分布于林地,存在连续但细碎化的分布特征.低水平生态韧性多分布于道路缓冲区2 km以内,路网的社会扰动内涵很大程度上影响生态韧性强度.20 a来平均生态韧性指数傣族所在地(0.6420)>彝族所在地(0.5602)>藏族所在地(0.5344).影响各世居民族所在地生态韧性的原因存在差异,地质灾害防护格局和水生环境安全格局是影响生态韧性的主要因素.

新能源汽车政策下居民出行意向多群组分析

为研究新能源汽车政策对不同群体居民出行意向影响存在的差异性问题,提出新能源汽车政策下居民出行意向多群组模型.以计划行为理论为基础,整合居民对新能源汽车政策的态度、响应程度以及低碳理念,构建新能源汽车政策下居民出行意向模型,并对模型进行检验及修正,划分多群组,对修正后的模型进行多群组分析,研究新能源汽车政策对不同出行方式偏好群体影响机理的差异性.研究结果表明:居民对新能源汽车政策的态度、响应以及低碳理念对出行态度、主观规范、知觉行为控制以及行为意向的影响在不同出行方式偏好下存在显著差异;居民对新能源汽车政策的态度越积极、低碳理念越强,则选择新能源汽车或公共交通出行的意向越强;居民对新能源汽车政策的响应越积极,则选择新能源汽车出行的意向越强;改善居民对新能源汽车政策的态度、响应,可促进新能源汽车的使用;通过提升居民的低碳理念,可提高居民采用公共交通或新能源汽车出行的意向.研究可为通过交通政策调整居民出行意向以及制定交通政策提供参考.

基于GRA-GCRITIC和改进加权双向投影的区间Fermatean模糊多属性群决策方法

针对司法案件决策环境的复杂性及评价信息的模糊性,提出一种基于GRA-GCRITIC(grey relational analysis-group criteria importance through intercriteria correlation)和改进加权双向投影的区间Fermatean模糊Hamacher-TODIM多属性群决策方法。首先考虑到各位专家对各评价方案下各指标评价信息的差异性,提出一种GRA-GCRITIC方法,该方法将灰色关联融入到CRITIC中,以确定指标综合权重比单一获取的指标权重更加客观可靠;其次,结合信任关系对加权双向投影法进行改进,兼顾主客观关系,利用专家个体与群体评价信息的隶属度及非隶属度矩阵间的相似度得到专家权重;最后,考虑到决策者的损失规避心理,将融合了Hamacher算子的TODIM方法拓展至区间Fermatean模糊环境中,通过具体算例可得到其综合优势度及排序,验证了所提方法的可行性及灵活性。

面向用户多样化业务需求的多波束卫星系统动态资源分配算法

多波束卫星通信系统由于其高吞吐量和高资源利用率而受到广泛关注.已有研究主要考虑多波束卫星通信系统的信道或功率分配问题,但较少考虑用户分组和动态资源分配策略的联合优化设计,导致系统性能受限.此外,现有研究往往假设固定的波束覆盖半径,忽略了波束覆盖半径可变性对波束覆盖性能提升的影响.本文研究了多波束卫星通信系统中的用户分组和资源分配问题,提出了一种两阶段资源管理方案.针对动态和多样化的用户服务需求,首先设计一种基于Voronoi图的迭代用户分组算法以实现分组之间的负载均衡,然后将子信道和功率分配问题建模为系统平均效用函数最大化问题.为解决该问题,将每个波束视为一个智能体,采用一种基于多智能体深度Q网络(Deep Q Network,DQN)的算法来确定子信道和功率分配策略.仿真结果表明,与K-均值用户分组方案相比,本文所提出的基于Voronoi图的迭代用户分组算法对应的用户组负载差异值可降低49.2%,体现了本文所提算法在实现用户组间负载均衡方面的优势.此外,本文所提两阶段资源管理方案与现有文献中所提算法相比,系统所提供容量与用户需求差值可降低83.43%,体现了本文所提算法在实现系统资源高效利用及用户服务需求保障方面的性能优势.

群体决策可靠性的分层反馈与多级度量

为了提高群体决策质量,获得更加可靠的决策结果,结合语言环境下考虑专家自信度的异构多属性群决策问题,建立了群体决策可靠性的分层反馈机制与多级度量模型。利用三支决策思想将各方案各属性下对应子群体中的专家按照自信度的高、中、低划分成三类,进而,依次从子群体的专家构成、自信度以及共识度3个层次对决策可靠性进行量化分析,建立由粗到细、逐层细化的反馈机制,为决策过程的可靠性调整和控制提供途径;综合考虑子群体中高、中自信度专家的占比以及自信度和共识度等影响因素,构建多级可靠性度量模型,并形成针对方案级决策和整体决策的两级可靠性判定规则,有效提升决策结果的可解释性。在此基础上,提出一种可靠性驱动的异构多属性群决策方法,通过供应商选择实例分析并验证了所提方法的可行性和有效性。

《格萨尔》多民族交融的特点与启示

多民族共创、共享、共传的英雄史诗《格萨尔》,是中华民族共同体形成与发展过程中多民族之间相互理解、相互欣赏、相互尊重、相互学习的范例,生动地展现了少数民族文学之间的相互影响、汉族文学对少数民族文学的影响以及少数民族文学对汉族文学影响的特点,对深刻理解和认识中华民族共同体有着独特的学术价值和现实意义。中华人民共和国成立后,多民族学者构成的研究队伍对《格萨尔》的搜集与研究不仅是贯彻执行党的民族政策与文艺政策的典范,更是铸牢中华民族共同体意识的生动实践。应该客观地描述《格萨尔》流布过程中呈现出的中国多民族交往交流交融的历史和现实,科学地阐释其呈现出的特点和规律,为铸牢中华民族共同体意识的理论建设提供重要的支撑和启示,充分利用人文数字技术,使《格萨尔》以多模态的形式走进了中国各民族生活中,成为中华民族共享的文化符号,进而有效地推进铸牢中华民族共同体意识的实践工作向纵深发展。