完美伍配

本文讨论图存在完美伍配的充要条件,并证明一个定理。最后,给出一个求完美伍配的算法。     

3—连通、3—正则图中的圈

本文介绍了3—连通、3—正则图中包含给定点集的大子集的圈。     

治理机制与企业网络的规模:嵌入性视角的研究

企业网络的规模直接影响着一国产业的竞争力。本文以能够使成员企业合作激励达到最大的自由交易的概率衡量企业网络规模的大小．运用随机图表示企业网络内部的关系结构。通过博弈分析研究了企业网络规模与网络治理机制的关系。结果表明。企业网络的规模是由合作的张力决定的．当企业单纯依靠网络成员之间自发的嵌入关系维持相互间的合作时．网络规模只能在较低的水平上达到均衡。要想从根本上扩张企业网络的规模。必须引入外部治理机制。我国当前推动企业网络的发展。重点应放在强化外部司法惩罚机制上。     

Strength of Preference in the Graph Model for Conflict Resolution

A new preference structure that includes a simple relative measure of strength of preference is developed and integrated into some of the stability definitions for the graph model for conflict resolution. In this triplet preference structure, a decision-maker may greatly prefer or prefer one state or scenario to another, or may be indifferent between them. Four stability definitions (solution concepts), Nash stability (R), general metarationality (GMR), symmetric metarationality (SMR), and sequential stability (SEQ), are extended to include strong and weak stabilities for the case of conflicts with two decision makers. Theorems that clarify the interrelationships of the strong and weak versions of these solution concepts are presented. The application of this new preference structure and the associated solution concepts is demonstrated in an environmental conflict model, called the Sustainable Development Conflict. This case shows that valuable strategic insights are gained when strength of preference is integrated into the stability analysis.     

THEORY AND CALIBRATION OF SWAP MARKET MODELS

This paper introduces a general framework for market models, named Market Model Approach, through the concept of admissible sets of forward swap rates spanning a given tenor structure. We relate this concept to results in graph theory by showing that a set is admissible if and only if the associated graph is a tree. This connection enables us to enumerate all admissible models for a given tenor structure. Three main classes are identified within this framework and correspond to the co-terminal, co-initial, and co-sliding model. We prove that the LIBOR market model is the only admissible model of a co-sliding type. By focusing on the co-terminal model in a lognormal setting, we develop and compare several approximating analytical formulae for caplets, while swaptions can be priced by a simple Black-type formula. A novel calibration technique is introduced to allow simultaneous calibration to caplet and swaption prices. Empirical calibration of the co-terminal model is shown to be faster, more robust, and more efficient than the same procedure applied to the LIBOR market model. We then argue that the co-terminal approach is the simplest and most convenient market model for pricing and hedging a large variety of exotic interest-rate derivatives.     

家庭农场研究：知识图谱、研究热点与前沿趋势

作为新型农业经营主体的主力军,家庭农场高质量发展需要具体实践与理论研究的良好互动。自2013年中央一号文件发布以来,家庭农场成为众多学者研究的热点,且研究内容与中央政策的导向高度契合,因而有必要厘清我国家庭农场研究的发展脉络、热点演进及前沿趋势。本文以中国知网数据库中2012—2021年在中文核心期刊、CSSCI和CSCD来源期刊上发表的以“家庭农场”为主题的学术论文为研究对象,利用CiteSpace软件对家庭农场研究的核心作者与重点文献、研究热点与核心体系、热点演进及前沿趋势等进行系统梳理和可视化分析,得出如下结论：（1）我国家庭农场领域的研究方兴未艾,经历了2012—2014年的爆发期、2015—2017年的高峰期和2018—2021年的稳定期;从事家庭农场研究的核心力量突出、新兴力量活跃,但跨机构的合作研究有待加强;重点文献形成了“基础性理论探讨—现实性实践探索—新时代背景契合”的完整研究体系。（2）家庭农场研究热点呈现“中心密集、多点爆发、拓展较广”的网络结构,且具有明显的政策指向性;各热点间综合交叉、互促互融,进而形成由“新型农业经营主体”“土地流转和适度规模经营”“现代农业禀赋”“乡村振兴战略”4大板块组成的核心体系。（3）各阶段家庭农场研究的侧重不同,但前后关联相继,研究内容由传统小农户转型、新型农业经营主体培育、农地流转和适度规模经营等逐渐拓展到家庭农场发展的影响因素分析与经济绩效评价,并积极开展新时代乡村振兴和农业农村现代化背景下家庭农场高质量发展的实践应用性研究,其中“经营绩效”“乡村振兴”“三权分置”“人力资本”等仍将是短期内家庭农场研究的热点。当前我国家庭农场研究与前沿经济学理论的契合还不够充分,经验分析的数据获取较为困难且研究方法受限,研究视角也有待进一步拓展。未来的家庭农场研究需要充分融合前沿经济学理论,构建更具时代指导性的理论框架,实现多学科、多领域、多形式的交叉融合发展。同时,要基于典型样本总结家庭农场发展的中国经验,并进行理论提升,进而为家庭农场理论发展贡献中国智慧,为世界各国的家庭农场实践提供路径借鉴。此外,还应积极扩充数据来源,不断改进家庭农场研究的实证分析方法,并契合家庭农场发展的时代背景（共同富裕、乡村振兴、农业农村现代化、数字化、绿色低碳化、智能化、网络化等）不断扩宽研究视角。     

采用混合图的双向异质频谱拍卖算法

为了解决频谱稀缺的问题,提高频谱利用率,采用频谱拍卖方法激励主用户（卖家）出售空闲的频谱,次用户（买家）通过在拍卖中获胜得以接入其急需的频谱,提出了一种采用混合图的双向异质频谱拍卖算法(Double Auction based on Mixed Graph for heterogeneous spectrums,MGDA)。该算法使用混合图能够更准确地量化买家之间对于频谱的干扰情况,使频谱交易数量最大化,显著提高了频谱利用率。MGDA还考虑了频谱的异质性,允许买家表达对不同频率频谱的偏好,为不同的频谱建立不同的频谱干扰图。仿真结果表明,MGDA在空间利用率、买家满意度和拍卖收益等方面具有良好的性能,空间利用率比采用无向图的拍卖算法提高5.8%~13.6%。     

投资基金、资本市场及其因果分析

本文从宏观和市场发展层面上,利用格兰杰因果分析和有向非循环图（DAG）技术,对我国2002-2010年的证券投资基金与股票、M2、债券和居民存款之间的因果关系进行了分析。研究结果表明,我国金融市场仍处于分割状态,证券投资基金还没有有效地发挥联系渠道和资产优化配置的功能。证券投资基金存在着导致资本市场风险波动的羊群行为和惯性行为,这是对发展不完善的资本市场所作出的被动性的适应性反应。中国证券投资基金对股票市场具有显著性影响,规范和发展证券投资基金对促进股票市场健康发展具有重要作用。     

Factors influencing the co-occurrence of visits to attractions: The case of Madrid,Spain

Large destinations such as cities usually offer multiple and diverse attractions, a selection of which will be visited by tourists during their stay. This study analyses the factors influencing the probability of the co-occurrence of visits to attractions in the city of Madrid (Spain). On the basis of five years (2013–2018) of user-generated data, we built a network formed by the attractions visited by the tourists and fitted it to an exponential random graph model. The results show that a tourist's decision to visit a particular attraction was influenced by its popularity and rating. In addition, homophily in popularity, rating and some attraction categories was detected. In the analysis made of the temporal trend of the attraction network, it was found that homophily in the category of museums and theatres strengthened over the study period. Identifying the forces that connect attractions is crucial for their efficient management, promotion, and preservation.     

访问控制策略一致性和完备性检测方法研究

为实现对复杂访问控制策略的统一管理,检测并排除冲突和不完备的访问控制策略,提出了利用访问控制策略集合中的偏序信息构造融合主体、客体层级结构的有向无环图模型。首先从理论上证明了构建有向无环图模型的可行性,并提出利用偏序关系构建有向无环图模型的实施算法,然后利用有向无环图模型的节点集合设计了访问控制策略一致性和完备性检测算法,最后对模型构建算法及访问控制策略一致性和完备性检测算法进行实验验证。实验结果表明,融合主体、客体层级结构的有向无环图模型可以有效管理复杂系统中访问控制策略中出现的冲突与策略不完备情况。相关算法可以有效地实现对复杂访问控制策略的统一管理。