求解度约束最小生成树的一种启发式方法

针对网络设计和优化中度约束最小生成树问题,提出了一种基于贪心思想的启发式算法求解度约束最小生成树.在最小生成树的基础上,将超过度约束的顶点降低度数使之满足度约束条件.经大量数据测试并与其他算法进行比较,表明了该算法的有效性和通用性.     

二叉树形冲突分解算法研究

采用了一种新的二叉树形算法分析技术，对随机存取系统中报文分组冲突分解进行了研究，得到了冲突报文分组平均分解次数的解析式和动态吞吐率和静态吞吐率的解析式。给出了报文分组冲突分解的计算机模拟实验值。改进了Ｊ．Ｉ．Ｃａｐｅｔａｎａｋｉｓ的二叉树形冲突分解算法分析。     

食品企业舆情涌现的致错因子体系及作用机理

食品安全关系到公众利益与社会稳定,是国家战略性问题。多发的食品安全事件损害了消费者的身心健康,由其形成的食品安全舆情也损害了企业的品牌形象和声誉。如何正确应对和引导食品安全舆情,对于食品行业和企业以及应急管理研究来说都是一个亟待解决又颇具挑战性的课题。运用系统分析、应急管理与故障树等有关理论和方法,进行食品安全突发事件舆情及其形成和传播机理、食品安全舆情涌现的致错因子体系与作用机理,并以A食品公司为例进行案例分析。     

Design Improvements for Message Propagation in Malleable Social Networks

This study presents the formal problem definition and computational analysis of the network design improvements for idea and message propagation in both enterprise and consumer social networks (ESN and CSN, respectively). Message propagation in social networks is impacted by how messages are seeded in the network, and by propagation characteristics of the network topology itself. It has been recognized that the propagation properties of these networks can be actively influenced by network design interventions, such as the deliberate creation of new connections. We address the problem of finding cost‐effective message seeding, and identifying potential new network connections that allow improved propagation in social networks with cascade propagation. We use the hop‐constrained minimum spanning tree (HMST) model to find the seeds and possible new connections that result in networks with improved propagation properties. Moreover, we present new heuristic algorithms that substantially improve the solution quality for the HMST problem. Computational results posit that the design improvements proposed by the HMST approach can greatly improve cascade propagation performance of the networks at low cost.     

论公共政策设计的逻辑和模式

通过对公共政策的逻辑结构分析,在创建综合浴盆曲线图的基础上,提出政策功能分析模式、政策时间与空间分析模式,以及制定配套政策和替换政策来弥补基本政策失效阶段的政策效力,并进一步提出了全新的公共政策决策树方法,引入公众反应概率、专家评估权重和政府权重系数等因素,以促使决策制度和决策方式改革的科学化。     

数控机床故障概率计算方法的研究

本文提出了计算数控机床各种常见故障发生概率的一般方法,以此来确定故障发生的各种可能性,从而为提高数控机床可靠性提供理论依据,并通过示例证明其有效性。     

黑胸散白蚁肠道鞭毛虫共生细菌的初步研究

黑胸散白蚁(Reticulitermes chinensis)是在我国广泛分布的一种木食性白蚁,它的肠道内共生着大量的原生动物和原核生物。对其肠道内共生微生物的研究,有助于阐明木食性白蚁消化木质纤维素等植物源食物的机制。运用分子克隆技术对该白蚁肠道中鞭毛虫(Pyrsonympha grandis)相关共生细菌进行系统发育分析的结果。构建了与黑胸散白蚁肠道内共生鞭毛虫P.grandis相关的共生细菌的16SrDNA文库,通过对挑选克隆的RFLP分析选择了4个克隆进行测序,系统发育分析表明这4个克隆分别属于拟杆菌,"白蚁菌群1(Termite group 1)",γ-紫细菌,和β-紫细菌。     

Computational methods for local regression

Local regression is a nonparametric method in which the regression surface is estimated by fitting parametric functions locally in the space of the predictors using weighted least squares in a moving fashion similar to the way that a time series is smoothed by moving averages. Three computational methods for local regression are presented. First, fast surface fitting and evaluation is achieved by building ak-d tree in the space of the predictors, evaluating the surface at the corners of the tree, and then interpolating elsewhere by blending functions. Second, surfaces are made conditionally parametric in any proper subset of the predictors by a simple alteration of the weighting scheme. Third degree-of-freedom quantities that would be extremely expensive to compute exactly are approximated, not by numerical methods, but through a statistical model that predicts the quantities from the trace of the hat matrix, which can be computed easily.     

大气污染对杉木生长影响的初步研究

对资江氮肥厂附近大乘山杉木生长情况所作的研究工作包括大气监测、杉叶叶绿素、钾离子外渗率、电解质外渗率及其营养元素N、P、K、Ca、Mg、全S含量的测定,树干解析,结果表明:离厂越近,大气污染物SO_2、NO_2、和NH_3等的浓度越高,杉叶叶绿素及其P、K、Ca、Mg等营养元素含量:对照区>污染区;而杉叶钾离子外渗率和电解质外渗率及其全S、全N含量为:污染区>对照区,且叶中全S和全N含员随着时间的推移逐渐增加,分析表明:大气污染是大乘山杉木衰亡的重要原因。     

Spanning trees and identifiability of a single-factor model

The aim of this paper is to propose conditions for exploring the class of identifiable Gaussian models with one latent variable. In particular, we focus attention on the topological structure of the complementary graph of the residuals. These conditions are mainly based on the presence of odd cycles and bridge edges in the complementary graph. We propose to use the spanning tree representation of the graph and the associated matrix of fundamental cycles. In this way it is possible to obtain an algorithm able to establish in advance whether modifying the graph corresponding to an identifiable model, the resulting graph still denotes identifiability.