The densest <Emphasis Type="Italic">k</Emphasis>-subgraph problem on clique graphs

The Densest k-Subgraph (DkS) problem asks for a k-vertex subgraph of a given graph with the maximum number of edges. The problem is strongly NP-hard, as a generalization of the well known Clique problem and we also know that it does not admit a Polynomial Time Approximation Scheme (PTAS). In this paper we focus on special cases of the problem, with respect to the class of the input graph. Especially, towards the elucidation of the open questions concerning the complexity of the problem for interval graphs as well as its approximability for chordal graphs, we consider graphs having special clique graphs. We present a PTAS for stars of cliques and a dynamic programming algorithm for trees of cliques. M.L. is co-financed within Op. Education by the ESF (European Social Fund) and National Resources. V.Z. is partially supported by the Special Research Grants Account of the University of Athens under Grant 70/4/5821.     

关于规范地方财政投融资体系的若干思考

地方财政投融资是以地方政府信用为基础 ,为实现政府基本目标 ,采取有偿融资和投资方式所进行的经济活动及所形成的制度体系。改革开放以来 ,投融资业务对地方经济发展起到了积极作用 ,但由于理论研究的严重滞后 ,以及政策措施不配套 ,地方财政投融资尚处于初步发展阶段 ,我们有必要总结其在发展中面临的问题 ,促进地方财政投融资体系的进一步完善     

The eligibility question – the real source of depersonalisation?

There have been a number of high-profile strategies over recent decades to raise social care above what is widely regarded as an unacceptable service in the United Kingdom. Quite apart from all too frequent high-profile scandals, it is seen as a service that is depersonalising and stigmatising. None of the strategies to bring about change, most of them introduced to great fanfares, have delivered the changes they promised. This article sets out a view that the reason why they have all failed is that none of them have identified or therefore tackled the underlying problem, which is the relationship between needs and resources. Underfunding has long been a serious concern for campaigning organisations. The article does not detract from that contention. However, it sets out how strategies to manage the gap between needs and resources, more than the funding gap per se, are themselves the root cause of depersonalised and chronically impoverished services. The unlikely source of these strategies can be traced to the unintended consequences of an Act of Parliament that had the best of intentions.     

基于LUC密码体制防欺诈的秘密共享方案

基于LUC密码体制,提出一种防欺诈的(t,n)门限秘密共享方案。在秘密恢复过程中,任何参与者能够对其他参与者所出示的子秘密进行验证,不仅能有效地阻止敌手窃取秘密,也能有效地防止内部成员之间的相互欺骗;各参与者的子秘密长度与秘密长度相同,方案的信息率为1,是一个理想的方案。该方案的安全性是基于LUC密码体制和Shamir的(t,n)门限秘密共享方案的安全性。     

多孔介质中可压缩混溶驱动问题的特征：混合元方法

本文考虑二维一般有界区域中的多孔介质同可压缩混溶动问题的数值解方法，给出了全离散特征－混合元格，证明了格式的唯一可解性，得到最佳Ｈ－模误差估计。     

大工50周年校庆标志创作及环境设计综述

阐述大连理工大学建校 5 0周年校庆标志设计及环境设计策划实施的主要创作思想、创意的整体过程 ,以及创意成果的筛选和在实际过程中的应用     

摘要写作与篇章图式的培养

语言的输入和输出是二语习得中经常讨论的话题。要使语言能够自然地习得,就必须给学习者提供大量的可理解性输入,并能把这些可理解性知识输入转化为有效的输出。在读写过程中,篇章图式是理解和生成文章的一个关键的因素,因此,要从篇章语法、语义和语用三个方面培养学生的篇章图式。我们可将阅读形式作为输入,摘要写作形式作为输出,从而有效地提高学生的读写水平。     

Estimation of parameters in incomplete data models defined by dynamical systems

Parametric incomplete data models defined by ordinary differential equations (ODEs) are widely used in biostatistics to describe biological processes accurately. Their parameters are estimated on approximate models, whose regression functions are evaluated by a numerical integration method. Accurate and efficient estimations of these parameters are critical issues. This paper proposes parameter estimation methods involving either a stochastic approximation EM algorithm (SAEM) in the maximum likelihood estimation, or a Gibbs sampler in the Bayesian approach. Both algorithms involve the simulation of non-observed data with conditional distributions using Hastings–Metropolis (H–M) algorithms. A modified H–M algorithm, including an original local linearization scheme to solve the ODEs, is proposed to reduce the computational time significantly. The convergence on the approximate model of all these algorithms is proved. The errors induced by the numerical solving method on the conditional distribution, the likelihood and the posterior distribution are bounded. The Bayesian and maximum likelihood estimation methods are illustrated on a simulated pharmacokinetic nonlinear mixed-effects model defined by an ODE. Simulation results illustrate the ability of these algorithms to provide accurate estimates.     

发挥农业政策性金融作用，服务社会主义新农村建设

2006年,中央一号文件明确指出,建设社会主义新农村是我国现代化建设进程中的重大历史任务,新农村建设需要巨大的资金投入,作为我国唯一的农业政策性金融机构的农业发展银行,肩负着为新农村建设提供资金的历史任务。然而,目前的农业政策性金融还存在一些缺陷,满足不了新农村建设的需求,我们需要改革农业政策性金融,使其更好地为社会主义新农村建设服务。