On optimal placement of relay nodes for reliable connectivity in wireless sensor networks

The paper addresses the relay node placement problem in two-tiered wireless sensor networks. Given a set of sensor nodes in Euclidean plane, our objective is to place minimum number of relay nodes to forward data packets from sensor nodes to the sink, such that: 1) the network is connected, 2) the network is 2-connected. For case one, we propose a (6+ε)-approximation algorithm for any ε > 0 with polynomial running time when ε is fixed. For case two, we propose two approximation algorithms with (24+ε) and (6/T+12+ε), respectively, where T is the ratio of the number of relay nodes placed in case one to the number of sensors. We further extend the results to the cases where communication radiuses of sensor nodes and relay nodes are different from each other.     

品牌资产的界定及其评估模型评介

基于不同目的和受个人背景局限,人们赋予了品牌资产不同的含义并采用了不同的评估模型和方法,本文系统化地整理比较了过去学术界和实业界有关品牌资产的观点和评估模型、方法,并进行了分类和评价,最后提出了后续研究的努力方向。     

产业群内企业依存关系的生态学分析

本文旨在从生态学的角度出发,对产业群这一特殊的经济模式进行一个新层面的探讨.首先对种群的相互依存模型进行阐述,接着基于产业群的特点,运用模型结论提出建立产业群内主体企业和非主体企业的稳定依存关系的建议.     

政治资源、商业模式与民营企业总部选址

本文在前人研究基础上,重点关注政治资源及商业模式的相关性如何影响出生于小城市优秀民营企业的总部选址决策,并通过构建政治资源、商业模式与民营企业总部选址的研究模型,采用案例研究方法探寻其中的理论规律.研究结果表明,政治资源的可获得性、企业家政治资源回避思维、商业模式的政治资源优化性以及商业模式的政治资源关联性分别对民营企业总部选址决策产生了实质性的影响.     

Revisiting the concept “dialogue” in public relations

This paper follows a critical approach in exploring the philosophical underpinnings and key features of dialogue in public relations practice and thinking. It argues that dialogue has been uncritically equated to two-way symmetrical communication, which has not done justice to the nature of dialogue, and has effectively stifled concrete development of a dialogic theory in public relations. The paper draws from a range of literature, including mainstream public relations and communication philosophy—in particular the philosophy of Martin Buber. The purpose of this paper is to inform public relations thinking by encouraging debate rather than proposing a new theoretical approach. As such, it sets out to explore the concept of dialogue and its philosophical underpinning, considers its practical application and suggests that it should not be seen as superior to persuasion.     

企业增长机会与股权再融资股价反应相关性分析

以2002—2004年间92家曾经进行股权再融资的中国上市公司为样本,检验了企业增长机会与融资公告股价反应的相关性。实证结果表明,总的说来市场对股权再融资有负面反应,但是市场区别对待了高增长企业和低增长企业的融资公告。平均来说,高增长企业在公告股权再融资时股票价格的反应明显好于低增长企业。实证结果表明股票价格对股权再融资公告的反应与企业的增长机会有关。     

康乾盛世成因蠡析——兼论历史必然性与偶然性

关于康乾盛世的出现,论者多强调是康、雍、乾三帝正确治国之策的作用,但实际上康乾盛世形成的原因有三:在明、清交替之际的长期动乱之后,人心思治是康乾盛世出现不可逆转的客观规律;历史为康雍乾盛世的出现准备好了必要的条件;康雍乾三代帝王正确的治国思想和方针政策是盛世出现的必要因素。康乾盛世的出现是明末清初社会历史发展的自然结果与康、雍、乾三帝实行的正确治国方策相结合的产物,是历史发展的必然性和偶然性共同作用的结果。     

具有变系数的2n+1阶中立型微分方程正解的存在性

本文利用 Ｋｎａｓｔｅｒ不动点定理，Ｌｅｖｉ引理，给出具有变系数 Ｐ（ｔ）的 ２ｎ＋ １阶中立型微分 方程［ｘ（ｔ）－ｐ（ｔ）_ｘ（ｔ－２）］~（２ｎ＋１）＋ｆ（ｔ，ｘ（ｔ－τ_１（ｔ）），…，ｘ（ｔ－τ_ｍ（ｔ））＝０正解存在的几个充分 条件．本文结果部分地回答了文２１提出的问题．     

四川棉花育成品种产量结构分析

采用相关分析和通径分析，对四川10年来育成品种（组合）的单株铃数、单铃重、衣分与皮棉产量的关系进行了分析。其中常规棉各结构因素与皮棉产量均为极显著正相关，而杂交棉仅衣分达极显著正相关，表明杂交棉的产量潜力比常规棉大。在对皮棉产量比CK增产5％以上的常规棉和增产10％以上的杂交棉的分析中，铃重与皮棉产量均为负相关。表明常规棉和杂交棉高产潜力的进一步改良，重点应提高结铃数和衣分。     

On the Sampling Performance of an Improved Stein Inequality Restricted Estimator

Using the Stein (1964) variance estimator, this paper defines a modified Stein inequality constrained estimator and derives its exact risk under quadratic loss. Numerical evaluations show that over a wide range of the parameter space, the modified Stein inequality constrained estimator has lower risk than the traditional Stein inequality constrained estimator introduced by Judge et al . (1984).