基于计数排序的最小种子集贪心算法

网络最小种子集问题与网络影响最大化问题相关,研究的是对于具有节点阈值的网络,构造网络的最小节点子集,使得如果这个子集中的节点是活的,则在给定的影响传播模型下整个网络都受到影响。为此提出了新的贪心算法,以节点的度与阈值的差为关键值对网络节点进行计数排序,然后取值最小的节点进行处理。新算法在时间复杂度上改进了基于最小堆的种子点选取算法。在简单多数阈值模型上针对经典的无标度网络得到了所构造的种子集规模上界。实验在随机生成网络和一些实际网络数据集上进行,结果表明所提方法的有效性,特别在无标度网络上生成的种子集具有比相关算法更小的规模。     

Robert Louis Stevenson and the Portrait Photographers

This article is prompted by the remarkable characteristic of nineteenth-century Scotland that circumstances congregate to give an unprecedentedly generous or democratic view of life. Four forms of communication – the statistical accounts, which were followed by the British census records, the boom in publishing, especially in newspapers and journals, and inexpensive communication promoted by the penny post, even the information in street directories and advertisements – all combine with the exploitation of photography to give us insights, which can be disconcertingly specific, acting as occasional spotlights on the landscape. This article is prompted by one particular letter from Robert Louis Stevenson, written when he was a young man, and is followed through two lines of connected thought: the practice of studio photography in Scotland and Stevenson's continuing interest in the photographic portrait.     

Occurence of Culturable Vibrio cholerae from Lake Victoria,and Rift Valley Lakes Albert and George,Uganda

Vibrio cholerae, a bacterium that causes cholera, poses a human health risk when consumed via untreated or contaminated water. Monthly investigations into the presence of V. cholerae from Lakes Albert, George and Victoria were conducted, with the goal being to examine the relationship between the occurrences of V. cholerae with various water quality parameters at fish landing sites in major water bodies in Uganda. The pH, temperature and electrical conductivity were measured at three fishing sites in each of the three study lakes; namely Gabba in Lake Victoria, Butiaba in Lake Albert and Kayanzi in Lake George. The pH values varied from 7.76 to 9.36 at Butiaba, 8.68 to 9.85 at Kayanzi and 6.6 to 9.88 at Ggaba. The temperature ranged from 17.9 to 32.3 °C at Butiaba, 22.5 to 29 °C at Kayanzi and 18.2 to 30.5 °C at Ggaba. The electrical conductivity ranged from 129.2 to 984 μS cm^?1 at Butiaba, 658 to 1090 μS cm^?1 at Kayanzi and 119 to 218 μS cm^?1 at Ggaba, for Lakes Albert, George and Victoria, respectively. Enrichment techniques were used to detect culturable V. cholerae on TCBS culture media. Seventy‐five (75%) of the samples (n = 90) were positive for V. cholera. The occurrence of V. cholerae was positively associated with water quality parameters over the 10‐month period of study. Vibrio cholerae was more frequently detected during the dry season (warmer) than during the wet season. These study results suggest the investigated study lakes are natural reservoirs for V. cholerae.     

Gold Medal Award for Life Achievement in the Science of Psychology: Albert Bandura.

The American Psychological Foundation (APF) Gold Medal Awards recognize distinguished and enduring records of accomplishment in four areas of psychology: the application of psychology, the practice of psychology, psychology in the public interest, and the science of psychology. The 2006 recipient of the Gold Medal Award for Life Achievement in the Science of Psychology is Albert Bandura. Dorothy W. Cantor, president of the APF, will present the APF Gold Medal Awards at the 114th Annual Convention of the American Psychological Association on August 11, 2006, at 4:00 p.m. Members of the 2006 APF Board of Trustees are Dorothy W. Cantor, president; Norman Abeles, secretary; Charles L. McKay, treasurer; Elisabeth R. Straus, executive vice president/executive director; Norman Anderson; Camilla Benbow; Charles L. Brewer; Patrick H. DeLeon; William C. Howell; Steven E. James; Joseph D. Matarazzo; Robert J. Sternberg; Philip G. Zimbardo; and Jessica Henderson Daniel, APA Board of Directors liaison. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Leading Lady: Monica Pidgeon,Editor of Architectural Design, 1946 to 1975

Peter Murray pays tribute to Monica Pidgeon (1913-2009). Editor of Architectural Design for almost three decades, Monica was responsible for establishing Architectural Design as the premier international architectural magazine. Murray highlights her immense contribution to architecture over the years, as well as evoking the experience of working for Monica as one of her ‘boys’, or technical editors. Copyright © 2010 John Wiley & Sons, Ltd.     

Albert湖盆中-高渗储层非均质性分析

乌干达Albert湖盆南区K油田为中-高渗类型储层,非均质性较强。主要运用37 m岩心及280样次的薄片、粒度、扫描电镜、X-衍射、压汞、以及物性等化验分析结果,对储层进行层内、层间及微观储层非均质性分析并研究其控制因素。研究发现,储层渗透率变异系数为0.83~1.81,非均质性强,黏土及多种碳酸盐成岩方式的差异和沉积颗粒粒级变化是储层非均质主要影响因素。据此,将K油田Zone1A、Zone1B及Zone1C层岩石类型主要划分为粗-中粒颗粒包壳式泥质胶结砂岩、细-中粒碳酸盐质孔隙式胶结砂岩及中-粗粒颗粒包壳式和孔隙式泥质胶结砂岩。     

The Unified Project

Albert Pope argues that a unified architectural and urban project is not possible without addressing the conceptual divide that exists between building and infrastructure. It is a split that was first set in motion by the breakdown of Modernism in the 1960s and was reaffirmed by the rise of Postmodernism. Since then, architectural form and urban infrastructure have not only remained disjointed, but have been overtly celebrated by the collages and juxtapositions of the contemporary and the historic in our cities.