农业信息化多种接入方式格式转换方法研究

互联网上的信息资源大部分都是针对电脑屏幕分辨率设计的,即在800×600或更高的分辨率下可以达到最佳效果,而农村用户通过电视机接入网络,由于屏幕分辨率较低,无法正常显示网页。以农村普及的电视为研究对象,针对低分辨率的电视机不能正常显示网页信息的问题,把网页分为导航页面和内容页面,针对于导航页面给出了采用缩略图进行网页格式转换的方法,并对网页缩略图转换进行了试验验证,证明了所给出方法能够有效的将现有的Web页面转换为适合于普通电视显示的页面。     

论网页问卷调查在图书馆中的应用

在提出网页问卷调查应用原理的基础上,重点分析了图书馆中设计网页问卷调查应注意的问题,并指出网页问卷调查相比于传统问卷调查的优势所在,最后提出研究网页问卷调查在图书馆中的应用具有非常重要的方法论意义。     

利用网页过滤技术实现水中倒影

网页过滤技术能使网页呈现出奇异多彩的效果,每一种过滤效果对应着一个过滤对象,JavaScript脚本语言可动态地操控过滤对象,使网页显示出变幻的可视状态。利用网页过滤技术和JavaScript脚本语言对网页中的图片进行操作,使静态图片产生了水中倒影的动态特效。     

中文农业搜索引擎字符编码识别

针对农业网页中汉字编码标识混乱的情况,提出了一种综合运用编码规则和网页文本特征的字符编码识别模型。利用卡方检验算法,结合最小二乘多元线性回归方法,得到了基于网页文本特征的字符识别模型。实验结果显示,在适当的选取阈值（r ＝1,阈值＝属于某一编码的字符数/网页总字符数）和文本特征数（≥65）的基础上,模型准确率达到100％,且结果稳定。     

Strong regularities in world wide web surfing

One of the most common modes of accessing information in the World Wide Web is surfing from one document to another along hyperlinks. Several large empirical studies have revealed common patterns of surfing behavior. A model that assumes that users make a sequence of decisions to proceed to another page, continuing as long as the value of the current page exceeds some threshold, yields the probability distribution for the number of pages that a user visits within a given Web site. This model was verified by comparing its predictions with detailed measurements of surfing patterns. The model also explains the observed Zipf-like distributions in page hits observed at Web sites.     

Geologic Age from Metamict Minerals

In our article "Mesons Produced by the Cyclotron" (Gardner, E. et al. Science, 1950, 111, 191) there is a typographical error on page 196 in the table near the top of the page. The first entry in the right-hand column reads 28.8 and should read 26.8.     

观赏树木学网络课程的规划设计

在对<观赏树木学>课程的特点分析的基础上,对该课程的规划设计分为知识模块的规划设计与功能模块的规划设计两部分,知识模块属于静态网页的内容,用Frontpage、Dreamweaver制作,主要通过框架布局来实现课本知识的展示;功能模块属于动态网页的内容,主要通过JSP技术来实现.     

网站英文信息写译技巧实例分析

提出写译网站英文信息应注意把握新闻报刊文体的语言特征,遵循不同文体的写译规范.结合实例分析,对简介类信息,网站主页信息以及其他实用信息资源的写译技巧展开了探讨.     

Errata

In Wilder Penfield's article, "The interpretive cortex," [Science 129, 1719 (26 June 1959)], the word psychical should be substituted for physical on page 1719, column 3, line 15. On page 1723, column 3, last line, reference should be made to Fig. 6, not Fig. 3.     

基于ASP.NET的页面数据持久和页面逻辑的探讨

本文讨论了在实际开发ASP．NET应用系统中，如何实现Web页面数据持久化，以及如何处理Web页面逻辑，给基于B／S架构的应用系统提供了参考。     

Erratum

In the report by J. E. Kutzbach (2 Oct., p. 59), an error appeared. On page 61, column 1, eight lines from the bottom of the page, the word "pressure" should be "precipitation."     

VFP中通用报表页面设置表单的设计与实现

利用VFP制作一个通用的报表页面设置表单，让用户通过可视化的界面对指定的数据表进行相关设置，并调用EXCEL打印输出结果，从而弥补VFP应用系统中报表打印输出的不足。     

Erratum

The "turritid gastropod" referred to on page 713 (column 2, line 22) of the article "Hydrothermal vent animals: Distribution and biology" by J. Frederick Grassle (23 Aug.) should have been a "turrid gastropod." The first reference 26 on page 716 (column 2, line 14) should have been to R. A. Lutz and D. C. Rhoads, Eos 64, 1017 (1983). The statement at the end of page 716 that vent animals have metabolic rates that are orders of magnitude higher than relatives in other parts of the deep sea cannot be substantiated because, although many deep-sea organisms have low metabolic rates, benthic decapod crustacea and echinoderms from areas away from hydrothermal vents in the deep sea have metabolic rates similar to those of vent species when measured at the same temperature. This is further discussed in a forthcoming issue of the Bulletin of the Biological Society of Washington.     

五龙鹅(豁眼鹅)良种资源推广网的设计与制作

五龙鹅良种资源推广网以推广五龙鹅良种资源为主要目的，采用ASP编程语言结合Access数据库功能来实现。该网页将五龙鹅的科学研究、技术推广、养殖供求信息、疾病防治、资源下载等整合为一个信息化资源平台。通过网站，访问者可以和网站管理员进行在线交流。     

Corrections and clarifications

In the Research News article "Pot, heroin unlock new areas for neuroscience" by Marcia Barinaga (18 Dec., p. 1882), the diagram of the molecule anandamide on page 1883 was incorrect. The correct structure appears on page 1948 of the same issue, in figure 1A of the report "Isolation and structure of a brain constituent that binds to the cannabinoid receptor" by W. A. Devane et al. (p. 1946).     

数字图书馆文本分类特征提取方法研究与改进

从数字图书馆应用文本分类的重要性入手, 介绍了文本分类的含义及基本技术, 重点分析了文本分类中常用的两种特征提取方法：互信息算法和 统计量算法, 指出两种算法存在的不足并提出相应的改进措施。     

Erratum

In R. Jeffrey Smith's News and Comment article "Antisatellite weapon sets dangerous course" (14 Oct., p. 140), a remark on page 141 (column 3) by Richard Garwin about the usefulness of rockets, balloons, and aircraft to supplant U.S. photoreconnaissance and meterological satellites was inadvertently attributed to Robert Buchheim. And a characterization on page 141 (column 2) of the Soviet antisatellite weapon, or ASAT, was actually made by General Lewis Allen, the former Air Force chief of staff, not by General David Jones, the former chairman of the Joint Chiefs of Staff. Finally, a footnote on page 142 should have identified the Patriot as an air-to-air missile, not an air-to-ground missile.     

Erratum

Shirey Malcom, in her editorial "Plugging the pipeline" (18 Oct., p. 353) mentions the AAAS Mentor Award and directs readers to page 387 of that issue. Because of a printer's error, a Call for Nominations for the Mentor Award did not appear on page 387 and appears instead in this issue (25 Oct., p. 587).     

CORRESPONDENCE

How to obtain the Brain of the Cat, (Wilder).-Correction: Page 158, second column, line 7, "grains," should be "grams;" page 159, near middle of 2nd column, "successily," should be "successively;" page 161, the number of Flower's paper is 3.     

Erratum

In the article "String as a theory of everything" by M. Mitchell Waldrop (Research News, 20 Sept., p. 1251), the last line of the first column was inadvertantly omitted. The affected sentence should have read, "Not only were the strong interactions far more complex than predicted by field theory, but the particles that participated in the strong interactions-the hadrons, a group that includes protons, neutrons, pi mesons, and many others-seemed to be relatively large, extended objects as much as 1 Fermi across (10(-13) centimeter)." In the next-to-the-last line of the second full paragraph in column 2 on page 1252, 10(-19) should have been 10(+19). Finally, the words "quandary" (page 1251, column 1, paragraph 6, line 2) and "quark" (page 1252, column 3, last paragraph, line 18) were misspelled.