Making Sense of your Usage Statistics

Usage statistics are a key decision making tool for most librarians. In this tactics session, Bob Schufreider showed how some libraries are using their vendor's usage statistics to inform purchase decisions and justify expenses, discussed the latest technologies and standards designed to make collection and integration of these statistics less time-consuming and more effective, and outlined some of the problems and pitfalls encountered with the collection of usage statistics.     

无密度制约的Lotka-Volterra模型捕食-食饵系统同时捕获的最优化

对无密度制约的Lotka-Volterra模型捕食-食饵系统的平衡点进行了定性分析,从生态学意义上解释了中心奇点外周围周期解的存在性。此外分λ为已知正常数和λ未知两种情况给出了此系统的两种群同时捕获时的最大持续受益的条件。     

北京市城市雨水利用的成本效益分析

科学、合理、高效地利用雨水资源,不仅可以缓解城市缺水状况,而且能够涵养与保护水资源、控制城市水土流失和内涝,减少水污染和改善城市生态环境等.目前世界上很多城市都开展了雨水利用方面的研究.如何科学的评价雨水利用的成本效益是城市雨水利用研究的热点.本文根据城市水文学原理和经济学原理建立了城市雨水利用成本效益分析模型,对北京市2007年267项雨水利用工程进行了分析.结果表明:①北京市雨水利用效益指数α达到了2.3,综合效益非常显著;②根据α的值,将全市分为4个区:①雨水利用无效益区(α＜1.0).包括朝阳区、西城区、东城区和丰台区,占22.2%;②雨水利用低效益区(1.0≤α≤1.5),包括通州区、平谷区、石景山,占16.7%;③雨水利用利用效益区(1.5＜α＜3.0),共包括9个区县,占50.O%;④雨水利用利用高效益区(α≥3.0).共包括2个区县,占11.1%;③从α的空间分布来看,北京市城区的效益指数总体上小于郊区,α与各区县面积呈较好的正相关关系(r=0.65,R2=0.432),这主要是由于城区雨水利用的空间相对郊区来说受到的限制较多,可选择的雨水利用方式比较单一,多以小型的蓄水池和透水地面为主.     

Discovery Products and the Open Archives Initiative Protocol for Metadata Harvesting

Discovery products promise to offer library patrons one-stop shopping for library resources. In order to accomplish this, they harvest metadata from various library databases and repositories such as integrated library systems, institutional repositories, and digital libraries. Discovery products then index this metadata along with the metadata for resources from the discovery service into a single product for search. The most common method used to harvest local metadata is the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). This column first looks at discovery, then it describes OAI-PMH and some of the issues involved with effectively harvesting library metadata.     

无密度制约的Lotka-Volterra模型捕食-食饵系统同时捕获的最优化

对无密度制约的Lotka-Volterra模型捕食-食饵系统的平衡点进行了定性分析,从生态学意义上解释了中心奇点外周围周期解的存在性。此外分λ为已知正常数和λ未知两种情况给出了此系统的两种群同时捕获时的最大持续受益的条件。     

运用OAI提供增值服务的探讨

OAI协议提供了一个元数据资源共享的平台协议，服务提供方可以通过对收割的元数据进行处理、提供个性化的服务等实现增值服务。本文对OAI协议及收割原理进行了简单的介绍，对增值服务进行了一些探讨，以充分发挥数字化图书馆在信息化中的重要作用。     

Bifurcation analysis in a predator-prey system with stage-structure and harvesting

In this paper, we consider a predator-prey model with stage-structure and harvesting. This model is the same as the one developed by Kar and Pahari (2007) [9], but we make bifurcation analysis more general than their work. In particular, using the approach of Beretta and Kuang (2002) [4], we show that the positive steady state can be destabilized through a Hopf bifurcation. We also investigate the stability and direction of periodic solutions bifurcating from Hopf bifurcation by using the normal form theory and the center manifold theorem presented in Hassard et al. (1981) [8]. Numerical simulations are then carried out as supporting evidences of our analytical results.     

Controlling the Production of EAD Encoded Documents,Extracting Metadata and Publishing Them on the Web: Methods and Tools,France

SUMMARY

This article presents four projects geared towards providing the community of EAD users with methods and tools to control the quality of archival finding aids, to extract metadata from them in Dublin Core and qualified Dublin Core for use in OAI-PMH repositories, and to publish them on the Web along with the digital images produced by digitization of the material described. The first two projects were conducted in 2004 by the Centre Historique des Archives Nationales together with AJLSM and resulted in the writing of reports and programs. The other projects are PLEADE and Navimages, which consist of open source applications that allow the building of Web-based search and viewing applications. All these tools can be used by archivists to create a complete publishing suite.