Lake Chivero: A management case study

Lake Chivero in Zimbabwe was shown to be hypereutrophic. Historical data showed that the eutrophication process had been arrested in the late 1970s. However, a combination of poor planning, multiplicity of jurisdiction, mismatch between rate of urbanization and waste management investment, recent changes in the local climate and a permissive, immature political system that called for no public accountability resulted in environmental management breakdown leading to hypereutrophication of the lake. The case of Lake Chivero is presented as an example of a wider global issue regarding the status of environmental management in competition with other priorities in emerging democracies.     

WAVE INTERACTION WITH PERFORATED CAISSON BREAKWATERS

The reflection coefficient of perforated caissons and the total horizontal forces acting on them were experimentally and numerically analyzed and discussed when wave propagates normally. To consider the viscosity effect of fluid and nonlinear action of waves on structures, the VOF (Volume Of Fluid) method combined with the k-ε turbulence model was used to simulate the interaction between waves and structures. Governing equations were solved with the finite difference method. Through 2D experimental study in the wave flume, the empirical relationship between the reflection coefficient of perforated caissons and the main affecting factors were obtained from the experimental data using the least square method. Also the correlation between the ratio of the total horizontal force acting on perforated caisson and the force acting on solid caisson and the main affecting factors were regressed from the experimental data.     

Efficient Liability Rules: Complete Characterization

Received May, 18, 2000; revised version received March, 19, 2001     

平衡纵剖面数值试验及其对防洪的影响研究

本文采用一维非恒定流非均匀沙的水沙数学模型，以长江中游螺山汉口河段为背景，进行了根化数值模拟试验，分析了该概化河段平衡纵剖面的变化规律及其与上游来水来沙条件的关系，并和相应的理论公式进行了比较。在此基础上，对水沙条件发生较在变化时的平衡纵比降以及带来的对长江中下游防洪的影响进行了分析。     

建设项目全寿命期综合计划体系

建立了建设项目综合计划的工作过程和工作内容。与传统的狭义的项目计划不同，建设项目全寿命期综合计划必须以全寿命期项目目标为主导，以项目的功能建设和运行为核心．包括设计、组织策划、实施方案和实施过程计划、运行策划等，它们之间有复杂的内在联系，具有高度的系统性。     

Multilateral Comparison of Cost Structures in the Input–Output Tables of Japan,the US and West Germany

This paper presents a multilateral comparison of relative levels and structures of costs of production in Japan, the US and West Germany. The analysis is carried out by using harmonized input–output tables, which are converted at US prices by using adjusted sectoral purchasing power parities. A new accounting methodology is derived from recent developments of index number theory, whereas the chosen multilateral comparison procedure gives results that are invariant with respect to the order of the pairs of countries examined.     

关于饱和软土地基堤坝边坡稳定分析总应力法的讨论

在饱和的软土地基上修筑堤坝,由于孔隙水压力不易准确测定,需采用“φ=0”的总应力法进行稳定分析。这一做法在国外已明确纳入设计规范,在国内工程界较少受到重视,导致过高地估计了安全系数。本文首先系统地回顾了临界状态土力学中的伏斯列夫强度理论,在理论上阐述了饱和软土地基快速填筑时采用总应力法的原因,同时引用了Bishop和Bjerrum、美国联邦公路局、美国陆军工程师团与我国水电水利工程边坡设计规范的相关条文,确认在饱和软土地基采用总应力法进行稳定分析的合理性。以花敖泡土石坝和拉哇水电站围堰为工程实例,分别采用对土的固结不排水剪的两种做法开展稳定性分析,结果表明,直接将土的固结不排水剪强度指标ccu与φcu作为填筑后的强度参数,将严重高估其安全系数。因此建议正在修订的碾压式土石坝与边坡设计规范增加相应条文,并期望引起工程界对这一问题的重视。     

信息技术在工程建设领域中应用的发展趋势--信息孤岛与信息集成

详细分析了国际上信息技术在工程建设领域中应用的发展趋势，主要包括三个方面的内容：首先是介绍信息技术在工程建设领域中应用的信息孤岛现象，然后引进并阐述总体项目系统的概念，最后则描述了基于信息模型的集成和基于Internet的集成等两种解决思路。     

Polyhedral Combinatorics in Combinatorial Optimization

Polyhedral combinatorics is a subarea of combinatorial optimization of increasing practical importance. It deals with the application of the theory of linear systems and linear algebra to combinatorial problems. The paper is not intended as a survey on polyhedral combinatorics but it reviews some of the main concepts and proof techniques.     

加入WTO后对我国产品质量管理的新思考

我国加入 WTO后对产品质量管理应有一个新的认识新的思考 ,本文研究了质量管理环境的变化 ,分析了世界质量管理的发展趋势 ,提出了质量管理内涵的扩展。鉴于质量管理已成为新世纪产品战略的制高点 ,针对质量管理的新认识提出质量管理保证体系的思考。