Land use change and carbon exchange in the tropics: III. Structure,basic equations,and sensitivity analysis of the model

The rationale, assumptions, structure and basic mathematical functions of the model used to produce the simulation results reported in the first two articles of this series are described in detail. Sensitivity analysis indicates that the most important parameters in the model, and, presumably, in the carbon exchange between tropical forests and the atmosphere, are: (a) the conversion rate of forests to permanent pasture and agriculture, (b) the changes that are occurring and have occurred in the shifting cultivation system, and (c) the fate of cleared vegetation. Although it is not possible to validate the model against direct measurements of carbon exchange, the model has been proven robust when subject to a series of explicit analyses and comparisons with other assessments.     

《安全工程》专业(本科)的一个崭新的专业领域——计算机安全

以“计算机安全是安全科学的组成部分和安全工程专业开设《计算机安全》必修课”为观点，进一步论述了安全工程专业开设计算机安全专业的发展方向和现实意义，给出了建立该专业的一个教学计划（含课程设置）框架和说明，特别是该专业大学生的知识结构关系图和“横纵双向三段式”的培养模式     

Assessing Public Perceptions of Computer-Based Models

Although there is a solid body of research on both collaborative decision-making and on processes using models, there is little research on general public attitudes about models and their use in making policy decisions. This project assessed opinions about computer models in general and attitudes about a specific model being used in water planning in the Middle Rio Grande Region of New Mexico, United States. More than 1000 individuals were surveyed about their perceptions of computer-based models in general. Additionally, more than 150 attendees at public meetings related to the Middle Rio Grande planning effort were surveyed about their perceptions of the specific Rio Grande-based model. The results reveal that the majority of respondents are confident in their ability to understand models and most believe that models are appropriate tools for education and for making policy decisions. Responses also reveal that trust in who develops a model is a key issue related to public support. Regarding the specific model highlighted in this project, the public revealed tremendous support for its usefulness as a public engagement tool as well as a tool to assist decision-makers in regional water planning. Although indicating broad support for models, the results do raise questions about the role of trust in using models in contentious decisions.     

视屏作业人员作业工效学调查研究

以人类工效学原则为尺度，根据作业人员一般状况作业体位、人——机测量、劳动休息制度、劳动强度、工作环境……等几方面对视屏作业人员肌肉骨骼损伤的形成和特点，进行分析，结果表明过分低头、向前弯腰、向两侧弯腰、手抬高过肩和长期坐位等不良体位和作业姿势，是视屏作业人员出现肌肉骨骼损伤的重要因素     

Timber harvest planning—A combined optimization/simulation model

A special cascading fixed charge structure can be used to characterize a forest management planning problem in which the objectives are to identify the optimal shape of forest harvest cutting units and simultaneously to assign facilities for logging those units. We describe a four-part methodology that has been developed to assist forest managers in analyzing areas proposed for harvesting. This methodology performs an analysis of harvesting feasibility, computes the optimal solution to the cascading fixed charge problem, undertakes a GASP IV simulation to provide additional information about the proposed harvesting operation, and permits the forest manager to perform a time-cost analysis that may lead to a more realistic, and thus improved, solution.     

Towards a new planning system for the 1990s and beyond

The paper outlines the emerging effects of the Information Technological revolution and examines the likely consequences for planning in Britain. A number of possible scenarios are described as a basis for thinking about the design of a new planning system for the future.     

The contribution of computer‐based information systems to partnership between public agencies and voluntary environmental groups

This paper considers the contribution of computing to the implementation of a policy of partnership between public environmental agencies and local voluntary groups. The present policy commitment to partnerships of this kind is reviewed. Particular information needs arise when public agencies seek to give co‐ordinated support to the environmental action undertaken by local groups. These stem from the disaggregated nature of the structure and functions of the voluntary sector. Computer‐based information systems are identified as a bridge between the regional organisation of public agencies and the local activities of voluntary groups. A computer system devised to aid the forward planning of public support for voluntary action is described. It is considered that this technique has value as part of a wider strategy of interaction between the public and voluntary sectors.     

CAD技术在人－机－环境系统工程中的应用

从以下几个方面介绍了ＣＡＤ技术在人－机－环境系统工程中的应用：ＣＡＤ技术与人－机－环境系统工程的关系；计算机图形技术在人－机－环境系统仿真中的应用；计算机几何建模技术在人－机－环境系统建模中的应用；国内外该领域的软件开发情况。     

城市防灾救灾计算机集成管理系统初论

本文通过分析现代城市灾害的特点和城市灾害管理的原则，提出了城市减灾集成管理的思想，并按此思想初步分析和设计了一个城市防灾救灾计算机集成管理系统。     

Maximum likelihood fitting of the Poisson lognormal distribution

In this paper some properties and analytic expressions regarding the Poisson lognormal distribution such as moments, maximum likelihood function and related derivatives are discussed. The author provides a sharp approximation of the integrals related to the Poisson lognormal probabilities and analyzes the choice of the initial values in the fitting procedure. Based on these he describes a new procedure for carrying out the maximum likelihood fitting of the truncated Poisson lognormal distribution. The method and results are illustrated on real data. The computer program for calculations is freely available.