综采工作面粉尘浓度分布的数值解法

分析工作面流场和粉尘分布的特点，采用气──固两相流原理，导出描述综采工作面粉尘分布的数学模型。用数值方法一有限容积法求解数学模型，编制了计算综采工作面三维空间内风速和粉尘浓度分布的计算机程序。     

安全科学学科中的计算机安全教育

指出了保护计算机信息安全的迫切性和培养计算机安全人才的重要性，强调了在安全科学学科中要加强计算机安全教育，阐述了计算机安全是安全科学的组成部分和在《安全工程》专业开设《计算机安全》必修课的观点。     

Evaluation of a fire behavior information integration system for southern California chaparral wildlands

Close contact between arid, fire-vulnerable chaparral wildlands and urban development in southern California results in conflagrations that have burned 200,000 ha, destroyed 700 structures, and claimed 16 lives in a single year. In 1972, the U.S. Congress established FIRESCOPE to assist southern California fire and emergency agencies and to develop computer methods for the simulation of wildland fire behavior.     

APPLICATION OF COMPUTER INTENSIVE STATISTICS TO PARAMETER UNCERTAINTY IN STREAMFLOW SYNTHESIS1

ABSTRACT: This paper introduces the application of Computer Intensive Statistics (CIS) to the evaluation of parameter uncertainty with specific reference to the parameters in the ARMA models used in the synthesis of streamflows. The CIS provides an empirically derived joint distribution for all parameters. Random values from this distribution can be drawn for application in the model for the generation of a specific synthetic sample. The CIS originally proposed by Efron and discussed herein is of general applicability in the evaluation of uncertainty in any statistic derived from a set of data. Some comments and limitations of the CIS are discussed in the concluding remarks.     

《计算机文化基础》课的教学改革设想与实践

随着计算机技术的飞速发展，高校计算机教育面临着新的形势。目前在《计算机文化基础》课程教学中存在着学生基础参差不齐、教学模式呆板和考试模式僵硬等问题，提出了相应的改革设想，并在教学实践中初见成效。     

A life cycle based multi-objective optimization model for the management of computer waste

The accelerating pace of waste generation from used electrical and electronic equipment is of growing global concern. Within this waste stream, computer hardware is quite significant in terms of both volume and risk to the environment because of the hazardous materials within it. The waste management hierarchy of prevention, reuse, recycle, treatment and disposal in landfill is accepted as a universal guideline for waste management. The contemporary concept of integrated solid waste management is very complex comprising of not only the environmental aspects or the technical aspects of the waste management hierarchy, but also incorporating economic, institutional, perceived risk and social issues in the context of complete life cycle of waste. Moreover, when to shift from one stage of hierarchy to another, is an involved decision warranting inclusion of several case specific issues. This paper presents a life cycle based multi-objective model that can help decision makers in integrated waste management. The proposed model has been applied to a case study of computer waste scenario in Delhi, India, which apart from having computer waste from its native population receives large quantities of imported second hand computers. The model has been used to evaluate management cost and reuse time span or life cycle of various streams of computer waste for different objectives of economy, perceived risk and environmental impact. The model results for different scenarios of waste generation have been analyzed to understand the tradeoffs between cost, perceived risk and environmental impact. The optimum life cycle of a computer desktop was observed to be shorter by 25% while optimizing cost than while optimizing impact to the environment or risk perceived by public. Proposed integrated approach can be useful for determining the optimum life cycle of computer waste, as well as optimum configuration of waste management facilities, for urban centers where computer waste related issues are of growing concern.     

Modeling obsolete computer stock under regional data constraints: An Atlanta case study

In this paper, we report on our efforts to develop a research framework that can be used to quantify waste flows for different geographical areas in the face of limited waste data availability. We demonstrate this framework in our case study of obsolete computers in the Atlanta metropolitan area. We develop computer obsolescence rates at the national metropolitan level, and couple this data with economic information at the census tract level to generate product inventory estimates (PIE) of the stock of obsolete computers from both business and household sectors in the Atlanta metropolitan area. We seek to improve the accuracy of waste flow estimates for specific geographic areas over those of previous studies, provide an easily replicable and cost effective methodology, highlight the ensuing spatial implications for collection and recycling systems using GIS, and demonstrate the potential economic benefits from diverting electronic wastes within a region. The modeling framework we have developed is intended to be applicable to other regions and to other medium range durable goods discarded by households, businesses, or obtained from buildings.     

Procedure for assessing visual quality for landscape planning and management

Incorporation of aesthetic considerations in the process of landscape planning and development has frequently met with poor results due to its lack of theoretical basis, public involvement, and failure to deal with spatial implications. This problem has been especially evident when dealing with large areas, for example, the Adirondacks, Scenic Highways, and National Forests and Parks. This study made use of public participation to evaluate scenic quality in a portion of the Niagara Escarpment in Southern Ontario, Canada. The results of this study were analyzed using thevisual management model proposed by Brown and Itami (1982) as a means of assessing and evaluating scenic quality. Themap analysis package formulated by Tomlin (1980) was then applied to this assessment for the purpose of spatial mapping of visual impact. The results of this study illustrate that it is possible to assess visual quality for landscape/management, preservation, and protection using a theoretical basis, public participation, and a systematic spatial mapping process.     

Plans to distribute the next billion computers by 2015 creates lead pollution risk

Major computer and software companies, along with governments and philanthropic organizations have embarked on ambitious plans to put computers in the hands of more than one billion new computer users over the next five to six years in untapped markets in emerging economies. The most frequently proposed solution to overcome the electricity shortfall in communities where new computer users will be located is to use rechargeable lead-acid batteries to provide primary and back-up power for computers. This paper calculates the lead emissions from battery manufacturing and recycling that will result if independent market projections to greatly expand the number, geographic, and socioeconomic distribution of computer users are realized. By examining several possible scenarios, we estimate that between 1250 and 2300 kt of lead – between four and seven times the weight of the Empire State Building – could be released into the environment in the developing world to provide power to computers sold through 2015. Increased lead exposure has a negative impact on children's neurological development as measured by reduced school performance and on standardized tests. In order to realize the educational achievement and economic development benefits of reducing the “digital divide” proponents will need to encourage improvements in lead battery production and recycling in targeted markets.     

Land classification used to select abandoned hazardous waste study sites

The biological effects of hazardous substances in the environment are influenced by climate, physiography, and biota. These factors interact to determine the transport and fate of chemicals, but are difficult to model accurately except for small areas with a large data base. The requirement for a large data base may be reduced locally if the regional influences of these factors were predetermined from existing data. Knowledge of the regional factors would also relax the restriction to considering only small areas. This paper advocates consideration of regional characteristics of the environment in the early stages of waste management strategy development. It presents as an example a procedure for selecting study sites from candidate-abandoned hazardous waste dumpsites in the southeastern United States. It uses small-scale maps of low resolution from the National Atlas to delineate the boundaries and to determine the environmental characteristics that prevail over units of land within the region. A computer map-overlay and graphic approach is used to facilitate the grouping of land types. Abandoned hazardous waste dumpsites found within land types that best represent the region are surveyed for selecting a study site. It is expected that environmental impact data obtained from a representative site would be useful for predicting impact potentials in similar remotely located areas within the same general region.