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.     

双机热备计算机联锁控制系统的安全性和可用性分析

从现场的实际情况出发 ,笔者研究了双机热备计算机联锁控制系统的安全度和可用度指标。对实际应用中双机热备计算机联锁控制系统的失效情况进行了分析 ,其结果表明双机热备计算机联锁控制系统出现直接导致系统完全失效的故障概率很小 ,因此 ,引入了系统的故障可用系数 ,并研讨了故障可用系数对系统的可靠度、安全度和可用度的影响。通过双机热备计算机联锁控制系统的安全度和可用度的分析和仿真计算结果表明 ,引入故障可用系数后系统的安全性不变 ,系统的可靠度和可用度有显著提高。     

The use of virtual environments for percentage view analysis

It is recognised that Visual Impact Assessment (VIA), unlike many other aspects of Environmental Impact Assessments (EIA), relies less upon measurement than upon experience and judgement. Hence, it is necessary for a more structured and consistent approach towards VIA, reducing the amount of bias and subjectivity. For proposed developments, there are very few quantitative techniques for the evaluation of visibility, and these existing methods can be highly inaccurate and time consuming. Percentage view changes are one of the few quantitative techniques, and the use of computer technology can reduce the inaccuracy and the time spent evaluating the visibility of either existing or proposed developments. For over 10 years, research work undertaken by the authors at the University of Nottingham has employed Computer Graphics (CG) and Virtual Reality (VR) in civilian and industrial contexts for environmental planning, design visualisation, accident reconstruction, risk analysis, data visualisation and training simulators. This paper describes a method to quantitatively assess the visual impact of proposed developments on the landscape using CG techniques. This method allows the determination of accurate percentage view changes with the use of a computer-generated model of the environment and the application of specialist software that has been developed at the University of Nottingham. The principles are easy to understand and therefore planners, authorisation agencies and members of the public can use and understand the results. A case study is shown to demonstrate the application and the capabilities of the technology.     

计算机辅助金属塑性加工生产及其集成化

计算机辅助技术在各个领域的应用都取得了很大的成就,但各自独立的发展已经影响了它们在工业生产中的应用和推广,只有把它们集成起来才能进一步提高生产力,现生产自动化.此文阐述了金属塑性加工生产中的主要CA功能及其集成系统的形成.     

基于混合遗传算法的模拟电路自动设计研究

模拟电路在电子系统设计中具有重要意义．模拟电路设计包括电路拓扑结构设计和元件值设计，这两个方面对计算机辅助模拟电路设计都很重要．但是，传统的遗传算法在不断进化电路元件值时效率低．因此，本文提出一种具有超突变和精英策略的混合遗传算法HME-GA．该方法不仅可以用来设计电路的拓扑结构，而且可用于设计电路的元件值．实验结果表明，HEM-GA算法优于简单遗传算法GA，可作为计算机辅助模拟电路设计的有效方法，在模拟电路自动化设计中具有非常重要的意义和巨大的应用潜力．     

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.     

3D geometric structures and biological activity: Application to microbial soil organic matter decomposition in pore space

During the past 10 years, soil scientists have started to use 3D Computed Tomography in order to gain a clearer understanding of the geometry of soil structure and its relationships with soil properties. We propose a geometric model for the 3D representation of pore space and a practical method for its computation. Our basic idea consists in representing pore space using a minimal set of maximal balls (Delaunay spheres) recovering the shape skeleton. In this representation, each ball could be considered as a maximal local cavity corresponding to the “intuitive” notion of a pore as described in the literature. The space segmentation induced by the network of balls (pores) was then used to spatialize biological dynamics. Organic matter and microbial decomposers were distributed within the balls (pores). A valuated graph representing the pore network, organic matter and distribution of micro-organisms was then defined. Microbial soil organic matter decomposition was simulated by updating this valuated graph. The method was implemented and tested using real CT images. The model produced realistic simulated results when compared with data in the literature in terms of the water retention curve and carbon mineralization. A decrease in water pressure decreased carbon mineralization, which is also in accordance with findings in the literature. From our results we showed that the influence of water pressure on decomposition is a function of organic matter distribution in the pore space. As far as we know, this is the approach to have linked pore space geometry and biological dynamics in a formal way. Our next goal will be to compare the model with experimental data of decomposition using different soil structures, and to define geometric typologies of pore space shape that can be attached to specific biological and dynamic properties.     

Simulating the impacts of fire: A computer program

Recurrent fire has played a dominant role in the ecology of southwestern ponderosa pine forests. To assess the benefits or losses of fire in these forests, a computer simulation model, called BURN, considers vegetation (mortality, regeneration, and production of herbaceous vegetation), wildlife (populations and habitats), and hydrology (streamflow and water quality). In the formulation of the model, graphical representations (time-trend response curves) of increases or losses (compared to an unburned control) after the occurrence of fire are converted to fixedterm annual ratios, and then annuities for the simulation components. Annuity values higher than 1.0 indicate benefits, while annuity values lower than 1.0 indicate losses. Studies in southwestern ponderosa pine forests utilized in the development of BURN are described briefly.     

计算机辅助海运安全管理系统技术研究

以海运安全管理的基本理论与机制 ,强调保障安全必须通过管理实现对“人 -机 -环境”系统的有效干预 ,指出已实行数年的海运安全管理体系 (SMS) ,因系统庞大不便使用而妨碍了安全管理效能的发挥 ,而现有的管理信息系统技术对此作为甚小。鉴此 ,以语义Web和RDF技术为核心 ,研发了计算机辅助海运安全管理系统 (CASMS) ,包括海运安全文档知识库系统 (RDMS)、海运安全管理体系文档管理系统 (SMDS)、计算机辅助海运安全审核系统 (EES) ,为实现全面高效准确的SMS文件管理与工作表管理 ,提高海运公司和政府的SMS审核质量 ,实现地区级、国家级网络化安全管理提供了新技术。该技术可普遍用于质量管理体系、职业安全与健康管理体系、环境管理体系等系统及其综合系统。     

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。