计算机安全技术

在当今信息时代，林业安全管理所需要的信息要实现网络化必须以计算机安全技术为基础。本文主要介绍了计算机安全技术所需要注意的一些问题，同时举例说明实现单机运行安全的几种方法。     

COMPARATIVE STUDY OF OPTIMIZATION TECHNIQUES FOR IRRIGATION PROJECT PLANNING1

ABSTRACT: This study presents three optimization techniques for on‐farm irrigation scheduling in irrigation project planning: namely the genetic algorithm, simulated annealing and iterative improvement methods. The three techniques are applied to planning a 394.6 ha irrigation project in the town of Delta, Utah, for optimizing economic profits, simulating water demand, and estimating the crop area percentages with specific water supply and planted area constraints. The comparative optimization results for the 394.6 ha irrigated project from the genetic algorithm, simulated annealing, and iterative improvement methods are as follows: (1) the seasonal maximum net benefits are $113,826, $111,494, and $105,444 per season, respectively; and (2) the seasonal water demands are 3.03*10³ m³, 3.0*10³ m³, and 2.92*10³ m³ per season, respectively. This study also determined the most suitable four parameters of the genetic algorithm method for the Delta irrigated project to be: (1) the number of generations equals 800, (2) population size equals 50, (3) probability of crossover equals 0.6, and (4) probability of mutation equals 0.02. Meanwhile, the most suitable three parameters of simulated annealing method for the Delta irrigated project are: (1) initial temperature equals 1,000, (2) number of moves equal 90, and (3) cooling rate equals 0.95.     

供水管线震害量化参数--渗漏面积的估算方法

为了分析管线破坏状态对震后供水管网功能的影响，首先需要对管线的震害状态进行量化。建议用管线渗漏面积标定管线的破坏状态。在管线震害分析和理论计算的基础上，提出了震后管线渗漏面积的计算方法，为进一步进行供水管网抗震分析和设计提供了研究基础。     

Maplnfo机助制图在土地利用总体规划中的应用

在土地利用总体规划中，传统的模拟制图日益暴露出其局限性。随着信息时代的到来，计算机机助制图以其强大的优势逐步取代了传统的模拟制图。阐述了在土地利用总体规划中应用Maplnfo机助制图的必要性和工作原理，并着重探索其在土地利用总体规划中的应用过程。     

Integration of Environmental Assessment into the Regional Development Planning Process of the Galilee

/ The Galilee region on the northern edge of Israel constitutes more than 15% of the state's territory, supplies more than half of its drinking water needs, and is an important recreational resource and destination for Israelis. One of the main objectives of the plan for the Galilee was to devise a regional physical and economic development strategy for the years 1992-2007 that would arrest the trend of emigration of its residents, attract newly arrived immigrants to the region, and at the same time protect natural resources and environmental quality. This paper is limited to discussion of the environmental aspects of the plan. It analyzes spatial concepts for distribution of projected population growth, evaluates environmental impacts of alternative plans, and proposes a decision-making framework and tools for minimizing natural resources loss from development at the local level. Assessment of potential environmental impacts generated quantitative data of natural resources areas. Application of the data in the plan evaluation stage showed that the alternative that concentrated most of the new development in central Galilee was the second-best choice environmentally, but was preferred as the best choice for overall qualities. The planning study offers an alternative environmental impact assessment (EIA) process to the one presently used in Israel by incorporating environmental considerations at the initial plan-making stage and not at the plan-approval stage. It demonstrated that in order to be effective, environmental assessment and land-use planning should be seen as one effort that is integrated from the start and in each stage of the plan-making process.KEY WORDS: Environmental assessment; Development planning; Galilee     

QUALITY OF HYDROMETEOROLOGICAL DATA IN COLD REGIONS1

ABSTRACT: Many users of hydrometeorological records are not aware of the number of inconsistencies and biases that occur in hydrometeorological records. Examples are presented illustrating how the exposures of sites for measurement of precipitation, wind, snow on the ground, and evaporation determine to a large extent how useful the records are for estimating areal conditions. For areas where precipitation in the form of snow produces a significant portion of the runoff, a smaller number of quality records may be more valuable for modeling than a much larger number of records of lower quality. Information is presented to show that the overall value of an operational hydrometeorological network is dependent upon how consistent and representative of average conditions the collected records are, especially for mountainous areas in cold regions.     

神经网络及其在水库调洪演算中的应用

结合洪水灾害管理的特点建立了水库调洪演算的人工神经网络模型，阐述了其基本原理及算法，并结合某水库调洪演算实例说明了其应用。     

Using digital image projections to visualize forest landscape changes due to management activities and forest growth

A pedagogic problem in forestry and landscape management is to visualize future landscape effects of forest growth and current management activities in the forest. This paper presents a method for forecasting digital image projections of forest landscape dynamics. Static nonlinear regression functions estimate the digital numbers in a Landsat Thematic Mapper image. Regressors used are forest stand variables. By estimating the future forest stand data, based on intermediate treatment and growth, future satellite digital images are created. In a case study example, the future landscape of a forest block in the province of Västernorrland, Sweden, is projected to demonstrate the application of this visualization technique.     

Evaluation of the california environmental quality act

The California Environmental Quality Act (CEQA) has evolved from a mini-NEPA, first enacted in 1970, into a procedural act that affects the approval process of all large developments in California. In 1990, California local governments produced over 1600 environmental impact reports and 30,000 initial studies under CEQA. Because of its widespread use, CEQA has periodically drawn the attention of the state legislature, most recently in 1993, when over 60 CEQA reform bills were introduced. This paper describes the CEQA process and evaluates its success at meeting its explicit and implicit goals. The research includes a statewide survey of CEQA practice, sent to the planning departments of all 513 local governments in California in 1991. Survey respondents agreed that CEQA helps in evaluating environmental impacts, reducing impacts, informing the public, and coordinating public agency review. It is effective in reducing the environmental impacts of individual projects, but is not as effective in improving environmental quality on an areawide scale. This research concludes that CEQA has led to positive outcomes and is not as deeply flawed as many of its critics claim. Still, CEQA as currently designed may not be the optimal vehicle for ensuring environmental quality.     

Analysis of Lower Green Bay and Fox River,Collingwood Harbour,Spanish Harbour,and the Metro Toronto and Region remedial action plan (RAP) processes

This article presents a model of remedial action planning, which includes four key variables that determine progress in plan development and implementation and explain the differing level of achievement in individual sites. The model is illustrated by the characteristics and developments of four remedial action plan (RAP) processes (Lower Green Bay and Fox River, Collingwood Harbour, Spanish Harbour, and the Metro Toronto and Region RAPs). Differences in the local context of the plans have, to a significant degree, predisposed individual planning and implementation experiences. Local context includes three variables, namely geographical—technical and sociopolitical aspects and the previous history of water pollution management in the area. RAP precursors are a necessary precondition for progress in planning and substantive achievements. While there is a tendency that most geographically focused RAPs in administratively simple areas accomplish most, the motivation and political clout of RAP participants are strongly intervening factors. Resource input from upper levels of government, in particular financial commitment for plan implementation, is the fourth necessary ingredient for progress due to the RAPs' weak regulatory and institutional framework. Unfortunately, upper levels of government have shown widespread reluctance to lead in remedial action planning. This was only in part offset by local commitment and support for RAP and its cause.