SMOOTHED DATA AND GRADIENTS USING SLIDING POLYNOMIALS WITH OPTIONAL CONTROLS1

ABSTRACT: Sliding polynomials differ from other piecewise interpolation and smoothing methods in their functional continuity at the nodes. This functional continuity was used to establish optional spacing of nodes and optional boundary controls in data smoothing while still maintaining mathematically continuous rates or gradients. Cyclic as well as noncyclic data can be smoothed. Variance of the individual nodal values. derived through least-squares optimization, can be calculated using the rigorously determined weighting coefficients between data points and nodes. Such nodal variances are estimates of localized uncertainty in the data which complement the localization of smoothing through use of piecewise functions. Choice of controls in smoothing and calculation of variance have been incorporated in a computer program for user convenience.     

SEARCH: A GAGED WATERSHED INVENTORY1

ABSTRACT: A method, adapted to an APL interactive terminal, is described which allows the operator to thoroughly search a large set of gaged watersheds in order to find sources of comparable hydrologic data for detailed analysis. Bases of the search - and inventory - include drainage basin size and elevation, and geographical and temporal parameters, and should enhance opportunities for more reliable use of existing data.     

HYDROLOGIC CONSIDERATIONS OF THE UPPER ST. JOHNS RIVER BASIN,FLORIDA1

ABSTRACT: Since the early 1900's the Upper St. Johns River Basin, Florida, has been experiencing rapid agricultural development, through reclamation of the low-lying marshland by organized drainage districts, private land owners and corporations. These low-lying marsh areas, which constitute the floodplain, have been altered by the creation of levees, thereby reducing the natural storage capacity and permanently altering the regime of the system. This floodplain encroachment has resulted in both higher and lower water levels occurring in the upper basin area, and an increase in hydroperiod. This paper discusses the history and background of the basin accompanied by a hydrologic discussion, and suggests recommendations for a water management plan that could improve the overall operation and management of the Upper St. Johns River basin.     

METHODS AND DATA REQUIREMENTS FOR RIVER-QUALITY ASSESSMENT1

ABSTRACT: The U.S. Geological Survey is now (1975) conducting an intensive river-quality assessment of the Willamette River basin, Oregon. The objectives are to (1) define a practical framework for conducting comprehensive river-quality assessments, (2) develop and document methods for evaluating basin-development alternatives in terms of potential impacts on river quality, (3) determine the kinds and amounts of data required to adequately assess various types of river-quality problems, and (4) apply the framework, data, and methods to assess the existing or potential river-quality problems of the Willamette River basin. This paper covers objectives 2, 3, and 4 by examining the rationales behind the selection and application of methods and the design of data programs for assessing specific river-quality problems. The rationales are those developed for assessing (1) the effect of population and industrial growth and resulting waste discharges on river-dissolved oxygen, (2) the potentially harmful effects on land and river quality of accelerated erosion resulting from intensive land-use development, and (3) the potential for nuisance algal growth. The goal of the assessment program and, thus, the context of the rationales is to provide technically sound information that is appropriate and adequate for resource planning and management.     

WATER DATA - A NEW AWARENESS1

ABSTRACT: One of the most significant changes m the field of hydrology in the past few years has been the increase m demand for basic data resulting from a new awareness on the part of planners, developers and managers of the essential nature of such data. For many years data collection has been an onerous, routine operation, following which the data were processed and stored - either in publications or file drawers - and the job considered completed. Two developments have changed that picture: the realization that we are drastically altering OUT environment, and the advent of the computer. The first forced us into a recognition of our need for accurate basic data and the second provided a new methodology for handling and using it. The change is evidenced m many ways and numerous activities are underway at both State and Federal level for all facets of the acquisition and handling of water data. The collection of basic data still involves hard routine work and a conscientious-effort to maintain a high level of quality. Hopefully, recognition of the absolutely essential nature of an adequate data base will result in the continued enhancement of the basic data collector and the concomitant increase in support of his activities.     

Uncertainty Assessment for Management of Soil Contaminants with Sparse Data

In order for soil resources to be sustainably managed, it is necessary to have reliable, valid data on the spatial distribution of their environmental impact. However, in practice, one often has to cope with spatial interpolation achieved from few data that show a skewed distribution and uncertain information about soil contamination. We present a case study with 76 soil samples taken from a site of 15 square km in order to assess the usability of information gleaned from sparse data. The soil was contaminated with cadmium predominantly as a result of airborne emissions from a metal smelter. The spatial interpolation applies lognormal anisotropic kriging and conditional simulation for log-transformed data. The uncertainty of cadmium concentration acquired through data sampling, sample preparation, analytical measurement, and interpolation is factor 2 within 68.3 % confidence. Uncertainty predominantly results from the spatial interpolation necessitated by low sampling density and spatial heterogeneity. The interpolation data are shown in maps presenting likelihoods of exceeding threshold values as a result of a lognormal probability distribution. Although the results are not deterministic, this procedure yields a quantified and transparent estimation of the contamination, which can be used to delineate areas for soil improvement, remediation, or restricted area use, based on the decision-makers probability safety requirement.     

A data mining approach to simulating farmers' crop choices for integrated water resources management

Water and land resources in Thailand are increasingly under pressure from development. In particular, there are many resource conflicts associated with agricultural production in northern Thailand. Communities in these areas are significantly constrained in the land and water management decisions they are able to make. This paper describes the application of a data mining approach to describing and simulating farmers' decision rules in a catchment in northern Thailand. This approach is being applied to simulate social, economic and biophysical constraints on farmers' decisions in these areas as part of an integrated water management model.     

大巴山区自然资源及其开发利用

大巴山地处川、陕、渝的接合部,大气质量较好;由于特殊的地质构造,这里矿产资源较丰富;生物资源极其丰富,局部保存有原始森林,具有重要的科研、经济价值;旅游资源也极其丰富,是开展生态旅游和红色旅游的极好地区.     

浅谈网络安全策略

由于计算机网络表现的脆弱性使网络容易受到各种攻击，所以网络信息的安全和保密是一个非常重要的问题。本文从计算机网络安全策略出发，对解决计算机网络安全策略原则及网络的安全技术进行了综述。     

浅谈环境监测数据的审核

阐述了环境监测数据审核程序与内容,对监测数据的审核方法进行了综述。