矢量地图空间信息度量及其变化分析方法   总被引：1，自引：0，他引：1  

陈杰  邓敏  陈晓勇  孙金礼  潘智虎 《地理信息世界》2010,8(1):78-83

如何计算地图的空间信息含量是评价制图质量、地图综合算法以及实现空间信息有效传输的重要基础。论文在详细分析现有的空间信息度量方法的基础上,提出了一种空间信息度量的新方法。该方法分别从几何、专题、拓扑以及专题拓扑4个方面来度量地图空间信息。然后,提出利用膨胀和序贯膨胀形态学算子分析几何信息熵、专题信息熵、拓扑信息熵以及专题拓扑信息熵随地图符号影响范围不同而引起的变化。通过算例分析发现,利用Voronoi图计算得到的结果是论文方法的一个极值结果(即特例),并且该方法便于定量分析地图空间信息熵度量随符号影响范围(或大小)的变化情况。  相似文献   

Seasonal variation in water column conditions in the upper Gulf of Thailand     

Anukul Buranapratheprat  Tetsuo Yanagi  Satsuki Matsumura   《Continental Shelf Research》2008,28(17):2509-2522

Seasonal variation in water column conditions in the upper Gulf of Thailand (UGoT) was analyzed by considering four major factors including surface heat flux, freshwater discharge, tidal and wind stirrings. The coincidence of surface heat loss, low river discharge and strong wind resulted in vertical well-mixing in December. Strong stratification developed in September and October due to large river discharge and moderate heat flux. Strong surface heating in April and May has a potential to generate strong stratification, although not as large as that in September and October due to low river discharge. Although no factors are prominent during January and March, and June and August, weak to moderate stratification results, because the influences of river discharge and surface heating are still larger than those of tidal and wind stirrings. The results of water column analysis based on monthly average data agree well with analyses derived from cruise data in the same months. Most analytical results correspond to the distributions of temperature and salinity from field observations. Disagreement, however, was found in December 2003 (cruise CU-2) when stratification in some small regions occurs in the distribution of water properties, but the water column analysis suggests vertical well-mixing. This phenomenon is triggered by non-uniform distribution of freshwater over UGoT, which is related to river discharge, monsoonal wind and current. Compared to a previous study regarding surface chlorophyll dynamics, water column conditions may be used to explain the occurrence of phytoplankton bloom in this region.  相似文献   

High urine hippuric acid level among police working close to traffic in an urban area,Thailand: a preliminary study     

Viroj Wiwanitkit  Jamsai Suwansaksri  Suphan Soogarun 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(2):281-283

Toluene is of particular concern because recent research indicating that toluene exposure can result in several toxicities. Hence, toluene exposure is of particular concern because of ongoing exposure to thousands of workers in the industrial plants. Determination of the urine hippuric acid level is accepted as a helpful for monitoring risk groups of workers. Apart from the industrial workers, there are other occupations with high risk for toluene exposure. In this study, we study another at-risk occupation, the police. In this study, 45 urine samples were obtained from 45 Thai police working close to traffic in an urban area for determination for urine hippuric acid level. The average urine hippuric acid level was 0.70 ± 0.70 mg/gCr, respectively. This average is significant higher than that of the control non-exposed Thais (P < 0.05). Working in the air pollution in the urban area can be health hazard for the police. Exposure to the toluene from automobile exhaust can be an important occupational problem for these police.  相似文献   

PM10 in the atmosphere and incidence of respiratory illness in Chiangmai during the smoggy pollution     

Viroj Wiwanitkit 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(3):437-440

Adverse health effects of atmospheric exposure to particles have been described in numerous epidemiological studies. In early of March 2007, there was a big environmental crisis in the northern area of Thailand. Smoggy pollution due to the fires covered many provinces in this area. Here, the author analyzes the correlation on incidence of respiratory illness and PM10 level in Chiangmai, a province in northern Thailand where the pollution occurred. The finding of emerging of the respiratory illness is similar to those previous reports on other smoggy pollutions due to fires. However, there is not a direct statistical significant relationship. It is proved that PM10 might be a risk for respiratory illness attack.  相似文献   

High blood lead level among the Mahayana Buddhist monk: a note for environmental implication     

Viroj Wiwanitkit  Jamsai Suwansaksri  Suphan Soogarun 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(6):805-807

Lead has no biological function and is one of the most toxic metals. Of several heavy metals, monitoring of lead is an important focus in occupational medicine. In exposure and risk evaluation, monitoring lead biologically has several advantages over technical exposure assessment. In this article, the authors report a very high blood lead level among the Mahayana Buddhist monks. This is a forgotten high-risk population. The environmental implication in the monitoring and controlling of this population is raised.  相似文献   

Coupled groundwater flow and transport: 2. Thermohaline and 3D convection systems     

《Advances in water resources》1998,21(5):401-425

This work continues the analysis of variable density flow in groundwater systems. It focuses on both thermohaline (double-diffusive) and three-dimensional (3D) buoyancy-driven convection processes. The finite-element method is utilized to tackle these complex non-linear problems in two and three dimensions. The preferred numerical approaches are discussed regarding appropriate basic formulations, balance-consistent discretization techniques for derivative quantitites, extension of the Boussinesq approximation, proper constraint conditions, time marching schemes, and computational strategies for solving large systems. Applications are presented for the thermohaline Elder and salt dome problem as well as for the 3D extension of the Elder problem with and without thermohaline effects and a 3D Bénard convection process. The simulations are performed by using the package FEFLOW. Conclusions are drawn with respect to numerical efforts and the appropriateness for practical needs.  相似文献   

Editorial Board     

《Applied Geochemistry》1998,13(1):CO2

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Organic geochemistry of the Lower Permian Tak Fa Formation in Phetchabun Province,Thailand: implications for its paleoenvironment and hydrocarbon generation potential     

Chenrai  Piyaphong  Fuengfu  Supawich 《中国地球化学学报》2020,39(3):291-306

Acta Geochimica - The outcrop samples of the Tak Fa Formation (Lower Permian) in Phetchabun Province have been studied to determine their organic geochemical characteristic, depositional...  相似文献   

Response of the flood peak to the spatial distribution of rainfall in the Yom River basin,Thailand     

Pawee?KlongvessaEmail authorView author&#;s OrcID profile  Minjiao?Lu  Srilert?Chotpantarat 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(10):2871-2887

The response of the flood peak to the spatial distribution of rainfall has been reported in basins with nonuniform characteristics. However, prioritization of the influences of these characteristics is still poorly understood. This study evaluated the variability in the flood peak with the spatial distribution of rainfall at Sukhothai (city) in the Yom River basin, Thailand, and investigated the influence of the basin characteristics on the flood peak. For each of the 2-, 5- and 10-y rainfalls with durations of 24, 48 and 72 h, 1000 simulated rainfall events with various spatial distributions were generated according to the observed data by using a Monte Carlo analysis and Cholesky randomization. The floods from these rainfalls were then simulated, and the peak discharges were evaluated. The flood peaks from 24-h rainfalls were usually small but highly variable and could be extremely large when the rainfalls were concentrated over the mountainous region. The flood peaks from 48 to 72-h rainfalls were consistently large and correlated with the rainfalls over the joint area between the mountainous region and plain area. The basin characteristics that influenced the response of the flood peak to the spatial distribution of the rainfall appeared to depend on the rainfall duration and magnitude. For short-duration rainfalls, the response was mainly influenced by the surface storage when the rainfall was small and by the terrain steepness when the rainfall was large. For long-duration rainfalls, the response was mainly influenced by the soil percolation rate.  相似文献   

Rocking vibrations of rigid foundations on multi-layered poroelastic media     

S. Keawsawasvong  R. Plangmal  W. Kaewjuea 《Marine Georesources & Geotechnology》2020,38(4):480-492

Abstract

This paper presents rocking vibrations of a rigid foundation resting on a multi-layered poroelastic half-space. The foundation is assumed to be rigid and massless, and subjected to a time–harmonic moment. In addition, each layer of the multi-layered half-space is governed by Biot’s theory of poroelastodynamics. The contact surface between the foundation and the layered half-space is smooth, and either fully permeable or impermeable. This dynamic interaction problem is studied by employing a discretization technique and an exact stiffness matrix scheme. Comparisons with existing solutions on rocking vibrations of rigid foundations on elastic and poroelastic media are shown to verify the accuracy of the present scheme. Selected numerical results on rocking compliances of rigid foundations of various shapes and mudmat foundations are presented. In addition, a dynamic interaction problem involving closely spaced foundations under rocking vibrations is also presented to demonstrate the applicability of the present solution scheme.  相似文献