半平面上有限级随机Dirichlet级数的增长性

证明了右半平面上有限级随机Dirichlet级数的增长性几乎必然与其在每条水平直线上的增长性相同。     

Subsampling Variance Estimation for Non-stationary Spatial Lattice Data

ABSTRACT.  Most proposed subsampling and resampling methods in the literature assume stationary data. In many empirical applications, however, the hypothesis of stationarity can easily be rejected. In this paper, we demonstrate that moment and variance estimators based on the subsampling methodology can also be employed for different types of non-stationarity data. Consistency of estimators are demonstrated under mild moment and mixing conditions. Rates of convergence are provided, giving guidance for the appropriate choice of subshape size. Results from a small simulation study on finite-sample properties are also reported.     

Remedial Policies in Radiologically-Contaminated Forests: Environmental Consequences and Risk Assessment

As a result of the Chernobyl nuclear power plant accident in 1986, large forested areas in Europe were contaminated by radionuclides. Extensive societal pressure has been exerted to decrease the radiation dose to the population and to the environment. Thus, in making abatement and remediation policy decisions not only economic costs, but also human and environmental risk assessment are desired. Forest remediation by organic layer removal, one of the most promising cleanup policies, is considered in this paper. Ecological risk assessment requires evaluation of the radionuclide distribution in forests. The FORESTPATH model^(1,2) is used for predicting the radionuclide fate in forest compartments after deposition as well as for evaluating the application of the remedial policy. Time of intervention and radionuclide deposition profile was predicted as being crucial for the remediation efficiency. Risk assessment conducted for a critical group of forest users in Belarus shows that consumption of forest products (berries and mushrooms) leads to about 0.004% risk of a fatal cancer. Cost-benefit analysis for forest cleanup suggests that complete removal of organic layer is too expensive for application in Belarus.     

MRF和GM模型高光谱图像地物标记

利用马尔可夫随机场和高斯混合模型构造了一种对高光谱图像进行地物标记的新方法。该方法利用PCA降维后的高光谱图像及其差分图像的先验信息建立高光谱图像的随机模型,并把最大后验估计作为地物标记优化的评判标准,用模拟退火算法实现地物标记。实验结果显示该算法是一种精确、高效、稳定的图形标记算法。     

对北京市公益林市场化经营的思考

北京市的公益林作为传统意义上的公共物品,一直以来由全市各级政府投资建设,成本高,效率低,代价大。因此,提高公益林的经营效率和质量,对于北京市公益林的持续、健康发展至关重要。笔者就如何在北京市公益林的经营中引入市场机制进行思考,并力求构建一个较为合理的公益林市场化经营模式。     

Inference in hybrid Bayesian networks using dynamic discretization

We consider approximate inference in hybrid Bayesian Networks (BNs) and present a new iterative algorithm that efficiently combines dynamic discretization with robust propagation algorithms on junction trees. Our approach offers a significant extension to Bayesian Network theory and practice by offering a flexible way of modeling continuous nodes in BNs conditioned on complex configurations of evidence and intermixed with discrete nodes as both parents and children of continuous nodes. Our algorithm is implemented in a commercial Bayesian Network software package, AgenaRisk, which allows model construction and testing to be carried out easily. The results from the empirical trials clearly show how our software can deal effectively with different type of hybrid models containing elements of expert judgment as well as statistical inference. In particular, we show how the rapid convergence of the algorithm towards zones of high probability density, make robust inference analysis possible even in situations where, due to the lack of information in both prior and data, robust sampling becomes unfeasible.     

通过林业经营和管理制度创新加快“林纸一体化”进程

林纸结合离不开规模经营。国家的林业和纸业产业发展政策，对林业经营和管理制度提出了新的要求。要解决纸浆林基地问题，需要进行林业经营和管理制度的创新，建立商品 林采伐申报制度，通过普遍的订单管理制度为造纸企业提供充足的原料基地，在家庭私有化 林场的基础上实现股份制规模经营，从而实现集体商品林生产和木浆林生产的“双赢”和可持续发展。     

自然保护区禁伐令的探析——以天目山国家自然保护区为例

自然保护区禁伐令时保护生物多样性有着积极的意义，但其一刀切做法，使得天目山等生物多样性受到威胁的保护区备受法律困扰。通过分析天目山案例中出现的实际情况，根据森林生态学原理，提出修改自然保护区禁伐令的法律程序和法律规定。修改禁伐令后将会给自然保护区提供经费支持，增加当地农民收入，改善景区景观。     

The number of records within a random interval of the current record value

LetX ₁,X ₂, … be a sequence of i.i.d. random variables with some continuous distribution functionF. LetX(n) be then-th record value associated with this sequence and μ _n ⁻ , μ _n ⁺ be the variables that count the number of record values belonging to the random intervals(f−(X(n)), X(n)), (X(n), f+(X(n))), wheref−, f+ are two continuous functions satisfyingf−(x)<x, f+(x)>x. Properties of μ _n ⁻ , μ _n ⁺ are studied in the present paper. Some statistical applications connected with these variables are also provided.     

森林生态系统管理的主体与基本步骤

生态系统管理要求以生态学的理论系统科学地管理森林生态系统，维持森林生态系统的整体性、多样性、可持续性和健康．森林生态系统管理的主体具有多元化的特征，包括政府、森林经营者、公众、科学家等，在政府的主导下，多元化主体在管理过程中，广泛参与，彼此协调，相互合作。实施森林生态系统管理的基本步骤包括范围界定、问题辨识、确定目标、制定政策方案、组织实施、监测评价和适应性调整等7个步骤．