一种新的基于Gabor小波的非监督纹理分割方法

提出了一种新的基于Gabor小波的非监督纹理分割方法,与传统Gabor方法相比,该方法最大的特点在于分割的过程中利用了纹理尺度之间的依存关系和像素之间的空间约束关系。为了克服增加特征所带来的"维数灾难"问题,用独立分量分析(ICA)进行特征的整合。采用Brodatz测试集的实验结果验证了方法的有效性。     

空间数据挖掘技术在分析型客户关系管理中的应用

随着企业竞争的日益激烈,以"客户为中心"的服务理念日趋成熟,具有强大分析功能的分析型客户关系管理也就随之成为市场的研究热点,可以毋庸置疑地说它是决定企业能否在竞争中处于不败之地的重要因素.而分析型客户关系管理离不开数据挖掘技术的支持,如今,随着空间数据的日益膨胀,空间数据挖掘技术在客户关系管理中的应用显得日益突出.从分析型客户关系管理的功能和空间数据挖掘的过程出发,阐述了基于空间数据挖掘技术的集成分析型CRM的总体框架及其空间数据挖掘技术在分析型CRM中的具体应用.     

Quantitative relationship between surface sedimentary diatoms and water depth in North-Central Bohai Bay,China

To study the quantitative relationship between surface sedimentary diatoms and water depth, 67 surface samples were collected for diatom analysis on eight profiles with water depth variation from the muddy intertidal zone to the shallow sea area in North-Central Bohai Bay, China. The results showed that the distribution of diatoms changed significantly in response to the change in water depth. Furthermore, the quantitative relationship between the distribution of dominant diatom species, their a...     

论高等学校学科建设与专业建设的关系

在分析学科与专业关系的基础上,阐述了学科建设与专业建设的联系与区别,并就如何做好高等学校的学科建设与专业建设工作提出了建议。     

Strongly nonlinear long interfacial waves in uniform basic flows and their dispersion relationship

In this paper, long interfacial waves of finite amplitude in uniform basic flows are considered with the assumption that the aspect ratio between wavelength and water depth is small. A new model is derived using the velocities at arbitrary distances from the still water level as the velocity variables instead of the commonly used depth-averaged velocities. This significantly improves the dispersion properties and makes them applicable to a wider range of water depths. Since its derivation requires no assumption on wave amplitude, the model thus can be used to describe waves with arbitrary amplitude.     

应用水温数据对印度洋黄鳍金枪鱼亲体-补充量Ricker模型的扩展

海洋环境是影响印度洋黄鳍金枪鱼(Thunnus albacares)资源量的重要原因之一。本文根据1960-2002年印度洋黄鳍金枪鱼亲体-补充量数据,基于以0~40m海水垂直平均温度(Verticalaverage sea temperature,VAST)为代表的环境因子对Ricker式亲体补充量模型进行了优化。分析表明,印度洋4月0~5°N、80°E~85°E,5月、6月0~5°N、45°E~50°E,7月、8月5°N-10°N、90°E-95°E,12月5°N-10°N、70°E-75°E等海域的VAST对印度洋黄鳍金枪鱼的补充量影响最为显著,加入这些VAST环境因子的Ricker模型,其AIC(Akaike information criterion)值明显降低,拟合效果得到明显提高,这表明水温等环境因子对黄鳍金枪鱼的种群补偿过程产生了干扰。     

电子海图VPF要素关系模型的实现

电子海图数据格式纷繁复杂,为了提高海图数据的可重用性,便于海图数据的共享更新,介绍了美国国防部的海图数据格式VPF,并对其理论模型和要素关系模型进行了深入研究,通过对VPF模型结构的实验,在VC6.0平台下实现了对VPF数据的解读显示,从而为VPF格式海图向其他海图的转换提供了重要基础。     

Population structure, size at maturity and condition of sardine, Sardina pilchardus (Walb., 1792), in the nursery ground of the eastern Adriatic Sea (Krka River Estuary, Croatia)

A total of 1125 specimens of sardine, Sardina pilchardus, ranging in total length from 4.9 to 12.5 cm (mean 8.31 ± 1.41 cm) and in weights between 1.02 g and 11.18 g (mean 4.40 ± 1.87 g) were randomly sampled using a beach seine from the Krka River estuary. Samples were collected monthly according to their occurrence in this area from October to February during 2002/03, 2003/04 and 2004/05, which is during the spawning period of this species. Monthly fluctuations in the length frequency distributions of sardine were observed during that time. The length–weight relationship of all sardine specimens was described by the equation: W=0.007L^2.9587(r² = 0.9626); and the isometric nature of relative growth was established (t = −5.1495; p < 0.05). According to the allometric condition factor K_a, sardine specimens were in better somatic condition at the beginning of their appearance (spawning period) in the Krka River estuary. The length at which 50% of sardines were mature (L₅₀) was calculated to be 7.9 cm.     

Small is beautiful: An inverted view of habitat fragmentation in seagrass beds

An intertidal Zostera marina landscape in Torbay, Devon, UK, was sampled to investigate the relationship between patch size, diversity and infaunal assemblage composition with the intention of defining a minimum Zostera patch size where the infaunal seagrass assemblage becomes distinct from the bare sand assemblage. All Zostera patches were found to support a higher level of biodiversity than the surrounding bare sand. However, the size of the Zostera patch had no impact on the level of diversity; it was just the presence or absence of seagrass that made a difference. The sediment and seagrass variables were not significantly different across the range of Zostera patch sizes, indicating that the environment characteristics were homogeneous within the Zostera patches at the patch scale. Multivariate analysis revealed that assemblage composition did vary between the patch types, although the opportunistic polychaete Capitella capitata was present in all patch types and was the most abundant species overall. The presence of opportunistic species and the homogeneity of the Zostera patch variables may be due to the location of this intertidal seagrass bed, which is relatively exposed compared to the locations of other seagrass beds along the south coast of Devon, resulting in a more dynamic and disturbed environment. Nevertheless, our results demonstrate that even small patches of seagrass comprising a few plants support a higher abundance and diversity of infaunal invertebrates than bare sand, indicating that Zostera patches have conservation value whatever their size.     

Study on Interaction Relationship for Submarine Pipeline with Axial Corrosion Defects

Corrosion is one of the main reasons to cause the operation accident of submarine oil and gas transmission pipelines. As the major corrosion pattern in submarine pipelines, the effects of corrosion clusters consisting of the adjacent corrosion defects on failure pressure are investigated through non-linear large-deformation finite element method. Typically, the failure behavior and limit strength of submarine pipeline with axial groove-groove corrosion defect pair exposed to internal pressure are analyzed. The effects of corrosion depth and axial spacing between a pair of corrosion defects on failure pressure are concluded. An interaction relationship for corrosion defects in pipelines, as well as prediction formulations for assessing the remaining strength of corroded pipelines are proposed. The expressions based on the proposed interaction relationship give more accurate results than the methods used in the existing design guidelines.