用改进的灰色识别法评价地表水环境质量——以北京石景山区莲花河新开渠为案例

简要论述了利用改进的灰色识别法评价地表水环境质量的计算原理、方法和步骤。改进的灰色识别法以灰色关联法为基础,针对运用灰色关联法对水环境质量进行评价中存在的问题,引入关联离散度和隶属度算法加以改进,并将水环境质量标准等级与相应的隶属度加权平均求得精确水质类别,进一步提高了分辨率和实用性。以北京市石景山区莲花河新开渠为案例,对地表水环境质量进行评价,确定其水质等级以及变化趋势,为水环境保护规划提供科学依据。结果表明:改进的灰色识别法可比性强,分辨率高,具有较高的实用价值。     

Spatially constrained clustering and upper level set scan hotspot detection in surveillance geoinformatics

We discuss upper level set (ULS) scan as a type of spatially constrained clustering in relation to two ways of imposing the spatial constraint, retrospectively versus progressively. We show that ULS scan produces the same results both ways; whereas two popular clustering techniques, single-linkage and K-means, can yield different results when spatial constraints are imposed retrospectively versus progressively. The ULS scan approach examines spatially connected components of a tessellation as a threshold is moved from the highest level (value) in the data to the lowest level. When the variable of interest on the tessellation is a rate of incidence, then a significance test is available based on binomial or Poisson null models and Monte Carlo techniques. This is a common context for detecting hotspots of diseases in epidemiological work. We also discuss an approach for extending the univariate methodology to accommodate multivariate contexts. Received: September 2005 / Revised: February 2006 This material is based upon work supported by (i) the National Science Foundation under Grant No. 0307010, (ii) the United States Environmental Protection Agency under Grant No. CR-83059301 and (iii) the Pennsylvania Department of Health using Tobacco Settlement Funds under Grant No. ME 01324. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the agencies.     

上市航空公司盈利能力综合评价

自2008年以来,我国航空业一直处于发展低谷,评价航空公司的盈利能力及分析提高盈利能力的对策是一关键问题.许多学者习惯于应用单一的评价方法对航空上市企业进行评价,然而在对同一批航空上市企业进行评价时,不同的方法得出了不同的评价结果.基于此状况,提出一种系统的综合评价方法,并对全国12家典型航空上市企业进行综合评价,克服了以往应用单一方法在评价中的片面性,使评价结果更加全面客观.     

Abundance, behavior, and movement patterns of western gray whales in relation to a 3-D seismic survey, Northeast Sakhalin Island, Russia

A geophysical seismic survey was conducted in the summer of 2001 off the northeastern coast of Sakhalin Island, Russia. The area of seismic exploration was immediately adjacent to the Piltun feeding grounds of the endangered western gray whale (Eschrichtius robustus). This study investigates relative abundance, behavior, and movement patterns of gray whales in relation to occurrence and proximity to the seismic survey by employing scan sampling, focal follow, and theodolite tracking methodologies. These data were analyzed in relation to temporal, environmental, and seismic related variables to evaluate potential disturbance reactions of gray whales to the seismic survey. The relative numbers of whales and pods recorded from five shore-based stations were not significantly different during periods when seismic surveys were occurring compared to periods when no seismic surveys were occurring and to the post-seismic period. Univariate analyses indicated no significant statistical correlation between seismic survey variables and any of the eleven movement and behavior variables. Multiple regression analyses indicated that, after accounting for temporal and environmental variables, 6 of 11 movement and behavior variables (linearity, acceleration, mean direction, blows per surfacing, and surface-dive blow rate) were not significantly associated with seismic survey variables, and 5 of 11 variables (leg speed, reorientation rate, distance-from-shore, blow interval, and dive time) were significantly associated with seismic survey variables. In summary, after accounting for environmental variables, no correlation was found between seismic survey variables and the linearity of whale movements, changes in whale swimming speed between theodolite fixes, mean direction of whale movement, mean number of whale exhalations per minute at the surface, mean time at the surface, and mean number of exhalations per minute during a whales surface-to-dive cycle. In contrast, at higher received sound energy exposure levels, whales traveled faster, changed directions of movement less, were recorded further from shore, and stayed under water longer between respirations.     

Distribution and abundance of western gray whales off northeastern Sakhalin Island, Russia, 2001’003

In 2001–2003, >60,000 km of aerial surveys and 7,700 km of vessel surveys were conducted during June to November when critically endangered Korean–Okhotsk or western gray whales (Eschrichtius robustus) were present off the northeast coast of Sakhalin Island, Russia. Results of surveys in all years indicated gray whales occurred in predominantly two areas, (1) adjacent to Piltun Bay, and (2) offshore from Chayvo Bay, hereafter referred to as the Piltun and offshore feeding areas. In the Piltun feeding area, the majority of whales were observed in waters shallower than 20 m and were distributed from several hundred meters to ∼ 5 km from the shoreline. In the offshore feeding area during all years, the distribution of gray whales extended from southwest to northeast in waters 30–65 m in depth. During all years, the distribution and abundance of whales changed in both the Piltun and offshore feeding areas, and both north–south and inshore–offshore movements were documented within and between feeding seasons. The discovery of a significant number of whales feeding in the offshore area each year was a substantial finding of this study and raises questions regarding western gray whale abundance and population levels, feeding behavior and ecology, and individual site-fidelity. Fluctuations in the number of whales observed within the Piltun and offshore feeding areas and few sightings outside of these two areas indicate that gray whales move between the Piltun and offshore feeding areas during their summer–fall feeding season. Seasonal shifts in the distribution and abundance of gray whales between and within both the Piltun and offshore feeding areas are thought, in part, to be a response to seasonal changes in the distribution and abundance of prey. However, the mechanism driving the movements of whales along the northeast coast of Sakhalin Island is likely very complex and influenced by a multitude of factors. *Deceased     

聚类GO术语在基因表达差异研究中的应用

针对基因功能分类体系基因本体(Gene Ontology,GO)特殊的有向无环图特点,改进传统的用单个GO术语检测基因差异表达信号的缺陷,设计出"聚类GO术语提升差异表达检测(ScaGO)"算法.通过简单的输入对照和实验组表达谱上的全部基因表达信号,来研究一些比较新的差异表达功能组,有助于进一步解释基因差异表达的生物学意义,如疾病发病机制、药物作用机理等.将ScaGO和基于单GO术语差异分析法应用到急性淋巴细胞性白血病数据集和酵母Rap1 DNA绑定突变体差异表达数据集上,结果显示,ScaGO能比基于单GO术语差异分析法发现一些新的与差异表达相关联的功能类基因,对于指导实验具有积极意义.图1表3参21     

基于灰色聚类方法的航空公司飞机进近着陆阶段安全性评估

进近着陆阶段时间短、任务重、环境复杂,是飞行事故多发阶段。飞行机组应当具备过硬的心理素质和熟练的驾驶技术,严格执行标准操作程序,提升稳定进近能力和复飞的决断能力,保障飞行安全。本文通过综合分析民用飞机在进近着陆时的影响因素和QAR译码数据,建立相关指标体系,构造出相应灰色聚类评价模型,根据综合聚类系数对航空公司某阶段飞机进近着陆安全性进行评估。该研究为航空公司进行进近着陆阶段安全性评估提供了一种较为科学的定量化依据,对于保障飞行安全具有现实意义。     

煤层自燃危险程度的灰色关联分析

将灰色关联分析法应用于煤矿自燃危险程度的评价中,全面考虑影响煤矿生产系统安全的各种因素,结合实例建立了煤矿自燃危险程度的数学模型,阐明了灰色关联分析法的原理和算法,较好地反映了评价过程和评价因素的灰色概念,为制定防范措施和管理决策提供科学依据。     

鄂西清江三峡旅游资源多层次灰色评价

清江三峡位于湖北省西部长阳县境内,主要包括百岛湖,巴山峡和伴峡三个风景区,景区风景质量各具特色,规模不尽相同。其中,百岛湖风景区为国家级森林公园,是目前长阳县境内开发最早,景点功能较为齐全,旅游资源最为丰富的风景区;巴山峡以岩高峡险而著称,以峡谷,溶洞与革命纪念馆为特色;伴峡风景区多奇峰异洞,辅以盐池温泉的开发和巴民族廪君文化的展现更增添了伴峡风光的魅力。为了有助于当地旅游资源的开发和利用。结合清     

灰理论在企业职工工伤事故频率预测中的应用

简述了灰理论中GM(1,1)动态预测模型的特点及其建模过程,并将其应用于企业职工工伤事故频率预测中。经检验,模型的精度良好,预测结果可靠,有利于企业发现和掌握安全生产规律,以及对生产的未来状态作出科学的定量预测。通过实例验证了该模型的有效性。