华池—南梁油田长8油藏高阻水层解释方法

鄂尔多斯盆地华池—南梁油田长8油藏存在高阻水层,油水层对比度低,油层识别难度大。为提高油层判识率,以大量测井、录井资料和岩石物理实验为基础,确定油藏水层高阻的主控因素。根据不同类型高阻水层测井响应特征,利用中子、密度和声波时差测井数据,评价孔隙结构,识别复杂孔隙结构型高阻水层;利用中子—密度曲线交会特征进行电性因子校正,扩大油水流体特征,有效识别复杂润湿型高阻水层。通过对不同主控因素高阻水层测井响应特征研究,采用相应测井技术方法有效识别,提高图版油水特征值的准确度和测井解释符合率。     

Abstraction of levels of abstraction

The notion of level of abstraction (LoA) is one of the foundations of the Floridi's Philosophy of Information. It also serves for many practical purposes as in information ethics. But the notion of abstraction is not new; it has been given many different meanings in various fields, especially in scientific disciplines and, in particular, in computer science. Our purpose here is to examine the use of abstraction in Floridi's works in conjunction with some of the meanings of abstraction in computer science. The article is divided into five sections. After a general introduction to the Floridi's method of abstraction (MoA) in Section 1, Section 2 revisits Floridi's definition of abstraction and Section 3 gives the different senses of abstraction in computer science. The Section 4 compares them with the Floridi's LoAs and proposes to generalise the Floridi's approach to abstraction using an abstraction of the LoAs, while Section 5 concludes on what we think to be some new arguments in favour of MoA and LoA.     

基于POSC的油田业务分析与建模方法

通过分析总结国际石油数据模型标准POSC模型的业务域和业务流程的划分方法和描述方法,结合国内油田企业业务特点,以测井解释等业务为例研究其中的油田业务分析与建模方法。     

计算机层次分析法的图像判读研究

运用AHP和聚类分析法对图像判读决策进行了定量与定性研究,在判读人员主观判断的基础上,获取评估结果并对这些数据做出分析。     

Property preserving abstractions for the verification of concurrent systems

We study property preserving transformations for reactive systems. The main idea is the use of simulations parameterized by Galois connections (, ), relating the lattices of properties of two systems. We propose and study a notion of preservation of properties expressed by formulas of a logic, by a function mapping sets of states of a systemS into sets of states of a systemS'. We give results on the preservation of properties expressed in sublanguages of the branching time -calculus when two systemsS andS' are related via (, )-simulations. They can be used to verify a property for a system by verifying the same property on a simpler system which is an abstraction of it. We show also under which conditions abstraction of concurrent systems can be computed from the abstraction of their components. This allows a compositional application of the proposed verification method.This is a revised version of the papers [2] and [16]; the results are fully developed in [28].This work was partially supported by ESPRIT Basic Research Action REACT.Verimag is a joint laboratory of CNRS, Institut National Polytechnique de Grenoble, Université J. Fourier and Verilog SA associated with IMAG.     

From tabular data to knowledge graphs: A survey of semantic table interpretation tasks and methods

Tabular data often refers to data that is organized in a table with rows and columns. We observe that this data format is widely used on the Web and within enterprise data repositories. Tables potentially contain rich semantic information that still needs to be interpreted. The process of extracting meaningful information out of tabular data with respect to a semantic artefact, such as an ontology or a knowledge graph, is often referred to as Semantic Table Interpretation (STI) or Semantic Table Annotation. In this survey paper, we aim to provide a comprehensive and up-to-date state-of-the-art review of the different tasks and methods that have been proposed so far to perform STI. First, we propose a new categorization that reflects the heterogeneity of table types that one can encounter, revealing different challenges that need to be addressed. Next, we define five major sub-tasks that STI deals with even if the literature has mostly focused on three sub-tasks so far. We review and group the many approaches that have been proposed into three macro families and we discuss their performance and limitations with respect to the various datasets and benchmarks proposed by the community. Finally, we detail what are the remaining scientific barriers to be able to truly automatically interpret any type of tables that can be found in the wild Web.     

A scalable approach to mapping annual land cover at 250 m using MODIS time series data: A case study in the Dry Chaco ecoregion of South America

Land use and land cover (LULC) maps from remote sensing are vital for monitoring, understanding and predicting the effects of complex human-nature interactions that span local, regional and global scales. We present a method to map annual LULC at a regional spatial scale with source data and processing techniques that permit scaling to broader spatial and temporal scales, while maintaining a consistent classification scheme and accuracy. Using the Dry Chaco ecoregion in Argentina, Bolivia and Paraguay as a test site, we derived a suite of predictor variables from 2001 to 2007 from the MODIS 250 m vegetation index product (MOD13Q1). These variables included: annual statistics of red, near infrared, and enhanced vegetation index (EVI), phenological metrics derived from EVI time series data, and slope and elevation. For reference data, we visually interpreted percent cover of eight classes at locations with high-resolution QuickBird imagery in Google Earth. An adjustable majority cover threshold was used to assign samples to a dominant class. When compared to field data, we found this imagery to have georeferencing error < 5% the length of a MODIS pixel, while most class interpretation error was related to confusion between agriculture and herbaceous vegetation. We used the Random Forests classifier to identify the best sets of predictor variables and percent cover thresholds for discriminating our LULC classes. The best variable set included all predictor variables and a cover threshold of 80%. This optimal Random Forests was used to map LULC for each year between 2001 and 2007, followed by a per-pixel, 3-year temporal filter to remove disallowed LULC transitions. Our sequence of maps had an overall accuracy of 79.3%, producer accuracy from 51.4% (plantation) to 95.8% (woody vegetation), and user accuracy from 58.9% (herbaceous vegetation) to 100.0% (water). We attributed map class confusion to limited spectral information, sub-pixel spectral mixing, georeferencing error and human error in interpreting reference samples. We used our maps to assess woody vegetation change in the Dry Chaco from 2002 to 2006, which was characterized by rapid deforestation related to soybean and planted pasture expansion. This method can be easily applied to other regions or continents to produce spatially and temporally consistent information on annual LULC.     

An algorithmic mitigation of large spurious interprocedural cycles in static analysis

We present a simple algorithmic extension of the approximate call‐strings approach to mitigate substantial performance degradation caused by spurious interprocedural cycles. Spurious interprocedural cycles are, in a realistic setting, the key reasons for why approximate call‐return semantics in both context‐sensitive and ‐insensitive static analysis can make the analysis much slower than expected. In the approximate call‐strings‐based context‐sensitive static analysis, because the number of distinguished contexts is finite, multiple call‐contexts are inevitably joined at the entry of a procedure and the output at the exit is propagated to multiple return‐sites. We found that these multiple returns frequently create a single large cycle (we call it ‘butterfly cycle’) covering almost all parts of the program and such a spurious cycle makes analyses very slow and inaccurate. Our simple algorithmic technique (within the fixpoint iteration algorithm) identifies and prunes these spurious interprocedural flows. The technique's effectiveness is proven by experiments with a realistic C analyzer to reduce the analysis time by 7–96%. As the technique is algorithmic, it can be easily applicable to existing analyses without changing the underlying abstract semantics, it is orthogonal to the underlying abstract semantics' context‐sensitivity, and its correctness is obvious. Copyright © 2010 John Wiley & Sons, Ltd.     

降低协同设计虚拟机启动开销的译码后指令缓存技术

协同设计虚拟机采用动态二进制翻译实现不同体系结构间的二进制兼容,对源指令的翻译和处理影响了协同设计虚拟机的启动性能.研究发现,在一个采用解释执行和翻译相结合的协同设计虚拟机中,处理非热点代码的解释执行是虚拟机启动开销的主要来源.发现了协同设计虚拟机中的解释例程局部性,并提出了一种硬件译码后指令缓存结构DICache(d...     

基于环境一号小卫星CCD图像的滨海湿地监测研究

湿地生态系统是与森林和海洋并列的三大生态系统之一,在全球气候和环境保护中发挥着非常重要的作用,因此,湿地的监测对环境保护和人类健康至关重要。本文以渤海湾-莱州湾为研究区域,利用环境与灾害监测预报小卫星（简称HJ-1）CCD图像通过分层分类法提取滨海湿地的分布,并以黄骅市为例对湿地的变化进行景观格局的动态分析。结果表明,利用HJ-1 CCD图像进行滨海湿地的监测是可行的,且与Landsat图像相比HJ-1 CCD数据具有高获取频率和宽覆盖范围,从而可以为湿地分布和变化的监测与管理提供经济有效的支撑。对湿地景观格局的评价表明,由于人类活动的影响,近年来湿地景观正在悄然地发生变化,天然湿地逐渐减少,人工湿地相对增多,人类的影响正日益加剧,需要引起重视。