Risk-based decision-making for drilling waste discharges using a fuzzy synthetic evaluation technique   总被引：5，自引：0，他引：5  

Rehan Sadiq  Tahir Husain  Neil Bose 《Ocean Engineering》2004,31(16):1929-1953

Offshore petroleum drilling wastes contain toxic substances that are potentially harmful to the marine ecosystem. Despite environmentally benign characteristics, wastes associated with synthetic-based fluids still contain a certain amount of pollutants due to contamination with formation oil and the presence of trace heavy metals in barite, which may pose risk when discharged into the marine environment. A framework is presented here for a decision support system for the selection of the best drilling waste discharge option. Uncertainties in the quantification of risk, cost and technical feasibility are expressed by fuzzy numbers. An analytical hierarchy process with a technique called fuzzy synthetic evaluation is employed to determine the best management alternative (discharge scenario).  相似文献   

Minimizing the effects of inaccurate sediment description in borehole data using rough sets and transition probability     

Gift Dumedah  Nadine Schuurman 《Journal of Geographical Systems》2008,10(3):291-315

  相似文献   

区域水资源开发模式研究   总被引：2，自引：2，他引：2  

孙才志 《吉林大学学报(地球科学版)》2002,32(1):46-50

正确的不资源开发模式对于指导合理开发利用区域水资源并最大限度降低环境生态负效应具有重要的意义。以松嫩盆地为例，根据研究区内的水文、水文地质条件，应用模糊集理论与方法确定出松嫩盆地各县市的水资源开发模式，并对各种开发模式做了简要论述。  相似文献   

岩体可爆性分级物元分析模型及其应用   总被引：4，自引：0，他引：4  

程绪涛  冯玉国 《地质灾害与环境保护》2003,14(2):57-59

首次提出用物元分析进行岩体可爆性分级的新方法。该模型将岩体可爆性类别、分类指标及其特征值作为物元，根据岩体可爆性分级标准建立关联函数，通过计算综合关联度判断岩体可爆性类别，用实例与其他方法进行了对比，得到一致的结果。该方法计算简便、分类合理，实用性强。  相似文献   

Grade estimation using fuzzy- set algorithms   总被引：1，自引：0，他引：1  

T. D. Pham 《Mathematical Geology》1997,29(2):291-305

This paper presents a new approach for estimating unknown ore grades within a mining deposit in a fuzzy environment using fuzzy c- means clustering and a fuzzy inference system. Based on a collection of cluster centers obtained from fuzzy c- means, a fuzzy rule base and fuzzy search domains are established to compute grades at these cluster centers. These cluter center- grade pairs act as control information in the fuzzy space- grade system in order to infer unknown grades on the basis of fuzzy interpolation, fuzzy extrapolation, and a defuzzification process of fuzzy control.  相似文献   

Fuzzy set approaches to classification of rock masses   总被引：6，自引：0，他引：6  

A. Aydin   《Engineering Geology》2004,74(3-4):227-245

Rock mass classification is analogous to multi-feature pattern recognition problem. The objective is to assign a rock mass to one of the pre-defined classes using a given set of criteria. This process involves a number of subjective uncertainties stemming from: (a) qualitative (linguistic) criteria; (b) sharp class boundaries; (c) fixed rating (or weight) scales; and (d) variable input reliability. Fuzzy set theory enables a soft approach to account for these uncertainties by allowing the expert to participate in this process in several ways. Hence, this study was designed to investigate the earlier fuzzy rock mass classification attempts and to devise improved methodologies to utilize the theory more accurately and efficiently. As in the earlier studies, the Rock Mass Rating (RMR) system was adopted as a reference conventional classification system because of its simple linear aggregation.

The proposed classification approach is based on the concept of partial fuzzy sets representing the variable importance or recognition power of each criterion in the universal domain of rock mass quality. The method enables one to evaluate rock mass quality using any set of criteria, and it is easy to implement. To reduce uncertainties due to project- and lithology-dependent variations, partial membership functions were formulated considering shallow (<200 m) tunneling in granitic rock masses. This facilitated a detailed expression of the variations in the classification power of each criterion along the corresponding universal domains. The binary relationship tables generated using these functions were processed not to derive a single class but rather to plot criterion contribution trends (stacked area graphs) and belief surface contours, which proved to be very satisfactory in difficult decision situations. Four input scenarios were selected to demonstrate the efficiency of the proposed approach in different situations and with reference to the earlier approaches.  相似文献   

数字社区数据标准研究   总被引：4，自引：1，他引：4  

邬伦  徐宜勤  王晓明  刘岳峰  汪大明 《地理与地理信息科学》2005,21(4):20-23

当前数字社区建设缺乏统一的智能化综合管理平台以及相应的各项数据标准，使得数字社区难以真正实现统一的数字化管理。该文参考国内外相应数据标准，研究数字社区的标准体系结构。针对现有标准体系缺乏相关数据标准的现状，提出数字社区系列数据标准，包括数据接口层标准、数据分类编码标准、数据模型、数据字典和元数据标准。阐述系列标准中各标准间的相互关系以及各标准所包含的具体内容。  相似文献   

Progradational and backstepping shoreface deposits in the Ladinian to Early Norian Snadd Formation of the Barents Sea          下载免费PDF全文

Tore G. Klausen  Alf Ryseth  William Helland‐Hansen  Helge K. Gjelberg 《Sedimentology》2016,63(4):893-916

Shoreface sandstone deposits within the Early Carnian part of the Snadd Formation of the Norwegian Barents Sea can be traced for hundreds of kilometres in the depositional strike direction and for tens of kilometres in the depositional‐dip direction. This study uses three‐dimensional seismic attribute mapping and two‐dimensional regional seismic profiles to visualize the seismic facies of these shoreface deposits and to map their internal stratigraphic architecture at a regional scale. The shoreface deposits are generally elongate but show variable width from north‐east to south‐west, which corresponds to a sediment source in the northern part of the basin and a southward decrease in longshore sediment transport. The Snadd Formation presents an example of how large‐scale progradational shoreface deposits develop. The linear nature of its shoreface deposits contrasts with more irregular, cuspate wave‐dominated deltaic shorelines that contain river outlets, and instead implies longshore drift as the main sediment source. In map view, discrete sets of linear features bounded by truncation surfaces scale directly to beach ridge sets in modern counterparts. The shoreface deposits studied here are characteristic in terms of scale and basin‐wide continuity, and offer insight into the contrast between shallow marine deposition under stable Triassic Greenhouse and fluctuating Holocene Icehouse climates. Findings presented herein are also important for hydrocarbon exploration in the Barents Sea, because they describe a hitherto poorly understood reservoir play in the Triassic interval, wherein the most prominent reservoir plays have so far been considered to be found in channelized deposits in net‐progradational delta‐plain strata that form the topsets to shelf‐edge clinoforms. The documented presence of widespread wave‐dominated shoreface deposits also has implications for how the relative importance of different sedimentary processes is considered within the basin during this period.  相似文献   

一种针对规则冲突的规则集语义比较算法     

李林  卢显良  徐海湄  李泽平  李梁 《中国海洋大学学报(自然科学版)》2008,(Z1)

应用DFD(Diverse Firewall Design)方法进行防火墙规则集设计时,需使用规则集语义比较算法,判断多个规则集是否语义一致。规则冲突是导致规则集语义不一致的主要原因。因此,需要研究针对规则冲突的规则集语义比较算法。而现有算法时空复杂度较高,性能低下。文中提出了1种基于关键数据包选取映射的规则集语义比较算法(KPCM)。KPCM算法针对规则冲突选取关键数据包,并通过比较这些数据包在不同规则集中的处理动作,判断这些规则集是否语义一致。理论分析和测试表明,KPCM算法时空性能均优于现有算法。  相似文献   

一种新的L-集表现定理   总被引：1，自引：1，他引：0  

方进明  韩元良 《中国海洋大学学报(自然科学版)》2008,38(6)

在隶属度值格仅为完备格的条件下,研究了L-集轮和L-开集轮的特征性质,并以2种集轮为工具给出基于L-集轮和L-开集轮的L-集表现定理.由于隶属度值格仅为完备格,得到的L-集表现定理更有一般意义.  相似文献