An application of the analytic hierarchy process and fuzzy logic inference in a decision support system for forage selection

Forage selection plays a prominent role in the process of returning cultivated lands back into grasslands. The conventional method of selecting forage species can only provide attempts for problem-solving without considering the relationships among the decision factors globally. Therefore, this study is dedicated to developing a decision support system to help farmers correctly select suitable forage species for the target sites. After collecting data through a field study, we developed this decision support system. It consists of three steps: (1) the analytic hierarchy process (AHP), (2) weights determination, and (3) decision making. In the first step, six factors influencing forage growth were selected by reviewing the related references and by interviewing experts. Then a fuzzy matrix was devised to determine the weight of each factor in the second step. Finally, a gradual alternative decision support system was created to help farmers choose suitable forage species for their lands in the third step. The results showed that the AHP and fuzzy logic are useful for forage selection decision making, and the proposed system can provide accurate results in a certain area (Gansu Province) of China.

Optical intrinsically fuzzy mathematical morphology for gray-scale image processing

Intrinsically fuzzy morphological erosion and dilation are extended to a total of eight operations that have been formulated in terms of a single morphological operation--biased dilation. Based on the spatial coding of a fuzzy variable, a bidirectional projection concept is proposed. Thus, fuzzy logic operations, arithmetic operations, gray-scale dilation, and erosion for the extended intrinsically fuzzy morphological operations can be included in a unified algorithm with only biased dilation and fuzzy logic operations. To execute this image algebra approach we present a cellular two-layer processing architecture that consists of a biased dilation processor and a fuzzy logic processor. (C) 1996 Optical Society of America

FUZZY SOLID SETS FOR MATHEMATICAL MORPHOLOGY AND OPTICAL IMPLEMENTATION

Fuzzy sets in the subject space are transformed to fuzzy solid sets in an increased object space on the basis of the development of the local umbra concept. Further, a counting transform is defined for reconstructing the fuzzy sets from the fuzzy solid sets, and the dilation and erosion operators in mathematical morphology are redefined in the fuzzy solid-set space. The algebraic structures of fuzzy solid sets can lead not only to fuzzy logic but also to arithmetic operations. Thus a fuzzy solid-set image algebra of two image transforms and five set operators is defined that can formulate binary and gray-scale morphological image-processing functions consisting of dilation, erosion, intersection, union, complement, addition, subtraction, and reflection in a unified form. A cellular set-logic array architecture is suggested for executing this image algebra. The optical implementation of the architecture, based on area coding of gray-scale values, is demonstrated. (C) 1995 Optical Society of America

模糊逻辑的采用软件开发工作量估算

软件估算是有半个世纪发展历史的计算机科学领域的一个巨大挑战，因为软件估算涉及到软件项目的成本和计划。开发人员需要能够获得基于他们自己的程序得到的包含了工作量估算的实践。软件成本估算主要估算开发软件系统所需的工作量、时间、人力资源等。一种有效的方式是在项目早期确定成本时估算工作量。软件成本主要依据项目的需求规格说明书来确定。目前，实施可靠、准确的成本估算仍是软件工程领域的一个挑战。 在项目早期阶段，许多项目属性尚未确定。此时的软件估算通常是不准确的，估算 的准确程度取决于用于估算的可靠且可用的信息的数量。在后续的项目分析和设计阶段，对项目的了解更加深入，估算不确定性减少，估算准确性提高。大部分估算模型未考虑这种不确定性，只是得到了确定的估算结果。这些模型需要改进，以得到估计范围和估算结果的发生概率。 新的方法（如：模糊逻辑）可能提供了软件工作量估算的替代方案。软件开发总是可以用一组具有一定程度模糊性的参数来表征。这就需要在模型中引入一定程度的不确定性，以使模型更接近实际。模糊逻辑在这方面很合适。应用模糊逻辑可以解决目前工作量估算模型存在的许多问题。而且，模糊逻辑已经与算法的和非算法的工作量估算模型结合，用于解决固有不确定性问题。 本文提出一种基于模糊逻辑规模的软件开发工作量估算方法。软件规模不是一个单个数字，可以看作是一个三角模糊数(triangular fuzzy number, TFN)。应用本文方法，可以通过改变约束条件对任意常数中的工作量估算结果进行优化。基于对本文方法中模糊权重的平均方差解释%(Variance Accounted For, VAF%) ， 提出了一种最优化算法。应用COCOMO 公开数据集进行了验证实验。与实际工作量估算的比较结果表明，基于偏差系数，本文提出的模型提供了较好的估算结果。 最后，提出了一种改进的基于模糊案例的推理(Fuzzy Case-Based Reasoning , FCBR)方法，该方法集成了agent 技术，可以从多个组织的分布式数据库中找到相似项目。基于该方法，可以从分布式预定义的项目成本数据库中收集软件成本数据，进而建立软件成本估算模型。该模型应用FCBR 方法，在不同软件组织的历史软件项目度量数据中找到类似项目。

一种用于异步电机效率优化的混合搜索方法

针对异步电机效率优化问题,提出了一种混合搜索方法。该方法起始于模糊自适应搜索,然后切换至黄金分割法以获取确定收敛速度。这样的搜索步骤能够降低转矩波动,避免在最优点附近发生振荡。利用一个包含铁损和机械损耗的异步电机模型,对该方法进行了矢量控制下的性能验证。仿真结果验证了该方法的有效性。

基于模糊推理水下作业系统运动控制研究

水下作业系统是运动学冗余系统,本文将模糊推理方法融入基于任务优先运动学控制算法,对系统载体与机械手进行协调运动分配,同时对系统多个任务进行优化。通过带有3自由度水下机械手的水下作业系统进行算例仿真研究,说明运动控制算法的有效性。

自适应模糊PID控制在AUV控制中的应用

自治潜水器(AUV,Autonomous Underwater Vehicle)是非线性、强耦合、大惯性的多输入多输出系统,又由于受到海流、传感器、执行机构等不确定性的影响,对AUV控制器的鲁棒性能提出了更高的要求。本文针对我国正在研制开发的长航程自治潜水器的特性及其对航行控制的要求,将PID控制与模糊控制的简便性、灵活性以及鲁棒性结合起来,为AUV设计了可在线修改PID参数的自适应模糊PID控制器,仿真结果证明了该种控制方法不但提高了AUV系统的动态特性,而且可在参数摄动和外界扰动时获得较好的控制性能。

基于模糊神经网络的多移动机器人自学习协调系统

研究多移动机器人的运动规划问题．针对机器人模型未知或不精确以及环境的动态变化，提出一种自学习模糊控制器（ＦＬＣ）来进行准确的速度跟踪．首先通过神经网络的学习训练构造ＦＬＣ，再由再励学习算法来在线调节ＦＬＣ的输出，以校正机器人运动状态，实现安全协调避撞

油气勘探风险评价与决策技术研究

PetroChina and other national petroleum incorporations need rigorous procedures and practical methods in risk evaluation and exploration decision at home and abroad to safeguard their international exploration practice in exploration licence bidding, finding appropriate ratio of risk sharing with partners, as well as avoiding high risk projects and other key exploration activities. However, due to historical reasons, we are only at the beginning of a full study and methodology development in exploration risk evaluation and decision. No rigorous procedure and practical methods are available in our exercises of international exploration. Completely adopting foreign procedure, methods and tools by our national incorporations are not practical because of the differences of the current economic and management systems in China. The objective of this study is to establish a risk evaluation and decision system with independent intellectual property right in oil and gas exploration so that a smooth transition from our current practice into international norm can take place. The system developed in this dissertation includes the following four components: 1. A set of quantitative criteria for risk evaluation is derived on the basis of an anatomy of the parameters from thirty calibration regions national wide as well as the characteristics and the geological factors controlling oil and gas occurrence in the major petroleum-bearing basins in China, which provides the technical support for the risk quantification in oil and gas exploration. 2. Through analysis of existing methodology, procedure and methods of exploration risk evaluation considering spatial information are proposed. The method, utilizing Mahalanobis Distance (MD) and fuzzy logic for data and information integration, provides probabilistic models on the basis of MD and fuzzy logic classification criteria, thus quantifying the exploration risk using Bayesian theory. A projection of the geological risk into spatial domain provides a probability map of oil and gas occurrence in the area under study. The application of this method to the Nanpu Sag shows that this method not only correctly predicted the oil and gas occurrence in the areas where Beibu and Laoyemiao oil fields are found in the northwest of the onshore area, but also predicted Laopu south, Nanpu south and Hatuo potential areas in the offshore part where exploration maturity was very low. The prediction of the potential areas are subsequently confirmed by 17 exploration wells in the offshore area with 81% success, indicating this method is very effective for exploration risk visualization and reduction. 3. On the basis of “Methods and parameters of economic evaluation for petroleum exploration and development projects in China”, a ”pyramid” method for sensitivity analysis was developed, which meets not only the need for exploration target evaluation and exploration decision at home, but also allows a transition from our current practice to international norm in exploration decision. This provides the foundation for the development of a software product “Exploration economic evaluation and decision system of PetroChina” (EDSys). 4. To solve problem in methodology of exploration decision, effort was made on the method of project portfolio management. A drilling decision method was developed employing the concept of geologically risked net present value. This method overcame the dilemma of handling simultaneously both geological risk and portfolio uncertainty, thus casting light into the application of modern portfolio theory to the evaluation of high risk petroleum exploration projects.

Pipeline Corrosion Analyzed by Fuzzy Reliability Methods

Fuzzy reliability methods are used to study the corrosion of pipelines. Three methods are used. They consist of using fracture failure modes, failure assessment diagram (FAD) and residual strength for establishing fuzzy reliability. Calculations are made by application of JC, improved GA-JC and Mente-carlo methods. Examples for oilfield injecting water pipeline show the residual strength well agree with field data. Mente-carlo methods appear to yield results that have better agreement with field data.

Parallel optical negabinary arithmetic based on logic operations

On the basis of signed-digit negabinary representation, parallel two-step addition and one-step subtraction can be performed for arbitrary-length negabinary operands.; The arithmetic is realized by signed logic operations and optically implemented by spatial encoding and decoding techniques. The proposed algorithm and optical system are simple, reliable, and practicable, and they have the property of parallel processing of two-dimensional data. This leads to an efficient design for the optical arithmetic and logic unit. (C) 1997 Optical Society of America.

Fuzzy reasoning morphological operators and their optical implementation

Fuzzy-reasoning theory is widely used in industrial control. Mathematical morphology is a powerful tool to perform image processing. We apply fuzzy-reasoning theory to morphology and suggest a scheme of fuzzy-reasoning morphology, including fuzzy-reasoning dilation and erosion functions. These functions retain more fine details than the corresponding conventional morphological operators with the same structuring element. An optical implementation has been developed with area-coding and thresholding methods. (C) 1997 Optical Society of America.

Compact parallel optical modified-signed-digit arithmetic-logic array processor with electron-trapping device

A compact two-step modified-signed-digit arithmetic-logic array processor is proposed. When the reference digits are programmed, both addition and subtraction can be performed by the same binary logic operations regardless of the sign of the input digits. The optical implementation and experimental demonstration with an electron-trapping device are shown. Each digit is encoded by a single pixel, and no polarization is included. Any combinational logic can be easily performed without optoelectronic and electro-optic conversions of the intermediate results. The system is compact, general purpose, simple to align, and has a high signal-to-noise ratio. (C) 1999 Optical Society of America.

Logic-operated mathematical morphology and its optical implementation

A more powerful tool for binary image processing, i.e., logic-operated mathematical morphology (LOMM), is proposed. With LOMM the image and the structuring element (SE) are treated as binary logical variables, and the MULTIPLY between the image and the SE in correlation is replaced with 16 logical operations. A total of 12 LOMM operations are obtained. The optical implementation of LOMM is described. The application of LOMM and its experimental results are also presented. (C) 1999 Optical Society of America.