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71.
模糊数学在机械工程材料选择中的应用 总被引:3,自引:0,他引:3
介绍了模糊数学中的基本概念、隶属函数及模糊评判的基本理论,并首次提出将模糊数学的理论知识、分析方法与人工智能基本理论相结合,并借助于计算机完成机械工程材料的选择,从而使机械工程材料选择更为科学、更为简单。本文还对此方法进行了实例验证,其效果良好,设计者只需输入工作要求,便可以确定出欲选材料的优先次序。 相似文献
72.
分析总结了国内外小直径深孔加工技术后,介绍了小直径深孔加工技术在航空机载行业中的应用,及其小直径深孔加工时设备选型需注意的问题。 相似文献
73.
Abstract Landmarks are salient objects in an environment. They play an important role in navigation by serving as orientation aids and marking decision points. Recently, there have been several efforts to design methods to automatically designate certain buildings with salient features as landmarks. All of these methodologies consist of similar steps: (a) establishing a neighborhood, usually around an intersection, (b) performing statistical or data mining analysis to find the building with outlier characteristics, and (c) establishing this salient building as the local landmark. Although these advances are significant, we believe that there are still several key issues that need to be fully addressed in order to realize the new generation of Automatic Landmark Detection Systems (ALDSs). Currently, the main shortcomings in the domain of ALDSs is the lack of a thorough and systematic study of attributes of objects that are analyzed to select landmarks, and deficient experimental verification of the benefits of ALDSs to the end users. Unless, these shortcomings are thoroughly addressed, the viability, applicability, and usefulness of ALDSs are uncertain. On the other hand, automatic landmark detection has the potential to be a dynamic, fascinating, and interdisciplinary research topic with wide applicability. Therefore, the goal of this paper is to discuss the current shortcomings in the domain of landmark detection, propose some preliminary solutions, and provide general guidelines for implementation of the new generation of ALDSs. Specifically, we discuss and promote the importance of: (a) widening the types of attributes analyzed in the landmark detection process, (b) weighting each attribute relative to its significance, (c) extending the types of objects considered as landmark candidates beyond just buildings, (d) identifying landmarks outside the vicinity of intersections, (e) identifying false landmarks along routes, and (f) using virtual environments for experiments with ALDSs. Throughout the paper, we discuss several demonstrative examples and experiments to clarify and support the ideas and concepts that are being promoted. 相似文献
74.
Performance optimization of cyber-physical systems(CPS)calls for co-design strategies that handle the issues in both computing domain and physical domain.Periods of controller tasks integrated into a uniprocessor system are related to both control performance and real-time schedulability analysis simultaneously.System performance improvement can be achieved by optimizing the periods of controller tasks.This paper extends an existing model to select task periods in real-time for CPS with fixed priority controller tasks scheduled by rate-monotonic algorithm.When all the tasks can be integrated,the analytic solution of the problem is derived by using the method of Lagrange multipliers and gradient descent method is evaluated to be suitable online.To further deal with the condition that the system is overloaded,an integrated method is proposed to select periods of tasks online by selecting a subset of tasks first and then optimizing the periods for them.Experimental results demonstrate that our method yields near-optimal result with a short running time. 相似文献
75.
为了快速准确地选择出合适的切削刀具,提出了一种基于实例推理的刀具选配方法,利用以往的经验和知识来解决新的刀具选择问题.重点研究了刀具选配实例的知识表示和检索匹配.最后举例验证了方法的可行性. 相似文献
76.
77.
D. Koc-San B.T. San V. Bakis M. Helvaci Z. Eker 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Astronomical observatory site selection is a complex problem that involves evaluation of multiple factors from different sources. The aim of this study is to select the best possible candidates for astronomical observations sites using Multi-Criteria Decision Analysis integrated with Geographical Information Systems and remote sensing technologies. The study was implemented in the Antalya province of Turkey, which is convenient for astronomical site observatory facilities with its appropriate climate properties and weather conditions. Eleven factors (cloud cover, precipitable water, earthquake zones, geology, landslide inventory, active fault lines, Digital Elevation Model, city lights, mining activities, settlement areas, roads) were determined, splitting into three categories; meteorological, geographical and anthropogenic criteria. These factors were evaluated using Analytical Hierarchy Process method and the weights of criteria layers were determined. As a result, the most suitable areas were located extensively in western and eastern part of Antalya. This study offers a robust, accurate, cost and time effective procedure for preliminary site selection for astronomical observatory. However, for a final decision of the best location of astronomical observatory, site testing measurements and atmospheric seeing observations will be further required in these preliminary areas. 相似文献
78.
王珍 《长沙航空职业技术学院学报》2010,10(3):62-64
针对航空、航天领域的半实物仿真关键设备-三轴仿真转台,重点从结构形式、电机选择、控制方式和控制算法等方面对其设计方法进行研究并提出相应的设计建议,对三轴仿真转台系统设计者具有一定的参考价值。 相似文献
79.
空间环境是空间态势感知的重要组成部分,在空间科学领域,受限于对日地系统物理规律的全面认知,现有的基于物理机制的空间环境预测模型目前还难以实用化,通常采用的多是基于数据的经验类模型。基于互信息的输入变量选择算法为空间环境要素预测模型的输入确定了思路。由于能充分考虑不同输入、输入与输出之间的潜在关系,基于互信息的输入变量选择算法近年来在回归及分类问题上得到了广泛的应用和发展。本文以输入变量选择算法的3个关键环节,即评价标准、搜索策略和停止准则为线索,从不同角度对基于互信息的过滤式变量选择算法进行了系统的分析与梳理,重点对不同变量评价标准依赖的假设条件进行了数学上的推导和说明。最后总结了其发展规律,可为后续研究尤其是建立空间环境预测模型提供借鉴。 相似文献
80.
针对临近空间高速飞行器爬升航迹问题,提出了一种涡轮冲压组合发动机尺寸选型的依据和一种固体火箭助推器辅助加速的爬升策略。以本文设计的一型临近空间高速飞行器为原型,基于hp自适应Radau伪谱法开展爬升航迹优化研究,将最优控制问题转化为非线性规划问题,以爬升消耗燃料质量最小为目标,利用序列二次规划算法求解最优航迹。在此基础上,分析了涡轮冲压组合发动机尺寸选型和采用固体火箭助推器加速爬升策略对爬升航迹和巡航航程的影响。结果表明,选取合理的发动机尺寸和助推器辅助爬升策略,均可有效减少飞行器爬升消耗燃料质量,提升巡航航程。 相似文献