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1.
The paper gives a review of the mathematical properties of the Coulomb radial wave functions, for attractive and repulsive potentials and for positive and negative energies, together with recommendations on best methods for their computation. It includes discussions of analytic continuations (complex energies, radial co-ordinates and angular momenta) and of relativistic Coulomb functions.  相似文献   

2.
Conformant planning is used to refer to planning for unobservable problems whose solutions, like classical planning, are linear sequences of operators called linear plans. The term ‘conformant’ is automatically associated with both the unobservable planning model and with linear plans, mainly because the only possible solutions for unobservable problems are linear plans. In this paper we show that linear plans are not only meaningful for unobservable problems but also for partially-observable problems. In such case, the execution of a linear plan generates observations from the environment which must be collected by the agent during the execution of the plan and used at the end in order to determine whether the goal had been achieved or not; this is the typical case in problems of diagnosis in which all the actions are knowledge-gathering actions.Thus, there are substantial differences about linear plans for the case of unobservable or fully-observable problems, and for the case of partially-observable problems: while linear plans for the former model must conform with properties in state space, linear plans for partially-observable problems must conform with properties in belief space. This differences surface when the problems are allowed to express epistemic goals and conditions using modal logic, and place the plan-existence decision problem in different complexity classes.Linear plans is one extreme point in a discrete spectrum of solution forms for planning problems. The other extreme point is contingent plans in which there is a branch point for every possible observation at each time step, and thus the number of branch points is not bounded a priori. In the middle of the spectrum, there are plans with a bounded number of branch points. Thus, linear plans are plans with zero branch points and contingent plans are plans with unbounded number of branch points.In this work, we lay down foundations and principles for the general treatment of linear plans and plans of bounded branching, and provide exact complexity results for novel decision problems. We also show that linear plans for partially-observable problems are not only of theoretical interest since some challenging real-life problems can be dealt with them.  相似文献   

3.
Huang  J.  Wan  P.-J.  Du  D.-Z. 《Real-Time Systems》1998,15(3):249-273
This paper presents design, analysis, and implementation of a multiresource management system that enables criticality- and QoS-based resource negotiation and adaptation for mission-critical multimedia applications. With the goal of maximizing the number of high-criticality multimedia streams and the degree of their QoS, it introduces a dynamic scheduling approach using on-line QoS adjustment and multiresource preemption. An integrated multiresource management infrastructure and a set of scheduling algorithms for multiresource preemption and on-line QoS adjustment are presented. The optimality and execution efficiency of two preemption algorithms are analyzed. A primal-dual-algorithm-based approximation solution is shown (1) to be comparable to the linear-programming-based solution, which is near optimal; (2) to outperform a criticality-cognitive baseline algorithm; and (3) to be feasible for on-line scheduling. In addition, the dynamic QoS adjustment scheme is shown to greatly improve the quality of service for video streams. The multiresource management system is part of the Presto multimedia system environment prototyped at Honeywell for mission-critical applications.  相似文献   

4.
5.
We prove upper bounds for combinatorial parameters of finite relational structures, related to the complexity of learning a definable set. We show that monadic second-order (MSO) formulas with parameters have bounded Vapnik–Chervonenkis dimension over structures of bounded clique-width, and first-order formulas with parameters have bounded Vapnik–Chervonenkis dimension over structures of bounded local clique-width (this includes planar graphs). We also show that MSO formulas of a fixed size have bounded strong consistency dimension over MSO formulas of a fixed larger size, for labeled trees. These bounds imply positive learnability results for the PAC and equivalence query learnability of a definable set over these structures. The proofs are based on bounds for related definability problems for tree automata.  相似文献   

6.
7.
Bowen  N.S. Pradham  D.K. 《Computer》1993,26(2):22-31
Several hardware-based techniques that support checkpoint and rollback recovery are presented. The focus is on hardware schemes for uniprocessors, shared-memory multiprocessors, and distributed virtual-memory systems. A taxonomy for processor and memory techniques based on the memory hierarchy is presented. This provides a basis for understanding subtle differences among the various schemes. Processor-based schemes that handle transient faults by using processor-based transparent rollback techniques and memory-based schemes that roll back data instead of instructions and can be integrated with the processor techniques or can be exploited by higher levels of software are discussed  相似文献   

8.
针对电网公司在开展输变电设备运维检修过程中存在的非结构化文本数据难以利用、全口径数据难以深度融合、数据应用手段仍处于简单统计状态等难题,本文研究设计了基于知识图谱的输变电设备运维知识问答系统的总体框架,以打破传统信息获取方式的局限性。首先,从多源输变电设备数据中提取出实体、关系、属性等元素,涵盖的数据既有结构化也有非结构化的数据。在此过程中,使用不同的技术和方法来提取这些元素。其次,利用图形数据库Neo4j将这些元素组合在一起,构建一个完整的输电变电设备运维知识图谱,从而将不同类型和业务数据整合并形成一个连贯统一的知识网络。最后,基于Neo4j +Python平台搭建输变电设备运维知识问答系统,为运维人员提供一种新的方法。  相似文献   

9.
Algorithms for computing Coulomb-Bessel functions are considered, with emphasis on obtaining accurate values when the argument x is inside the classical turning point xλ. Algorithms of Barnett et al. for the generalized Coulomb functions and their derivatives are discussed in the context of the phase integral formalism. Modified or alternative algorithms are considered that are designed to be valid for all values of argument x and index λ for the functions Fλ(x), Gλ(x). An algorithm for a ccelerating convergence of a power series by conversion to a continued fraction is presented, and is applied to the evaluation of spherical Bessel functions. An explicit formula for the integrand of the phase integral is presented for spherical Bessel functions. The methods considered need to be augmented by an efficient algorithm for computing the logarithmic derivative of G0 + iF0 for Coulomb functions when x is smaller than the charge parameter η.  相似文献   

10.
《Ergonomics》2012,55(10):1057-1077
Although based on a still immature technology, virtual environments appear to have potential for applications in industry, commerce, medicine and education. The role of ergonomics will be in development of improved virtual environment interfaces and in enabling better utilization of the technology through specifying user needs and requirements and developing evaluation methodologies. By extension, ergonomists will also be involved in building virtual environments for use in areas of ergonomics activity such as workplace layout, interface design, procedures testing, education and training. This paper overviews virtual environment attributes and capabilities and proposes a framework for their specification, development and evaluation, before summarizing current ergonomics research issues. Current work on participant side effects is summarized. A strong case is made for the potential value of ergonomics for virtual environments and vice versa.  相似文献   

11.
铁路超限超重货物具有长大、笨重和价值昂贵等特征,装载加固影响因素众多且无法完全量化表达,超限超重货物装载加固决策问题是一个半结构化问题,设计装载加固可拓实例推理技术对提升铁路超限超重货物安全装载水平和运输质量尤为重要。结合铁路超限超重货物特征及其装载加固决策要素,采用可拓基元与实例推理技术,构造超限超重货物装载加固实例推理基础数据与推理规则模块的可拓基元模型,分析装载加固可拓实例属性取值特征,给出局部与全局相似度计算公式,设计超限超重货物装载加固可拓实例推理算法,确定待解实例的解。实例运用表明所给出的可拓实例推理方法可制定出合理安全的装载加固方案,切实有效解决铁路超限超重货物装载加固决策问题。  相似文献   

12.
UML及面向对象的分析与设计的研究   总被引:18,自引:0,他引:18  
详细阐述了UML本身的特点和一些容易混淆的概念。对支持UML建模的各种工具和UML中的各种框图,也进行了详细的介绍。根据成、德、绵区域网络化制造系统的分析和设计经验,清晰地说明如何用UML来完成一个系统分析和设计,深入地研究了建模过程所需要用到的框图和各框图之间的关系,对面向对象的分析和设计有很强的指导性。  相似文献   

13.
Detailed knowledge about the function and morphology of temporomandibular joint are necessary for clinical applications and for analyses of the function of temporomandibular joint prosthesis. Movements of temporomandibular joint are biomechanically sophisticated and are up-to-date not clear. Therefore, the aim of the paper is to give the suitable mathematical approach for analyses of temporomandibular joint. In the paper the analysis of the temporomandibular joint, loaded by traction and compression forces, is presented and shortly discussed. The obtained results, based on two- and three-dimensional mathematical models, represent an introductory work for further studies of biomechanical aspects of temporomandibular joint and of its artificial replacements. The models are based on the theory of contact problems in linear elasticity. For the numerical solutions of the investigated problems the FEM approaches are used and the used algorithm is based on an active-set method for quadratic programming.  相似文献   

14.
Privacy-preserving set operations are a popular research topic. Despite a large body of literature, the great majority of the available solutions are two-party protocols and expect that each participant knows her input set in the clear. In this work, we put forward a new framework for secure multi-party set and multiset operations in which the inputs can be arbitrarily partitioned among the participants, knowledge of an input (multi)set is not required for any party, and the secure set operations can be composed and can also be securely outsourced to third-party computation providers. In this framework, we construct a comprehensive suite of secure protocols for set operations and their various extensions. Our protocols are secure in the information-theoretic sense and are designed to minimize the round complexity. We then also build support for multiset operations by providing (i) a generic conversion from a multiset to a set, which makes the protocols for set operations applicable to multisets and (ii) direct instantiations of multiset operations of improved performance. All of our protocols have communication and computation complexity of \(O(m \log m)\) and logarithmic round complexity for sets or multisets of size m, which compares favorably with prior work. Practicality of our solutions is shown through experimental results, and novel optimizations based on set compaction allow us to improve performance of our protocols in practice. Our protocols are secure in both semi-honest and malicious security models.  相似文献   

15.
This paper is concerned with methods of designing nonlinear state observers for polynomic systems, which can be modeled by state equations with linear, bilinear, and quadratic terms. The general structure of polynomic observers is introduced and simulation serves as a useful tool to determine the final observer parameters. In the case of polynomic systems and linear systems, where some of the parameters are unknown, the polynomic observer theory can also be applied for a combined estimation of states and parameters. Several examples are given to demonstrate the necessity of modeling and simulation for choosing the observer structure as well as for adjusting the observer parameters.  相似文献   

16.
17.
Using non-additive entropy of order 1 and type β and non-additive entropy of order α and type β, the variation of the equivocation and the average mutual information is studied for cascade channels. The equivocation inequality is shown to be satisfied by non-additive entropy of order 1 and type β (β,β > 0) for all channels and all probability distributions. It is shown that non-additive entropy of order α and type β satisfies this inequality for binary symmetric channels for certain probability distributions.  相似文献   

18.
This paper characterizes the development of a hybrid computer-based tool supporting design for safety practices in industrial plant component specification and layout definition. The tool combines simulation and fuzzy logic techniques for the systematic risk assessment of specified design and layout configurations for plants dealing with hazardous materials. In the hybrid system architecture, the simulation module provides the historical experience for a priori hazard identification and ranking, accounting for the domino effects of possible accidental occurrences, while the fuzzy module provides the correlation matrices for concurrent hazard evaluation and overall risk assessment. In particular, the fuzzy module enables the quantitative assessment and comparison among alternative design solutions providing design guidelines, which can be further tested and verified through simulation.  相似文献   

19.
This paper presents the design issues and hardware implementation for robot-operated automatic modular and adaptable fixtures. Modular fixtures are workholding devices made from stackable self-contained modular elements. Adaptable fixtures provide surface contact with the workpiece and therefore can adapt to the workpiece geometry. These fixtures are shown to have several advantages over conventional fixtures. Issues in modularity and adaptability for workpiece fixturing are discussed for the purpose of evaluating automatic modular fixtures in flexible manufacturing systems. The basic design requirements for robot-operated modular and adaptable fixturing systems are developed and classified into mechanical and operational. Automatic assembly issues such as the use of special mating surfaces, compact actuators for active modules, as well as the importance of communications between the robot manipulator and the modular fixture are discussed.

Hardware design and implementation of a shape memory alloy actuated locking module and a discrete conformable surface module are presented. Performance characteristics such as free-play, stiffness and time response were evaluated experimentally for the locking module. Several workpiece geometries are tested on the comformable surface module.  相似文献   


20.
线面拓扑和度量关系的细分描述和计算方法   总被引:1,自引:0,他引:1  
由于单独的拓扑关系、度量关系无法区分复杂要素之间的空间关系,在语义描述上存在歧义,提出一种二维空间R~2下空间关系的细分表达模型.该模型将面与线求交后,线面可以表示成n-1个拓扑和度量分量的序列矩阵,在语义上进行更细致的分段描述;采用折线节点微小圆求交的算法,考虑面带洞和目标的不确定性,归纳出线面拓扑关系细分判断的7个规则,以及长度、分割度等度量项的计算方法.最后以土地利用中图斑扣除线状地物计算地类面积为实例,验证了该模型和计算方法对解决实际问题的有效性.  相似文献   

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