共查询到20条相似文献,搜索用时 15 毫秒
1.
Howie Choset 《Annals of Mathematics and Artificial Intelligence》2001,31(1-4):113-126
This paper surveys recent results in coverage path planning, a new path planning approach that determines a path for a robot to pass over all points in its free space. Unlike conventional point-to-point path planning, coverage path planning enables applications such as robotic de-mining, snow removal, lawn mowing, car-body painting, machine milling, etc. This paper will focus on coverage path planning algorithms for mobile robots constrained to operate in the plane. These algorithms can be classified as either heuristic or complete. It is our conjecture that most complete algorithms use an exact cellular decomposition, either explicitly or implicitly, to achieve coverage. Therefore, this paper organizes the coverage algorithms into four categories: heuristic, approximate, partial-approximate and exact cellular decompositions. The final section describes some provably complete multi-robot coverage algorithms. 相似文献
2.
《Journal of Systems Architecture》2000,46(9):721-747
As the density of VLSI circuits increases it becomes attractive to integrate dedicated test logic on a chip. This built-in self-test (BIST) approach not only offers economic benefits but also interesting technical opportunities with respect to hierarchical testing and the reuse of test logic during the application of the circuit.Starting with an overview of test problems, test applications and terminology this survey reviews common test methods and analyzes the basic test procedure. The concept of BIST is introduced and discussed, BIST strategies for random logic as well as for structured logic are shown. 相似文献
3.
S. Gottwald 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2000,4(2):63-67
In fuzzy logic in wider sense, i.e. in the field of fuzzy sets applications, t-norms got a prominent rôle in recent times. In many-valued logic, the ?UKASIEWICZ systems, the GÖDEL sytems, and also the product logic all are t-norm based systems. The present paper discusses the more general problem of the adequate axiomatizability for such t-norm based logical systems in general, surveying results of the last years. The main emphasis in the present paper is on propositional logic. 相似文献
4.
We examined the relationships between physical activity and Internet use habits, using the Theory of Planned Behavior (TPB) and the Health Action Process Approach (HAPA) model as a framework. The purpose was to examine how Internet access, digital use, and time spent online correlate with the odds of engaging in three types of PA: strenuous, moderate, and muscle-strengthening Data relied on the Annual Social Survey conducted by Israel's Central Bureau of Statistics in 2010, with 6035 participants aged 20–65. Logistic regressions revealed that the odds of engaging versus not engaging in three types of physical activity were higher among Internet users compared to non-users. The odds of engaging versus not engaging in strenuous physical activity were higher among those who used the Internet for studying, social media, and downloading; in strengthening muscles were higher among those who used the Internet for seeking information and social media; and in moderate physical activity were higher among those who used the Internet for studying, compared to non-users. We suggest that the measured digital uses represent intention and action plans similar in their determinants to being physically active. Health care decision makers should increase availability of information on the Internet regarding a healthy lifestyle, concentrating on leisure-time physical activity habits. 相似文献
5.
Synchronization in complex networks and its application – A survey of recent advances and challenges
《Annual Reviews in Control》2014,38(2):184-198
Complex networks have, in recent years, brought many innovative impacts to large-scale systems. However, great challenges also come forth due to distinct complex situations and imperative requirements in human life nowadays. This paper attempts to present an overview of recent progress of synchronization of complex dynamical networks and its applications. We focus on robustness of synchronization, controllability and observability of complex networks and synchronization of multiplex networks. Then, we review several applications of synchronization in complex networks, especially in neuroscience and power grids. The present limitations are summarized and future trends are explored and tentatively highlighted. 相似文献
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Hybrid Energy Sources based on Storage Systems (HES) are increasingly used to improve the grid integration of renewable energy generators, or to improve the energy efficiency and the reliability of transport systems. This paper proposes a survey on the methodologies to design fuzzy logic based supervision strategies of this new kind of energy generating systems. Different ways to manage energy storage system are particularly discussed.A graphical modeling tool is used to facilitate the analysis and the determination of fuzzy control algorithms adapted to complex hybrid systems. The methodology is divided in different steps covering the design of a supervisor from the system work specifications to an optimized implementation of the control.An Experimental Design Methodology (EDM) combined with optimization algorithms is used to tune a set of parameters suitable for a fuzzy supervisor in order to optimize power, energy, efficiency, voltage quality, economic or environmental indicators.The application of this methodology to the supervision of different topologies of HES, based on renewable energy in a grid or in building applications or dedicated to transport systems, illustrates the performance and the systematic dimension of the approach. 相似文献
7.
Automated driving has the potential to improve the safety and efficiency of future traffic and to extend elderly peoples’ driving life, provided it is perceived as comfortable and joyful and is accepted by drivers. Driving comfort could be enhanced by familiar automated driving styles based on drivers’ manual driving styles. In a two-stage driving simulator study, effects of driving automation and driving style familiarity on driving comfort, enjoyment and system acceptance were examined. Twenty younger and 20 older drivers performed a manual and four automated drives of different driving style familiarity. Acceptance, comfort and enjoyment were assessed after driving with standardised questionnaires, discomfort during driving via handset control. Automation increased both age groups’ comfort, but decreased younger drivers’ enjoyment. Younger drivers showed higher comfort, enjoyment and acceptance with familiar automated driving styles, whereas older drivers preferred unfamiliar, automated driving styles tending to be faster than their age-affected manual driving styles.
Practitioner Summary: Automated driving needs to be comfortable and enjoyable to be accepted by drivers, which could be enhanced by driving style individualisation. This approach was evaluated in a two-stage driving simulator study for different age groups. Younger drivers preferred familiar driving styles, whereas older drivers preferred driving styles unaffected by age. 相似文献
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The maintenance and inspection of large vertical structures with autonomous systems is still an unsolved problem. A large number of different robots exist which are able to navigate on buildings, ship hulls or other human-made structures. But, most of these systems are limited to special situations or applications. This paper deals with different locomotion and adhesion methods for climbing robots and presents characteristics, challenges and applications for these systems. Based on a given set of requirements these principles are examined and in terms of a comprehensive state-of-the-art more than hundred climbing robots are presented. Finally, this schematics is applied to design aspects of a wall-climbing robot which should be able to inspect large concrete buildings. 相似文献
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Next generation heterogeneous wireless networks are expected to interwork with Internet Protocol (IP)-based infrastructures. Conventional network services operate like silos in that a specific set of services are offered over a specific type of access network. It is desirable for users to be able to roam between fixed and mobile networks that employ different access technologies. Therefore, mobility management with quality of service (QoS) support is of particular importance and one of the driving forces of convergence. Since service providers often provide more than one service to their subscribers, it is important to facilitate convergence of network charging architecture through a common charging framework. One of the main issues of IP-based convergence is security and privacy. This requires coordination of different security policies in diverse networks that have different security levels and capabilities. The business case for migration to an IP-based platform motivates operators to deliver more powerful services for customers as well as a better user experience. This paper provides an overview of converged mobile Internet architectures and their implications on QoS, charging/billing and security, as well as emerging business models for telecommunication services. 相似文献
10.
We present an overview of the most important methods that decompose an arbitrary binary object into a union of rectangles. We describe a run-length encoding and its generalization, decompositions based on quadtrees, on mathematical morphology, on the distance transform, and a theoretically optimal decomposition based on a maximal matching in bipartite graphs. We compare their performance in image compression, in moment computation and in linear filtering. We show that the choice is always a compromise between the complexity and time/memory consumption. We give advice how to select an appropriate method in particular cases. 相似文献
11.
Live video streaming applications have gained great popularity among users but exert great pressure on video servers and the Internet. Peer-to-Peer (P2P) networks provide an attractive solution due to their low cost and high scalability. A large number of P2P live video streaming schemes have been proposed and many deployments have appeared on the Internet. These schemes pursue vastly diverse directions, from mimicking IP multicast to BitTorrent-like swarming to distributed hash tables. In this paper, we provide a comprehensive and in-depth survey of P2P live video streaming schemes from an algorithmic perspective. Our purpose is to acquaint future designers with the critical design choices and their impacts on system performance. The primary objective of a P2P live video streaming system is to distribute packets from the video source to peers, and the collective paths through which a packet traverses form a tree. We focus on three aspects of how these trees are formed: determining the supplier–receiver relationships for each packet, handling the departure of the supplier or receiver before their relationship expires, and handling lost packets. We identify critical design choices in each aspect and propose a taxonomy according to these choices. Because the surveyed papers use different performance metrics and the reported results are heavily influenced by their experimental settings, we consider two measures to identify the impact of each design choice: we use a set of “internal” metrics in addition to the commonly used “external” metrics, and we examine performance metrics of schemes that have made the same design choice. For better understanding of how the design choices interact with one another and exposing future designers to the design choices specific to each individual scheme, we also provide systematic summaries for a large number of schemes. 相似文献
12.
《Information and Software Technology》2013,55(6):1004-1016
ContextThe number of students enrolled in universities at standard and on-line programming courses is rapidly increasing. This calls for automated evaluation of students assignments.ObjectiveWe aim to develop methods and tools for objective and reliable automated grading that can also provide substantial and comprehensible feedback. Our approach targets introductory programming courses, which have a number of specific features and goals. The benefits are twofold: reducing the workload for teachers, and providing helpful feedback to students in the process of learning.MethodFor sophisticated automated evaluation of students’ programs, our grading framework combines results of three approaches (i) testing, (ii) software verification, and (iii) control flow graph similarity measurement. We present our tools for software verification and control flow graph similarity measurement, which are publicly available and open source. The tools are based on an intermediate code representation, so they could be applied to a number of programming languages.ResultsEmpirical evaluation of the proposed grading framework is performed on a corpus of programs written by university students in programming language C within an introductory programming course. Results of the evaluation show that the synergy of proposed approaches improves the quality and precision of automated grading and that automatically generated grades are highly correlated with instructor-assigned grades. Also, the results show that our approach can be trained to adapt to teacher’s grading style.ConclusionsIn this paper we integrate several techniques for evaluation of student’s assignments. The obtained results suggest that the presented tools can find real-world applications in automated grading. 相似文献
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Hydrologic models for a particular watershed or a region are created for addressing a specific research or management problem, and most of the models do not get reused after the project is completed. Similarly, multiple models may exist for a particular geographic location from different researchers or organizations. To avoid the duplication of efforts, and enable model reuse and enhancement through collaborative efforts, a prototype cyberinfrastructure, called SWATShare, is developed for sharing, execution and visualization of Soil and Water Assessment Tool (SWAT). The objective of this paper is to present the software architecture, functional capabilities and implementation of SWATShare as a collaborative environment for hydrology research and education using the models published and shared in the system. Besides the capability of publishing, sharing, discovery and downloading of SWAT models, some of the functions in SWATShare such as model calibration are supported by providing access to high performance computing resources including the XSEDE and cloud. Additionally, SWATShare can create dynamic spatial and temporal plots of model outputs at different scales. SWATShare can also be used as an educational tool within a classroom setting for comparing the hydrologic processes under different geographic and climatic settings. The utility of SWATShare for collaborative research and education is demonstrated by using three case studies. Even though this paper focuses on the SWAT model, the system’s architecture can be replicated for other models as well. 相似文献
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Topology control is a fundamental issue in wireless ad hoc and sensor networks. Due to intrinsic characteristic of flatness, hierarchical topology can achieve the scalability and efficiency of a wireless network. To solve this problem, one can construct a virtual backbone network by using a connected dominating (CDS) set of a wireless network. In past few years, efficiently and fast construct a CDS in a wireless network as a virtual backbone has been the main research problem in hierarchical topology control. In this paper, we give a comprehensive survey for CDSs and related problems with various network models and specific applications. To conclude, some open problems and interesting issues in this field are proposed. 相似文献
18.
Walid Gomaa 《Natural computing》2012,11(1):37-49
The theory of analog computation aims at modeling computational systems that evolve in a continuous space. Unlike the situation
with the discrete setting there is no unified theory of analog computation. There are several proposed theories, some of them
seem quite orthogonal. Some theories can be considered as generalizations of the Turing machine theory and classical recursion
theory. Among such are recursive analysis and Moore’s class of recursive real functions. Recursive analysis was introduced
by Turing (Proc Lond Math Soc 2(42):230–265, 1936), Grzegorczyk (Fundam Math 42:168–202, 1955), and Lacombe (Compt Rend l’Acad Sci Paris 241:151–153, 1955). Real computation in this context is viewed as effective (in the sense of Turing machine theory) convergence of sequences
of rational numbers. In 1996 Moore introduced a function algebra that captures his notion of real computation; it consists
of some basic functions and their closure under composition, integration and zero-finding. Though this class is inherently
unphysical, much work have been directed at stratifying, restricting, and comparing it with other theories of real computation
such as recursive analysis and the GPAC. In this article we give a detailed exposition of recursive analysis and Moore’s class and the relationships between them. 相似文献
19.
《Automatica》1985,21(1):1-21
This paper attempts to give a unified overview of how direct methods solve the transient stability problem of large-scale power systems. Two distinct methodologies are considered and discussed. The first concerns application of the direct Lyapunov method to the conventional transient stability analysis. Both scalar and vector Lyapunov approaches are envisaged and their respective merits and potentialities are compared. Particular attention is also paid to the estimation of ‘practical’ stability domains, aiming to overcome the usual conservativeness of the Lyapunov criterion. The second methodology focuses on the derivation of stability indices, intended for on-line monitoring, contingency evaluation and security control. The present achievements and future trends are explored and tentatively assessed. 相似文献