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1.
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   

2.
The compressed sensing (CS) theory makes sample rate relate to signal structure and content. CS samples and compresses the signal with far below Nyquist sampling frequency simultaneously. However, CS only considers the intra-signal correlations, without taking the correlations of the multi-signals into account. Distributed compressed sensing (DCS) is an extension of CS that takes advantage of both the inter- and intra-signal correlations, which is wildly used as a powerful method for the multi-signals sensing and compression in many fields. In this paper, the characteristics and related works of DCS are reviewed. The framework of DCS is introduced. As DCS's main portions, sparse representation, measurement matrix selection, and joint reconstruction are classified and summarized. The applications of DCS are also categorized and discussed. Finally, the conclusion remarks and the further research works are provided.  相似文献   

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《Automatica》1987,23(1):7-32
Stimulated by microprocessor technology there is increasing interest in the issues of digital control implementation. This paper reviews these issues, from algorithms through current hardware up to the various problems arising with non-ideal behaviour of digital controllers.  相似文献   

5.
The authors propose two methods of estimating the number of so-called “good” permutations, which are defined in the article. The nature of both methods is statistical, but their methodologies are completely different. The use of these methods is illustrated by the example of the permutation length N = 25, which is of intense interest in cryptography. Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 10–16, September–October, 1999.  相似文献   

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《Automatica》1987,23(4):425-435
A survey of robustness of nonlinear state feedback is given. For series perturbations there are fairly complete results, showing that under mild restrictions an optimal controller can tolerate an infinite increase in gain. For gain reductions there are some results for systems linear in the control. In particular there is a 50% reduction tolerance if the control penalty is quadratic. Usually the optimal controller cannot be computed exactly. There are some results showing the effects of truncation on the robustness. Essentially robustness is maintained but in a reduced (computable) part of the state space.  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   

10.
The authors review and categorize the research in applications of artificial intelligence (AI) and expert systems (ES) in new product development (NPD) activities. A brief overview of NPD process and AI is presented. This is followed by a literature survey in regard to AI and ES applications in NPD, which revealed twenty four articles (twenty two applications) in the 1990–1997 period. The applications are categorized into five areas: expert decision support systems for NPD project evaluation, knowledge-based systems (KBS) for product and process design, KBS for QFD, AI support for conceptual design and AI support for group decision making in concurrent engineering. Brief review of each application is provided. The articles are also grouped by NPD stages and seven NPD core elements (competencies and abilities). Further research areas are pointed out.  相似文献   

11.
This paper introduces the research progress of the State Key Laboratory of Information Security (SKLOIS) in China during 2002–2006. This introduction covers four selected areas with each covering some selected research findings. The four selected areas are: the fundamentals of cryptography; the design, analysis and testing of block cipher algorithms; the design and analysis of security protocols based on computational intractability; authentication, authorization and their applications.  相似文献   

12.
《Automatica》1986,22(2):143-153
Digital computers have been used for process control in the pulp and paper industry for more than 20 years. This paper reviews the applications of advanced control methods to pulp and paper unit process control reported during the last decade. Modern control theory and adaptive control theory are most often applied to paper machine and headboxes. However a large number of reports deal only with simulated or laboratory scale processes. Indeed very few industrial applications are reported. Some of the reasons for this are analyzed and future trends briefly discussed.  相似文献   

13.
Our paper begins with an introduction to hypermedia presented with the example of a hypothetical hypermedia system. This is followed by an overview of the main hypermedia components visible to the user—data structures, authoring tools, navigation tools, and user interface. In the next section, we present a brief history of hypermedia, list applications in which hypermedia systems have been used, and describe several important commercial products and research projects. The last two sections introduce the major issues facing hypermedia technology and attempt to predict what direction it might take in the near future.  相似文献   

14.
《Automatica》1985,21(2):117-128
A survey of the field of optimal sensors and/or controllers location for dynamical distributed parameter systems modelled by partial differential equations is presented. The recent contributions in this field are grouped according to the main goal for which the location problem is developed, namely: system identification, state estimation, and optimal control. In order to pose the sensors and controllers location problem, the semigroup approach for modelling distributed linear systems is briefly reviewed together with its equivalent (infinite dimensional) and approximate (finite dimensional) Fourier expansion representations. After presenting a concise general review of the several methods considered in the current literature, a classification of methods is also proposed. The main classifying factor concerns the use of N-modal approximation schemes, and the different stages of the optimization procedure in which they are required.  相似文献   

15.
《Automatica》1986,22(1):1-19
Alternating current machines, in particular induction motors, are of simple mechanical construction but have a nonlinear, highly interacting multivariable control structure. This has made it difficult in the past to design controlled ac-drives with high dynamic performance, similar to converter-fed dcdrives. A satisfactory solution of this problem has not been available until Blaschke formulated the principle of field orientation, where the machine is controlled in a moving frame of reference. This paper presents a survey of controlling acmachines for use in high dynamic performance drives including different types of machines and converters with their specific control characteristics. It is shown that by combining a suitable machine model with the principle of rotor- or field-orientation a unifying basis for the design of ac-drives is created. The complicated signal structure of the control systems can very effectively be handled by microelectronics, i.e. by using software instead of elaborate hardware. This is shown in the paper with the help of examples.  相似文献   

16.
《Parallel Computing》1997,22(13):1837-1851
The PAPS (Performance Analysis of Parallel Systems) toolset is a testbed for the model based performance prediction of message passing parallel applications executed on private memory multiprocessor computer systems. PAPS allows to describe the execution behavior of the computer hardware and operating system software resources up to a very detailed level. This enables very accurate performance prediction of parallel applications even in the case of substantial performance degradation due to contention for shared resources. In this paper the fundamental design principles and implementation methodologies for the development of the PAPS toolset are presented and the PAPS parallel system specification formalisms are described. A simplified performance study of a parallel Gaussian elimination application on the nCUBE 2 multiprocessor system is used to demonstrate the usage of the tool.  相似文献   

17.
With the explosion of data generation, getting optimal solutions to data driven problems is increasingly becoming a challenge, if not impossible. It is increasingly being recognised that applications of intelligent bio-inspired algorithms are necessary for addressing highly complex problems to provide working solutions in time, especially with dynamic problem definitions, fluctuations in constraints, incomplete or imperfect information and limited computation capacity. More and more such intelligent algorithms are thus being explored for solving different complex problems. While some studies are exploring the application of these algorithms in a novel context, other studies are incrementally improving the algorithm itself. However, the fast growth in the domain makes researchers unaware of the progresses across different approaches and hence awareness across algorithms is increasingly reducing, due to which the literature on bio-inspired computing is skewed towards few algorithms only (like neural networks, genetic algorithms, particle swarm and ant colony optimization). To address this concern, we identify the popularly used algorithms within the domain of bio-inspired algorithms and discuss their principles, developments and scope of application. Specifically, we have discussed the neural networks, genetic algorithm, particle swarm, ant colony optimization, artificial bee colony, bacterial foraging, cuckoo search, firefly, leaping frog, bat algorithm, flower pollination and artificial plant optimization algorithm. Further objectives which could be addressed by these twelve algorithms have also be identified and discussed. This review would pave the path for future studies to choose algorithms based on fitment. We have also identified other bio-inspired algorithms, where there are a lot of scope in theory development and applications, due to the absence of significant literature.  相似文献   

18.
Since its inception of just over two decades ago, the World Wide Web has become a truly ubiquitous and transformative force in our life, with millions of Web applications serving billions of Web pages daily. Through a number of evolutions, Web applications have become interactive, dynamic and asynchronous. The Web׳s ubiquity and our reliance on it have made it imperative to ensure the quality, security and correctness of Web applications. Testing is a widely used technique for validating Web applications. It is also a long-standing, active and diverse research area. In this paper, we present a broad survey of recent Web testing advances and discuss their goals, targets, techniques employed, inputs/outputs and stopping criteria.  相似文献   

19.
Intelligent visual surveillance — A survey   总被引:3,自引:0,他引:3  
Detection, tracking, and understanding of moving objects of interest in dynamic scenes have been active research areas in computer vision over the past decades. Intelligent visual surveillance (IVS) refers to an automated visual monitoring process that involves analysis and interpretation of object behaviors, as well as object detection and tracking, to understand the visual events of the scene. Main tasks of IVS include scene interpretation and wide area surveillance control. Scene interpretation aims at detecting and tracking moving objects in an image sequence and understanding their behaviors. In wide area surveillance control task, multiple cameras or agents are controlled in a cooperative manner to monitor tagged objects in motion. This paper reviews recent advances and future research directions of these tasks. This article consists of two parts: The first part surveys image enhancement, moving object detection and tracking, and motion behavior understanding. The second part reviews wide-area surveillance techniques based on the fusion of multiple visual sensors, camera calibration and cooperative camera systems.  相似文献   

20.
Recent advances in both anthropomorphic robots and bimanual industrial manipulators had led to an increased interest in the specific problems pertaining to dual arm manipulation. For the future, we foresee robots performing human-like tasks in both domestic and industrial settings. It is therefore natural to study specifics of dual arm manipulation in humans and methods for using the resulting knowledge in robot control. The related scientific problems range from low-level control to high level task planning and execution. This review aims to summarize the current state of the art from the heterogenous range of fields that study the different aspects of these problems specifically in dual arm manipulation.  相似文献   

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