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The bible and multilingual optical character recognition

COMMUNICATIONS OF THE ACM 2005年第6期48卷 124-130页

作者： Kanungo, T Resnik, P Mao, S Kim, DW Zheng, QQ IBM Corp Almaden Res Ctr San Jose CA 95114 USA Univ Maryland UMIACS College Pk MD 20742 USA Univ Maryland Dept Linguist College Pk MD 20742 USA LG Elect Seoul South Korea Lucent Technol Westford MA USA

As global online access to information becomes more common, the technology ofmultilingual optical character recognition (OCR) increases in importance as a way to convert paperdocuments into electronic, searchable, text. In OCR, as in any evolving technology, carefulevaluation is an integral part of research and development. OCR evaluation is done by comparing asystem's output for a dataset of document test images with the corresponding correct symbolic text,known as ground truth. Unfortunately, the usual way of obtaining ground truth is by manual dataentry by humans, which is labor-intensive, time-consuming, expensive, and prone to errors. Worse,because no single set of ground truth evaluation data can be used in more than one language, therehas until now been no way to conduct carefully controlled OCR experiments in a multilingual setting.

关键词： OPTICAL character recognition devices ELECTRONIC data processing computer algorithms PATTERN recognition systems ELECTROMAGNETIC noise SCANNING systems

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MDA-Based Data Association with Prior Track Information for Passive Multitarget Tracking

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2011年第1期47卷 539-556页

作者： Sathyan, T. Sinha, A. Kirubarajan, T. Mcdonald, Michael Lang, Thomas CSIRO ICT Ctr Epping NSW 1710 Australia AUG Signals Toronto ON M5H 4E8 Canada McMaster Univ Dept Elect & Comp Engn Hamilton ON L8S 4K1 Canada DRDC Surveillance Radar Grp Ottawa ON K1A 0Z4 Canada Gen Dynam Canada Air & Naval Syst Ottawa ON K2H 5B7 Canada

An assignment-based solution for the data association problem in synchronous passive multisensor (Type 3) tracking systems involves two steps: first measurement-to-measurement or static association is solved using a multidimensional (S-dimensional or S-D with S sensors) assignment, and then measurement-to-track association is solved using a 2-D assignment. This solution is computationally very expensive and, to rectify an efficient (S + 1)-D assignment algorithm has been proposed in the literature. Two new assignment-based algorithms are proposed that use prior track information (i.e., predicted state and covariance) which result in improved tracking performance compared with the existing solutions, while requiring considerably less computations. One of the proposed algorithms, the gated assignment, is similar to the two-step solution mentioned above except that it uses prior track information and avoids the need to consider all possible association hypotheses in the static association step. The second algorithm, the gated (S + 1)-D assignment, combines the gated assignment and the (S + 1)-D algorithms. An approximation to the (S + 1)-D algorithm is also derived when sensor measurements are independent, which results in an extremely fast solution. Simulation results confirm that the proposed algorithms show improved tracking performance and faster execution times.

关键词： PERFORMANCE evaluation MEASUREMENT DETECTORS APPROXIMATION theory INFORMATION theory computer algorithms

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The characterization of data-accumulating algorithms

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THEORY OF COMPUTING SYSTEMS 2000年第1期33卷 85-96页

作者： Bruda, SD Akl, SG Queens Univ Dept Comp & Informat Sci Kingston ON K7L 3N6 Canada

Data-accumulating algorithms (d-algorithms for short), extensively studied in [12], work on an input considered as a virtually endless stream. The computation terminates when all the currently arrived data have been processed before another datum arrives. In this paper a finer characterization of the class of d-algorithms is given, and it is shown that this class is identical to the class of on-line algorithms under a proper definition of the latter. The parallel implementation of d-algorithms is then investigated. It is found that, in general, the speedup achieved through parallelism can be made arbitrarily large for almost any such algorithm. On the other hand, we prove that for d-algorithms whose static counterparts manifest only unitary speedup, no improvement is possible through parallel implementation.

关键词： computer algorithms algorithms

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Boolean satisfiability from Theoretical hardness to Practical success

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COMMUNICATIONS OF THE ACM 2009年第8期52卷 76-82页

作者： Malik, Sharad Zhang, Lintao Princeton Univ Dept Elect Engn Princeton NJ 08544 USA Microsoft Res Asia Beijing Peoples R China

The article presents a discussion of topics in computer science related to Boolean satisfiability. It focuses on solutions which can be readily used in applications software, and their effectiveness for solving certain types of problems. Topics addressed include the interaction between necessary values and constraints in generating computational complexity. Examples are provided using decision trees solved using various computer algorithms. The increasing commercial use of such programs in fields such as computer hardware and software testing and development is noted.

关键词： ALGEBRA Boolean COMPUTATIONAL complexity computer algorithms DECISION trees computer software computer programming

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Autonomous guidance and control of Earth-orbiting formation flying spacecraft: Closing the loop

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ACTA ASTRONAUTICA 2008年第11-12期63卷 1246-1258页

作者： Hamel, Jean-Francois de Lafontaine, Jean Univ Sherbrooke Dept Elect Engn Sherbrooke PQ J1K 2R1 Canada

Previous work on autonomous formation flying guidance and control identified three key challenges to overcome in order to obtain a fully autonomous guidance and control loop: an accurate but simple model of relative motion about elliptical and perturbed orbits, an efficient way of performing conflicting requirements trade-off with power-limited on-board computers, and finally an optimal or near-optimal control algorithm easy to implement on a flight computer. This paper first summarizes recent developments on each of these subject that help to overcome these challenges, developments which are then used as building blocks for an autonomous formation flying guidance and control system. This system autonomously performs trade-offs between conflicting requirements. i.e. minimization of fuel cost, formation accuracy and equal repartition of the fuel expenditure within the formation. Simulation results show that a complete guidance and control loop can be established using mainly analytical results and with very few numerical optimization which facilitates on-board implementation. (c) 2008 Elsevier Ltd. All rights reserved.

关键词： control ring airborne/spaceborne computers relative motion Guidance Building blocks Formation flight Autonomous guidance computer algorithms

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Selective encryption for consumer applications

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IEEE COMMUNICATIONS MAGAZINE 2004年第5期42卷 124-129页

作者： Lookabaugh, T Sicker, DC Univ Colorado Dept Comp Sci Boulder CO 80309 USA Univ Colorado INterdisciplinary Telecommun Program Boulder CO 80309 USA

Selective encryption is a technique to save computational complexity or enable interesting new system functionality by only encrypting a portion of a compressed bitstream while still achieving adequate security. Although suggested in a number of specific cases, selective encryption could be much more widely used in consumer electronic applications ranging from mobile multimedia terminals through digital cameras were it subjected to a more thorough security analysis. We describe selective encryption and develop a simple scalar quantizer example to demonstrate the power of the concept, list a number of potential consumer electronics applications, and then describe an appropriate method for developing and analyzing selective encryption for particular compression algorithms. We summarize results from application of this method to the MPEG-2 video compression algorithm.

关键词： Technological innovations Data encryption (computer science) computer security computer algorithms computer science computer network security

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Output feedback tracking control of uncertain non-holonomic wheeled mobile robots: a dynamic surface control approach

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IET CONTROL THEORY AND APPLICATIONS 2012年第2期6卷 216-228页

作者： Shojaei, K. Shahri, A. M. Iran Univ Sci & Technol Dept Elect Engn Elect Res Ctr Mechatron & Robot Res Lab Tehran Iran

This study addresses the trajectory tracking control problem of electrically driven wheeled mobile robots under non-holonomic constraints in the presence of model uncertainties without velocity measurement. By defining a suitable set of output equations, a new input-output model of wheeled mobile robots is developed, which helps the designer utilise the classic control algorithms of robot manipulators. An observer-based trajectory tracking controller is proposed for the new wheeled mobile robot (WMR) model. Then, in order to reduce the design complexity, the dynamic surface control approach is effectively exploited to propose a tracking controller considering the actuator dynamics. Adaptive robust techniques are also adopted to cope with the parametric and non-parametric uncertainties in the WMR model. A Lyapunov-based stability analysis is utilised to guarantee that tracking and state estimation errors are uniformly ultimately bounded. Simulation results are presented to illustrate the feasibility and efficiency of the proposed controller.

关键词： Parametric Stability analysis tracking controller Designers trajectory tracking computer algorithms wheeled mobile robots Speed measurement Velocimetry model uncertainty Output feedback Robot Manipulator tracking control State estimation

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Using high-resolution laboratory and ground-based solar spectra to assess CH₄ absorption coefficient calculations

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JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER 2017年 190卷 48-59页

作者： Mendonca, J. Strong, K. Sung, K. Devi, V. M. Toon, G. C. Wunch, D. Franklin, J. E. Univ Toronto Dept Phys Toronto ON Canada CALTECH Jet Prop Lab Pasadena CA USA Coll William & Mary Dept Phys Williamsburg VA 23185 USA CALTECH Pasadena CA 91125 USA Dalhousie Univ Dept Phys & Atmospher Sci Halifax NS Canada

A quadratic-speed-dependent Voigt line shape (qSDV) with line mixing (qSDV+LM), together with spectroscopic line parameters from Devi et al. [1,2] for the 2v(3) band of CH4, was used to retrieve total columns of CH4 front atmospheric solar absorption spectra. The qSDV line shape (Tran et al., 2013) [3] with line mixing (Levy et al., 1992) [4] was implemented into the forward model of GFIT (the retrieval algorithm that is at the heart of the GGG software (Wunch et al., 2015) [5]) to calculate CH4 absorption coefficients. High-resolution laboratory spectra of CH4 were used to assess absorption coefficients calculated using a Voigt line shape and spectroscopic parameters from the atm line list (Toon, 2014) [6]. The same laboratory spectra were used to test absorption coefficients calculated using the qSDV+LM line shape with spectroscopic line parameters from Devi et al. [1,2] for the 2v(3) band of CH4 and a Voigt line shape for lines that don't belong to the 2v3 band. The spectral line list for lines that don't belong to the 2v(3) band is an amalgamation of multiple spectral line lists. We found that for the P, Q, and R branches of the 2v(3) band, the qSDV+LM simulated the laboratory spectra better than the Voigt line shape. The qSDV+LM was also used in the spectral fitting of high-resolution solar absorption spectra from four ground-based remote sensing sites and compared to spectra fitted with a Voigt line shape. The average root mean square (RMS) residual for 131,124 solar absorption spectra fitted with absorption coefficients calculated using the qSDV+LM for the 2v(3) band of CH4 and the new Spectral line list for lines for lines that don't belong to the 2v(3) band, was reduced in the P, Q and R branches by 5%, 13%, and 3%, respectively when compared with spectra fitted using a Voigt line shape and the atm line list. We found that the average total column of CH4 retrieved from these 131,124 spectra, With the qSDV+LM was 1.1 +/- 0.3% higher than the retrievals perfo

关键词： SOLAR radiation ABSORPTION spectra ABSORPTION coefficients computer algorithms MONOTONIC functions computer software

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An Approach for Composing Services Based on Environment Ontology

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MATHEMATICAL PROBLEMS IN ENGINEERING 2013年第1期2013卷 1-11页

作者： Cai, Guangjun Zhao, Bin Chinese Acad Sci Inst Comp Technol Key Lab Intelligent Informat Proc Beijing 100190 Peoples R China Henan Univ Sci & Technol Elect Informat Engn Coll Luoyang 471023 Peoples R China Grad Univ Chinese Acad Sci Beijing 100049 Peoples R China

Service-oriented computing is revolutionizing the modern computing paradigms with its aim to boost software reuse and enable business agility. Under this paradigm, new services are fabricated by composing available services. The problem arises as how to effectively and efficiently compose heterogeneous services facing the high complexity of service composition. Based on environment ontology, this paper introduces a requirement-driven service composition approach. We propose the algorithms to decompose the requirement, the rules to deduct the relation between services, and the algorithm for composing service. The empirical results and the comparison with other services' composition methodologies show that this approach is feasible and efficient.

关键词： ONTOLOGY computer software computer algorithms SERVICE-oriented architecture (computer science) HETEROGENEOUS computing

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Steering kernel-based video moving objects detection with local background texture dictionaries

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computerS & ELECTRICAL ENGINEERING 2013年第3期39卷 797-808页

作者： Guo, Chunsheng Yu, Jian Hangzhou Dianzi Univ Coll Commun Engn Hangzhou 310018 Peoples R China

Texture and color information as important characters of video objects have been widely used in the detection of moving objects. A detection algorithm based on texture may cause detection errors in regions of blank texture and heterogeneous texture, and a detection algorithm based on color is easily influenced by illumination changes and shadows. In this paper, a new detection and fusion algorithm is proposed. At the detection stage based on texture, the background texture is classified according to the steering kernel. At the fusion stage, for the moving objects detected on the basis of texture and color respectively, a scheme based on a boundary selection strategy is proposed for combining the different detection objects. A relatively smooth boundary is selected as the true boundary, and the shadow detection is carried out to assist the boundary selection. Experimental results verify the advantages of the proposed algorithm as compared to the existing state-of-the-art algorithms. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： KERNEL functions TEXTURE analysis (Image processing) COLOR image processing ERROR analysis (Mathematics) CLASSIFICATION computer algorithms COMPUTATIONAL steering (computer science)

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