On-line String Searching

1997 ◽  
Author(s):  
A. Apostolico
Keyword(s):  
Suffix Tree ◽  
Classical Problem ◽  
Binary Search ◽  
Additional Cost ◽  
Suffix Trees ◽  
Parallel Methods ◽  
String Searching ◽  
On Line ◽  
Necessary And Sufficient ◽  
Better Than

In the previous two chapters, we have examined various serial and parallel methods to perform exact string searching in a number of operations proportional to the total length of the input. Even though such a performance is optimal, our treatment of exact searches cannot be considered exhausted yet: in many applications, searches for different, a-priorily unknown patterns are performed on a same text or group of texts. It seems natural to ask whether these cases can be handled better than by plain reiteration of the procedures studied so far. As an analogy, consider the classical problem of searching for a given item in a table with n entries. In general, n comparisons are both necessary and sufficient for this task. If we wanted to perform k such searches, however, it is no longer clear that we need kn comparisons. Our table can be sorted once and for all at a cost of O(n log n) comparisons, after which binary search can be used. For sufficiently large k, this approach outperforms that of the k independent searches. In this chapter, we shall see that the philosophy subtending binary search can be fruitfully applied to string searching. Specifically, the text can be pre-processed once and for all in such a way that any query concerning whether or not a pattern occurs in the text can be answered in time proportional to the length of the pattern. It will also be possible to locate all the occurrences of the pattern in the text at an additional cost proportional to the total number of such occurrences. We call this type of search on-line, to refer to the fact that as soon as we finish reading the pattern we can decide whether or not it occurs in our text. As it turns out, the auxiliary structures used to achieve this goal are well suited to a host of other applications. There are several, essentially equivalent digital structures supporting efficient on-line string searching. Here, we base our discussion on a variant known as suffix tree. It is instructive to discuss first a simplified version of suffix trees, which we call expanded suffix tree.

Stability of On-Line Bin Packing with Random Arrivals and Long-Run-Average Constraints

1990 ◽  
Vol 4 (4) ◽  
pp. 447-460 ◽  
Author(s):  
Coastas Courcobetis ◽  
Richard Weber
Keyword(s):  
Bin Packing ◽  
Random Processes ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Expected Number ◽  
Long Run ◽  
Different Types ◽  
On Line ◽  
Necessary And Sufficient ◽  
Uniformly Bounded

Items of various types arrive at a bin-packing facility according to random processes and are to be combined with other readily available items of different types and packed into bins using one of a number of possible packings. One might think of a manufacturing context in which randomly arriving subassemblies are to be combined with subassemblies from an existing inventory to assemble a variety of finished products. Packing must be done on-line; that is, as each item arrives, it must be allocated to a bin whose configuration of packing is fixed. Moreover, it is required that the packing be managed in such a way that the readily available items are consumed at predescribed rates, corresponding perhaps to optimal rates for manufacturing these items. At any moment, some number of bins will be partially full. In practice, it is important that the packing be managed so that the expected number of partially full bins remains uniformly bounded in time. We present a necessary and sufficient condition for this goal to be realized and describe an algorithm to achieve it.

DENOISING OF THREE-DIMENSIONAL DATA CUBE USING BIVARIATE WAVELET SHRINKING

2011 ◽  
Vol 25 (03) ◽  
pp. 403-413 ◽  
Author(s):  
GUANGYI CHEN ◽  
TIEN D. BUI ◽  
ADAM KRZYZAK
Keyword(s):  
Spectral Band ◽  
Gaussian White Noise ◽  
Three Dimensional ◽  
Classical Problem ◽  
Data Cube ◽  
Wavelet Thresholding ◽  
3D Data ◽  
Signal Image ◽  
3D Data Cube ◽  
Better Than

The denoising of a natural signal/image corrupted by Gaussian white noise is a classical problem in signal/image processing. However, it is still in its infancy to denoise high dimensional data. In this paper, we extended Sendur and Selesnick's bivariate wavelet thresholding from two-dimensional (2D) image denoising to three-dimensional (3D) data cube denoising. Our study shows that bivariate wavelet thresholding is still valid for 3D data cubes. Experimental results show that bivariate wavelet thresholding on 3D data cube is better than performing 2D bivariate wavelet thresholding on every spectral band separately, VisuShrink, and Chen and Zhu's 3-scale denoising.

Suffix Tree Data Structures for Matrices

1997 ◽  
Author(s):  
R. Giancarlo ◽  
R. Grossi
Keyword(s):  
Linear Space ◽  
Suffix Tree ◽  
Linear Time ◽  
Suffix Trees ◽  
Construction Time ◽  
Matching Problems ◽  
Tree Construction ◽  
The Matrix ◽  
Visual Databases ◽  
Efficient Construction

We discuss the suffix tree generalization to matrices in this chapter. We extend the suffix tree notion (described in Chapter 3) from text strings to text matrices whose entries are taken from an ordered alphabet with the aim of solving pattern-matching problems. This suffix tree generalization can be efficiently used to implement low-level routines for Computer Vision, Data Compression, Geographic Information Systems and Visual Databases. We examine the submatrices in the form of the text’s contiguous parts that still have a matrix shape. Representing these text submatrices as “suitably formatted” strings stored in a compacted trie is the rationale behind suffix trees for matrices. The choice of the format inevitably influences suffix tree construction time and space complexity. We first deal with square matrices and show that many suffix tree families can be defined for the same input matrix according to the matrix’s string representations. We can store each suffix tree in linear space and give an efficient construction algorithm whose input is both the matrix and the string representation chosen. We then treat rectangular matrices and define their corresponding suffix trees by means of some general rules which we list formally. We show that there is a super-linear lower bound to the space required (in contrast with the linear space required by suffix trees for square matrices). We give a simple example of one of these suffix trees. The last part of the chapter illustrates some technical results regarding suffix trees for square matrices: we show how to achieve an expected linear-time suffix tree construction for a constant-size alphabet under some mild probabilistic assumptions about the input distribution. We begin by defining a wide class of string representations for square matrices. We let Σ denote an ordered alphabet of characters and introduce another alphabet of five special characters, called shapes. A shape is one of the special characters taken from set {IN,SW,NW,SE,NE}. Shape IN encodes the 1x1 matrix generated from the empty matrix by creating a square.

A catalog of 159,238 white dwarf ages

2019 ◽  
Vol 15 (S357) ◽  
pp. 188-191
Author(s):  
Ted von Hippel ◽  
Adam Moss ◽  
Isabelle Kloc ◽  
Natalie Moticska ◽  
Jimmy Sargent ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
White Dwarf ◽  
White Dwarfs ◽  
Stellar Mass ◽  
Posterior Distributions ◽  
Trigonometric Parallaxes ◽  
On Line ◽  
Better Than

AbstractWe employ Pan-STARRS photometry, Gaia trigonometric parallaxes, modern stellar evolution and atmosphere models, and our Bayesian fitting approach to determine cooling and total ages for 159,238 white dwarfs. In many cases we are able to derive precise ages (better than 5%) for individual white dwarfs. These results are meant for broad use within the white dwarf and stellar astrophysics communities and we plan to make available on-line the posterior distributions for cooling age, total age, initial stellar mass, and other parameters.

Nonlinear Control of Dynamic Systems Using Single Multiplicative Neuron Models

2012 ◽  
Author(s):  
Jonathan G. Turner ◽  
Biswanath Samanta
Keyword(s):  
Nonlinear Control ◽  
Dynamic Systems ◽  
Optimization Technique ◽  
Real Life ◽  
Population Based ◽  
Motor Speed ◽  
Neuron Models ◽  
On Line ◽  
On Line Learning ◽  
Better Than

The paper presents an approach to nonlinear control of dynamic systems using artificial neural networks (ANN). A novel form of ANN, namely, single multiplicative neuron (SMN) model is proposed in place of more traditional multi-layer perceptron (MLP). SMN derives its inspiration from the single neuron computation model in neuroscience. SMN model is trained off-line, to estimate the network weights and biases, using a population based stochastic optimization technique, namely, particle swarm optimization (PSO). Both off-line training and on-line learning of SMN have been considered. The development of the control algorithm is illustrated through the hardware-in-the-loop (HIL) implementation of DC motor speed control in LabVIEW environment. The controller based on SMN performs better than MLP. The simple structure and faster computation of SMN have the potential to make it a preferred candidate for implementation of real-life complex control systems.

Navigation by Computer Processing of Marine Radar Images

1985 ◽  
Vol 38 (3) ◽  
pp. 375-383 ◽  
Author(s):  
G. L. Austin ◽  
A. Bellon ◽  
M. Riley ◽  
E. Ballantyne
Keyword(s):  
Radar Data ◽  
Computer Processing ◽  
Pattern Recognition Technique ◽  
Radar Images ◽  
Well Yield ◽  
Radar Imagery ◽  
On Line ◽  
Marine Radar ◽  
Recognition Technique ◽  
Better Than

The advantages of being able to process marine radar imagery in an on-line computer system have been illustrated by study of some navigational problems. The experiments suggest that accuracies of the order of 100 metres may be obtained in navigation in coastal regions using map overlays with marine radar data. A similar technique using different radar imagery of the same location suggests that the pattern-recognition technique may well yield a position-keeping ability of better than 10 metres.

Adaptive-passive structural vibration attenuation using distributed absorbers

2002 ◽  
Vol 216 (3) ◽  
pp. 223-235 ◽  
Author(s):  
N Jalili ◽  
E Esmailzadeh
Keyword(s):  
Vibration Suppression ◽  
Sufficient Conditions ◽  
Structural Vibration ◽  
Dynamic Vibration Absorber ◽  
Vibration Attenuation ◽  
Adaptive Capability ◽  
On Line ◽  
Lumped Masses ◽  
Necessary And Sufficient ◽  
Tuning Strategy

A distributed dynamic vibration absorber with adaptive capability is presented to improve vibration suppression characteristics of harmonically excited structures. A double-ended cantilever beam carrying intermediate lumped masses forms the absorber subsection. The adaptive capability is achieved through concurrent adjustment of the positions of the moving masses, along the beam, to comply with the desired optimal performance. The necessary and sufficient conditions for the existence of periodic oscillatory behaviour, along with some physical bounds placed on the absorber parameters, form a constrained optimization problem for the optimum tuning strategy. Through numerical simulations it is shown that adaptive tuning is achieved by the variation of tuning mass locations such that the first-mode natural frequency is modulated on-line. The optimally tuned absorber provides considerable vibration suppression improvement over the passive and detuned absorbers.

ON-LINE MODELLING AND FORECASTING OF A MOVING CAR INFORMATION USING TD-HMLP NETWORK

2015 ◽  
Vol 76 (12) ◽  
Author(s):  
Z. Saad ◽  
M. Y. Mashor ◽  
Wan Khairunizam
Keyword(s):  
Fuel Injection ◽  
Nonlinear Modeling ◽  
Trend Data ◽  
On Line ◽  
One Step ◽  
Multilayered Perceptron ◽  
The One ◽  
Recursive Prediction ◽  
Better Than ◽  
Modelling And Forecasting

The study proposed a model called trend data hybrid multilayered perceptron network (TD-HMLP) coupled with a modified recursive prediction error (MRPE) training algorithm as a nonlinear modeling. An on-line model was used to forecast speed, revolution and fuel balanced in a Proton Gen2 car tank. The car measured the injected fuel from fuel injection sensor and become an input for the TD-HMLP model to forecast the speed, revolution and fuel balanced in tank. These forecasted variables were also measured from the car sensors. The criterions for performances are based on the one step ahead forecasting (OSA), multi-step ahead forecasting (MSA) and adjusted R2. The forecasting result showed that TD-HMLP network is better than the conventional HMLP network to maintain higher value in adjusted R2 and produce better step in multi-step ahead forecasting. These preliminary results show that the proposed modeling approach is capable to be used as an on-line information forecaster of a moving car.

scholarly journals Fluorimetric Method for the Determination of Histidine in Random Human Urine Based on Zone Fluidics

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1665
Author(s):  
Antonios Alevridis ◽  
Apostolia Tsiasioti ◽  
Constantinos K. Zacharis ◽  
Paraskevas D. Tzanavaras
Keyword(s):  
Matrix Effect ◽  
Human Urine ◽  
Basic Medium ◽  
Medium Ph ◽  
Line Flow ◽  
On Line ◽  
Adult Volunteers ◽  
Fluorescent Derivative ◽  
Better Than

In the present study, the determination of histidine (HIS) by an on-line flow method based on the concept of zone fluidics is reported. HIS reacts fast with o-phthalaldehyde at a mildly basic medium (pH 7.5) and in the absence of additional nucleophilic compounds to yield a highly fluorescent derivative (λex/λem = 360/440 nm). The flow procedure was optimized and validated, paying special attention to its selectivity and sensitivity. The LOD was 31 nmol·L−1, while the within-day and day-to-day precisions were better than 1.0% and 5.0%, respectively (n = 6). Random urine samples from adult volunteers (n = 7) were successfully analyzed without matrix effect (<1%). Endogenous HIS content ranged between 116 and 1527 μmol·L−1 with percentage recoveries in the range of 87.6%–95.4%.

scholarly journals MOCAM: A 4k × 4k CCD Mosaic for the Canada-France-Hawaii Telescope Prime Focus

1995 ◽  
Vol 167 ◽  
pp. 213-220
Author(s):  
J. C. Cuillandre ◽  
Y. Melliers ◽  
R. Murowinski ◽  
D. Crampton ◽  
G. Luppino ◽  
...  
Keyword(s):  
Focal Plane ◽  
San Diego ◽  
Ccd Camera ◽  
Astronomical Observatory ◽  
Wide Field ◽  
On Line ◽  
Readout Noise ◽  
The University ◽  
Filter Wheel ◽  
Better Than

MOCAM is a wide field CCD camera, currently nearing completion, which will be offered to the Canada-France-Hawaii Telescope (CFHT) user community in 1995. The project is a collaboration between the CFHT, the Dominion Astronomical Observatory (DAO, Canada), the Institut des Sciences de l'Univers (INSU, France), Laboratoire d'Astrophysique de Toulouse (LAT, France) and the University of Hawaii (UH). In the interests of producing a reliable and effective camera in the shortest time, it was decided to use existing technologies rather than innovative ones. Two-edge buttable 2048 × 2048 15 μm pixel CCDs were obtained from the LORAL aerospace foundry, based on a mask designed by J. Geary at Smithsonian Astrophysical Observatory (SAO). They are mounted in a dewar designed by G. Luppino (UH); the focal plane mounting keeps the mosaic flat to within two pixels and the CCDs are aligned to within two pixels. A mechanical interface designed and fabricated by the DAO holds a 150 mm shutter and a filter wheel which has a positioning repeatability better than five μm.The four CCDs are operated in parallel by a San Diego GenIII controller adapted by LAT. The mosaic is read out in seven minutes and a single 33 Mb FITS file is generated to enable convenient on-line preprocessing. The user will control the system through a single CFHT Pegasus environment session. The camera field is 14′ × 14′ with a 0.″2 pixel sampling and the readout noise is less than seven electrons. The scientific goals of the initiators of the project are studies of distant clusters, deep galaxy counts and quasars surveys.

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