Showing papers in "Sadhana-academy Proceedings in Engineering Sciences in 2002"
TL;DR: Experimental results show that the technique for recognition of handwritten Devnagari numerals is effective and reliable and a multi-classifier connectionist architecture has been proposed for increasing reliability of the recognition results.
Abstract: This paper is concerned with recognition of handwritten Devnagari numerals. The basic objective of the present work is to provide an efficient and reliable technique for recognition of handwritten numerals. Three different types of features have been used for classification of numerals. A multi-classifier connectionist architecture has been proposed for increasing reliability of the recognition results. Experimental results show that the technique is effective and reliable.
157 citations
TL;DR: This paper briefly describes various components of a document analysis system and provides the background necessary to understand the detailed descriptions of specific techniques presented in other papers in this issue.
Abstract: Document image analysis refers to algorithms and techniques that are applied to images of documents to obtain a computer-readable description from pixel data. A well-known document image analysis product is the Optical Character Recognition (OCR) software that recognizes characters in a scanned document. OCR makes it possible for the user to edit or search the document’s contents. In this paper we briefly describe various components of a document analysis system. Many of these basic building blocks are found in most document analysis systems, irrespective of the particular domain or language to which they are applied. We hope that this paper will help the reader by providing the background necessary to understand the detailed descriptions of specific techniques presented in other papers in this issue.
143 citations
TL;DR: In this article, a numerical model called "numerical concrete" crack formation in normal and high strength concrete is simulated and results obtained are applied to predict shrinkage cracking under different boundary conditions.
Abstract: The crack path through composite materials such as concrete depends on the mechanical interaction of inclusions with the cement-based matrix. Fracture energy depends on the deviations of a real crack from an idealized crack plane. FRACTURE energy and strain softening of normal, high strength, and self-compacting concrete have been determined by means of the wedge splitting test. In applying the numerical model called “numerical concrete” crack formation in normal and high strength concrete is simulated. Characteristic differences of the fracture process can be outlined. Finally results obtained are applied to predict shrinkage cracking under different boundary conditions. Crack formation of high strength concrete has to be seriously controlled in order to achieve the necessary durability of concrete structures.
142 citations
TL;DR: A novel set of features are proposed for the recognition problem which are computationally simple to extract and independent of the font and size of the printed text and the system is seen to deliver reasonable performance.
Abstract: This paper describes an OCR system for printed text documents in Kannada, a South Indian language. The input to the system would be the scanned image of a page of text and the output is a machine editable file compatible with most typesetting software. The system first extractswords from the document image and then segments the words into sub-character level pieces. The segmentation algorithm is motivated by the structure of the script. We propose a novel set of features for the recognition problem which are computationally simple to extract. The final recognition is achieved by employing a number of 2-class classifiers based on the Support Vector Machine (SVM) method. The recognition is independent of the font and size of the printed text and the system is seen to deliver reasonable performance.
130 citations
TL;DR: A ‘web reader’ which ‘reads out’ the textual contents of a selected web page in Hindi or in English with Indian accent is described, which is passed on to an indigenously developed text-to-speech system for Hindi/Indian English, to generate spoken output.
Abstract: Incorporation of speech and Indian scripts can greatly enhance the accessibility of web information among common people. This paper describes a ‘web reader’ which ‘reads out’ the textual contents of a selected web page in Hindi or in English with Indian accent. The content of the page is downloaded and parsed into suitable textual form. It is then passed on to an indigenously developed text-to-speech system for Hindi/Indian English, to generate spoken output. The text-to-speech conversion is performed in three stages: text analysis, to establish pronunciation, phoneme to acoustic-phonetic parameter conversion and, lastly, parameter-to-speech conversion through a production model. Different types of voices are used to read special messages. The web reader detects the hypertext links in the web pages and gives the user the option to follow the link or continue perusing the current web page. The user can exercise the option either through a keyboard or via spoken commands. Future plans include refining the web parser, improvement of naturalness of synthetic speech and improving the robustness of the speech recognition system.
106 citations
TL;DR: Wittmann et al. as discussed by the authors highlighted the importance of the process zone ahead of the crack tip in the nonlinear fracture mechanics of concrete and proposed the size effect, which as proposed in fracture mechanics is different from Weibull's hypothesis for size effect.
Abstract: This special issue of Sādhanāis rightly dedicated to the fracture mechanics of concrete. In particular, the size effect is highlighted. As appropriately pointed out in the first international conference on fracture mechanics of concrete structures, FraMCos-I, organized by Z P Băzant, at Breckenridge, Colorado in 1992, fracture mechanics of concrete can be called the 3rd phase in the evolution of concrete structures. Since then the number of published papers on the topic have increased several-fold. Going back in the memory pipeline, it was M F Kaplan1 (in 1961) who tried to obtain the fracture toughness of concrete. It was observed later that there was no consistent value of fracture toughness of concrete. Therefore, towards the early eighties, nonlinear fracture theories were proposed. The process zone ahead of the crack tip was identified as having an important role to play in the nonlinear fracture mechanics of concrete. A little later, it led to the size effect, which as proposed in fracture mechanics is different from Weibull’s hypothesis for size effect. Later, there was a workshop on the size effect in concrete structures, organized by H Mihashi, H Okamura and Z P Bă zant, at Sendai, Japan in 1993. Various international committees were formed, the earliest one being the RILEM Committee chaired b y F H Wittmann. Several other important meetings took place at different places like the international workshop at Locarno, Switzerland in September, 1990 organised by Wittmann and Dungar, and the international workshop on concrete fracture, organised by A Carpinteri, at Torino in October 1991. In recent years, as high performance concrete is gaining importance, its fracture behaviour is being studied with great seriousness. High strength concrete is nearer to linear theories of fracture and is relatively more brittle. The challenge is whether one can make high strength concrete relatively more ductile by improving the cohesiveness of cracks. The next question is how to bring the size effect into codes of practice on the design of reinforced concrete structures, since large structures like dams, nuclear reactors, very tall towers, do contain large sized members. The issue to be addressed is whether it is in order to assume the same tensile strength as obtained in the laboratory for the full scale structure also. This special issue is intended to focus on the above features. Fracture mechanics of concrete has yet to go a long way. One may say that a complete textbook in the strict sense of the term came out only as recently as in 1995, written by B L Karihaloo. The contributors to this special issue , F H Wittmann, A Carpinteri and B Chiaia, V E Saouma and D Natekar, B Karihaloo and Q Z Xiao, Jin Keun Kim and Seong Tae Yi, and Vladimir Cervenkaet al, are all leading researchers in the field of fracture mechanics of concrete. This special issue will certainly be an important document relating to the latest research on the subject. It will also help active researchers to pursue further research on the topic.
105 citations
TL;DR: In this paper, three nonlinear material models available in ATENA are described: crack band model based on fracture energy, fracture-plastic model with non-associated plasticity and microplane material model.
Abstract: Advanced constitutive models implemented in the finite element system ATENA serve as rational tools to explain the behaviour of connection between steel and concrete. Three nonlinear material models available in ATENA are described: crack band model based on fracture energy, fracture-plastic model with non-associated plasticity and microplane material model. Nonlinear simulation using these advanced constitutive models can be efficiently used to support and extend experimental investigations and to predict behaviour of structures and structural details.
101 citations
TL;DR: In the work presented in this paper, a successful attempt has been made to identify the script, at the word level, in a bilingual document containing Roman and Tamil scripts.
Abstract: Identification of the script of the text in multi-script documents is one of the important steps in the design of an OCR system for the analysis and recognition of the page. Much work has already been reported in this area relating to Roman, Arabic, Chinese, Korean and Japanese scripts. In the Indian context, though some results have been reported, the task is still at its infancy. In the work presented in this paper, a successful attempt has been made to identify the script, at the word level, in a bilingual document containing Roman and Tamil scripts. Two different approaches have been proposed and thoroughly tested. In the first method, words are divided into three distinct spatial zones. The spatial spread of a word in upper and lower zones, together with the character density, is used to identify the script. The second technique analyses the directional energy distribution of a word using Gabor filters with suitable frequencies and orientations. Words with various font styles and sizes have been used for the testing of the proposed algorithms and the results are quite encouraging.
92 citations
TL;DR: A neural network-based script identification system which can be used in the machine reading of documents written in English, Hindi and Kannada language scripts and results are very encouraging and prove the effectiveness of the approach.
Abstract: The paper describes a neural network-based script identification system which can be used in the machine reading of documents written in English, Hindi and Kannada language scripts. Script identification is a basic requirement in automation of document processing, in multi-script, multi-lingual environments. The system developed includes a feature extractor and a modular neural network. The feature extractor consists of two stages. In the first stage the document image is dilated using 3 X 3 masks in horizontal, vertical, right diagonal, and left diagonal directions. In the next stage, average pixel distribution is found in these resulting images. The modular network is a combination of separately trained feedforward neural network classifiers for each script. The system recognizes 64 X 64 pixel document images. In the next level, the system is modified to perform on single word-document images in the same three scripts. Modified system includes a pre-processor, modified feature extractor and probabilistic neural network classifier. Pre-processor segments the multi-script multi-lingual document into individual words. The feature extractor receives these word-document images of variable size and still produces the discriminative features employed by the probabilistic neural classifier. Experiments are conducted on a manually developed database of document images of size 64 X 64 pixels and on a database of individual words in the three scripts. The results are very encouraging and prove the effectiveness of the approach.
87 citations
TL;DR: In this article, the effect of size on the compressive strength of cylindrical concrete specimens was studied, with the diameter, and the height/diameter ratio considered as the main parameters.
Abstract: It is important to consider the effect of size when estimating the ultimate strength of a concrete member under various loading conditions. Well known as the size effect, the strength of a member tends to decrease when its size increases. Therefore, in view of recent increased interest in the size effect of concrete this research focuses on the size effect of two main classes of compressive strength of concrete: pure axial compressive strength and flexural compressive strength. First, fracture mechanics type size effect on the compressive strength of cylindrical concrete specimens was studied, with the diameter, and the height/diameter ratio considered as the main parameters. Theoretical and statistical analyses were conducted, and a size effect equation was proposed to predict the compressive strength specimens. The proposed equation showed good agreement with the existing test results for concrete cylinders. Second, the size, length, and depth variations of a flexural compressive member have been studied experimentally. A series of C-shaped specimens subjected to axial compressive load and bending moment were tested. The shape of specimens and the test procedures used were similar to those by Hognestad and others. The test results are curve-fitted using Levenberg-Marquardt’s least squares method (LSM) to obtain parameters for the modified size effect law (MSEL) by Kim and co workers. The results of the analysis show that the effect of specimen size, length, and depth on ultimate strength is significant. Finally, more general parameters for MSEL are suggested.
83 citations
TL;DR: A prototype of the OCR system for printed Oriya script achieves 96.3% character level accuracy on average, and the feature detection methods are simple and robust, and do not require preprocessing steps like thinning and pruning.
Abstract: This paper deals with an Optical Character Recognition (OCR) system for printedOriya script. The development of OCR for this script is difficult because a large number of character shapes in the script have to be recognized. In the proposed system, the document image is first captured using a flat-bed scanner and then passed through different preprocessing modules like skew correction, line segmentation, zone detection, word and character segmentation etc. These modules have been developed by combining some conventional techniques with some newly proposed ones. Next, individual characters are recognized using a combination of stroke and run-number based features, along with features obtained from the concept of water overflow from a reservoir. The feature detection methods are simple and robust, and do not require preprocessing steps like thinning and pruning. A prototype of the system has been tested on a variety of printed Oriya material, and currently achieves 96.3% character level accuracy on average.
TL;DR: In this article, the authors have discussed the challenges in the development of fuel and materials for the Fast Breeder Test Reactor (FBR) at Kalpakkam in India.
Abstract: Fast breeder reactors (FBRs) are destined to play a crucial role in the Indian nuclear power programme in the foreseeable future. FBR technology involves a multi-disciplinary approach to solve the various challenges in the areas of fuel and materials development. Fuels for FBRs have significantly higher concentration of fissile material than in thermal reactors, with a matching increase in burn-up. The design of the fuel is an important aspect which has to be optimised for efficient, economic and safe production of power. FBR components operate under hostile and demanding environment of high neutron flux, liquid sodium coolant and elevated temperatures. Resistance to void swelling, irradiation creep, and irradiation embrittlement are therefore major considerations in the choice of materials for the core components. Structural and steam generator materials should have good resistance to creep, low cycle fatigue, creep-fatigue interaction and sodium corrosion. The development of carbide fuel and structural materials for the Fast Breeder Test Reactor at Kalpakkam was a great technological challenge. At the Indira Gandhi Centre for Atomic Research (IGCAR), advanced research facilities have been established, and extensive studies have been carried out in the areas of fuel and materials development. This has laid the foundation for the design and development of a 500 MWe Prototype Fast Breeder Reactor. Highlights of some of these studies are discussed in this paper in the context of our mission to develop and deploy FBR technology for the energy security of India in the 21st century.
TL;DR: In this paper, the phase velocities of quasi-P (qP) and quasi-SV (qSV) waves propagating in plane symmetry are obtained in terms of propagation vectors.
Abstract: The propagation of plane waves in fibre-reinforced media is discussed. The expressions of phase velocities of quasi-P (qP) and quasi-SV (qSV) waves propagating in plane symmetry are obtained in terms of propagation vectors. We have established a relation from which the displacement vector can be obtained in terms of the propagation vector. Expressions for the reflection coefficients of qP and qSV waves are obtained. Numerical results of reflection coefficients are obtained and presented graphically. The partition of energy between qP and qSV waves reflected on free and rigid boundaries due to incident qP and qSV waves are also obtained and presented graphically.
TL;DR: In this article, the authors investigated the combustion knock characteristics of diesel engines running on natural gas using pilot injection as a means of initiating combustion and found that the diesel engines knock under normal operating conditions but the knock referred to in this paper is an objectionable one.
Abstract: This paper investigates the combustion knock characteristics of diesel engines running on natural gas using pilot injection as means of initiating combustion. The diesel engines knock under normal operating conditions but the knock referred to in this paper is an objectionable one. In the dual-fuel combustion process we have the ignition stage followed by the combustion stage. There are three types of knock: diesel knock, spark knock and knock due to secondary ignition delay of the primary fuel (erratic knock). Several factors have been noted to feature in defining knock characteristics of dual-fuel engines that include ignition delay, pilot quantity, engine load and speed, turbulence and gas flow rate
TL;DR: In this article, the laser power utilized in the welding process was estimated using the experimental results and the dimensionless parameter model for laser welding; and also the energy balance equation model was studied.
Abstract: Laser welding of thin sheets of AISI 304 stainless steel was carried out with high power CW CO2 laser. The laser power utilized in the welding process was estimated using the experimental results and the dimensionless parameter model for laser welding; and also the energy balance equation model. Variation of laser welding efficiency with welding speed and mode of welding was studied. Welding efficiency was high for high-speed conduction welding of thin sheets and also in keyhole welding process at high laser powers. Effect of pre-oxidization of the surface and powder as filler material on laser power coupling is also reported. The paper also discusses effect of microstructure on the cracking susceptibility of laser welds.
TL;DR: In this paper, the authors investigated Rayleigh waves propagating on the surface of a visco-elastic solid under the linear theory of nonlocal elasticity and obtained dispersion relations.
Abstract: This paper investigates Rayleigh waves, propagating on the surface of a visco-elastic solid under the linear theory of nonlocal elasticity. Dispersion relations are obtained. It is observed that the waves are dispersive in nature for small wavelengths. Numerical calculations and discussions presented in this paper lead us to some important conclusions.
TL;DR: In this paper, the authors used a belt-dryer to obtain vegetables with 6% to 10% water content and good rehydration quality in a much shorter time than in continuous belt dryers.
Abstract: Fluid-bed drying of vegetable pieces has been investigated. The vegetables used have been potatoes, parsley roots, celery roots and carrots of various dimensions. Starting water content was: potatoes 78%, parsley roots 85.1%, celery roots 93.6%, and carrots 88.6%. Temperatures of fluidisation have varied from 60‡ to 100‡C at velocities of 0.71 ms-1. The goal has been to obtain dry vegetables with 6% to 10% water content and of good rehydration quality. Experimental data (bed height, gas temperature and velocity, pressure drop over the bed, drying time) have been measured and relevant values have been calculated. The results have shown that drying of vegetables in a fluidized bed produces dry vegetable pieces of excellent quality in a much shorter time than in continuous belt-dryers which are generally used
TL;DR: In this paper, the problem of scale-effects on the performances of concrete structures is discussed and the physical approach put forward by the authors takes into account the effects of microstructural disorder and seems to be valid in the whole size range, at least for unnotched structures.
Abstract: The problem of scale-effects on the performances of concrete structures is discussed. Experimentally observed decrease of nominal tensile strength, accompanied by structural embrittlement, occurring in large structures is of crucial importance in modern concrete engineering. Most of the previous approaches to the problem are restricted to notched structures and they often fail to predict mechanical behaviour in real situations. The physical approach put forward by us takes into adequate account the effects of microstructural disorder and seems to be valid in the whole size range, at least for unnotched structures. Thereby, reliable predictions can be made of the material properties in large-sized concrete structures.
TL;DR: A post-processing system for OCR of Gurmukhi script has been developed and an improvement of 3% in recognition rate, from 94.35% to 97.34%, has been reported on clean images using the post- processing techniques.
Abstract: A post-processing system for OCR of Gurmukhi script has been devel- oped. Statistical information of Punjabi language syllable combinations, corpora look-up and certain heuristics based on Punjabi grammar rules have been com- bined to design the post-processor. An improvement of 3% in recognition rate, from 94.35% to 97.34%, has been reported on clean images using the post-processing techniques.
TL;DR: In this article, an experimental study on the incipient motion of gravel and coal beds under unidirectional steady-uniform flow is presented, where the critical bed shear stresses for the experimental runs determined using side-wall correction show considerable disagreement with the standard curves.
Abstract: An experimental study on incipient motion of gravel and coal beds under unidirectional steady-uniform flow is presented. Experiments were carried out in a flume with various sizes of gravel and coal samples. The critical bed shear stresses for the experimental runs determined using side-wall correction show considerable disagreement with the standard curves. The characteristic parameters affecting the incipient motion of particles in rough-turbulent regime, identified based on physical reasoning and dimensional analysis, are the Shields parameter, particle Froude number, non-dimensional particle diameter and non-dimensional flow depth. Equations of critical bed shear stress for the initial movement of gravel and coal beds were obtained using experimental data. The method of application of critical bed shear stress equations is also mentioned.
TL;DR: In this paper, the authors present a study on laser cutting of mild steel with oxygen as an assist gas and estimate the optimum pressure required for melt ejection under laminar flow regime.
Abstract: We present a study on laser cutting of mild steel with oxygen as an assist gas. We correlate the cut surface quality with the melt film thickness. We estimate the optimum pressure required for melt ejection under laminar flow regime. The thickness of melt film inside the kerf is estimated using mass balance and the shear force acting on the cutting front assuming melt flow profile as linear. The dependence of melt film thickness on gas pressure, cutting velocity and work piece thickness is estimated and compared with experimental results.
TL;DR: In this article, the problem of surface wave propagation in fiber-reinforced anisotropic elastic media has been studied and the authors express the plane strain displacement components in terms of two scalar potentials to decouple the plane motion into P and SV waves.
Abstract: In the paper under discussion, the problem of surface waves in fibrereinforced anisotropic elastic media has been studied. The authors express the plane strain displacement components in terms of two scalar potentials to decouple the plane motion into P and SV waves. In the present note, we show that, for wave propagation in fibre-reinforced anisotropic media, this decoupling cannot be achieved by the introduction of the displacement potentials. In fact, the expressions for the displacement potentials used by the authors do not satisfy one of the equations of motion. Consequently, most of the equations and results of the subject paper are either irrelevant or incorrect
TL;DR: In this article, two methods are presented to analyze free overfall in Δ-shaped (equilateral triangle-shaped) channels using the momentum equation based on the Boussinesq approximation.
Abstract: In this paper, two methods are presented to analyse the free overfall in δ-shaped (equilateral triangle-shaped) channels. First, the flow upstream of a free overfall from smooth horizontal or mildly sloping Δ-shaped channels is analysed theoretically to determine the end-depth-ratio (EDR), applying the momentum equation based on the Boussinesq approximation. Second, an alternate method for analysing free overfall in Δ-shaped channels is also presented where the flow over a free overfall in a Δ-shaped channel is simulated by that over a sharp-crested weir to calculate the EDR. The method of estimation of discharge from the known end depth is also presented for both the methods. These approaches eliminate the need of an experimentally determined pressure coefficient. Experiments are conducted to verify the results obtained from the present methods. Comparisons of the computed and experimental results are satisfactory
TL;DR: An approach that combines the unsupervised and supervised learning techniques for unconstrained handwritten numeral recognition using the Kohonen self-organizing neural network in the first stage and the learning vector quantization model in the second stage to improve classification accuracy is proposed.
Abstract: In this paper, we propose an approach that combines the unsupervised and supervised learning techniques for unconstrained handwritten numeral recognition. This approach uses the Kohonen self-organizing neural network for data classification in the first stage and the learning vector quantization (LVQ) model in the second stage to improve classification accuracy. The combined architecture performs better than the Kohonen self-organizing map alone. In the proposed approach, the collection of centroids at different phases of training plays a vital role in the performance of the recognition system. Four experiments have been conducted and experimental results show that the collection of centroids in the middle of the training gives high performance in terms of speed and accuracy. The systems developed also resolve the confusion between handwritten numerals.
TL;DR: In this paper, the propagation of shear waves in the transverse isotropic fluid saturated porous plate has been studied, and it is observed that the frequency of the propagation is damped due to two-phase character of the porous medium.
Abstract: In the present context, we consider the propagation of shear waves in the transverse isotropic fluid saturated porous plate. The frequency spectrum for SH-modes in the plate has been studied. It is observed that the frequency of the propagation is damped due to the two-phase character of the porous medium. The dimensionless phase velocities of the shear waves have also been calculated and presented graphically. It is interesting to note that the frequency and phase velocity of shear waves in porous media differ significantly in comparison to that in isotropic elastic media.
TL;DR: In this article, the failure loads of three point bend (TPB) beams are analyzed according to the size effect formulae of Bažant and of Karihaloo for notched beams and according to those of Carpinteri for unnotched beams, and the results of this analysis presented.
Abstract: This paper reports on the range of applicability of the various size effect formulae available in the literature. In particular, the failure loads of three point bend (TPB) beams are analysed according to the size effect formulae of Bažant and of Karihaloo for notched beams and according to those of Bažant and of Carpinteri for unnotched beams, and the results of this analysis presented. Improvements to Karihaloo’s size effect formula are also proposed.
TL;DR: In this article, the authors used a recently developed technique for determining fracture criteria in sheet metals, results are generated on critical CTOD and fracture toughness and the differences are within 1 to 4%.
Abstract: Efforts made over the last three decades to understand the fracture behaviour of structural materials in elastic and elasto-plastic fracture mechanics are numerous, whereas investigations related to fracture behaviour of materials in thin sheets or general yielding fracture regimes are limited in number. Engineering simulative tests are being used to characterize formability and drawability of sheet metals. However, these tests do not assure consistency in quality of sheet metal products. The prevention of failure in stressed structural components currently requires fracture mechanics based design parameters like critical load, critical crack-tip opening displacement or fracture toughness. The present attempt would aim to fulfill this gap and generate more information thereby increased understanding on fracture behaviour of sheet metals. In the present investigation, using a recently developed technique for determining fracture criteria in sheet metals, results are generated on critical CTOD and fracture toughness. Finite element analysis was performed to support the results on various fracture parameters. The differences are within 1 to 4%. At the end it is concluded that magnitude of critical CTOD and/or critical load can be used as a fracture criterion for thin sheets.
TL;DR: A method for approximating min and max type constraints, and a polynomial-time algorithm for computing approximate time separation bounds in choice-free systems without repeated events are described.
Abstract: Finding bounds on time separation of events is a fundamental problem in the verification and analysis of asynchronous and concurrent systems. Unfortunately, even for systems without repeated events or choice, computing exact bounds on time separation of events is an intractable problem when both min and max type timing constraints are present. In this paper, we describe a method for approximating min and max type constraints, and develop a polynomial-time algorithm for computing approximate time separation bounds in choice-free systems without repeated events. Next, we develop a pseudo-polynomial time technique for analysing a class of asynchronous systems in which events repeat over time. Unlike earlier works, our algorithms can analyse systems with both min and max type timing constraints efficiently. Although the computed bounds are conservative in the worst-case, experimental results indicate that they are fairly accurate in practice. We present formal proofs of correctness of our algorithms, and demonstrate their efficiency and accuracy by applying them to a suite of benchmarks. A complete asynchronous chip has been modelled and analysed using the proposed technique, revealing potential timing problems (already known to designers) in the datapath design.
TL;DR: This work identifies a subclass of timed automata called product interval automata and develops its theory, and shows that the resulting automata are expressive enough to model the timed behaviour of asynchronous digital circuits.
Abstract: We identify a subclass of timed automata called product interval automata and develop its theory. These automata consist of a network of timed agents with the key restriction being that there is just one clock for each agent and the way the clocks are read and reset is determined by the distribution of shared actions across the agents. We show that the resulting automata admit a clean theory in both logical and language theoretic terms. We also show that product interval automata are expressive enough to model the timed behaviour of asynchronous digital circuits.
TL;DR: A knowledge-based approach for the recognition of PSL strokes, which comprises preprocessing, determination of starting and final points, acquisition of quadrant knowledge, graph-based traversal and finally a rule-based inference process for generating phonetic equivalent of English language characters for the strokes.
Abstract: The Pitman shorthand language (PSL) is a recording medium practised in all organizations, where English is the transaction medium. It has the practical advantage of high speed of recording, more than 120–200 words per minute, because of which it is universally acknowledged. This recording medium has its continued existence in spite of considerable developments in speech processing systems, which are not universally established yet. In order to exploit the vast transcribing potential of PSL a new area of research on automation of PSL processing is conceived. It has three major steps, namely, shape recognition of PSL strokes, their validation and English text production from these strokes.