Structure recognition methods for various types of documents

In this paper, we describe experimental methods of recognizing the document structures of various types of documents in the framework of document understanding. Namely, we interpret document structures with individually characterized document knowledge. The document understanding process is divided into three procedures: the first is the recognition of document structures from a two-dimensional point of view; the second is the recognition of item relationships from a one-dimensional point of view; and the third is the recognition of characters from a zero-dimensional point of view. The procedure for recognizing structures plays the most important role in document understanding. This procedure extracts and classifies the logical item blocks from paper-based documents distinctly. We discuss the structure recognition methods for three classes of documents: 1) table-form documents, filled-in forms, cataloging lists, etc. — each item block is surrounded by horizontal and vertical line segments; 2) library cataloging cards, name cards, letters, etc. — each item block is separated by spaces; 3) newspapers, pamphlets, etc. — each item block is constructed hierarchically and by combining under roughly specified layouts. The structure recognition procedure is characterized by individual recognition methods: in class 1 documents, binary trees indicating the connective relationships among neighboring item blocks, which are surrounded by line segments; in class 2 documents, binary trees defining the spatial and geometric relationships among neighboring item blocks, which are separated by spaces; and in class 3 documents, composition rules specifying the constructive relationships among neighboring item blocks, which are represented by adjacent relationship graphs. The methods are effective under the knowledge-based frame-work and are integrated complementarily from the top-down (model-driven) and bottom-up (data-driven) approaches. Of course, the integration means vary according to document classes.     

Effects of isoflurane on in vivo release of acetylcholine in the rat cerebral cortex and striatum

BACKGROUND: Acetylcholine (ACh) is one of the major excitatory neurotransmitters in the central nervous system, and changes in neural activity induced by anesthesia alter the release of ACh. However, the effects of isoflurane, one of the most widely used volatile anesthetics, on ACh release are not known. The present study attempts to clarify the dose-effect relationship of isoflurane on the in vivo release of ACh in rat brains. METHODS: Changes in the extracellular concentration of ACh and choline in the cerebral cortex and striatum induced by 0.5, 1.0, and 1.5 minimum alveolar concentration (MAC) of isoflurane were determined using a brain microdialysis technique. RESULTS: In the cortex, the ACh release decreased to 30.8+/-10.1 (mean+/-SEM), 10.2+/-4.1, and 8.1+/-2.9% of basal value by increasing doses of isoflurane, and in the striatum, to 73.3+/-4.4, 49.2+/-4.2, and 40.7+/-4.5%. The ACh release rapidly recovered control levels with the discontinuance of isoflurane. Choline concentration was not changed significantly by isoflurane except for a decrease to 74.8+/-4.6% in the striatum by 0.5 MAC. In both the cortex and striatum, the choline concentration decreased with the discontinuance of isoflurane to 70.3+/-13.3, and 68.2+/-5.4%, respectively. CONCLUSION: The fact that all classic anesthetics reported previously, as well as isoflurane, reduce ACh release supports the hypothesis that the suppression of cholinergic cells is, at least in part one of the mechanisms of anesthesia.     

One-dimensional propagation speed of an elastic-plastic-viscoplastic stress wave

A one-dimensional elastic-plastic-viscoplastic constitutive equation with the introduction of overstress and understress is proposed, and the propagation speed of an elastic-plastic-viscoplastic stress wave is derived using this equation. Employing the propagation theory of this wave, the strain-rate dependence of the stress, a quasi-static stress-strain curve, the high-strain-rate dependence of the stress, and the strain and strain-rate dependence of the speed can be expressed. It is also shown that the extent of the strain-rate dependence of the stress and the speed can be expressed by changing the viscoplastic coefficient n and the modulus k₂ in the elastic -plastic-viscoplastic constitutive equation and in the equation of the elastic -plastic-viscoplastic stress wave.     

Si-OEIC with a built-in PIN-photodiode

A Si-OEIC with a built-in PIN-photodiode has been developed by a new device structure. We have successfully fabricated an optical link receiver with a speed of 50 Mb/s. The new device structure consists of stacked epitaxial layers each with a buried diffusion region. The cutoff frequency of the photodiode thus realized is 300 MHz and the fall time is 1.6 ns. In this paper, the structure of this new device is presented along with its fabrication process, while the performance is analyzed using device simulation. It was found that the speed of the PIN-photodiode in the Si-OEIC is dominated by carrier transit time in the n⁺-buried region. Further investigation was made by device simulation on two advanced structures. The speed of response of PIN-photodiode will be improved to as fast as 1 ns by the current Si technology. By more advanced technology, 0.7 ns will be achieved for the fall time showing the ultimate characteristic of Si-OEIC     

Double mutations of the N-ras gene in a patient with acute myelomonocytic leukemia

We report a patient with acute myelomonocytic leukemia (AMMoL) who showed two independent point mutations of the N-ras gene at codons 12 and 13. Longitudinal analysis revealed that one mutation at codon 13 was detectable throughout his disease course and the other at codon 12 emerged as a second mutation 14 months after the diagnosis was made, at the refractory stage. Cloning to vector and subsequent sequencing confirmed that these mutations occurred in different alleles. Chromosome findings showed a simple abnormal karyotype at presentation and further karyotypic aberrations during his disease course, concomitantly with the second mutation of the N-ras gene. These findings revealed a close relationship among the disease progression, karyotypic evolution and a newly-appearing N-ras mutation.     

Sheet stretching: A theoretical-experimental comparison

This paper presents numerical solutions of axisymmetric sheet stretching employing an experimentally determined stress-strain curve and measured overall coefficient of friction along the punch-sheet interface. Experiments have been conducted on thin sheet metals such as mild steel, aluminum and brass with a hemispherical steel punch. Predicted values of loads, deflections, strain distributions and other relevant data are favorably compared with experimental values of these same quantities.