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Sabri A. Mahmoud Irfan Ahmad Wasfi G. Al-Khatib Mohammad Alshayeb Mohammad Tanvir Parvez Volker Märgner Gernot A. Fink 《Pattern recognition》2014
A comprehensive Arabic handwritten text database is an essential resource for Arabic handwritten text recognition research. This is especially true due to the lack of such database for Arabic handwritten text. In this paper, we report our comprehensive Arabic offline Handwritten Text database (KHATT) consisting of 1000 handwritten forms written by 1000 distinct writers from different countries. The forms were scanned at 200, 300, and 600 dpi resolutions. The database contains 2000 randomly selected paragraphs from 46 sources, 2000 minimal text paragraph covering all the shapes of Arabic characters, and optionally written paragraphs on open subjects. The 2000 random text paragraphs consist of 9327 lines. The database forms were randomly divided into 70%, 15%, and 15% sets for training, testing, and verification, respectively. This enables researchers to use the database and compare their results. A formal verification procedure is implemented to align the handwritten text with its ground truth at the form, paragraph and line levels. The verified ground truth database contains meta-data describing the written text at the page, paragraph, and line levels in text and XML formats. Tools to extract paragraphs from pages and segment paragraphs into lines are developed. In addition we are presenting our experimental results on the database using two classifiers, viz. Hidden Markov Models (HMM) and our novel syntactic classifier. 相似文献
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Jonathan P. Caulkins Dieter Grass Gustav Feichtinger Gernot Tragler 《Computers & Operations Research》2008
This paper deals dynamically with the question of how recruitment to terror organizations is influenced by counter-terror operations. This is done within an optimal control model, where the key state is the (relative) number of terrorists and the key controls are two types of counter-terror tactics, one (“water”) that does not and one (“fire”) that does provoke recruitment of new terrorists. The model is nonlinear and does not admit analytical solutions, but an efficient numerical implementation of Pontryagin's minimum principle allows for solution with base case parameters and considerable sensitivity analysis. Generally, this model yields two different steady states, one where the terror organization is nearly eradicated and one with a high number of terrorists. Whereas water strategies are used at almost any time, it can be optimal not to use fire strategies if the number of terrorists is below a certain threshold. 相似文献
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Thomas Plötz Gernot A. Fink 《International Journal on Document Analysis and Recognition》2009,12(4):269-298
Since their first inception more than half a century ago, automatic reading systems have evolved substantially, thereby showing
impressive performance on machine-printed text. The recognition of handwriting can, however, still be considered an open research
problem due to its substantial variation in appearance. With the introduction of Markovian models to the field, a promising
modeling and recognition paradigm was established for automatic offline handwriting recognition. However, so far, no standard
procedures for building Markov-model-based recognizers could be established though trends toward unified approaches can be
identified. It is therefore the goal of this survey to provide a comprehensive overview of the application of Markov models
in the research field of offline handwriting recognition, covering both the widely used hidden Markov models and the less
complex Markov-chain or n-gram models. First, we will introduce the typical architecture of a Markov-model-based offline handwriting recognition system
and make the reader familiar with the essential theoretical concepts behind Markovian models. Then, we will give a thorough
review of the solutions proposed in the literature for the open problems how to apply Markov-model-based approaches to automatic
offline handwriting recognition. 相似文献
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Given the constantly raising world-wide energy demand and the accompanying increase in greenhouse gas emissions that pushes the progression of climate change, the possibly most important task in future is to find a carbon-low energy supply that finds the right balance between sustainability and energy security. For renewable energy generation, however, especially the second aspect turns out to be difficult as the supply of renewable sources underlies strong volatility. Further on, investment costs for new technologies are so high that competitiveness with conventional energy forms is hard to achieve. To address this issue, we analyze in this paper a non-autonomous optimal control model considering the optimal composition of a portfolio that consists of fossil and renewable energy and which is used to cover the energy demand of a small country. While fossil energy is assumed to be constantly available, the supply of the renewable resource fluctuates seasonally. We further on include learning effects for the renewable energy technology, which will underline the importance of considering the whole life span of such a technology for long-term energy planning decisions. 相似文献
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T Rand M Breitenseher J Haller W Graninger H Imhof S Trattnig 《Canadian Metallurgical Quarterly》1996,36(8):617-623
Rheumatoid arthritis is a chronic, multisystemic disease. The characteristic feature is persistent inflammatory synovitis. The knee joint is commonly involved with synovial hypertrophy, chronic effusion, and frequently ligamentous laxity. Pain and swelling behind the knee may be caused by extension of inflamed synovium into the popliteal space (Baker's cyst). Plain radiographs of the knee joint remain the basic radiological procedure, although early in the disease they might not provide significant changes. Sonography sufficiently reveals synovial fluid and Baker cysts, but cannot be recommended for evaluation of synovial proliferations or pannus formation. Computer tomography has only limited indications and may be used for the evaluation of subtle erosive lesions or the quantitation of osteoporotic changes. Magnetic resonance imaging has shown excellent visualization of cartilage, fluid, synovium and soft tissues and is the method of choice for the demonstration of early affection and the evaluation of pannus activity and therapy control. With administration of contrast agents (gadolinium), dynamic studies may demonstrate inflammatory activity. Modern MR sequences, such as T1 SE "fat sat" or magnetization transfer, further improve the discrimination of cartilage, pannus and synovial fluid. 相似文献
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We compare four tools regarding their suitability for teaching formal software verification, namely the Frege Program Prover,
the Key system, Perfect Developer, and the Prototype Verification System (PVS). We evaluate them on a suite of small programs, which are typical of courses dealing with Hoare-style verification, weakest
preconditions, or dynamic logic. Finally we report our experiences with using Perfect Developer in class. 相似文献