2,356 research outputs found

    Construction and evaluation of classifiers for forensic document analysis

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    In this study we illustrate a statistical approach to questioned document examination. Specifically, we consider the construction of three classifiers that predict the writer of a sample document based on categorical data. To evaluate these classifiers, we use a data set with a large number of writers and a small number of writing samples per writer. Since the resulting classifiers were found to have near perfect accuracy using leave-one-out cross-validation, we propose a novel Bayesian-based cross-validation method for evaluating the classifiers.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS379 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Historical Analyses of Disordered Handwriting

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    Handwritten texts carry significant information, extending beyond the meaning of their words. Modern neurology, for example, benefits from the interpretation of the graphic features of writing and drawing for the diagnosis and monitoring of diseases and disorders. This article examines how handwriting analysis can be used, and has been used historically, as a methodological tool for the assessment of medical conditions and how this enhances our understanding of historical contexts of writing. We analyze handwritten material, writing tests and letters, from patients in an early 20th-century psychiatric hospital in southern Germany (Irsee/Kaufbeuren). In this institution, early psychiatrists assessed handwriting features, providing us novel insights into the earliest practices of psychiatric handwriting analysis, which can be connected to Berkenkotter’s research on medical admission records. We finally consider the degree to which historical handwriting bears semiotic potential to explain the psychological state and personality of a writer, and how future research in written communication should approach these sources

    An examination of quantitative methods for Forensic Signature Analysis and the admissibility of signature verification system as legal evidence.

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    The experiments described in this thesis deal with handwriting characteristics which are involved in the production of forged and genuine signatures and complexity of signatures. The objectives of this study were (1) to provide su?cient details on which of the signature characteristics are easier to forge, (2) to investigate the capabilities of the signature complexity formula given by Found et al. based on a different signature database provided by University of Kent. This database includes the writing movements of 10 writers producing their genuine signature and of 140 writers forging these sample signatures. Using the 150 genuine signatures without constrictions of the Kent’s database an evaluation of the complexity formula suggested in Found et al took place divided the signature in three categories low, medium and high graphical complexity. The results of the formula implementation were compared with the opinions of three leading professional forensic document examiners employed by Key Forensics in the UK. The analysis of data for Study I reveals that there is not ample evidence that high quality forgeries are possible after training. In addition, a closer view of the kinematics of the forging writers is responsible for our main conclusion, that forged signatures are widely different from genuine especially in the kinematic domain. From all the parameters used in this study 11 out of 15 experienced significant changes when the comparison of the two groups (genuine versus forged signature) took place and gave a clear picture of which parameters can assist forensic document examiners and can be used by them to examine the signatures forgeries. The movements of the majority of forgers are signi?cantly slower than those of authentic writers. It is also clearly recognizable that the majority of forgers perform higher levels of pressure when trying to forge the genuine signature. The results of Study II although limited and not entirely consistent with the study of Found that proposed this model, indicate that the model can provide valuable objective evidence (regarding complex signatures) in the forensic environment and justify its further investigation but more work is need to be done in order to use this type of models in the court of law. The model was able to predict correctly only 53% of the FDEs opinion regarding the complexity of the signatures. Apart from the above investigations in this study there will be also a reference at the debate which has started in recent years that is challenging the validity of forensic handwriting experts’ skills and at the effort which has begun by interested parties of this sector to validate and standardise the field of forensic handwriting examination and a discussion started. This effort reveals that forensic document analysis field meets all factors which were set by Daubert ruling in terms of theory proven, education, training, certification, falsifiability, error rate, peer review and publication, general acceptance. However innovative methods are needed for the development of forensic document analysis discipline. Most modern and effective solution in order to prevent observational and emotional bias would be the development of an automated handwriting or signature analysis system. This system will have many advantages in real cases scenario. In addition the significant role of computer-assisted handwriting analysis in the daily work of forensic document examiners (FDE) or the judicial system is in agreement with the assessment of the National Research Council of United States that “the scientific basis for handwriting comparison needs to be strengthened”, however it seems that further research is required in order to be able these systems to reach the accomplishment point of this objective and overcome legal obstacles presented in this study

    Finding the way forward for forensic science in the US:a commentary on the PCAST report

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    A recent report by the US President’s Council of Advisors on Science and Technology (PCAST) [1] has made a number of recommendations for the future development of forensic science. Whereas we all agree that there is much need for change, we find that the PCAST report recommendations are founded on serious misunderstandings. We explain the traditional forensic paradigms of match and identification and the more recent foundation of the logical approach to evidence evaluation. This forms the groundwork for exposing many sources of confusion in the PCAST report. We explain how the notion of treating the scientist as a black box and the assignment of evidential weight through error rates is overly restrictive and misconceived. Our own view sees inferential logic, the development of calibrated knowledge and understanding of scientists as the core of the advance of the profession

    Drawing, Handwriting Processing Analysis: New Advances and Challenges

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    International audienceDrawing and handwriting are communicational skills that are fundamental in geopolitical, ideological and technological evolutions of all time. drawingand handwriting are still useful in defining innovative applications in numerous fields. In this regard, researchers have to solve new problems like those related to the manner in which drawing and handwriting become an efficient way to command various connected objects; or to validate graphomotor skills as evident and objective sources of data useful in the study of human beings, their capabilities and their limits from birth to decline

    The Palaeographical Method under the Light of a Digital Approach

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    This paper has the twofold aim of reflecting upon a humanities computing approach to palaeography, and of making such reflections - together with its related experimental results - fruitful at the implementation level. Firstly, the paper explores the methodological issues related to the use of a digital tool to support the palaeographical analysis of medieval handwriting. It claims that humanities computing methods can assist in making explicit those processes of the palaeographical research that encompass detailed analyses, in particular of the handwriting and, more generally, of other idiosyncratic features of written cultural artefacts. Thus, palaeographical tools are to be contextualised and used within a broader methodological framework where their role is to mediate the vision, the comparison, the representation, the analysis and the interpretation of these objects. Secondly, the paper attempts to evaluate the experimentations carried out with a specific software and, in so doing, to test a humanities computing approach to palaeography at a practical level, so as to direct future implementations. Some of these implementations have already been carried out by the current developers of the application in question with whom the author collaborates closely, while others are still in progress and in need of future iterative refinements

    Spray paint writings on walls: Is conventional reference material adequate for comparison?

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    Forensic document experts may be asked to examine questioned items written with spray paint on vertical surfaces. In such cases, they may not dispose of reference material written under similar conditions. A critical question follows: is conventional reference material (e.g. executed with a ballpoint pen on a paper placed horizontally) suitable for comparison? In order to investigate the influence of this particular writing condition, samples written with spray paint on vertical surfaces were compared to samples written on paper by a same writer. This comparison was carried out on the writings of 27 volunteers. The results have shown that the amount of similarities between both writing conditions was strongly dependent on the writer. Overall, while some similarities in style (script, cursive), shape and construction of letters were observed, several discordances in connections, slant, spacing, size and proportions were highlighted between both writing conditions. Therefore, the findings of this study stress out the need for reference material produced under similar conditions when examining questioned spray paint writings on vertical surfaces

    Handwriting in Forensic Investigations

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    The process of automatic handwriting investigation in forensic science is described. The general scheme of a computer-based handwriting analysis system is used to point out at the basic problems of image enhancement and segmentation, feature extraction and decision-making. Factors that may compromise the accuracy of expert’s conclusion are underlined and directions for future investigations are marked

    Police Science Technical Abstracts and Notes

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    Towards a Bayesian evaluation of features in questioned handwritten signatures

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    In this work, we propose the construction of a evaluative framework for supporting experts in questioned signature examinations. Through the use of Bayesian networks, we envision to quantify the probative value of well defined measurements performed on questioned signatures, in a way that is both formalised and part of a coherent approach to evaluation. At the current stage, our project is explorative, focusing on the broad range of aspects that relate to comparative signature examinations. The goal is to identify writing features which are both highly discriminant, and easy for forensic examiners to detect. We also seek for a balance between case-specific features and characteristics which can be measured in the vast majority of signatures. Care is also taken at preserving the interpretability at every step of the reasoning process. This paves the way for future work, which will aim at merging the different contributions to a single probabilistic measure of strength of evidence using Bayesian networks
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