Περί διαχωρισμού της γραφής διδύμων/ On the Discriminability of the Handwriting of Twins

Στο καινούργιο τευχος του Journal of Forensic Sciences ( Volume 53 Issue 2 Page 430-446, March 2008), οι Sargur Srihari, Chen Huang και Harish Srinivasan παρουσιάζουν μια εργασία με τίτλο: "Περί διαχωρισμού της γραφής διδύμων/On the Discriminability of the Handwriting of Twins ".

In the new Issue of Journal of Forensic Sciences International ( Volume 53 Issue 2 Page 430-446, March 2008),Sargur Srihari, Chen Huang and Harish Srinivasan present a paper titled: "On the Discriminability of the Handwriting of Twins".

Περίληψη/Abstract: As handwriting is influenced by physiology, training, and other behavioral factors, a study of the handwriting of twins can shed light on the individuality of handwriting. This paper describes the methodology and results of such a study where handwriting samples of twins were compared by an automatic handwriting verification system. The results complement that of a previous study where a diverse population was used. The present study involves samples of 206 pairs of twins, where each sample consisted of a page of handwriting. The verification task was to determine whether two half-page documents (where the original samples were divided into upper and lower halves) were written by the same individual. For twins there were 1236 verification cases—including 824 tests where the textual content of writing was different, and 412 tests where it was the same. An additional set of 1648 test cases were obtained from handwriting samples of nontwins (general population). To make the handwriting comparison, the system computed macro features (overall pictorial attributes), micro features (characteristics of individual letters), and style features (characteristics of whole-word shapes and letter pairs). Four testing scenarios were evaluated: twins and nontwins writing the same text and writing different texts. Results of the verification tests show that the handwriting of twins is less discriminable than that of nontwins: an overall error rate of 12.91% for twins and 3.7% for nontwins. Error rates with identical twins were higher than with fraternal twins. Error rates in all cases can be arbitrarily reduced by rejecting (not making a decision on) borderline cases. A level of confidence in the results obtained is given by the fact that system error rates are comparable to that of humans (lower than that of lay persons and higher than that of questioned document examiners [QDEs]).


http://www.blackwell-synergy.com/doi/abs/10.1111/j.1556-4029.2008.00682.x

Controlled electrostatic methodology for imaging indentations in documents

Στο καινούργιο τευχος του Forensic Science International (Volume 177, Issues 2-3, 20 May 2008, Pages 97-104), οι Luke Yaraskavitch, Matthew Graydon, Tobin Tanaka και Lay-Keow Ng παρουσιάζουν μια εργασία με τίτλο: "Controlled electrostatic methodology for imaging indentations in documents".

In the new Issue of Forensic Science International (Volume 177, Issues 2-3, 20 May 2008, Pages 97-104), Luke Yaraskavitch, Matthew Graydon, Tobin Tanaka and Lay-Keow Ng present a paper titled: "Controlled electrostatic methodology for imaging indentations in documents".

Περίληψη/Abstract: The electrostatic process for imaging indentations on documents using the ESDA device is investigated under controlled experimental settings. An in-house modified commercial xerographic developer housing is used to control the uniformity and volume of toner deposition, allowing for reproducible image development. Along with this novel development tool, an electrostatic voltmeter and fixed environmental conditions facilitate an optimization process. Sample documents are preconditioned in a humidity cabinet with microprocessor control, and the significant benefit of humidification above 70% RH on image quality is verified. Improving on the subjective methods of previous studies, image quality analysis is carried out in an objective and reproducible manner using the PIAS-II. For the seven commercial paper types tested, the optimum ESDA operating point is found to be at an electric potential near −400 V at the Mylar surface; however, for most paper types, the optimum operating regime is found to be quite broad, spanning relatively small electric potentials between −200 and −550 V. At −400 V, the film right above an indented area generally carries a voltage which is 30–50 V less negative than the non-indented background. In contrast with Seward's findings [G.H. Seward, Model for electrostatic imaging of forensic evidence via discharge through Mylar–paper path, J. Appl. Phys. 83 (3) (1998) 1450–1456; G.H. Seward, Practical implications of the charge transport model for electrostatic detection apparatus (ESDA), J. Forensic Sci. 44 (4) (1999) 832–836], a period of charge decay before image development is not required when operating in this optimal regime. A brief investigation of the role played by paper-to-paper friction during the indentation process is conducted using our optimized development method.

http://dx.doi.org/10.1016/j.forsciint.2007.11.004

Stable isotope ratio mass spectrometry and physical comparison for the forensic examination of grip-seal plastic bags

Στο καινούργιο τευχος του Forensic Science International (Volume 177, Issues 2-3, 20 May 2008, Pages 214-220), οι Erica Taylor, James F. Carter, Jenny C. Hill, Carolyn Morton, Niamh Nic Daeid και Richard Sleeman παρουσιάζουν μια εργασία με τίτλο:"Stable isotope ratio mass spectrometry and physical comparison for the forensic examination of grip-seal plastic bags "

In the new Issue of Forensic Science International (Volume 177, Issues 2-3, 20 May 2008, Pages 214-220), Erica Taylor, James F. Carter, Jenny C. Hill, Carolyn Morton, Niamh Nic Daeid and Richard Sleeman present a paper titled:"Stable isotope ratio mass spectrometry and physical comparison for the forensic examination of grip-seal plastic bags "

Περίληψη/Abstract: Plastic bags are frequently used to package drugs, explosives and other contraband. There exists, therefore, a requirement in forensic casework to compare bags found at different locations. This is currently achieved almost exclusively by the use of physical comparisons such as birefringence patterns. This paper discusses some of the advantages and shortcomings of this approach, and presents stable isotope ratio mass spectrometry (IRMS) as a supplementary tool for effecting comparisons of this nature. Carbon and hydrogen isotopic data are presented for sixteen grip-seal plastic bags from a wide range of sources, in order to demonstrate the range of values which is likely to be encountered. Both isotopic and physical comparison (specifically birefringence) techniques are then applied to the analysis of rolls of bags from different manufacturing lots from a leading manufacturer. Both approaches are able to associate bags from a common production batch. IRMS can be applied to small fragments which are not amenable to physical comparisons, and is able to discriminate bags which could be confused using birefringence patterns alone. Similarly, in certain cases birefringence patterns discriminate bags with similar isotopic compositions. The two approaches are therefore complementary. When more than one isotopically distinct region exists within a bag (e.g. the grip-seal is distinct from the body) the ability to discriminate and associate bags is greatly increased.

http://dx.doi.org/10.1016/j.forsciint.2008.01.006

Decision theoretic properties of forensic identification: Underlying logic and argumentative implications

Στο καινούργιο τευχος του Forensic Science International (Volume 177, Issues 2-3, 20 May 2008, 120-132), οι A. Biedermann, S. Bozza και F. Taroni παρουσιάζουν μια εργασία με τίτλο: Decision theoretic properties of forensic identification: "Underlying logic and argumentative implications"

In the new Issue of Forensic Science International (Volume 177, Issues 2-3, 20 May 2008, Pages 120-132), A. Biedermann, S. Bozza and F. Taroni present a paper titled: "Decision theoretic properties of forensic identification: Underlying logic and argumentative implications"

Περίληψη/Abstract:

The field of forensic science has profited from recent advances in the elicitation of various kinds probabilistic data. These provide the basis for implementing probabilistic inference procedures (e.g., in terms of likelihood ratios) that address the task of discriminating among competing target propositions. There is ongoing discussion, however, whether forensic identification, that is, a conclusion that associates a potential source (such as an individual or object) with a given item of scientific evidence (e.g., a biological stain or a tool mark), can, if ever, be based on purely probabilistic argument. With regard to this issue, the present paper proposes to analyze the process of forensic identification from a decision theoretic point of view. Existing probabilistic inference procedures are used therein as an integral part. The idea underlying the proposed analyses is that inference and decision are connected in the sense that the former is the point of departure for the latter. As such the approach forms a coordinated whole, that is a framework also known in the context as ‘full Bayesian (decision) approach’. This study points out that, as a logical extension to purely probabilistic reasoning, a decision theoretic conceptualization of forensic identification allows the content and structure of arguments to be examined from a reasonably distinct perspective and common fallacious interpretations to be avoided.

http://linkinghub.elsevier.com/retrieve/pii/S0379073807008055

Book Reviews

Στο νέο τεύχος του Science & Justice (Volume 48, Issue 2, Pages 59-106 (June 2008)) παρουσιάζονται και σχολιάζονται δύο βιβλία σχετικά με τη Δικαστική Γραφλολογία.

Forensic handwriting examination: A definitive guide, Reed Hayes, Reed Hayes Publications, Honolulu, HI, ISBN No. 0-9778415-0-2, 254 pp, ($49.95). Page 104 M.J. Allen

Jan Seaman Kelly and Brian S. Lindblom, Editors, Scientific Examination of Questioned Documents (2nd Edition) (04/27/2006) ISBN 9780849320446 ISBN 10:0849320445, CAT #: 2044, Price: $139.95. Page 104 K. Barr

All that is iron-ink is not always iron-gall!

Στο προηγούμενο τευχος του Journal of Raman Spectroscopy (April 2008), οι Marina Bicchieri, Michela Monti, Giovanna Piantanida & Armida Sodo παρουσιάζουν μια εργασία με τίτλο: "All that is iron-ink is not always iron-gall!".

In the previous Issue of Journal of Raman Spectroscopy (April 2008), Marina Bicchieri, Michela Monti, Giovanna Piantanida & Armida Sodo present a paper titled: "All that is iron-ink is not always iron-gall!".

Περίληψη/Abstract: A number of different inks were used, with the type and precise composition depending on geographical area and historical period. China, iron-gall and logwood were the most widespread, although a number of other graphic media were also used at particular times and places. Because of a problem encountered while planning the restoration of a manuscript apparently written with different media, we have carried out a systematic characterization of the inks involved. The manuscript (Francesco Maria da Ponticelli, Nova Rhetorica, 18th century) showed alternately, sometimes in the same page, dark-black well-defined inks and reddish-brown smudged ones. The latter ones were very difficult to be read and historians identified it as an iron-gall. Our first investigations of the document revealed that the ink had variable composition, but it always showed some typical features of logwood ink. To obtain a better understanding, we prepared, following ancient recipes, logwood inks with the addition of various metallic (Fe, Cr and Cu) salts or amorphous carbon. Iron-gall ink was also used for comparison and in order to obtain an unambiguous and full characterization of the most widespread inks used in manuscripts. Raman and infrared spectroscopies allowed us to identify the characteristic vibrational features of each prepared medium. These techniques, together with X-ray fluorescence (XRF) and multispectral investigations of the original document led us to hypothesize that iron salts were periodically added to the original logwood ink. These sequences of ink quality can be ascribed to a shortage of ink during the writing of the manuscript. A small amount of iron salt immediately darkens the logwood extract, allowing its prolonged use. The presence of iron complexes produces a reddish-brown coloration and causes ink migration in the paper. Combining all the information, we were able to suggest an appropriate restoration treatment and to choose infrared illumination to maximize the readability of the text.

Article

Reconstruction of ripped-up documents using fragment stack analysis procedures

Στο καινούργιο τευχος του Forensic Sciences International (Volume 176, Issues 2-3, 7 April 2008, Pages 124-136), ο Patrick De Smet παρουσιάζει μια εργασία με τίτλο: "Reconstruction of ripped-up documents using fragment stack analysis procedures/ Ανακατασκευή κατεστραμμένων εγγράφων χρησιμοποιόντας διαδικασίες fragment stack analysis ".


In the new Issue of Journal of Forensic Sciences International (Volume 176, Issues 2-3, 7 April 2008, Pages 124-136), Patrick De Smet present a paper titled: "Reconstruction of ripped-up documents using fragment stack analysis procedures ".

Περίληψη/Abstract: Reconstruction of ripped-up documents can be a very time-consuming task for forensic experts. Currently, this task is often carried out using various homespun or loosely defined procedures. Under the main assumption that a (partially) ordered set of fragments can be recovered, we propose and discuss a more formal analysis methodology for this type of reconstruction problem. We discuss several complications that can occur in real-life problems and illustrate the efficiency of the proposed methods. Although several avenues for further research remain, we show that the proposed approach offers both a better understanding of the problem, as well as important strategies for devising very fast manual and semi-automatic fragment reassembly procedures.