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GRAFOTYP

The Polish Forensic Association. University of Warsaw. GRAFOTYP. Project financed by the Ministry of Science and Higher Education in Poland from funds on science in years 2009 – 2011 as development project. Programme Guide. Authors of software: Andrzej Łuszczuk M.Sc .

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GRAFOTYP

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  1. ThePolish Forensic Association University of Warsaw GRAFOTYP Project financed by theMinistry of Science and HigherEducationin Poland fromfunds on science inyears 2009 – 2011 as development project Programme Guide Authors of software: Andrzej ŁuszczukM.Sc. Krystyn ŁuszczukM.Sc. Eng. Scientific consultation: Prof.Tadeusz Tomaszewski Dr Mieczysław Goc Englishversion: Agnieszka Łukomska (M.A.) Software producer and distributor: Research and Training Centre of PolishForensicAssociation www.kryminalistyka.pl

  2. Theprogrammeapplies: • graphometricalexaminedmethod, • basicnotions: • shapecoefficient, • sizeproportion, • Grafotyp, • Grafotypesmatch. • Whichwereworked out by authors of programme.

  3. TO ENSURE PROPER RUNNING OF PROGRAMME THE FOLLOWING REQUIREMENTS SHOULD BE MET: • Operating system: Windows XP,Windows Vista,Windows 7 or Windows 8. 2.IMPORTANT: required monitor (display) resolution 1024 × 600 or higher. In lower resolution, the programme cannot be started. System and equipmentrequirements: 3. Recommended default font size "9" at 96 dpi (not more than 120 dpi). 4. In Windows „.NET Framework" platform in v.2.0.50727 or more recent version should be installed.It is necessary for proper running of the programe.

  4. Definitions: Specimens - corresponding fragments of handwriting "A" and "B" selected for analysis, e.g. syllable, morpheme, word, illegible construction (signature). Shapecoefficient (Wk) - structural parameter of handwriting expressed through quotient of area of a polygon, constituting "contour" of the area of specimen selected for analysis (questioned and reference material)by square circumference of that polygon Wk = Σ | F | / (ΣL^2). For specimen A - shape coefficient (Wka) and for specimen B - shape coefficient (Wkb). Size proportion (Pw) - quotient of lenghts (shorter to longer) of two, most characteristic segments in specimens "A" and "B"(horizontal, vertical or slanting) set according tothe same criteria,i.e. these segments should link corresponding points in specimens "A" and "B". Grafotyp (G) - structural property of handwriting, individualizing its writer. Mathematically it constitutes a product of shape coefficient (Wk) and size proportion (Pw). G = Wk × Pw Grafotypsimilarity (%) - percentage rate of structural shape similarity between specimens "A" and "B", which demonstrates the authorship similarity.Mathematically it constitutes a quotient of Grafotypes (lower to higher value) multiplied by 100%.

  5. GRAFOTYP – method of calculation l2 l7 l1 l6 l8 l3 l4 l5 W1 l17 F W2 l9 l16 l14 l13 l12 l11 l10 l15 Surface(green) „of contour” = F Circumference „of contour” P = l1+l2+l3+…+l15+l16+l17 (sum of lenghts of red segments) ShapecoefficientWk = 100 * F / P² SizeproportionPw = W1 / W2 , where: 0 < Pw <= 1 GRAFOTYP G = Wk × Pw

  6. GRAFOTYP • GRAFOTYPallows for evaluation of degree of similarity between handwriting specimens basing on the following: • Shape coefficients match Wk • Size proportion Pw • Grafotypes match G

  7. GRAFOTYP – interface(specimens prepared for examination)

  8. Specimensafteranalysis – positiveverification Shapecoefficient of specimen B Shapecoefficient of specimen A Shapecoefficientsmatch Grafotypesmatch Message of quantile test

  9. Specimensafteranalysis – negativeverification Shapecoefficient of specimenB Shapecoefficient of specimen A Shapecoefficientsmatch Grafotypesmatch Message of quantile test

  10. A quantile statistical test, used in the programme, is entirely independent from Wk, Pw values calculated before and Grafotypes. It is necessary for the specimen "contour" polygon to have from 6 up to 30 (optimally around 20) sides. Quantile test constitutes a separateexaminationmethod. Ifthe test demonstrates a properdistribution of quotients of correspondingsides, thismayattest for a match of shapes of specimens’ „contours”. The test helpsexpertinmakingsuchdecision. Furthermore, the test serves as a certainverification of earliermeasurements. Notes on statistical test applied: If, for instance, the test will show the possibility of match between specimens at low Grafotype similarity, this provides for inaccurate or wrong designation of "contours", W1-W2 segments in particular. In such instances the analysis should be repeated.

  11. The following messages of quantile test can appear as result of analysis:

  12. Basic principles of verification of handwriting specimens in GRAFOTYP Statistical certainty of verification increases with the number of sides in „contour” polygons. GRAFOTYP is a measuring tool, which examines geometrical shape of specimens. It does not account for other features (such as tremor, points of stoppage, shading distribution) which may appear in examined specimens and be in conflict with high geometrical similarity. PROGRAMME IS A MEASURING TOOL AND DOES NOT INTEND TO SUBSTITUTE THE EXPERT A final decision on match of examined entries belongs to the user !!!

  13. Youarewelcome to useourprogramme

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