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Tillmar, Andreas. "Populations and Statistics in Forensic Genetics." Doctoral thesis, Linköpings universitet, Institutionen för klinisk och experimentell medicin, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-54742.
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DNA has become a powerful forensic tool for solving cases such as linking a suspect to a crime scene, resolving biological relationship issues and identifying disaster victims. Traditionally, DNA investigations mainly involve two steps; the establishment of DNA profiles from biological samples and the interpreta-tion of the evidential weight given by theses DNA profiles. This thesis deals with the latter, with focus on models for assessing the weight of evidence and the study of parameters affecting these probability figures. In order to calculate the correct representative weight of DNA evidence, prior knowledge about the DNA markers for a relevant population sample is required. Important properties that should be studied are, for example, how frequently certain DNA-variants (i.e. alleles) occur in the population, the differences in such frequencies between subpopulations, expected inheritance patterns of the DNA markers within a family and the forensic efficiency of the DNA markers in casework. In this thesis we aimed to study important population genetic parameters that influence the weight of evidence given by a DNA-analysis, as well as models for proper consideration of such parameters when calculating the weight of evi-dence in relationship testing. We have established a Swedish frequency database for mitochondrial DNA haplotypes and a haplotype frequency database for markers located on the X-chromosome. Furthermore, mtDNA haplotype frequencies were used to study the genetic variation within Sweden, and between Swedish and other European populations. No genetic substructure was found in Sweden, but strong similari-ties with other western European populations were observed. Genetic properties such as linkage and linkage disequilibrium could be im-portant when using X-chromosomal markers in relationship testing. This was true for the set of markers that we studied. In order to account for this, we pro-posed a model for how to take linkage and linkage disequilibrium into account when calculating the weight of evidence provided by X-chromosomal analysis. Finally, we investigated the risk of erroneous decisions when using DNA in-vestigations for family reunification. We showed that the risk is increased due to uncertainties regarding population allele frequencies, consanguinity and compet-ing close relationship between the tested individuals. Additional information and the use of a refined model for the alternative hypotheses reduced the risk of making erroneous decisions. In summary, as a result of the work on this thesis, we can use mitochondrial DNA and X-chromosome markers in order to resolve complex relationship in-vestigations. Moreover, the reliability of likelihood estimates has been increased by the development of models and the study of relevant parameters affecting probability calculations.
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Chung, Yuk-ka, and 鍾玉嘉. "On the evaluation and statistical analysis of forensic evidence in DNAmixtures." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B45983586.
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Johansson, Åsa, and Teresé Stattin. "Footwear Impression as Forensic Evidence - Prevalence, Characteristics and Evidence Value." Thesis, Linköping University, Department of Mathematics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11805.
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Den forensiska vetenskapen innefattar en mängd olika vetenskaper som tillämpas för att bistå och besvara frågor av intresse för rättsväsendet. Skoavtrycksjämförelser har använts sedan slutet av 1700-talet för att bistå i brottsutredningar. Genom att undersöka egenskaper hos ett skoavtryck kan en forensiker ge utredaren värdefull information om skon och ibland även om bäraren. I bästa fall är skoavtrycket så unikt att det kan individualiseras och identifieras till en specifik sko.
För att underlätta och förbättra den forensiska bevisvärderingen är det av stort intresse att statistiskt erhålla förekomsten av ett bevis. Genom att samla in data gällande sulmönster och sedan etablera en databas kan styrkan hos ett specifikt skoavtryck fastställas. I denna studie samlades 687 avtryck in slumpmässigt och lades in i ett visualiserat databasklassificeringssystem, SIMSALAPIM, varpå en statistisk utvärdering utfördes.
Resultatet i denna studie visar på att ett specifikt sulmönster generellt förekommer endast en gång i databasen, varför det kan sägas att ett skoavtryck tillför en viss styrka/värde som forensiskt bevis även om det inte besitter några individualiserande detaljer. Vidare, genom ytterliggare statistiska utvärderingar, kunde även ett samband mellan ålder och typ av sko ses.
The Forensic Science comprises a variety of sciences that are applied in order to assist and answer questions of interest to the legal system. Since the end of the 18th century footwear impression comparison has been applied to assist in crime investigations. By examining the characteristics of a footwear impression the forensic scientist may provide the investigator with valuable information about the footwear and sometimes even about the wearer. Ultimately, the footwear impression is so unique that it can be individualized and identified to a specific shoe.
In order to facilitate and improve the forensic evidence evaluation it is of great interest to statistically establish the prevalence of evidence. By collecting data of outsole patterns and then recording it in a database the strength of a specific footwear impression can be determined. In this survey 687 impressions were randomly collected and recorded in a visualised database classification system, SIMSALAPIM1, whereupon a statistical evaluation was performed.
The result of this survey indicates that a specific outsole pattern typically only occurs once in the database, wherefore it can be stated that any footwear impression provides some strength/value as forensic evidence even though there are no individual characteristics present. Moreover, through additional statistical evaluations, a relation between age and shoe type also was revealed.
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Rinke, Caitlin. "Selective Multivariate Applications in Forensic Science." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5459.
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A 2009 report published by the National Research Council addressed the need for improvements in the field of forensic science. In the report emphasis was placed on the need for more rigorous scientific analysis within many forensic science disciplines and for established limitations and determination of error rates from statistical analysis. This research focused on multivariate statistical techniques for the analysis of spectral data obtained for multiple forensic applications which include samples from: automobile float glasses and paints, bones, metal transfers, ignitable liquids and fire debris, and organic compounds including explosives. The statistical techniques were used for two types of data analysis: classification and discrimination. Statistical methods including linear discriminant analysis and a novel soft classification method were used to provide classification of forensic samples based on a compiled library. The novel soft classification method combined three statistical steps: Principal Component Analysis (PCA), Target Factor Analysis (TFA), and Bayesian Decision Theory (BDT) to provide classification based on posterior probabilities of class membership. The posterior probabilities provide a statistical probability of classification which can aid a forensic analyst in reaching a conclusion. The second analytical approach applied nonparametric methods to provide the means for discrimination between samples. Nonparametric methods are performed as hypothesis test and do not assume normal distribution of the analytical figures of merit. The nonparametric permutation test was applied to forensic applications to determine the similarity between two samples and provide discrimination rates. Both the classification method and discrimination method were applied to data acquired from multiple instrumental methods. The instrumental methods included: Laser Induced-Breakdown Spectroscopy (LIBS), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, and Gas Chromatography-Mass Spectrometry (GC-MS). Some of these instrumental methods are currently applied to forensic applications, such as GC-MS for the analysis of ignitable liquid and fire debris samples; while others provide new instrumental methods to areas within forensic science which currently lack instrumental analysis techniques, such as LIBS for the analysis of metal transfers. The combination of the instrumental techniques and multivariate statistical techniques is investigated in new approaches to forensic applications in this research to assist in improving the field of forensic science.Ph.D.
Doctorate
Chemistry
Sciences
Chemistry
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Garner, Jeffrey Lee. "Forensic Detection for Earnings Management in Selected Code Law Nations of Europe." Thesis, Walden University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10932861.
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This study investigated earnings management in European firms. The private investors became victims of manipulated earnings where few laws offered regulatory oversight. The study forensically examined the attributes of earnings management identified using a discretionary accrual model published in Jones’ work and Schippers’ work. The firms’ managers should fulfil agency theory when they made reporting decisions, and they should act in the investors’ best interests to fulfil stewardship theory. The managers failed as they seemed to favor insiders when they reported manipulated earnings to outsiders like small investors even though the managers published financial reports conforming to the International Financial Reporting Standards. The investors depended on the decision usefulness of the reports. The study used the data of 432 listed firms in 11 code law nations. The paired t test identified significant differences between reported and economic earnings to find earnings management attributes and between economic and restated earnings to find earnings management cases. The research found that managers seemed to manipulate discretionary accruals to misstate earnings and reduce the decision usefulness of reporting. The data came from published financial reports and databases. The firms represented 11 nations and 9 industries that excluded banking and insurance. Almost 17% of nations and industry segments reflected earnings management attributes. About 29% of firms restated at least one annual earnings, and 84% of the restatements appeared to offset manipulation. The research results should prompt social change for small investors where regulators would redress the manipulation using stronger investor protection laws to improve the reported earnings quality and its decision usefulness.
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Curran, James Michael. "Forensic Applications of Bayesian Inference to Glass Evidence." Thesis, University of Auckland, 1996. http://hdl.handle.net/2292/2454.
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The role of the scientist in the courtroom has come under more scrutiny this century than ever before. As a consequence, scientists must constantly look for ways to improve the validity of the evidence they deliver. It is here that the professional statistician can provide assistance. The use of statistics in the courtroom and in forensic science is not new, but until recently has not been common either. Statistics can provide objectivity to subjective assessments and strengthen a case for the prosecution or the defence, but only if is used correctly. The aim of this thesis is to enhance and replace the existing technology used in statistical analysis and presentation of trace evidence, i.e. all non-genetic evidence (hairs, fibres, glass, paint, etc.) and transfer problems.
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Graversen, Therese. "Statistical and computational methodology for the analysis of forensic DNA mixtures with artefacts." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:4c3bfc88-25e7-4c5b-968f-10a35f5b82b0.
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This thesis proposes and discusses a statistical model for interpreting forensic DNA mixtures. We develop methods for estimation of model parameters and assessing the uncertainty of the estimated quantities. Further, we discuss how to interpret the mixture in terms of predicting the set of contributors. We emphasise the importance of challenging any interpretation of a particular mixture, and for this purpose we develop a set of diagnostic tools that can be used in assessing the adequacy of the model to the data at hand as well as in a systematic validation of the model on experimental data. An important feature of this work is that all methodology is developed entirely within the framework of the adopted model, ensuring a transparent and consistent analysis. To overcome the challenge that lies in handling the large state space for DNA profiles, we propose a representation of a genotype that exhibits a Markov structure. Further, we develop methods for efficient and exact computation in a Bayesian network. An implementation of the model and methodology is available through the R package DNAmixtures.
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Forbes, Peter G. M. "Quantifying the strength of evidence in forensic fingerprints." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:0915280a-22cc-429d-90dc-77f934d61dde.
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Part I presents a model for fingerprint matching using Bayesian alignment on unlabelled point sets. An efficient Monte Carlo algorithm is developed to calculate the marginal likelihood ratio between the hypothesis that an observed fingerprint and fingermark pair originate from the same finger and the hypothesis that they originate from different fingers. The model achieves good performance on the NIST-FBI fingerprint database of 258 matched fingerprint pairs, though the computed likelihood ratios are implausibly extreme due to oversimplification in our model. Part II moves to a more theoretical study of proper scoring rules. The chapters in this section are designed to be independent of each other. Chapter 9 uses proper scoring rules to calibrate the implausible likelihood ratios computed in Part I. Chapter 10 defines the class of compatible weighted proper scoring rules. Chapter 11 derives new results for the score matching estimator, which can quickly generate point estimates for a parametric model even when the normalization constant of the distribution is intractable. It is used to find an initial value for the iterative maximization procedure in §3.3. Appendix A describes a novel algorithm to efficiently sample from the posterior of a von Mises distribution. It is used within the fingerprint model sampling procedure described in §5.6. Appendix B includes various technical results which would otherwise disrupt the flow of the main dissertation.
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Napier, Gary. "A Bayesian hierarchical model of compositional data with zeros : classification and evidence evaluation of forensic glass." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5793/.
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A Bayesian hierarchical model is proposed for modelling compositional data containing large concentrations of zeros. Two data transformations were used and compared: the commonly used additive log-ratio (alr) transformation for compositional data, and the square root of the compositional ratios. For this data the square root transformation was found to stabilise variability in the data better. The square root transformation also had no issues dealing with the large concentrations of zeros. To deal with the zeros, two different approaches have been implemented: the data augmentation approach and the composite model approach. The data augmentation approach treats any zero values as rounded zeros, i.e. traces of components below limits of detection, and updates those zero values with non-zero values. This is better than the simple approach of adding constant values to zeros as it reduces any artificial correlation produced by updating the zeros as part of the modelling procedure. However, due to the small detection limit it does not necessarily alleviate the problems of having a point mass very close to zero. The composite model approach treats any zero components as being absent from a composition. This is done by splitting the data into subsets according to the presence or absence of certain components to produce different data configurations that are then modelled separately. The models are applied to a database consisting of the elemental configurations of forensic glass fragments with many levels of variability and of various use types. The main purposes of the model are (i) to derive expressions for the posterior predictive probabilities of newly observed glass fragments to infer their use type (classification) and (ii) to compute the evidential value of glass fragments under two complementary propositions about their source (forensic evidence evaluation). Simulation studies using cross-validation are carried out to assess both model approaches, with both performing well at classifying glass fragments of use types bulb, headlamp and container, but less well so when classifying car and building windows. The composite model approach marginally outperforms the data augmentation approach at the classification task; both approaches have the edge over support vector machines (SVM). Both model approaches also perform well when evaluating the evidential value of glass fragments, with false negative and false positive error rates below 5%. The results from glass classification and evidence evaluation are an improvement over existing methods. Assessment of the models as part of the evidence evaluation simulation study also leads to a restriction being placed upon the reported strength of the value of this type of evidence. To prevent strong support in favour of the wrong proposition it is recommended that this glass evidence should provide, at most, moderately strong support in favour of a proposition. The classification and evidence evaluation procedures are implemented into an online web application, which outputs the corresponding results for a given set of elemental composition measurements. The web application contributes a quick and easy-to-use tool for forensic scientists that deal with this type of forensic evidence in real-life casework.
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Lewey, Heather. "Examining Significant Differences of Gunshot Residue Patterns Using Same Make and Model of Firearms in Forensic Distance Determination Tests." Digital Commons @ East Tennessee State University, 2007. https://dc.etsu.edu/etd/2064.
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In many cases of crimes involving a firearm, police investigators need to know how far the firearm was held from the victim when it was discharged. Knowing this distance, vital questions regarding the re-construction of the crime scene can be known. Often, the original firearm used in commission of a suspected crime is not available for testing or is damaged. Crime laboratories require the original firearm in order to conduct distance determination tests. However, no empirical research has ever been conducted to determine if same make and model firearms produce different results in distance determination testing. It was the purpose of this study to determine if there are significant differences between the same make and model of firearms in distance determination testing. The findings indicate no significant differences; furthermore they imply that if the original firearm is not available, another firearm of the same make and model may be used.
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Wright, David. "Stylistics versus statistics : a corpus linguistic approach to combining techniques in forensic authorship analysis using Enron emails." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/8278/.
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This thesis empirically investigates how a corpus linguistic approach can address the main theoretical and methodological challenges facing the field of forensic authorship analysis. Linguists approach the problem of questioned authorship from the theoretical position that each person has their own distinctive idiolect (Coulthard 2004: 431). However, the notion of idiolect has come under scrutiny in forensic linguistics over recent years for being too abstract to be of practical use (Grant 2010; Turell 2010). At the same time, two competing methodologies have developed in authorship analysis. On the one hand, there are qualitative stylistic approaches, and on the other there are statistical ‘stylometric’ techniques. This study uses a corpus of over 60,000 emails and 2.5 million words written by 176 employees of the former American company Enron to tackle these issues in the contexts of both authorship attribution (identifying authors using linguistic evidence) and author profiling (predicting authors’ social characteristics using linguistic evidence). Analyses reveal that even in shared communicative contexts, and when using very common lexical items, individual Enron employees produce distinctive collocation patterns and lexical co-selections. In turn, these idiolectal elements of linguistic output can be captured and quantified by word n-grams (strings of n words). An attribution experiment is performed using word n-grams to identify the authors of anonymised email samples. Results of the experiment are encouraging, and it is argued that the approach developed here offers a means by which stylistic and statistical techniques can complement each other. Finally, quantitative and qualitative analyses are combined in the sociolinguistic profiling of Enron employees by gender and occupation. Current author profiling research is exclusively statistical in nature. However, the findings here demonstrate that when statistical results are augmented by qualitative evidence, the complex relationship between language use and author identity can be more accurately observed.
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Sangaramoorthy, Thurka. "We all have AIDS: Circulations of risk, race, and statistics in HIV/AIDS prevention." Diss., Search in ProQuest Dissertations & Theses. UC Only, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3311350.
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Thesis (Ph.D.)--University of California, San Francisco with the University of California, Berkeley, 2008.Source: Dissertation Abstracts International, Volume: 69-06, Section: A, page: 2336. Adviser: Charles L. Briggs.
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Garner, Jef Lee. "Forensic Detection for Earnings Management in Selected Code Law Nations of Europe." ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/5863.
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This study investigated earnings management in European firms. The private investors became victims of manipulated earnings where few laws offered regulatory oversight. The study forensically examined the attributes of earnings management identified using a discretionary accrual model published in Jones' work and Schippers' work. The firms' managers should fulfil agency theory when they made reporting decisions, and they should act in the investors' best interests to fulfil stewardship theory. The managers failed as they seemed to favor insiders when they reported manipulated earnings to outsiders like small investors even though the managers published financial reports conforming to the International Financial Reporting Standards. The investors depended on the decision usefulness of the reports. The study used the data of 432 listed firms in 11 code law nations. The paired t test identified significant differences between reported and economic earnings to find earnings management attributes and between economic and restated earnings to find earnings management cases. The research found that managers seemed to manipulate discretionary accruals to misstate earnings and reduce the decision usefulness of reporting. The data came from published financial reports and databases. The firms represented 11 nations and 9 industries that excluded banking and insurance. Almost 17% of nations and industry segments reflected earnings management attributes. About 29% of firms restated at least one annual earnings, and 84% of the restatements appeared to offset manipulation. The research results should prompt social change for small investors where regulators would redress the manipulation using stronger investor protection laws to improve the reported earnings quality and its decision usefulness.
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Waddell, Erin. "Chemometric Applications to a Complex Classification Problem: Forensic Fire Debris Analysis." Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5883.
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Fire debris analysis currently relies on visual pattern recognition of the total ion chromatograms, extracted ion profiles, and target compound chromatograms to identify the presence of an ignitable liquid according to the ASTM International E1618-10 standard method. For large data sets, this methodology can be time consuming and is a subjective method, the accuracy of which is dependent upon the skill and experience of the analyst. This research aimed to develop an automated classification method for large data sets and investigated the use of the total ion spectrum (TIS). The TIS is calculated by taking an average mass spectrum across the entire chromatographic range and has been shown to contain sufficient information content for the identification of ignitable liquids. The TIS of ignitable liquids and substrates, defined as common building materials and household furnishings, were compiled into model data sets. Cross-validation (CV) and fire debris samples, obtained from laboratory-scale and large-scale burns, were used to test the models. An automated classification method was developed using computational software, written in-house, that considers a multi-step classification scheme to detect ignitable liquid residues in fire debris samples and assign these to the classes defined in ASTM E1618-10. Classifications were made using linear discriminant analysis, quadratic discriminant analysis (QDA), and soft independent modeling of class analogy (SIMCA). Overall, the highest correct classification rates were achieved using QDA for the first step of the scheme and SIMCA for the remaining steps. In the first step of the classification scheme, correct classification rates of 95.3% and 89.2% were obtained for the CV test set and fire debris samples, respectively. Correct classifications rates of 100% were achieved for both data sets in the majority of the remaining steps which used SIMCA for classification. In this research, the first statistically valid error rates for fire debris analysis have been developed through cross-validation of large data sets. The error rates reduce the subjectivity associated with the current methods and provide a level of confidence in sample classification that does not currently exist in forensic fire debris analysis.Ph.D.
Doctorate
Chemistry
Sciences
Chemistry
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陳家麗 and Ka-lai Chan. "Some statistical aspects in forensic science." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31222237.
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Chan, Ka-lai. "Some statistical aspects in forensic science /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2148241X.
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Herrin, Amy Elizabeth. "Assessing, Modifying, and Combining Data Fields from the Virginia Office of the Chief Medical Examiner (OCME) Dataset and the Virginia Department of Forensic Science (DFS) Datasets in Order to Compare Concentrations of Selected Drugs." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd/1057.
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The Medical Examiner of Virginia (ME) dataset and the Virginia Department of Forensic Science Driving Under the Influence of Drugs (DUI) datasets were used to determine whether people have the potential to develop tolerances to diphenhydramine, cocaine, oxycodone, hydrocodone, methadone, and morphine. These datasets included the years 2000-2004 and were used to compare the concentrations of these six drugs between people who died from a drug-related cause of death (of the drug of interest) and people who were pulled over for driving under the influence. Three drug pattern groups were created to divide each of the six drug-specific datasets in order to compare concentrations between individuals with the drug alone, the drug and ethanol, or a poly pharmacy of drugs (multiple drugs). An ANOVA model was used to determine if there was an interaction effect between the source dataset (ME or DUI) and the drug pattern groups. For diphenhydramine and cocaine, an interaction was statistically significant, but for the other drugs, it was not significant. The other four drug-specific datasets showed that the DUI and ME were statistically significantly different from each other, and all of those datasets except for methadone showed that there was a statistically significant difference between at least two drug pattern groups. Showing that all of these datasets showed differences between the ME and DUI datasets did not provide sufficient evidence to suggest the development of tolerances to each of the six drugs. One exception was with methadone because there were 14 individuals that had what is defined as a "clinical 'lethal' blood concentration". These individuals provide some evidence for the possibility of developing tolerances.The main outcomes of this study include suggesting changes to make to the ME datasets and the DUI datasets with regard to the way data is kept and collected. Several problems with the fields of these datasets arose before beginning the analysis and had to be corrected. Some of the changes suggested are currently being considered at the Virginia Office of the Chief Medical Examiner as they are beginning to restructure their database.
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Skanderová, Valentýna. "Analýza rychlosti cyklistů ve věkové kategorii 4 až 10 let." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-232644.
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The diploma thesis Cyclists speed analysis at the age bracket of 4 to 10 deals with history and origin of bicycle, description and types of the contruction of bicycles for children at the age bracket mentioned above. The thesis includes the statistics of accidents involving cyclists and regulations providing for the ride on a bicycle on a carriageway. The practical part includes measuring cyclists speed when passing a measured section and the analysis of these data. The analysis of data is processed in terms of gear systems as the equipment. Complementary measuring was made in a slight rising. In the second part of the practical part is measured braking of cyclists at a particular age bracket and the evaluation of their deceleration. The conclusion includes comparison with measuring of other authors made so far.
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Daniels, Jason M. "Forensic and Anti-Forensic Techniques for OLE2-Formatted Documents." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/141.
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Common office documents provide significant opportunity for forensic and anti-forensic work. The Object Linking and Embedding 2 (OLE2) specification used primarily by Microsoft’s Office Suite contains unused or dead space regions that can be over written to hide covert channels of communication. This thesis describes a technique to detect those covert channels and also describes a different method of encoding that lowers the probability of detection.
The algorithm developed, called OleDetection, is based on the use of kurtosis and byte frequency distribution statistics to accurately identify OLE2 documents with covert channels. OleDetection is able to correctly identify 99.97 percent of documents with covert channel and only a false positive rate 0.65 percent.
The improved encoding scheme encodes the covert channel with patterns found in unmodified dead space regions. This anti-forensic technique allows the covert channel to masquerade as normal data, lowering the ability probability for any detection tool to is able to detect its presence.
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Qiao, Tong. "Statistical detection for digital image forensics." Thesis, Troyes, 2016. http://www.theses.fr/2016TROY0006/document.
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Le XXIème siècle étant le siècle du passage au tout numérique, les médias digitaux jouent un rôle de plus en plus important. Les logiciels sophistiqués de retouche d’images se sont démocratisés et permettent de diffuser facilement des images falsifiées. Ceci pose un problème sociétal puisqu’il s’agit de savoir si ce que l’on voit a été manipulé. Cette thèse s'inscrit dans le cadre de la criminalistique des images. Trois problèmes sont abordés : l'identification de l'origine d'une image, la détection d'informations cachées dans une image et la détection d'un exemple falsification : le rééchantillonnage. Ces travaux s'inscrivent dans le cadre de la théorie de la décision statistique et proposent la construction de détecteurs permettant de respecter une contrainte sur la probabilité de fausse alarme. Afin d'atteindre une performance de détection élevée, il est proposé d'exploiter les propriétés des images naturelles en modélisant les principales étapes de la chaîne d'acquisition d'un appareil photographique. La méthodologie, tout au long de ce manuscrit, consiste à étudier le détecteur optimal donné par le test du rapport de vraisemblance dans le contexte idéal où tous les paramètres du modèle sont connus. Lorsque des paramètres du modèle sont inconnus, ces derniers sont estimés afin de construire le test du rapport de vraisemblance généralisé dont les performances statistiques sont analytiquement établies. De nombreuses expérimentations sur des images simulées et réelles permettent de souligner la pertinence de l'approche proposéeThe remarkable evolution of information technologies and digital imaging technology in the past decades allow digital images to be ubiquitous. The tampering of these images has become an unavoidable reality, especially in the field of cybercrime. The credibility and trustworthiness of digital images have been eroded, resulting in important consequences in terms of political, economic, and social issues. To restore the trust to digital images, the field of digital forensics was born. Three important problems are addressed in this thesis: image origin identification, detection of hidden information in a digital image and an example of tampering image detection : the resampling. The goal is to develop a statistical decision approach as reliable as possible that allows to guarantee a prescribed false alarm probability. To this end, the approach involves designing a statistical test within the framework of hypothesis testing theory based on a parametric model that characterizes physical and statistical properties of natural images. This model is developed by studying the image processing pipeline of a digital camera. As part of this work, the difficulty of the presence of unknown parameters is addressed using statistical estimation, making the application of statistical tests straightforward in practice. Numerical experiments on simulated and real images have highlighted the relevance of the proposed approach
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Doan, Thi Ngoc Canh. "Statistical Methods for Digital Image Forensics." Thesis, Troyes, 2018. http://www.theses.fr/2018TROY0036.
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L’explosion de la technologie d’imagerie numérique s’est considérablement accrue, posant d’énormes problèmes pour la sécurité de l’information. Grâce à des outils d'édition d'images à faible coût, l'omniprésence des images falsifiées est devenue une réalité incontournable. Cette situation souligne la nécessité d'étendre les recherches actuelles dans le domaine de la criminalistique numérique afin de restaurer la confiance dans les images numériques. Deux problèmes importants sont abordés dans cette thèse: l’estimation du facteur de qualité d’une image JPEG et la détection de la falsification des images numériques. Ces travaux s’inscrivent dans le cadre de la théorie des tests d’hypothèse et proposent la construction de détecteurs permettant de respecter une contrainte sur la probabilité de fausse alarme. Afin d’atteindre une performance de détection élevée, il est proposé d’exploiter un modèle statistique des images naturelles. Ce modèle est construit à partir du processus de formation des images. Des expériences numériques sur des images simulées et réelles ont mis en évidence la pertinence de l'approche proposéeDigital imaging technology explosion has grown significantly posing tremendous security concerns to information security. Under the support of low-cost image editing tools, the ubiquity of tampered images has become an unavoidable reality. This situation highlights the need to improve and extend the current research in the field of digital forensics to restore the trust of digital images. Since each stage of the image history leaves a specific trace on the data, we propose to extract the digital fingerprint as evidence of tampering. Two important problems are addressed in this thesis: quality factor estimation for a given JPEG image and image forgery authentication. For the first problem, a likelihood ratio has been constructed relied on a spatial domain model of the variance of 8 × 8 blocks of JPEG images. In the second part of thesis, the robust forensic detectors have been designed for different types of tampering in the framework of the hypothesis testing theory based on a parametric model that characterizes statistical properties of natural images. The construction of this model is performed by studying the image processing pipeline of a digital camera. The statistical estimation of unknown parameters is employed, leading to application of these tests in practice. This approach allows the design of the most powerful test capable of warranting a prescribed false alarm probability while ensuring a high detection performance. Numerical experiments on simulated and real images have highlighted the relevance of the proposed approach
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Pasquini, Cecilia. "Statistical and deterministic approaches for multimedia forensics." Doctoral thesis, Università degli studi di Trento, 2016. https://hdl.handle.net/11572/369281.
Full textAbstract:
The increasing availability and pervasiveness of multimedia data in our society is before our very eyes.
As a result of globalization and worldwide connectivity, people from all over the planet are exchanging constantly increasing amounts of images, videos, audio recordings on a daily basis. Coupled with the easy access to user-friendly editing software, this poses a number of problems related to the reliability and trustworthiness of such content, as well as its potential malevolent use. For this reason, the research field of multimedia forensics focuses on the development of forensic tools for verifying the authenticity of multimedia data. The hypothesis of pristine status of images, videos or audio tracks is called into question and can be rejected if traces of manipulation are detected with a certain degree of confidence. In this framework, studying traces left by any operation that could have been employed to process the data, either for malicious purposes or simply to improve their content or presentation, turns out to be of interest for a comprehensive forensic analysis.
The goal of this doctoral study is to contribute to the field of multimedia forensics by exploiting intrinsic statistical and deterministic properties of multimedia data.
With this respect, much work has been devoted to the study of JPEG compression traces in digital images, resulting in the development of several innovative approaches. Indeed, some of the main related research problems have been addressed and solution based on statistical properties of digital images have been proposed. In particular, the problem of identifying traces of JPEG compressions in images that have been decompressed and saved in uncompressed formats has been extensively studied, resulting in the design of novel statistical detectors. Given the enormous practical relevance, digital images in JPEG formats have also been considered. A novel method aimed at discriminating images compressed only once and more than once has been developed, and tested on a variety of images and forensic scenarios. Being the potential presence of intelligent counterfeiters ever increasingly studied, innovative counterforensic techniques to JPEG compression based on smart reconstruction strategies are proposed.
Finally, we explore the possibility of defining and exploiting deterministic properties related to a certain processing operation in the forensic analysis. With this respect, we present a first approach targeted to the detection in one-dimensional data of a common data smoothing operation, the median filter. A peculiarity of this method is the ability of providing a deterministic response on the presence of median filtering traces in the data under investigation.
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Pasquini, Cecilia. "Statistical and deterministic approaches for multimedia forensics." Doctoral thesis, University of Trento, 2016. http://eprints-phd.biblio.unitn.it/1771/1/Pasquini_PhD-Thesis.pdf.
Full textAbstract:
The increasing availability and pervasiveness of multimedia data in our society is before our very eyes.
As a result of globalization and worldwide connectivity, people from all over the planet are exchanging constantly increasing amounts of images, videos, audio recordings on a daily basis. Coupled with the easy access to user-friendly editing software, this poses a number of problems related to the reliability and trustworthiness of such content, as well as its potential malevolent use. For this reason, the research field of multimedia forensics focuses on the development of forensic tools for verifying the authenticity of multimedia data. The hypothesis of pristine status of images, videos or audio tracks is called into question and can be rejected if traces of manipulation are detected with a certain degree of confidence. In this framework, studying traces left by any operation that could have been employed to process the data, either for malicious purposes or simply to improve their content or presentation, turns out to be of interest for a comprehensive forensic analysis.
The goal of this doctoral study is to contribute to the field of multimedia forensics by exploiting intrinsic statistical and deterministic properties of multimedia data.
With this respect, much work has been devoted to the study of JPEG compression traces in digital images, resulting in the development of several innovative approaches. Indeed, some of the main related research problems have been addressed and solution based on statistical properties of digital images have been proposed. In particular, the problem of identifying traces of JPEG compressions in images that have been decompressed and saved in uncompressed formats has been extensively studied, resulting in the design of novel statistical detectors. Given the enormous practical relevance, digital images in JPEG formats have also been considered. A novel method aimed at discriminating images compressed only once and more than once has been developed, and tested on a variety of images and forensic scenarios. Being the potential presence of intelligent counterfeiters ever increasingly studied, innovative counterforensic techniques to JPEG compression based on smart reconstruction strategies are proposed.
Finally, we explore the possibility of defining and exploiting deterministic properties related to a certain processing operation in the forensic analysis. With this respect, we present a first approach targeted to the detection in one-dimensional data of a common data smoothing operation, the median filter. A peculiarity of this method is the ability of providing a deterministic response on the presence of median filtering traces in the data under investigation.
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White, Katie Margaret. "Statistical analysis of visible absorption spectra and mass spectra obtained from dyed textile fibers." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4646.
Full textAbstract:
The National Academy of Sciences recently published a report which calls for improvements to the field of forensic science. Their report criticized many forensic disciplines for failure to establish rigorously-tested methods of comparison, and encouraged more research in these areas to establish limitations and assess error rates. This study applies chemometric and statistical methods to current and developing analytical techniques in fiber analysis. In addition to analysis of commercially available dyed textile fibers, two pairs of dyes are selected for custom fabric dyeing based on the similarities of their absorbance spectra and dye molecular structures. Visible absorption spectra for all fiber samples are collected using microspectrophotometry (MSP) and mass spectra are collected using electrospray ionization (ESI) mass spectrometry. Statistical calculations are performed using commercial software packages and software written in-house. Levels of Type I and Type II error are examined for fiber discrimination based on hypothesis testing of visible absorbance spectra profiles using a nonparametric permutation method. This work also explores evaluation of known and questioned fiber populations based on an assessment of statistical p-value distributions from questioned-known fiber comparisons with those of known fiber self-comparisons. Results from the hypothesis testing are compared with principal components analysis (PCA) and discriminant analysis (DA) of visible absorption spectra, as well as PCA and DA of ESI mass spectra. The sensitivity of a statistical approach will also be discussed in terms of how instrumental parameters and sampling methods may influence error rates.ID: 030423335; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2010.; Includes bibliographical references (p. 112-119).
M.S.
Masters
Department of Chemistry
Sciences
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Mahfoudi, Gaël. "Authentication of Digital Images and Videos." Thesis, Troyes, 2021. http://www.theses.fr/2021TROY0043.
Full textAbstract:
Les médias digitaux font partie de notre vie de tous les jours. Après des années de photojournalisme, nous nous sommes habitués à considérer ces médias comme des témoignages objectifs de la réalité. Cependant les logiciels de retouches d'images et de vidéos deviennent de plus en plus puissants et de plus en plus simples à utiliser, ce qui permet aux contrefacteurs de produire des images falsifiées d'une grande qualité. L'authenticité de ces médias ne peut donc plus être prise pour acquise. Récemment, de nouvelles régulations visant à lutter contre le blanchiment d'argent ont vu le jour. Ces régulations imposent notamment aux institutions financières de vérifier l'identité de leurs clients. Cette vérification est souvent effectuée de manière distantielle au travers d'un Système de Vérification d'Identité à Distance (SVID). Les médias digitaux sont centraux dans de tels systèmes, il est donc essentiel de pouvoir vérifier leurs authenticités. Cette thèse se concentre sur l'authentification des images et vidéos au sein d'un SVID. Suite à la définition formelle d'un tel système, les attaques probables à l'encontre de ceux-ci ont été identifiées. Nous nous sommes efforcés de comprendre les enjeux de ces différentes menaces afin de proposer des solutions adaptées. Nos approches sont basées sur des méthodes de traitement de l'image ou sur des modèles paramétriques. Nous avons aussi proposé de nouvelles bases de données afin d'encourager la recherche sur certains défis spécifiques encore peu étudiésDigital media are parts of our day-to-day lives. With years of photojournalism, we have been used to consider them as an objective testimony of the truth. But images and video retouching software are becoming increasingly more powerful and easy to use and allow counterfeiters to produce highly realistic image forgery. Consequently, digital media authenticity should not be taken for granted any more. Recent Anti-Money Laundering (AML) relegation introduced the notion of Know Your Customer (KYC) which enforced financial institutions to verify their customer identity. Many institutions prefer to perform this verification remotely relying on a Remote Identity Verification (RIV) system. Such a system relies heavily on both digital images and videos. The authentication of those media is then essential. This thesis focuses on the authentication of images and videos in the context of a RIV system. After formally defining a RIV system, we studied the various attacks that a counterfeiter may perform against it. We attempt to understand the challenges of each of those threats to propose relevant solutions. Our approaches are based on both image processing methods and statistical tests. We also proposed new datasets to encourage research on challenges that are not yet well studied
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Choy, Yan-tsun. "Statistical evaluation of mixed DNA stains." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42664287.
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Thai, Thanh Hai. "Statistical modeling and detection for digital image forensics." Thesis, Troyes, 2014. http://www.theses.fr/2014TROY0024/document.
Full textAbstract:
Le XXIème siècle étant le siècle du passage au tout numérique, les médias digitaux jouent maintenant un rôle de plus en plus important dans la vie de tous les jours. De la même manière, les logiciels sophistiqués de retouche d’images se sont démocratisés et permettent aujourd’hui de diffuser facilement des images falsifiées. Ceci pose un problème sociétal puisqu’il s’agit de savoir si ce que l’on voit a été manipulé. Cette thèse s'inscrit dans le cadre de la criminalistique des images numériques. Deux problèmes importants sont abordés : l'identification de l'origine d'une image et la détection d'informations cachées dans une image. Ces travaux s'inscrivent dans le cadre de la théorie de la décision statistique et proposent la construction de détecteurs permettant de respecter une contrainte sur la probabilité de fausse alarme. Afin d'atteindre une performance de détection élevée, il est proposé d'exploiter les propriétés des images naturelles en modélisant les principales étapes de la chaîne d'acquisition d'un appareil photographique. La méthodologie, tout au long de ce manuscrit, consiste à étudier le détecteur optimal donné par le test du rapport de vraisemblance dans le contexte idéal où tous les paramètres du modèle sont connus. Lorsque des paramètres du modèle sont inconnus, ces derniers sont estimés afin de construire le test du rapport de vraisemblance généralisé dont les performances statistiques sont analytiquement établies. De nombreuses expérimentations sur des images simulées et réelles permettent de souligner la pertinence de l'approche proposéeThe twenty-first century witnesses the digital revolution that allows digital media to become ubiquitous. They play a more and more important role in our everyday life. Similarly, sophisticated image editing software has been more accessible, resulting in the fact that falsified images are appearing with a growing frequency and sophistication. The credibility and trustworthiness of digital images have been eroded. To restore the trust to digital images, the field of digital image forensics was born. This thesis is part of the field of digital image forensics. Two important problems are addressed: image origin identification and hidden data detection. These problems are cast into the framework of hypothesis testing theory. The approach proposes to design a statistical test that allows us to guarantee a prescribed false alarm probability. In order to achieve a high detection performance, it is proposed to exploit statistical properties of natural images by modeling the main steps of image processing pipeline of a digital camera. The methodology throughout this manuscript consists of studying an optimal test given by the Likelihood Ratio Test in the ideal context where all model parameters are known in advance. When the model parameters are unknown, a method is proposed for parameter estimation in order to design a Generalized Likelihood Ratio Test whose statistical performances are analytically established. Numerical experiments on simulated and real images highlight the relevance of the proposed approach
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Alkahtani, Abdulaziz M. A. l.-Musa. "Free hand simulation of Arabic signatures : Forensic examination and statistical observations." Thesis, Staffordshire University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522387.
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Steele, C. D. "Statistical issues surrounding the analysis of forensic low-template DNA samples." Thesis, University College London (University of London), 2016. http://discovery.ucl.ac.uk/1513271/.
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Increased sensitivity of forensic DNA profiling over the last decade has led to increased stochasticity in the resulting profiles, causing difficulties for interpretation that were acknowledged by the Caddy Report [Caddy et al., 2008]. These difficulties were largely overcome with the adoption of statistical models allowing for dropout and dropin, but interpretation issues remain, several of which are tackled in this thesis. One such issue concerns the choice of allele frequency databases when the ethnic background of the true source of the crime scene DNA is unknown. I propose a heuristic for choosing a single database and adjusting the likelihood ratio calculations to allow for the possibility that a different database may be more appropriate. Another issue in general, and specifically for the database choice heuristic, is the choice of an appropriate value for the population genetics parameter FST to account for distant relatedness between the alleged contributor and an alternative source of the DNA. I present empirical estimates of FST in worldwide populations, relative to the continental-scale reference databases that are used for UK forensic DNA profiles. In the last few years many software packages for the evaluation of low-template DNA samples have emerged, including likeLTD originally developed by my supervisor Prof Balding but greatly improved and reprogrammed by myself as part of my PhD work. There remains little consensus on how to validate these software packages. I present a method of validation based on the use of multiple-replicate crime stain profiles. It relies on the intuition that sufficient replicates of even very noisy DNA profiling runs eventually generate the same information as a single high-quality replicate. I show that likeLTD performs well when assessed by this approach. Finally, I present a new statistical model that extends likeLTD to incorporate the peak height information in a crime scene profile. I show results based on simulation and laboratory trials verifying the good performance of the new model in improved discrimination between true and false hypotheses.
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Choy, Yan-tsun, and 蔡恩浚. "Statistical evaluation of mixed DNA stains." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42664287.
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Schober, Cassandra C. (Cassandra Carolyn). "The Evolution, Applications, and Statistical Interpretations of DNA Typing in Forensic Science." Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc332776/.
Full textAbstract:
This thesis examines the evolution, applications, and statistical interpretations of DNA typing as a tool in the field of forensic science as well as in our criminal justice system. The most controversial aspect of DNA typing involves the determination of how likely it is that two people share the same DNA profile. This involves the use of population genetics and databases of allelic frequencies as well as some assumptions about population structuring.
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Hu, Yueqing, and 胡躍清. "Some topics in the statistical analysis of forensic DNA and genetic family data." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38831491.
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Hu, Yueqing. "Some topics in the statistical analysis of forensic DNA and genetic family data." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38831491.
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McIntee, Erin. "FORENSIC ANALYSIS OF AUTOMOBILE PAINTS BY ATOMIC AND MOLECULAR SPECTROSCOPIC METHODS AND STATISTICAL DATA ANALYSES." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3131.
Full textAbstract:
The analysis of 110 automotive paint samples was conducted for the research presented here. Laser-induced breakdown spectroscopy (LIBS) was the central instrument utilized for analysis although scanning electron microscopy / energy dispersive x-ray spectroscopy (SEM/EDS) and Fourier transform infrared spectroscopy – attenuated total reflection (FTIR-ATR) analyses were also performed. Two separate methods of LIBS analysis of samples were used: a cross sectional analysis and a drill down analysis. SEM/EDS analysis focused on the cross section while FTIR-ATR analysis concentrated on the clearcoat layer. Several different data/statistical analyses were evaluated including principal components analysis (PCA), two tailed t-tests based on several different metrics (Hit Quality Index (HQI), Pearson's correlation and Sorenson index), multivariate analysis of variance and receiver operating characteristic (ROC) curves. Full spectrum data analysis from LIBS spectra resulted in 99.7% discrimination between different sample comparisons and 12% between same sample comparisons based on HQI and t-tests. Peak analysis of LIBS spectra resulted in 87.5% discrimination between different sample comparisons and 5% between same sample comparisons based on MANOVA. When combining the results of the FTIR-ATR and SEM/EDS analyses, 88% of the samples could be discriminated.M.S.
Department of Chemistry
Sciences
Forensic Science MS
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Riess, Christian [Verfasser], and Joachim [Akademischer Betreuer] Hornegger. "Physics-based and Statistical Features for Image Forensics / Christian Riess. Betreuer: Joachim Hornegger." Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2013. http://d-nb.info/1034425455/34.
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Krätzer, Christian [Verfasser], and Jana [Akademischer Betreuer] Dittmann. "Statistical pattern recognition for audio-forensics : empirical investigations on the application scenarios audio steganalysis and microphone forensics / Christian Krätzer. Betreuer: Jana Dittmann." Magdeburg : Universitätsbibliothek, 2013. http://d-nb.info/1054420408/34.
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Yang, Chi-ting, and 楊志婷. "Pharmacokinetics of alcohol using breath measures and some statisticalaspects in forensic science." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46506159.
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Carvalho, Lígia Alexandra da Silva. "A valoração do testemunho da criança vítima de abuso sexual intra-familiar no contexto da avaliação forense." Master's thesis, Faculdade de Medicina da Universidade do Porto, 2007. http://hdl.handle.net/10216/7544.
Full textAbstract:
Mestrado em Ciências ForensesMaster Degree Course in Forensic Sciences
Em situações de abuso sexual de crianças, designadamente no abuso sexual intra-familiar, o testemunho dos menores é um dos meios de prova fundamental, não raras vezes, o único. Impõe-se, assim, aprofundar o conhecimento científico sobre a forma como o seu testemunho é ou não valorizado no âmbito de processos judiciários, bem como sobre as suas implicações para a condução do processo judicial e para a prevenção da, vitimação secundária destas crianças. Este estudo teve como objectivo geral perceber a relevância atribuída ao relato de crianças vítimas de abuso sexual no contexto familiar, no âmbito de processos judiciais, e as implicações eventuais desse testemunho e da valoração que dele é feita. Para tal, analisaram-se os resultados das perícias de sexologia forense e os da avaliação psicológica forense (avaliação da veracidade do testemunho, capacidade de testemunhar e impacto do abuso) das mesmas crianças. Trata-se de um estudo de análise documental, de carácter retrospectivo, recorrendo a dados respeitantes ao espaço temporal compreendido entre 2002 e 2005. Foram analisados os processos relativos a todas as crianças entre os 3 e os 12 anos (n=134) que, tendo sido alegadamente vítimas de abuso sexual no contexto familiar, foram observadas no Serviço de Clínica Médica da Delegação do Porto do Instituto Nacional de Medicina Legal e, posteriormente, realizaram avaliação psicológica no Gabinete de Estudo e Atendimento a Vítimas da Faculdade de Psicologia e Ciências da Educação da Universidade do Porto (n=40). Dos resultados obtidos, salientam-se os que dizem respeito às conclusões dos dois tipos de relatórios periciais, à relação entre os dois tipos de exame pericial, principais diferenças e complementaridades entre eles, bem como à valoração dos testemunhos que foi feita em cada um dos contextos, em particular, à significativa percentagem de crianças que, tendo produzido narrativas sobre o abuso no decurso da avaliação psicológica forense, apresentaram indicadores fortes de veracidade do testemunho, além de sintomatologia e outros indicadores reveladores de impacto traumático.
In child sexual abuse cases, specifically in cases of intra-familial sexual abuse, the testimony provided by minors is one of the most important means of proof, often, the only proof. It is crucial, therefore, to deepen the scientific knowledge regarding the way in which the testimony is or is not valued in the context of the judicial processes and its implications to the evolution of the process and decision making process. This study has as main goal to understand the relevance attributed to testimony provided by children victims of intrafamilial sexual abuse, and the eventual implications of that testimony. To achieve this purpose, we analysed the results of forensic sexology expertises and the reports on the forensic psychological evaluation expertises of the same cases of child intra-familial sexual abuse. We analysed the way in which the testimony was valued, and also the procedures relating to the forwarding of clinical cases for psychological evaluation, namely the criteria underlying the decision. The totality of the forensic sexology reports of victims of intra-familial child sexual abuse, between the ages of 3 and 12, that were examined at the Medical Clinic Department of the Institute of Legal Medicine of Porto, between 2002 and 2005 (n=134) were analyzed at the first moment of the study. At a second moment, we analyzed, in an in-depth study and analysis, those that were referred to the Centre for Research an Counselling of Victims and Offenders of the Faculty of Psychology and Educational Sciences of the University of Porto for psychological assessment of the credibility of the testimony and of the traumatic impact of the abuse (n=40). Amongst the results obtained, we highlight those concerning the conclusions of the two kinds of expertise reports, major differences and complementarities on there results, and the implications of the child testimony to the judicial decision making. Particularly emphasized are the results concerning the value attributed to the child testimony on both contexts, mainly those concerning the significant percentage of children that, having produced narratives about the sexual abuse in the context of the forensic psychological evaluation, have presented strong indicators of the testimony veracity, over and above symptoms and other revealing indicators of the traumatic impact of the abusive situations.
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Carvalho, Lígia Alexandra da Silva. "A valoração do testemunho da criança vítima de abuso sexual intra-familiar no contexto da avaliação forense." Dissertação, Faculdade de Medicina da Universidade do Porto, 2007. http://hdl.handle.net/10216/7544.
Full textAbstract:
Mestrado em Ciências ForensesMaster Degree Course in Forensic Sciences
Em situações de abuso sexual de crianças, designadamente no abuso sexual intra-familiar, o testemunho dos menores é um dos meios de prova fundamental, não raras vezes, o único. Impõe-se, assim, aprofundar o conhecimento científico sobre a forma como o seu testemunho é ou não valorizado no âmbito de processos judiciários, bem como sobre as suas implicações para a condução do processo judicial e para a prevenção da, vitimação secundária destas crianças. Este estudo teve como objectivo geral perceber a relevância atribuída ao relato de crianças vítimas de abuso sexual no contexto familiar, no âmbito de processos judiciais, e as implicações eventuais desse testemunho e da valoração que dele é feita. Para tal, analisaram-se os resultados das perícias de sexologia forense e os da avaliação psicológica forense (avaliação da veracidade do testemunho, capacidade de testemunhar e impacto do abuso) das mesmas crianças. Trata-se de um estudo de análise documental, de carácter retrospectivo, recorrendo a dados respeitantes ao espaço temporal compreendido entre 2002 e 2005. Foram analisados os processos relativos a todas as crianças entre os 3 e os 12 anos (n=134) que, tendo sido alegadamente vítimas de abuso sexual no contexto familiar, foram observadas no Serviço de Clínica Médica da Delegação do Porto do Instituto Nacional de Medicina Legal e, posteriormente, realizaram avaliação psicológica no Gabinete de Estudo e Atendimento a Vítimas da Faculdade de Psicologia e Ciências da Educação da Universidade do Porto (n=40). Dos resultados obtidos, salientam-se os que dizem respeito às conclusões dos dois tipos de relatórios periciais, à relação entre os dois tipos de exame pericial, principais diferenças e complementaridades entre eles, bem como à valoração dos testemunhos que foi feita em cada um dos contextos, em particular, à significativa percentagem de crianças que, tendo produzido narrativas sobre o abuso no decurso da avaliação psicológica forense, apresentaram indicadores fortes de veracidade do testemunho, além de sintomatologia e outros indicadores reveladores de impacto traumático.
In child sexual abuse cases, specifically in cases of intra-familial sexual abuse, the testimony provided by minors is one of the most important means of proof, often, the only proof. It is crucial, therefore, to deepen the scientific knowledge regarding the way in which the testimony is or is not valued in the context of the judicial processes and its implications to the evolution of the process and decision making process. This study has as main goal to understand the relevance attributed to testimony provided by children victims of intrafamilial sexual abuse, and the eventual implications of that testimony. To achieve this purpose, we analysed the results of forensic sexology expertises and the reports on the forensic psychological evaluation expertises of the same cases of child intra-familial sexual abuse. We analysed the way in which the testimony was valued, and also the procedures relating to the forwarding of clinical cases for psychological evaluation, namely the criteria underlying the decision. The totality of the forensic sexology reports of victims of intra-familial child sexual abuse, between the ages of 3 and 12, that were examined at the Medical Clinic Department of the Institute of Legal Medicine of Porto, between 2002 and 2005 (n=134) were analyzed at the first moment of the study. At a second moment, we analyzed, in an in-depth study and analysis, those that were referred to the Centre for Research an Counselling of Victims and Offenders of the Faculty of Psychology and Educational Sciences of the University of Porto for psychological assessment of the credibility of the testimony and of the traumatic impact of the abuse (n=40). Amongst the results obtained, we highlight those concerning the conclusions of the two kinds of expertise reports, major differences and complementarities on there results, and the implications of the child testimony to the judicial decision making. Particularly emphasized are the results concerning the value attributed to the child testimony on both contexts, mainly those concerning the significant percentage of children that, having produced narratives about the sexual abuse in the context of the forensic psychological evaluation, have presented strong indicators of the testimony veracity, over and above symptoms and other revealing indicators of the traumatic impact of the abusive situations.
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Fletcher, Emily. "Weapons of choice: A statistical comparison between different weapons and resulting injuries, opportunist weapon selection and forensic awareness." Thesis, Fletcher, Emily (2022) Weapons of choice: A statistical comparison between different weapons and resulting injuries, opportunist weapon selection and forensic awareness. Masters by Research thesis, Murdoch University, 2022. https://researchrepository.murdoch.edu.au/id/eprint/65761/.
Full textAbstract:
Homicide is a known term for the unlawful killing of another person, which can be classified into three subcategories; Mass, Spree and Serial Homicide. Serial Homicide is the chosen focus for this literature review, and the following study to come. A Serial Killer can be described as an individual who takes the life of at least two people, each within a separate event to one another. Specifically, the weapons of choice by these Serial Killers is the main concentration of the study, and how different external variables can change their choosing, as well as the resulting injuries the victim sustains from these weapons. Variables such as victimology of both the offender and the victim, the level of forensic awareness known by the offender and whether the weapon was an opportunist circumstance or not are detailed to identify the changes in weapon choice and injury infliction as these variables change between offenders. The literature review aims to display what information is already present in the field, with the relation of all factors in weapon choice and injuries and if there is already a link between any. The review ultimately defined that there is a big gap in research about weapons of opportunity and the factors which can cause an offender to use an unplanned weapon to cause injury, as well as how the injuries differ between opportunity and planned weapon selection. The review also revealed there is an obvious gap in knowledge linking all of these mentioned variables, to the way the offender inflicts injuries on the victim. The proposed study will hopefully fill these research gaps by comparing victimology, opportunity and planned weapons, forensic awareness knowledge and clean-up to the type of weapon used and the resulting injuries, the hope is to link them all together, as well as identify individual characteristics of each which can change offenders weapon selection.
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Khodai-Joopari, Mehrdad Information Technology & Electrical Engineering Australian Defence Force Academy UNSW. "Forensic speaker analysis and identification by computer : a Bayesian approach anchored in the cepstral domain." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Information Technology and Electrical Engineering, 2007. http://handle.unsw.edu.au/1959.4/38715.
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This thesis advances understanding of the forensic value of the automatic speech parameters by addressing the following question: what is the potentiality of the speech cepstrum as a forensic-acoustic parameter? Despite many advances in automatic speech and speaker recognition, robust and unconstrained progress in technical forensic speaker identification has been partly impeded by our incomplete understanding of the interaction and relation between forensic phonetics and the techniques employed in state-of-the-art automatic speech and speaker recognition. The posed question underlies the recurrent and longstanding issue of acoustic parameterisation in the area of forensic phonetics, where 1) speaker identification often must be carried out under less than optimal conditions, and 2) views differ on the usefulness and trustworthiness of the formant frequency measurements. To this end, a new formulation for the forensic evaluation of speech data was derived which is effectively a spectral likelihood ratio with enhanced sensitivity to the local peaks of the formant structure of the speech spectrum of vowel sounds, while retaining the characteristics of the Bayesian framework. This new hybrid formula was used together with a novel approach, which is founded on a statistically-based matched-pairs technique to account for various levels of variation inherent in speech recordings, thereby providing a spectrally meaningful measure of variations between two speech spectra and hence the true worth of speech samples as forensic evidence. The experimental results are obtained based on a forensically-realistic database of a relatively large population of 297 native speakers of Japanese. In sum, the research conducted in this thesis is a major step forward in advancing the forensic-phonetic field which broadens the objective basis of the forensic speaker identification. Beyond advancing knowledge in the field, the semi data-independent nature of the new formula ultimately has great implications in technical forensic speaker identification. It also provides us with a valuable biometric tool with both academic and commercial potential in crime investigation in a field which is already suffering from the lack of adequate data.
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Polvi, Natalie Heather. "The prediction of violence in pre-trial forensic patients, the relative efficacy of statistical versus clinical predictions of dangerousness." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0024/NQ51911.pdf.
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Bunch, Nathan. "Oral Fluid Method Validation for Bowling Green State University." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1586969951770212.
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Moody, Sarah Jean. "Automated Data Type Identification And Localization Using Statistical Analysis Data Identification." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/9.
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This research presents a new and unique technique called SÁDI, statistical analysis data identification, for identifying the type of data on a digital device and its storage format based on data type, specifically the values of the bytes representing the data being examined. This research incorporates the automation required for specialized data identification tools to be useful and applicable in real-world applications. The SÁDI technique utilizes the byte values of the data stored on a digital storage device in such a way that the accuracy of the technique does not rely solely on the potentially misleading metadata information but rather on the values of the data itself. SÁDI provides the capability to identify what digitally stored data actually represents. The identification of the relevancy of data is often dependent upon the identification of the type of data being examined. Typical file type identification is based upon file extensions or magic keys. These typical techniques fail in many typical forensic analysis scenarios, such as needing to deal with embedded data, as in the case of Microsoft Word files or file fragments. These typical techniques for file identification can also be easily circumvented, and individuals with nefarious purposes often do so.
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Yang, Chi-ting, and 楊志停. "A study of alcohol pharmacokinetic of local Chinese in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B26647564.
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Barette, Tammy S. "A Bayesian approach to the estimation of adult skeletal age assessing the facility of multifactorial and three-dimensional methods to improve accuracy of age estimation /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1180543680.
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Vike, Kristine. "Oil spill forensics : Identification of sources for oil spills by using data generated by GC-MS and ICP-MS combined with multivariate statistics and the COSIWeb database." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24920.
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This work has been a preliminary study, aimed at investigating whether or not trace metal Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) analysis could be a viable tool in the oil spill investigation toolbox, after having been abandoned over 20 years ago. The sample material was two previous oil spills, Full City and Server, and various heavily weathered oil samples gathered from islands off the Trøndelag coast. The islands were Kya, Sula, Vesterkalven, Storkalven, Kunna, and the bay Kjervågsundet on the larger island Frøya. The samples were prepared in a laboratory and analysed by Gas Chromatography-Flame Ionization Detector (GC-FID), Gas Chromatography-Mass Spectrometry-Selective Ion Monitoring (GC-MS-SIM) and ICP-MS. Through integration of key elements in the oil, also known as biomarkers, by an online database called COSIWeb, the weathered samples were classified as “crude oil”, “non-NS (North Sea) crude oil”, “bunker oil”, “unknown” and “not oil”. This classification was used as a guide to assess the viability of the trace metal analysis done by ICP-MS. The database also provided correlation calculations and five of the weathered bunker oil samples were linked to oils outside the database by “probable match”. Principal Component Analysis (PCA) was used to investigate the ability each dataset had to classify the different weathered oil types and oil spill samples Full City and Server. Subsequently, Partial Least Squares-Regression (PLS-R) was used to investigate the stability and robustness of both datasets from GC-MS-SIM and ICP-MS together, before Partial Least Squares-Discriminant Analysis (PLS-DA) was applied to investigate if the clusters seen in PCA were significant. By PLS-DA two subgroups of crude oils were identified, possibly related to terrestrial or marine source material in the oil. Of the 46 weathered samples found on various islands, 14 samples were classified as non-NS crude oils, 9 samples were classified as crude oils, 11 samples were classified as bunker oils, 7 samples were classified as unknown oil samples, and 5 samples were classified as not oil. The last group could be oil-like material such as plastic, rubber, coal or other organic material. The most important trace metal ratios identified in this study were ratios which have been previously been singled out as important in oil analysis. These were Ni/V, V/S, U/Pb and Mn/Fe. Other ratios were helpful as well, but these were the most influential ones. The Ni/V ratio was able to separate Full City samples from Server samples without any outliers or fuzzy classification.
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Lima, Fernando Fernandes de. "Determinantes do desempenho em laudos de criminalística no Departamento de Polícia Federal: uma abordagem multinível." reponame:Repositório Institucional do FGV, 2012. http://hdl.handle.net/10438/9812.
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O Departamento de Polícia Federal, em particular sua Diretoria Técnico-Científica, tem buscado adotar ferramentas modernas de administração para a melhoria da eficiência de seus processos, dentre as quais o uso de indicadores de desempenho. No caso específico da Criminalística, cuja gestão está a cargo daquela diretoria, ainda faltam estudos básicos que permitam conhecer os processos que lá se desencadeiam, para então serem adotados indicadores confiáveis e de fácil compreensão. Nessa direção, um dos primeiros passos é conhecer o tempo que cada processo demora, dadas suas características. Neste trabalho são utilizadas técnicas estatísticas para extrair da base de dados existente na Diretoria Técnico-Científica esta informação. Com a obtenção dessas informações é possível propor indicadores de desempenho adequados e de fácil acompanhamento, permitindo então aos gestores verificar o resultado efetivo de ações e decisões gerenciais.
The Brazilian Federal Police Department, through its Technical-Scientific Board, has been using modern administration tools in order to increase its processes efficiency, including performance indicators. The Criminalistics area, whose management is in charge of that board, still misses basic studies which allow the knowledge of its processes, for only then adopt reliable and easy performance indicators. In this direction, one important step is to have a realistic approach of the time that each process consumes, given its characteristics. In this work statistical techniques are used to extract this information from the databases available. With this information in hand, it is possible to propose adequate and easy to adopt performance indicators, which will allow the managers to check the result of managerial actions and decisions.
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Lê, Thi Ai Nhàn. "Statistical Modeling for Detection of Digital Image Forgery." Thesis, Troyes, 2021. http://www.theses.fr/2021TROY0046.
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À l’ère du numérique, la crédibilité du contenu des images est une préoccupation majeure en raison de la popularité des outils d’édition faciles à utiliser et peu coûteux. Les images falsifiées peuvent être utilisées pour manipuler l’opinion publique lors des élections, commettre des fraudes et discréditer ou faire chanter des personnes. Face à cette situation préoccupante, nous développons dans cette thèse trois techniques efficaces basées sur (i) les traces de dématriçage (ii) les traces de compression JPEG, et (iii) les traces de rééchantillonnage pour détecter les images falsifiées et localiser les différents types de falsification. Bien que ces techniques soient différentes, elles fonctionnent sous l’hypothèse commune que les manipulations peuvent altérer certaines propriétés statistiques sous-jacentes des images naturelles. Un processus de détection en deux étapes a été adopté pour chaque technique de détection : (i) analyser et modéliser les caractéristiques statistiques des images authentiques et falsifiées, puis (ii) concevoir un détecteur statistique pour différencier les images falsifiées des images authentiques en estimant les changements dans leurs modèles. Diverses expérimentations numériques sur plusieurs ensembles de données de référence bien connus mettent en évidence la qualité des performances et la robustesse des techniques de détection proposéesIn today’s digital age, the trustworthiness of image content is of great concern due to the dissemination of easy-to-use and low-cost image editing tools. Forged images can be used to manipulate public opinion during elections, commit fraud, discredit or blackmail people. Faced with such a serious situation, we develop in this doctoral project three versatile techniques based on (i) demosaicing traces (ii) JPEG compression traces, and (iii) resampling traces for detecting forged digital images and localizing various types of tampering therein. Although these techniques are different, they work under the common assumption that manipulations may alter some underlying statistical properties of natural images. A two-steps detection process has been adopted for every detection technique: (i) analyze and model statistical features of both the authentic and forged images associated with specific in-camera and/or post-camera traces, then (ii) design a statistical detector to differentiate between the authentic and forged images by estimating statistical changes in their models. Various numerical experiments on several well-known benchmark datasets highlight the performances and robustness of the proposed detection techniques
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Халимонов, В. В., and Д. В. Левченко. "Медико-статистическое исследование завершенных самоубийств среди взрослого населения по полу, возрастным категориям, меступроисшесствия и способам совершения в Харькове с 2012 по 2016 год." Thesis, Сумский государственный университет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/55003.
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Актуальность. Самоубийство является актуальной проблемой XXI века. Объект судебно-медицинского исследования – насильственная смерть и в том числе самоубийства. Поэтому эта проблема важна для судебной медицины.Цель: анализ случаев завершенных самоубийств среди взрослого населения по полу, возрасту, способу совершения самоубийства.