The interpretation of elemental composition measurements from forensic glass evidence III

In this paper we introduce a permutation testing approach to the interpretation of evidence which consists of elemental composition measurements, with glass evidence as an example. This work extends previous work of Curran et al. [J.M. Curran, C.M. Triggs, J.R. Almirall, J.S. Buckleton and K.A.J. Walsh, The interpretation of elemental composition measurements from forensic glass evidence, Science and Justice 37 (1997) 241–244.] and shows how we may remove some of the constraints that limited the applicability of the previous results. We provide the reader with tools for evidence pre-screening that may aid in the direction of further analyses of the data, rather than for the presentation of evidence interpretation in a court case.     

A general approach to Bayesian networks for the interpretation of evidence

Bayesian networks (BNs) are mathematically and statistically rigorous techniques for handling uncertainty. The field of forensic science has recently attributed increased attention to the many advantages of this graphical method for assisting the evaluation of scientific evidence. However, the majority of contributions that relate to this topic restrict themselves to the presentation of already "constructed" BNs, and often, only a few explanations are given as to how one obtains a specific BN structure for a given problem. Based on several examples, the present paper will therefore attempt to explain in more detail some guiding considerations that might be helpful for the elicitation of appropriate structures for BNs.     

Combining evidence in complex cases - a practical approach to interdisciplinary casework

Activity level evaluations, although still a major challenge for many disciplines, bring a wealth of possibilities for a more formal approach to the evaluation of interdisciplinary forensic evidence. This paper proposes a practical methodology for combining evidence from different disciplines within the likelihood ratio framework. Evidence schemes introduced in this paper make the process of combining evidence more insightful and intuitive thereby assisting experts in their interdisciplinairy evaluation and in explaining this process to the courts.When confronted with two opposing scenarios and multiple types of evidence, the likelihood ratio approach allows experts to combine this evidence in a probabilistic manner. Parts of the prosecution and defence scenarios for which forensic science is expected to be informative are identified. For these so called core elements, activity level propositions are formulated. Afterwards evidence schemes are introduced to assist the expert in combining the evidence in a logical manner. Two types of evidence relations are identified: serial and parallel evidence. Practical guidelines are given on how to deal with both types of evidence relations when combining the evidence.     

A practical approach to determining training-solvable problems

Training is a necessity to progressive companies, but how do you decide which problems would benefit from it? The authors' model, based on current literature and consulting experience with a large organization, stresses the importance of using existing data for a more exact and cost-effective diagnosis.     

The unregistered design right: interpretation and practical application of the must-match exemption

This Court of Appeal case interprets and applies the importantconcepts in unregistered design right law of (a) the meaningof a design, (b) originality, (c) commonplace, (d) the must-fitand must-match exceptions, (e) the exclusion of surface decoration,and (f) the duration of unregistered design right: it is howeverthe interpretation and the practical application of the must-matchexemption which makes this the most important decision on unregistereddesign right so far.     

玻璃破碎的物证分析研究

玻璃碎片及形态是案发现场常见的物证形式,开展对玻璃的物证分析研究,能够确定玻璃的来源与种类,推断玻璃破碎原因等,为案件的取证、重建和侦破提供线索和证据。简要介绍了常见玻璃的种类,分析了玻璃破碎的根本原因,总结了低速冲击和高速冲击下玻璃破碎的形态特征,还从玻璃碎片收集和检验两个方面探讨了玻璃实体物证的分析。     

Expert evidence: a practical guide

Legal context: expert witnesses now take part in many IP disputesand both experts and practitioners need to know the rules anddecisions affecting them. Key Points: we consider admissability of expert evidence, howto find an expert, appointment, how to change an expert, theexpert's duties, conflicts and the dangers of using an expert.It stresses the importance of finding an expert who knows thefield, will stick to it and communicates well. It is key notoversell or tempt the expert to oversell the evidence. Practitionersshould stay within the procedural rules, as mistakes can affectthe value of otherwise sound evidence. Practical significance: expert evidence is often decisive. Gettingit wrong can present a significant problem. English judges arenot slow to criticise any failure to meet the very high standardsthey expect of expert witnesses.     

A textile fibre survey as an aid to the interpretation of fibre evidence in the Sydney region.

Frequency figures of the fibre population on textile cinema seats were measured in Sydney, Australia, in winter. Sixteen seats were analysed from a very popular cinema complex, with 3025 fibres classified according to colour, generic class and fluorescence properties (100 grey-black cotton fibres only). The recovered fibres were mostly natural fibres (84%) with cotton the most common generic type (70%). On the contrary, man made fibres were relatively rare (15%) with rayon constituting the majority of these (51%). The most common colour/generic class combinations were grey-black cotton (33%) and blue cotton (30%) accounting for 63% of the total population. All other frequencies were below 5%, most below 1% using only the two properties of colour and generic class. Fluorescence properties were found to be very discriminating as far as grey-black cotton fibres were concerned. These features are considered and discussed and in particular, to emphasise the significance of fibres as evidence of contact.     

A single approach to the recovery of DNA and firearm discharge residue evidence.

The Laboratory of the Strathclyde Police Forensic Support Department extracts DNA from cellular material recovered from garments submitted as evidence. The standard method used an adhesive tape attached to a plastic or acetate support. This paper demonstrates a method whereby a single sample, recovered from clothing, can be examined for Firearm Discharge Residue and then extracted for DNA.     

Reporting of highly individual genetic typing results: a practical approach.

This paper considers the interpretation of serological typing data as a problem in forensic science, as opposed to a problem in population genetics or statistics. Controversies arising in this area are partly due to an overly narrow perspective that ignores basic forensic science principles. After an initial discussion of the special problem that deoxyribonucleic acid (DNA) blood typing poses to forensic science, the three difficulties common to all the proposed interpretive methods are discussed. These are: predicting genotype incidence from allele frequencies, predicting frequencies for the joint occurrence of genotypes in a number of different genetic marker systems, and determining the appropriate population to use to measure the frequencies. The inability to test assumptions that are inherent in our routine methods is noted. This is a procedural weakness that unnecessarily limits the admissibility of DNA typing evidence in court. A practical solution to this problem is offered that begins with minimal assumptions. Initially a statement is made based on (1) how many reference samples the laboratory has typed and (2) how many of these samples show genotypes corresponding to the case samples. The second stage of the presentation begins with a statement that additional assumptions are necessary to fully interpret the evidence and that although these assumptions are scientifically very reasonable, they cannot be absolutely proven. The presentation can then proceed, if desired, to consideration of the specific assumptions and frequency estimates of any of the methods that have been proposed to date. To follow this approach population data must be kept in a form that allows the simple first-stage statement to be made. This means that each individual's record would include typing results in each genetic marker system. Although this method of data storage differs from that used in most forensic science laboratories, it is exceptionally versatile, and allows great flexibility in data analysis.