On using gait in forensic biometrics

Given the continuing advances in gait biometrics, it appears prudent to investigate the translation of these techniques for forensic use. We address the question as to the confidence that might be given between any two such measurements. We use the locations of ankle, knee, and hip to derive a measure of the match between walking subjects in image sequences. The Instantaneous Posture Match algorithm, using Harr templates, kinematics, and anthropomorphic knowledge is used to determine their location. This is demonstrated using real CCTV recorded at Gatwick International Airport, laboratory images from the multiview CASIA-B data set, and an example of real scene of crime video. To access the measurement confidence, we study the mean intra- and inter-match scores as a function of database size. These measures converge to constant and separate values, indicating that the match measure derived from individual comparisons is considerably smaller than the average match measure from a population.     

Person identification by gait analysis and photogrammetry

Surveillance images from a bank robbery were analyzed and compared with images of a suspect. Based on general bodily features, gait and anthropometric measurements, we were able to conclude that one of the perpetrators showed strong resemblance to the suspect. Both exhibited a gait characterized by hyperextension of the leg joints, and bodily measurements did not differ by more than 6 mm on average. The latter was quantified by photogrammetry: i.e., measuring by using images of the perpetrator as captured by surveillance cameras. Using the computer software Photomodeler Pro, synchronous images from different cameras were compared and concurrent body features were identified. The program could then render the perpetrator as a three dimensional, high-precision, scalable and measurable object.     

The effect of frame rate on the ability of experienced gait analysts to identify characteristics of gait from closed circuit television footage

Forensic gait analysis is increasingly being used as part of criminal investigations. A major issue is the quality of the closed circuit television (CCTV) footage used, particularly the frame rate which can vary from 25 frames per second to one frame every 4 s. To date, no study has investigated the effect of frame rate on forensic gait analysis. A single subject was fitted with an ankle foot orthosis and recorded walking at 25 frames per second. 3D motion data were also collected, providing an absolute assessment of the gait characteristics. The CCTV footage was then edited to produce a set of eight additional pieces of footage, at various frame rates. Practitioners with knowledge of forensic gait analysis were recruited and instructed to record their observations regarding the characteristics of the subject's gait from the footage. They were sequentially sent web links to the nine pieces of footage, lowest frame rate first, and a simple observation recording form, over a period of 8 months. A sample-based Pearson product-moment correlation analysis of the results demonstrated a significant positive relationship between frame rate and scores (r = 0.868, p = 0.002). The results of this study show that frame rate affects the ability of experienced practitioners to identify characteristics of gait captured on CCTV footage. Every effort should therefore be made to ensure that CCTV footage likely to be used in criminal proceedings is captured at as high a frame rate as possible.     

A review of the historical use and criticisms of gait analysis evidence

The use of gait analysis is a well-established facet of practice for many professions and a fundamental aspect of clinical practice. In recent times, gait analysis evidence has emerged as a new area of forensic practice. As its use has continued to spread and develop, the area of work has come under close scrutiny and subsequent criticism. The purpose of this paper is to examine the historical use of gait analysis evidence and consider the criticisms of this work. Through the use of the historical records of cases within the public domain it has been determined that gait analysis as evidence was first presented in court over 175?years ago, although it has only been utilized by experts in more recent times. The quality of analysis underpinning such evidence has been variable, and has been undertaken by both non-expert and expert witnesses. The work undertaken by expert witnesses appears to have been both non-scientific and scientific in nature, though there is limited reporting of cases involving scientific approaches. Given the variation in the quality of the methodologies utilized, there is the potential for confusion within the courts, where it may be difficult for the judge or jury to determine the appropriate weight that can be attributed to the evidence. It is concluded that future publications should explore the scientific basis of forensic gait analysis to evaluate standards, reliability and validity, as well as reporting the methodologies utilized in relevant cases in the field. It is also recommended that courts consider in greater depth an expert's theoretical approach and experience prior to admitting their evidence. The publication of ‘Forensic gait analysis: a primer for courts’, although limited in some aspects of its consideration of practice, is a welcome addition to the information available for guidance.     

从足底压力分布看步法特征的可靠性

利用比利时FootScan压力传感器,对154名年龄在18至55岁之间的健康男性赤足正常行走时的足底压力数据进行提取,以运动生理学、运动生物力学及足迹步法特征理论为基础,用数理统计学方法对足迹压力数据进行了计算分析,对步法特征形成不同时期足与承受客体相互间的作用过程和作用方式进行深入、系统、定量的研究,进而对步法特征的传统理论进行验证,阐明了对步法特征理论中未经过科学验证部分的认识,并对步法特征理论中各类特征的可靠性及特征价值进行了初步的探讨,为今后的足迹步法特征检验鉴定工作和步法特征的发展完善都提供了有力的依据。     

The identification of individuals by observational gait analysis using closed circuit television footage

This study investigated the ability of individuals with experience in gait analysis to identify people by observing features of gait recorded by closed circuit television cameras (CCTV). Seven experienced analysts each viewed five samples of footage. Each sample showed a “target walker” and five “suspect walkers.” The task of the experienced analysts was to determine which, if any, of the “suspect walkers” was the “target walker.” All of the participant “walkers” wore identical loose fitting clothing to mask anatomical and body contour features, and balaclavas to obscure facial features. The overall results showed that the experienced analysts made a correct decision in 124 of 175 cases (71%), significantly better than would have been expected to have occurred by chance (p < 0.05). A significant variation in correct decisions (p < 0.05) was shown to occur between the various angles from which the footage was recorded, footage recorded in the saggital plane showing the highest number of correct decisions. Significantly more correct decisions (p < 0.05) were also shown to occur when the footage of the “target walker” and that of the “suspect walker” were taken from the same angle. The results suggest that individuals with experience in gait analysis perform well in the comparative identification of suspects from CCTV footage, and therefore do have a role to play as expert witnesses in this field.     

Let him wed a female who has the graceful gait of an elephant

With thanks to Maarten Henket for his commentary, and Donald Gardner for his help with the translation.     

Pre-set estimation-based in-silico silhouette-based methodology for improving the robustness to viewing direction difference for assisting forensic gait analysis

Forensic gait analysis is used to visually and quantitatively analyze information regarding the appearance and style of walking that can be presented as evidence in the court. The demand for analyzing CCTV pedestrian footage in video surveillance has been increasing. The dependence of the accuracy of semiautomatic silhouette-based analysis, often used in forensic science, on the differences in the viewing directions is a very challenging issue that is yet to be resolved for real case applications. Currently, the different viewing directions used in comparison footage significantly decrease the accuracy of same person analysis when using the silhouette-based method, often used in the Japanese forensic science domain. A calibration-based method was previously prosed to resolve this problem, but it requires performing an elaborate measurement procedure at the camera installation site for an accurate analysis. In this study, we propose a novel in-silico silhouette-based analysis method that significantly expands the number of viewing direction pre-set settings to 900 from the 24 used in the previous method. Several software tools have been developed to ensure that all the procedures can be executed on a computer. The experimental results confirm that the accuracy of the proposed method is comparable to that of the calibration-based method. Furthermore, the practical comparison results from actual consultation confirmed the effectiveness of the proposed method under existing viewing direction differences. We therefore anticipate that the proposed method will be beneficial for improving the analysis accuracy in real cases and therefore serve as a substitute of the previous method.     

The identification of individuals by observational gait analysis using closed circuit television footage: Comparing the ability and confidence of experienced and non-experienced analysts

Gait is known to have been used as evidence since 1839, initially based on the apocryphal belief that a person can be identified by their gait. The potential uniqueness of gait has yet to be proven, and therefore gait is currently considered to be a contributor to identification rather than a method of identification. In 2013 Birch et al. [1] published the findings of an investigation into the ability of individuals with experience in gait analysis to identify people by observing features of gait recorded by closed circuit television cameras. The study showed that the participants made correct decisions in 71% of cases, significantly better than would have been expected to have occurred by chance. However, the presentation of gait evidence is not limited to witnesses with experience in gait analysis. This study compared the abilities and confidence of participants with experience in gait analysis with those of participants with no experience of gait analysis using the methodology of Birch et al. 2013 [1]. The results showed no statistically significant difference in the number of correct identification decisions made by the two groups of participants, although the participants with experience of gait analysis made slightly more false negative than false positive decisions, whereas the participants with no experience made more false positive than false negative decisions. The participants with no experience in gait analysis reported significantly more confidence in their decisions than did the participants with experience (p < 0.05). The results suggest that lay people giving gait based evidence are likely to be more confident in their assertions as to identity based on that evidence, than would a witness with experience of gait analysis. Careful consideration therefore needs to be given to the submission of gait based evidence by lay witnesses.     

中国法治政体的始创辛亥政治革命的法治论剖析与省思

法治政体理论在根本上把法治理解为,只有立宪政体才会要求并实现法律统治的一个政体问题。建立民主立宪的法治政体是辛亥政治革命的目标。为达成这一目标,民国初年的《临时约法》等法律初步构建了中华民国法治政体的雏形,但这一政体也陷入多重困厄之中。孙中山等人对这一政体及其困厄进行了富有价值的探索与反思。从法治政体理论及民初缔造法治政体的实践出发,可以对治法型法治的思想观念进行比较性的检视。     

论合同生效要件之证明责任分配

民法教义学中,合同履行请求权至少应包括合同生效要件。其中,合同的特别生效要件由原告承担证明责任,学说及实践中已无异议;合同的＂一般生效要件＂,并无＂符合＂与否的问题,而只有＂违反＂如何的问题。私法自治原则要求,证明责任分配在参与民法外部体系的构建时,将合同效力要件规定为＂效力阻却要件＂,交由被告承担证明责任,所以,应对《证据规定》第5条规定之＂生效要件＂作目的性限缩。此种以证明责任为解释目标的进路,表明证明责任分配也是法规范之关联脉络的一种,解释论亦应以证明责任分配为解释目标。     

《左传》训诂丛札

<左传>文辞古奥,义蕴深微.由于时代悬隔,虽经历代训释,疑义犹夥.本义湮没,通假不明,指代不清,诸般情形,在在多有.本文就襄公时期若干训诂问题予以新的探讨.     

关于侵权诉因排除提单管辖权条款适用的反思——以无单放货案件的处理为视角

提单的管辖权是正确处理无单放货等提单纠纷的首要问题。提单的管辖权条款属于协议管辖,是国际私法中“当事人意思自治原则”的产物。无单放货案件存在违约责任与侵权责任竞合的情形,所谓的“侵权纠纷一般不适用协议管辖条款”的规则并不能当然适用。根据现行法以及民事侵权的基本法理,分析中国法院用于否定提单管辖权条款适用的“侵权诉因”及“与争议没有实际联系”两个主要事由,认为以“侵权诉因”排除提单管辖权条款适用的做法不仅于法无据,而且违背法理;而以“与争议没有实际联系”作为否定承运人总部或主营业地之管辖连接点的理由也过于极端。在上述批评的基础上,提出解决提单管辖权条款问题的三点策略。     

建立我国行政复议听证制度之构想

本文主要阐述了建立我国行政复议听证制度的必要性和主要内容。     

Grouping of ammunition types by means of frequencies of occurrence of GSR

An attempt was made to build a classification scheme for gunshot residues (GSR) samples originating from four types of ammunition, collected from shooters' hands immediately after shooting. The secured material was examined with the use of SEM-EDX method in the automatic manner. The obtained results were expressed as frequencies of occurrence of particles assigned to various chemical classes. In order to establish the most discriminative of these features the Mann-Whitney test was performed. Cluster analysis was performed for grouping the analysed samples according to their origin, i.e. the type of ammunition. It has been found that samples of GSR originating from Browning 7.65 mm and Luger 9 mm ammunition can be fairly easy differentiated from the remaining samples, whereas samples of GSR originating from of Makarov 9 mm and these of Tokarev 7.62 mm could not be differentiated using frequencies of occurrence of particles in the selected chemical classes.     

加强党的执政能力建设的理论体系

党的执政能力建设,在内容上不断丰富,是社会发展到一定程度而形成的科学的理论体系;在理论上不断创新,是相对独立的理论体系;在体系上不断完善,是发展和开放的理论体系。