Statistical Discrimination of Footwear: A Method for the Comparison of Accidentals on Shoe Outsoles Inspired by Facial Recognition Techniques

Abstract:  In the field of forensic footwear examination, it is a widely held belief that patterns of accidental marks found on footwear and footwear impressions possess a high degree of "uniqueness." This belief, however, has not been thoroughly studied in a numerical way using controlled experiments. As a result, this form of valuable physical evidence has been the subject of admissibility challenges. In this study, we apply statistical techniques used in facial pattern recognition, to a minimal set of information gleaned from accidental patterns. That is, in order to maximize the amount of potential similarity between patterns, we only use the coordinate locations of accidental marks (on the top portion of a footwear impression) to characterize the entire pattern. This allows us to numerically gauge how similar two patterns are to one another in a worst-case scenario, i.e., in the absence of a tremendous amount of information normally available to the footwear examiner such as accidental mark size and shape. The patterns were recorded from the top portion of the shoe soles (i.e., not the heel) of five shoe pairs. All shoes were the same make and model and all were worn by the same person for a period of 30 days. We found that in 20–30 dimensional principal component (PC) space (99.5% variance retained), patterns from the same shoe, even at different points in time, tended to cluster closer to each other than patterns from different shoes. Correct shoe identification rates using maximum likelihood linear classification analysis and the hold-one-out procedure ranged from 81% to 100%. Although low in variance, three-dimensional PC plots were made and generally corroborated the findings in the much higher dimensional PC-space. This study is intended to be a starting point for future research to build statistical models on the formation and evolution of accidental patterns.     

Effect of Gas Chromatography Temperature Program on the Association and Discrimination of Diesel Samples*†

Abstract: Five diesel samples were analyzed by gas chromatography–mass spectrometry (GC‐MS) using six GC temperature programs, aiming to investigate the effect of temperature program on association and discrimination of the samples. Temperature programs varied by ramp rate and incorporated one‐ or two‐step temperature ramps. Pearson product moment correlation coefficients and principal components analysis were used to evaluate differences in discrimination among the diesel samples afforded by each temperature program, based on the total ion chromatogram (TIC) and selected extracted ion profiles (EIPs). Association of diesel replicates and discrimination among samples based on the TIC and aromatic EIP were similar for all temperature programs based on scores plots. The alkane EIP was not useful in discriminating samples regardless of temperature program, because of similar alkane content of the diesel samples. The association and discrimination of diesel samples was largely unaffected by temperature programs that incorporated one‐ or two‐step temperature ramps.     

关于城市供水企业多种经营问题的讨论

论述了城市供水企业实施多种经营的必要性和发展形式 ,并对供水企业实施多种经营问题的积极作用和负面影响进行了讨论。指出在供水企业发展的初期要大力鼓励和发展多种经营 ,当供水企业经营状况比较完善后 ,要积极搞好主副业分离     

主犯若干问题的探讨

主犯是共同犯罪中人身危险性最大的共同犯罪人 ,历来是我国刑法打击的重点。我国目前并没有专门针对刑法总则共同犯罪条文在适用上予以解释的法律文件 ,但是 ,尚有针对刑法分则具体犯罪关于共同犯罪的相关解释中涉及主犯认定的内容 ,但这是否能够视为直接针对共同犯罪具体条文适用的一般性规定 ,还有疑问。本文就主犯的若干问题进行了探讨 ,以期对主犯的认识能够进一步深入。     

人类精子ABO血型抗原的间接免疫荧光研究

应用间接免疫荧光技术,对40份精子标本进行 ABO 血型抗原检测。A 型人精子上存在 A 抗原;B 型人精子上存在 B 抗原;AB 型人精液中,一部分精子带有 A 抗原,另一部分精子带 B 抗原。各血型人的精子均有 H 抗原。精子血型抗原为本身所固有,并非来源于精浆。不同人的精子血型抗原含量各不相等,与其供体是否为分泌状态或强弱无直接关系。精子 ABO 血型抗原主要存在于精子的颈部和顶体等区域。     

Rapid and non-destructive approach for characterization and differentiation of sealing wax using ATR-FTIR spectroscopy

Sealing wax is used for maintaining the integrity and authenticity of a document or physical evidence. Any tampering with the seal calls into question the overall integrity and authenticity of the tangible evidence or document. In these circumstances, determining the authenticity of the sealing material (physical and chemical) becomes imperative. In this study, ATR-FTIR spectroscopy supported by chemometrics has been used to differentiate sealing wax samples belonging to 12 different brands available across India. All the samples were first melted, cooled, and then analyzed using ATR-FTIR spectroscopy in the mid-infrared region (4000–600 cm⁻¹). The obtained spectra were first examined visually for the presence of different functional groups. Principal component analysis (PCA) and principal component analysis-linear discriminant analysis (PCA-LDA) were employed to analyze the sample clustering patterns and to categorize them into their respective groups, respectively. For classification, a PCA-LDA training model was applied, and it demonstrated 95.83% accuracy. The validation test resulted in an accuracy of 83.33%. PCA-LDA model offered 100% accurate prediction for samples on various substrates, including cloth, cardboard, and paper. A blind study was also performed using five unknown samples, which were accurately classified into their respective groups. PCA-LDA model will be helpful in providing investigative leads by linking a questioned sealing wax sample with its respective group.     

The Political Economy of State Failure: A Social Contract Approach

By employing the contract approach of state theory, this article provides a conceptual framework for the analysis of state failure phenomena which puts the emphasis on structural conditions as the root cause of state fragility and state failure. The article argues that the deep social fragility of some post-colonial societies, augmented by self-serving external interventions by foreign powers, is at the heart of their failure. Deep social fragility makes societies unable to cooperate and thus renders them powerless to discipline their leaders. Meanwhile, by linking leadership survival to the decisions and policies of a self-serving foreign power, intervention provides flawed incentives to the state leaders, which increases their predatory behaviour. In such situations, state leaders, rather than strengthening formal state institutions, again intensify the collective action problem and increase social fragility as mechanisms for survival.     

Identification and comparison of electrical tapes using instrumental and statistical techniques: I. Microscopic surface texture and elemental composition

Comparisons of polyvinyl chloride electrical tape typically rely upon evaluating class characteristics such as physical dimensions, surface texture, and chemical composition. Given the various techniques that are available for this purpose, a comprehensive study has been undertaken to establish an optimal analytical scheme for electrical tape comparisons. Of equal importance is the development of a quantitative means for sample discrimination. In this study, 67 rolls of black electrical tape representing 34 different nominal brands were analyzed via scanning electron microscopy and energy dispersive spectroscopy. Differences in surface roughness, calendering marks, and filler particle size were readily apparent, including between some rolls of the same nominal brand. The relative amounts of magnesium, aluminum, silicon, sulfur, lead, chlorine, antimony, calcium, titanium, and zinc varied greatly between brands and, in some cases, could be linked to the year of manufacture. For the first time, quantitative differentiation of electrical tapes was achieved through multivariate statistical techniques, with 36 classes identified within the sample population. A single-blind study was also completed where questioned tape samples were correctly associated with known exemplars. Finally, two case studies are presented where tape recovered from an improvised explosive device is compared with tape recovered from a suspect.     

Source Determination of Red Gel Pen Inks using Raman Spectroscopy and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy combined with Pearson's Product Moment Correlation Coefficients and Principal Component Analysis

The potential combination of two nondestructive techniques, that is, Raman spectroscopy (RS) and attenuated total reflectance–fourier transform infrared (ATR‐FTIR) spectroscopy with Pearson's product moment correlation (PPMC) coefficient (r) and principal component analysis (PCA) to determine the actual source of red gel pen ink used to write a simulated threatening note, was examined. Eighteen (18) red gel pens purchased from Japan and Malaysia from November to December 2014 where one of the pens was used to write a simulated threatening note were analyzed using RS and ATR‐FTIR spectroscopy, respectively. The spectra of all the red gel pen inks including the ink deposited on the simulated threatening note gathered from the RS and ATR‐FTIR analyses were subjected to PPMC coefficient (r) calculation and principal component analysis (PCA). The coefficients r = 0.9985 and r = 0.9912 for pairwise combination of RS and ATR‐FTIR spectra respectively and similarities in terms of PC1 and PC2 scores of one of the inks to the ink deposited on the simulated threatening note substantiated the feasibility of combining RS and ATR‐FTIR spectroscopy with PPMC coefficient (r) and PCA for successful source determination of red gel pen inks. The development of pigment spectral library had allowed the ink deposited on the threatening note to be identified as XSL Poppy Red (CI Pigment Red 112).     

财税法的衡平发展功能及其法治构造

当前我国社会主要矛盾已经转化为人民日益增长的美好生活需要和不平衡、不充分发展之间的矛盾。在"不平衡不充分"问题中,最关键的是"发展不平衡"问题。作为一种回应型法,财税法的社会利益本位性质和对社会经济发展的调控性决定了财税法具有促进社会平衡发展的作用。财税法衡平发展功能的内涵可从税收公平、财政转移支付和创新驱动发展三个维度展开。税收法定、预算公开和创新激励财税政策法治化形塑了财税法衡平发展功能的法治结构。财税法衡平发展功能是对发展不平衡不充分问题的能动回应,统一于促进社会平衡发展和人民共享发展成果的宏伟目标中。