Speech Watermarking: An Approach for the Forensic Analysis of Digital Telephonic Recordings*

Abstract: In this article, the authors discuss the problem of forensic authentication of digital audio recordings. Although forensic audio has been addressed in several articles, the existing approaches are focused on analog magnetic recordings, which are less prevalent because of the large amount of digital recorders available on the market (optical, solid state, hard disks, etc.). An approach based on digital signal processing that consists of spread spectrum techniques for speech watermarking is presented. This approach presents the advantage that the authentication is based on the signal itself rather than the recording format. Thus, it is valid for usual recording devices in police‐controlled telephone intercepts. In addition, our proposal allows for the introduction of relevant information such as the recording date and time and all the relevant data (this is not always possible with classical systems). Our experimental results reveal that the speech watermarking procedure does not interfere in a significant way with the posterior forensic speaker identification.     

Pore Sub‐Features Reproducibility in Direct Microscopic and Livescan Images—Their Reliability in Personal Identification

Abstract: Third level features have been reported to have equal discriminatory power as second level details in establishing personal identification. Pore area, as an extended set third level sub‐feature, has been studied by minimizing possible factors that could affect pore size. The reproducibility of pore surface area has been studied using direct microscopic and 500 ppi Livescan images. Direct microscopic pore area measurements indicated that the day on which the pore area was measured had a significant impact on the measured pore area. Pore area measurement was shown to be difficult to estimate in 500 ppi Livescan measurements owing to lack of resolution. It is not possible to reliably use pore area as an identifying feature in fingerprint examination.     

The Reliability of Visually Comparing Small Frontal Sinuses*

Abstract: Several studies have investigated frontal sinus comparison for personal identification. One study addressed the statistical reliability of correct identification using automated digital methods and resulted in a 96% accuracy rate. Missed matches with the digital methods generally involved small, less featured sinuses. This study investigates the hypothesis that human examiners may be able to more accurately identify correct matches than digital methods, even when the comparisons involve small frontal sinuses. Participants were provided two sets of 28 radiographs and were instructed to identify matching radiographs and list the radiographs that did not have a corresponding match. Overall, error rates were low, with correct associations identified at a rate of 0.983. No incorrect associations (“false positives”) were made. Correct association rates were highest among participants “experienced” examining radiographs. Results support previous assertions that frontal sinus radiographs are a reliable means of personal identification even when the frontal sinuses are small.     

Testing Discriminant Functions for Sex Determination from Deciduous Teeth*,†

Abstract: Three studies have proposed discriminant functions for sex determination from deciduous tooth crown dimensions, and this study tests the existing functions on a sample of 46 Portuguese immature skeletons of known sex, aged from birth to 10 years. Deciduous teeth were measured in their mesiodistal and faciolingual crown dimensions, and percentage of correct allocation accuracy in determining sex using each specific function was determined. Discriminant functions were also calculated from data collected for this study and tested using cross‐validation. Results show poor overall accuracy (33.3–75%) and poor cross‐validation (46.2–60.0%). This is related to low sexual dimorphism in deciduous tooth crown size, as well as differences in degree of sexual dimorphism and in overall tooth size between different samples. For these reasons, deciduous crown size does not seem to show significant forensic value as discriminator of sex, particularly when methods developed on one population are applied to individuals of another population.     

山东地区人群9个STR基因座遗传多态性及频率调查

应用AmpFISTRProfilerPlus试剂盒及377型测序仪对山东地区200例无关个体血样进行了9个STR基因座多态性及频率调查,经X2检验,9个基因座基因频率均符合Hardg-Weinberg平衡定律,家系分析均符合孟德尔遗传规律,并应用于案件检验取得良好效果。     

密码破解技术

简述了密码分析的一般方法,讨论密码破解的几种具体实现方法,包括清除密码、后门密码、网络窃听、社会工程、计算密码、暴力破解等。     

陕西省6～15岁汉族未成年人牙龄的研究

目的运用全口曲面断层影像技术,研究陕西省6-15岁汉族未成年人牙齿钙化规律,建立利用牙齿钙化程度推断陕西汉族6-15岁未成年人年龄的方法。方法按照中国汉族儿童及青少年牙齿钙化分级标准,对1997名（男934名,女1063名）陕西省6-15岁汉族未成年人的全口曲面断层影像中下颌恒牙钙化程度进行分级评分;将所得评分值及对应的年龄输入SPSS软件并进行统计分析,最终建立年龄推断的方程。结果下颌同名牙钙化评分值侧别间非参数检验结果 P〉0.05,而性别间非参数独立样本检验结果 P〈0.05;下颌左侧各颗恒牙钙化程度与年龄相关分析结果 r〉0.59;方程拟合优度检验所得校正决定系数均大于0.76,估计值标准误男性在0.85-1.05岁之间、女性在0.83-0.97岁之间。结论本研究建立的方法合理可靠,可用于陕西省汉族6-15岁未成年人年龄的推断。     

MAO基因遗传多态性及与精神疾病相关性研究进展

单胺氧化酶(monoamine oxidase,MAO)是调控儿茶酚胺和5-羟色胺等单胺类氧化脱氨的一类重要酶,广泛分布于包括神经系统在内的人体各种组织中,具有多种生物学功能。MAO有两种类型,MAO-A和MAO-B。MAO基因具有遗传多态性,其中部分多态性位点与某些精神疾病如严重抑郁障碍、酒精中毒、反社会情感障碍及精神分裂症等有一定的相关性。MAO基因遗传多态性的研究,可能为法医学个人识别与亲权鉴定提供新的遗传标记,并为司法精神病鉴定提供参考性遗传学指标。     

Comparing the performance of IBIS and BulletTRAX-3D technology using bullets fired through 10 consecutively rifled barrels

This study evaluates the abilities of the Integrated Ballistics Identification System (IBIS) and BulletTRAX-3D electronic imaging systems to identify bullets fired by the same weapon in a large database of images. Ten consecutively rifled handgun barrels were test fired to obtain reference sample and known match sample pairs for upload onto both bullet acquisition systems. Both copper-jacketed and lead bullets were uploaded, to account for variations in the manner in which markings are reproduced on the different metal compositions. Ranked correlation lists were examined and evaluated. For copper-jacketed bullet correlations, both IBIS and BulletTRAX-3D identified all reference samples to their known matches within the top 10 positions. For lead bullets, BulletTRAX-3D identified all reference samples to their known match in the top 10 positions while IBIS identified only 30%. For inter composition comparisons, BulletTRAX-3D was more successful than IBIS, identifying 100% of reference samples to their known match in the top 20 for copper-jacketed to lead comparisons and 90% for lead to copper-jacketed comparisons. These results suggest that BulletTRAX-3D is more effective than IBIS in the analysis of a wider range of bullet types and it was also found to produce images of superior quality.     

马流感病毒NP单克隆抗体的制备及特性鉴定

利用原核表达的马流感病毒(EIV)核蛋白(NP)为免疫原,经腹腔接种4周龄BALB/c小鼠,取其脾细胞与SP2/0骨髓瘤细胞进行融合,经4次有限稀释法克隆和间接ELISA法筛选,获得了3株稳定分泌单抗的杂交瘤细胞株2G11、3E10和4A1,并对它们进行了亚类鉴定、间接ELISA检测和特性鉴定。结果显示,单抗2G11为IgG1亚型,3E10为IgG2a亚型,4A1为IgM亚型,轻链均为κ链。单抗2G11、3E10和4A1的细胞上清液及腹水效价分别为1∶640、1∶640、1∶320和1∶409 600、1∶204 800、0。这3株单抗均能特异性识别EIV NP重组蛋白,并且能够与天然EIV结合;获得的3株单抗与马动脉炎病毒、马疱疹病毒1型、马疱疹病毒4型、马乙型脑炎病毒均不发生交叉反应。亲和力试验结果显示,单抗2G11和3E10与EIV的亲和力常数分别为4.39×106 M-1和2.20×106 M-1。