辨证认识话者自动识别系统

为了警示近年来我国司法话者识别领域中出现的一些崇外、盲目追求快速与省事的苗头,结合话者自动识别系统的研究、应用状况,从语音的共性与个性、话者识别结果的相对性与绝对性出发,通过分析比对话者自动识别与语音识别所用的特征参数及实现过程,辨证分析了制约话者自动识别系统准确率的根本原因。指出了话者自动识别系统尚无法达到人们对其的期望,以及适合于司法诉讼领域的话者自动识别系统的发展方向。     

法庭语音学

本文对法庭语音学进行了研究综述,主要介绍了该学科的核心内容：说话人鉴定。在实际办案中,当未找到嫌疑人,只有犯罪分子的检材语音时,可以使用说话人画像/说话人分类技术。若没有犯罪分子的录音证据时,可以让受害人和证人进行说话人的听觉辨认。具体的辨认形式有两种：对熟人辨认和对陌生人辨认,在对陌生人辨认时可以采用语音辨认的方法进行。当检材语音和样本语音都齐备的时候,法庭语音分析专家就可以对二者进行比对检验了。目前语音比对分析涉及到的问题和领域有：基于贝叶斯方法的法庭推理和似然比计算、共振峰频率的测量应用、非解析感知与样例理论、法庭说话人自动识别以及不同方法的综合应用等。     

法庭语音学

本文对法庭语音学进行了研究综述,主要介绍了该学科的核心内容:说话人鉴定。在实际办案中,当未找到嫌疑人,只有犯罪分子的检材语音时,可以使用说话人画像/说话人分类技术。若没有犯罪分子的录音证据时,可以让受害人和证人进行说话人的听觉辨认。具体的辨认形式有两种:对熟人辨认和对陌生人辨认,在对陌生人辨认时可以采用语音辨认的方法进行。当检材语音和样本语音都齐备的时候,法庭语音分析专家就可以对二者进行比对检验了。目前语音比对分析涉及到的问题和领域有:基于贝叶斯方法的法庭推理和似然比计算、共振峰频率的测量应用、非解析感知与样例理论、法庭说话人自动识别以及不同方法的综合应用等。     

Intra- and inter-speaker variations of formant pattern for lateral syllables in Standard Chinese

Speech variation of speakers is a crucial issue for speaker recognition and identification, especially for forensic practice. Greater intra-speaker variation is one main reason for incorrect speaker identification in real forensic situations. Understanding the stability of acoustic parameters and their variation in speech is therefore significant for the evaluation of effective parameters for speaker identification. In this paper, all vowels in Standard Chinese including five monophthongs, eight diphthongs and four triphthongs were combined with lateral /l/. Finally, 15 lateral syllables with different tones for 10 speakers were selected and acoustically analyzed. Central frequencies of the first four formants for each syllable were measured for quantitative comparison of intra- and inter-speaker variation in order to provide a general idea of speaker variation in Standard Chinese, and finally serving for forensic application. Results show that the overall intra-speaker variation is less than the inter-speaker variation in great extent under laboratory condition though occasionally they are contrary. This supports the basis for forensic speaker identification, that is, intra-speaker variation should be less than inter-speaker variation in many acoustic features, and further validates the probability and reliability of forensic speaker identification.     

伪装语音的自动话者识别研究

本文以语音自动话者识别系统为平台,对实际案件中出现频率较高的10种伪装语音类型进行自动话者识别测试。通过对20位发音人的正常语音和10种类型伪装语音的话者辨认和话者确认测试,分析不同语音伪装类型对自动话者识别的影响。该结果对于深入认识伪装语音的特性及其话者识别研究具有重要意义,也为自动话者识别技术的改进提供了参考。     

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.     

Voice disguise and automatic speaker recognition

In this paper a newly developed Forensic Automatic Speaker Recognition System (FASRS) was introduced and the effect of 10 types of voice disguises that are common in forensic casework on the performance of this system was studied. In this study 10 types of disguised voices and normal voices from 20 male college students were used as test samples. Each disguised voice was compared with all normal voices in the database to make speaker identification and speaker verification. The result of speaker recognition is summarized and the influence of voice disguises on the FASRS is evaluated.     

侦查案卷裁判主义——对中国刑事第二审程序的重新考察

在中国刑事第二审程序中,一直存在着一种两步式程序构造:二审法官首先通过"调查讯问式"审理,确定案件是否事实清楚,然后再决定是否开庭审理。这种程序构造导致侦查案卷成为二审法院进行事实复审的直接根据,那种单方面的阅卷则成为二审法院进行事实裁判的基础。只要侦查案卷具有这种预决的法律效力,那么,那种强调二审法院开庭审理的改革就注定难以产生实质性的积极效果。在侦查案卷裁判主义的诉讼构造中,所谓的"事实复审"是不可能实现的。     

似然比在法庭说话人确认中的应用

本文把成功应用于DNA检验的证据评估方法（似然比）应用于法庭语音证据评估之中,提取语音的LPC作为识别特征,并使用45人电话对话录音中元音/a/作为样本进行了测试。结果表明该方法不仅能正确识别说话人,而且能根据当前嫌疑人样本和问题语音样本的差异,量化该语音样本作为证据的力度,为法庭提供科学合理的证据评估结果和科学解释。同时,自动特征提取的引入比起人工提取共振峰特征,提高了工作效率,识别系统性能也获得大幅提升。     

A test of the effectiveness of speaker verification for differentiating between identical twins

This paper presents investigations into the ability of speaker verification technology to discriminate between identical twins. It is shown that whilst, in general, the genetic and non-genetic characteristics of voice are both of value to speaker verification capabilities, it is the latter which is highly beneficial in the separation of the speech of identical twins. It is further demonstrated that through the use of unconstrained cohort normalisation as a complementary means for the exploitation of such voice characteristics, the verification reliability can be considerably enhanced for both identical twins and unrelated speakers. Experiments were conducted using a bespoke clean-speech database consisting of utterances from 49 identical twin pairs. The paper details the problem in speaker verification posed by identical twins, discusses the experimental investigations and provides an analysis of the results.     

Forensic reference data on articulation rate in German.

Articulation rate (AR) is one of the parameters used in forensic voice comparisons for the purpose of providing evidence for or against speaker identity, yet at present multi-speaker studies on this parameter are very rare. In order to alleviate this situation AR was measured in the speech of 100 German-speaking male subjects. Histograms were provided from which the forensic expert can infer the percentages of different AR values in the population. Separate histograms were provided for mean AR and standard deviation of AR. It was also found that mean AR is significantly higher in read than spontaneous speech and that AR standard deviation is significantly smaller in read than spontaneous speech, although many individual speakers deviate from this general pattern.     

认识非语音信息在司法话者识别中的应用

通过介绍两起利用非语音信息最终辅助确认了说话人的司法话者识别检验案件,发现在说话人识别中,当待检语音无法满足语图比对条件时,充分利用非语音信息所揭示出的个体特性将有助于解决话者识别问题。得出了当待检语音条件不充分时,依靠非语音信息来辅助进行话者识别的方法。     

从话者识别角度认识山西汾城方言的紧喉音节

目的明确山西汾城方言紧喉音节与对应普通话音节在司法话者识别时的可比性及该紧喉音的声学特性。方法利用VS-99语音工作站对山西汾城方言紧喉音节及对应普通话音节的韵律特性、音质特性等声学特性进行定性与定量分析。结果得出了汾城方言紧喉音的发声态主要为嘎裂声,汾城方言紧喉音对声母没有明显影响,紧喉音韵母与普通话韵母在共振峰频率上的一致性要远高于共振峰相对强度上的一致性等认识。结论为在汾城方言与普通话之间进行司法话者识别以及田野调查提供了依据。     

Voice identification by human listeners: On earwitness reliability

This paper reviews what is currently known about voice identification by human listeners. Our own experimental data from a four-year research program into this topic is used to elucidate, support, and in some cases to contradict published work into the effects on voice identification of such factors as speech sample size and quality, voice disguise, delay in holding voice identification sessions, incidental as opposed to intentional memory for voices, the effects of the age of the witness, training in specific modes of encoding voices, and the relationship between objective accuracy and subjective feelings of certainty of correctness. It is concluded that the caution and suspicion currently accorded to visual identification must be extended also, and perhaps more so, to voice identification.Part of the research discussed in this paper was conducted under the auspices of a grant from the British Home Office to the author and Ray Bull. The author would like to thank the issue editor for his very useful comments on an earlier draft of this paper, and Harriet Rathborn for running many of the experiments.     

基于语料库的“普通话”地域性言语识别技术

目的探究汉语＂普通话＂中的地域性差别,发现言语特征,找到从有限的以普通话发音的语音材料中提取出更多地域性特征的途径和方法,提高地域性言语识别技术水平,更有效地为案件分析定向服务。方法在建立较大规模的《面向案件言语识别应用的汉语＂普通话＂语料库》及查询检索系统的基础上,进行统计分析、归纳总结。结果人们说普通话时会在声母、韵母、声调、重音、儿化、轻声等语音方面和词汇、语法等方面不同程度地出现其母语方言的固有特点。我们可以采用＂以调值特征为中心,声韵特征相结合＂、＂利用各类特征的总和进行综合评断＂等方法进行识别。结论利用＂普通话＂语声进行言语人地域性识别是一种切实可行的技术方法。     

论声纹鉴定意见的表述形式

本文针对目前国内外讨论比较热烈的声纹鉴定意见表述问题进行了评述.首先介绍了实践中正在使用的听觉分析法、声谱比对分析法、声学分析法、听觉-声学分析法和说话人自动识别五种鉴定方法,指出了各种方法的优缺点;然后对现存的二元判决、可能性等级、似然比和英国立场声明四种鉴定意见表述形式进行了介绍和评析,通过分析发现,上述四种意见表述形式都存在一定的问题,实践中选择何种形式表述鉴定意见要综合考虑其科学性、逻辑性、现实性和可行性等多种价值选项;最后认为解决该问题的根本方法是各相关领域的专家应加强在鉴定方法上的合作性的基础研究.     

Production of intoxication states by actors--acoustic and temporal characteristics

This paper is the second of a series; the first has been published (J Forensic Sci, 1998;43:1153-62). The goal in the initial pair of experiments was to determine if speakers (actors) could effectively mimic the speech of intoxicated individuals and also volitionally reduce the degradation to their speech that resulted from severe inebriation. To this end, two highly controlled experiments involving 12 actor-speakers were carried out. It was found that, even when sober, nearly all of them were judged drunker (when pretending) than when they actually were severely intoxicated. In the second experiment, they tried to sound sober when highly intoxicated; here most were judged less inebriated than they were. The goal of this second paper is to identify some of the speech characteristics that allowed the subjects to achieve the cited illusions. The focus here is on four paralinguistic factors: fundamental frequency (F0), speaking rate, vocal intensity, and nonfluency level. For the simulation of intoxication study, it was found that F0 was raised along with increased intoxication but raised even more when this state was feigned. A slowing of speaking rate was associated with increasing intoxication, but this shift also was greater when the speaker simulated intoxication. The most striking contrast was found for the nonfluencies; they were doubled for actual intoxication, but quadrupled when intoxication was simulated. On the other hand, the shifts exhibited by the subjects when they attempted to sound sober were not as clear cut. Indeed, no systematic relationships were found here for either F0 or vocal intensity. Both speaking rate and the number of nonfluencies shifted appropriately, but these changes were not statistically significant. In sum, discernable suprasegmental relationships occurred for both studies (but especially the first); further, it is predicted that useful cues also will be found embedded in the segmentals (the sounds of speech).     

A simple and efficient method for extracting DNA from old and burned bone

It has been a challenge to extract DNA from bones previously soaked in water, burned, or buried for a long time, due to the reduced quality and quantity of DNA in the bone samples. The dramatic degradation of the DNA and the presence of PCR inhibitors in the collagen significantly complicate the process of DNA identification in dated and charred bones. In this article, we present a novel strategy to obtain DNA from bones based on the use of cetyltrimethylammonium bromide (CTAB) lysis buffer and isoamyl alcohol-chloroform extraction with subsequent DNA purification using the DNA IQ System, or alternatively the QIAquick system. When applied to bones soaked, burned or buried for up to nine years, this method increases the purity and yield of DNA with respect to the traditional phenol-chloroform method and significantly improves multiplex STR genotyping using fluorescence-based methods. The results of this research will assist forensic scientists in the identification of DNA from victims whose bodies underwent significant trauma or burning, precluding the utilization of traditional forensic DNA identification techniques.     

Juror decision making in eyewitness identification cases

The lay-person's knowledge of the factors that influence eyewitness memory was examined by evaluating the manner in which mock jurors integrated eyewitness evidence to draw inferences about defendant culpability and the likelihood that an identification was correct. Three hundred and twenty-one undergraduates viewed a videotaped trial within which ten witness and identification factors were manipulated between trials. Manipulation checks showed that subjects demonstrated superior memory for the evidence and the manipulated variables had their intended impact on appropriate rating scales. However, only one variable, witness confidence, had reliable effects on subjects' perceptions of culpability, on the perceived likelihood that the identification was correct, and on several other relevant dependent variables. Eight variables that have been shown to affect identification accuracy in the empirical literature had trivial effects on mock jurors' inferences. It was concluded that lay-people are insensitive to the factors that influence eyewitness memory.     

论政治认同与中国共产党的"软权力"建设

政治认同是政治主体对政治体系的自觉接受和服从,是对政治统治客观事实的价值判断。执政党要维持国家的长治久安,保持自己统治的合法性,就必须获得公民的政治认同。而执政党若要获得公民的政治认同,不仅要有坚实的硬权力作基础,更要有强大的软权力作支撑。然而,目前,各种原因削弱了中国共产党的软权力,造成社会公众政治认同的下降。这种现象如果任其发展,将严重影响党执政地位的巩固和执政使命的实现。因而,中国共产党必须从意识形态、政治社会制度、执政方式等方面加强软权力建设,以提高公众的政治认同,巩固执政地位,实现执政使命,保持整个国家的繁荣与稳定。