A New Anti‐forensic Scheme—Hiding the Single JPEG Compression Trace for Digital Image

To prevent image forgeries, a number of forensic techniques for digital image have been developed that can detect an image's origin, trace its processing history, and can also locate the position of tampering. Especially, the statistical footprint left by JPEG compression operation can be a valuable source of information for the forensic analyst, and some image forensic algorithm have been raised based on the image statistics in the DCT domain. Recently, it has been shown that footprints can be removed by adding a suitable anti‐forensic dithering signal to the image in the DCT domain, this results in invalid for some image forensic algorithms. In this paper, a novel anti‐forensic algorithm is proposed, which is capable of concealing the quantization artifacts that left in the single JPEG compressed image. In the scheme, a chaos‐based dither is added to an image's DCT coefficients to remove such artifacts. Effectiveness of both the scheme and the loss of image quality are evaluated through the experiments. The simulation results show that the proposed anti‐forensic scheme can verify the reliability of the JPEG forensic tools.     

The Accuracy of Handheld Pre‐Arrest Breath Test Instruments as a Predictor of the Evidential Breath Alcohol Test Results

Drunk driving is a serious threat to public safety. All available and appropriate tools for curbing this threat should be employed to their full extent. The handheld pre‐arrest breath test instrument (PBT) is one tool for identifying the alcohol‐impaired driver and enforcing drunk driving legislation. A set of data was evaluated (n = 1779) where the PBT instrument was employed in drunk driving arrests to develop a multivariate predictive model. When maintained and operated by trained personnel, the PBT provides a reasonable estimate of the evidential test result within the relevant forensic range (95% prediction interval:  ± 0.003 g/210 L). ROC analysis shows that a multivariate model for PBT prediction of the evidentiary alcohol concentration above versus below the legal limit of 0.08 g/210 L has excellent performance with an AUC of 0.96. These results would be of value in evidential hearings seeking to admit the PBT results in drunk driving trials.     

Failings of Trauma‐Specific and Related Psychological Tests in Detecting Post‐Traumatic Stress Disorder in Forensic Settings

Judges and juries tend to be particularly impressed by test data, especially quantitative test data. Psychometric tests specific for assessing the presence of post‐traumatic stress disorder (PTSD) are commonly employed by forensic mental health evaluators. Most of these instruments, however, have been designed to detect PTSD in treatment or research, and not forensic, settings. Those who rely on these measures without adequate awareness of their often significant limits in correctly identifying malingering may induce finders of fact to inordinately confidently accept the presence of PTSD. This article reviews problematic structural and content components of trauma‐specific and related instruments used to evaluate PTSD and discusses the utility of specific techniques liable to be used in forensic settings to “fool” these measures.     

Diagnostic Value of PSA and AP Tests for the Detection of Spermatozoa in Postmortem Swabs from the Genital and Anal Region in Males

The aim of this study was to clarify whether positive results for prostate‐specific antigen (PSA) and acid phosphatase (AP) occur in postmortem swabs from the genito‐anal region in males (n = 80; 4 regions) and females (n = 20; 3 regions) and to calculate the positive predictive value (PPV) concerning the presence of spermatozoa. In male subjects, the highest incidence of positive test results was found in urethral swabs (PSA 76%, AP 71%) and the lowest frequencies appeared in perianal and rectal swabs (15–20%). Microscopic evaluation for spermatozoa was positive between 39% in urethral swabs and 1% in rectal swabs. PPV regarding positive identification of spermatozoa was 33.3% for PSA and 31.5% for AP. The combination of both tests yielded a PPV of 38.2%. In female cases, no spermatozoa were identified, and one case was PSA‐ and AP‐positive in perianal swabs. Our findings indicate that PSA and AP tests are of limited value for the postmortem detection of spermatozoa in male subjects.     

Understanding Variations of Soil Mapping Units and Associated Data for Forensic Science

Soil samples have potential to be useful in forensic investigations, but their utility may be limited due to the inherent variability of soil properties, the wide array of analytical methods, and complexity of data analysis. This study examined the differentiation of similar soils based on both gross (texture, color, mineralogy) and explicit soil properties (elemental composition, cation exchange, Fe‐oxyhydroxides). Soils were collected from Fallbrook and adjacent map units from Riverside and San Diego Counties in California. Samples were characterized using multiple techniques, including chemical extracts, X‐ray diffraction (XRD), and Fourier transform infrared spectroscopy. Results were analyzed using multiple analytical approaches to compare counties and land uses. Some analyses (XRD, extractions) were better at distinguishing among samples than others (color, texture). Ratios of rare earth elements were particularly useful for distinguishing samples between counties. This potential to “fingerprint” soils illustrates the usefulness of a comprehensive soil database for criminal investigators.     

Identification of Natural Images and Computer‐Generated Graphics Based on Statistical and Textural Features

To discriminate the acquisition pipelines of digital images, a novel scheme for the identification of natural images and computer‐generated graphics is proposed based on statistical and textural features. First, the differences between them are investigated from the view of statistics and texture, and 31 dimensions of feature are acquired for identification. Then, LIBSVM is used for the classification. Finally, the experimental results are presented. The results show that it can achieve an identification accuracy of 97.89% for computer‐generated graphics, and an identification accuracy of 97.75% for natural images. The analyses also demonstrate the proposed method has excellent performance, compared with some existing methods based only on statistical features or other features. The method has a great potential to be implemented for the identification of natural images and computer‐generated graphics.     

Who's Afraid of WikiLeaks? Missed Opportunities in Political Science Research

Leaked information, such as WikiLeaks’ Cablegate, constitutes a unique and valuable data source for researchers interested in a wide variety of policy‐oriented topics. Yet political scientists have avoided using leaked information in their research. This article argues that we can and should use leaked information as a data source in scholarly research. First, the methodological, ethical, and legal challenges related to the use of leaked information in research have been considered, concluding that none of these present serious obstacles. Second, how political scientists can use leaked information to generate novel and unique insights concerning political phenomena using a variety of quantitative and qualitative methods have been shown. Specifically, how leaked documents reveal important details concerning the Trans‐Pacific Partnership negotiations, and how leaked diplomatic cables highlight a significant disparity between the U.S. government's public attitude toward traditional knowledge and its private behavior have been demonstrated.     

PROFILING AND POLICE LEGITIMACY: PROCEDURAL JUSTICE,ATTRIBUTIONS OF MOTIVE,AND ACCEPTANCE OF POLICE AUTHORITY*

This paper reports the results of four studies that investigate racial profiling as an attribution about police motives. Each study explores, first, the types of police behavior that heighten or lessen the occurrence of profiling attributions and, second, the consequences of such attributions. Results support prior studies in finding that judgments about whether the police are profiling are associated with the level of public support for the police. The studies then extend the analysis of subjective profiling judgments by examining their antecedents. The findings support the procedural justice hypothesis that the fairness with which the police exercise their authority influences whether members of the public view the police as profiling.     

THE DELINQUENCY OF CHILDREN BORN TO YOUNG MOTHERS: RESULTS FROM THE ROCHESTER YOUTH DEVELOPMENT STUDY*

This paper examines the relationship between a mother's age at first childbirth and the delinquent behavior of her children. Using data from the Rochester Youth Development Study (RYDS), an ongoing longitudinal study of adolescent development, we found that children born to mothers who began childbearing at a young age were more prone to general delinquency, violence, and arrest than were children born to mothers who began childbearing when they were older. This “early first‐birth effect” was far larger in white and Hispanic families than in African‐American families. Mediating analyses found that the early first‐birth effect was most attributable to the unstable composition of families in which early childbearing occurs. That said, a substantial portion of the effect remains unmediated.     

SEX‐BASED DISPARITIES IN FELONY DISPOSITIONS BEFORE VERSUS AFTER SENTENCING REFORM IN OHIO*

Extending Koons‐Witt's (2002) study of whether sex‐based disparities in imprisonment likelihoods changed under sentencing guidelines in Minnesota, we examined similar models for Ohio with additional analyses of felony conviction likelihoods and sentence length for 5,472 felony defendants from twenty‐four trial courts. The main effects of a defendant's sex on imprisonment were significant during both periods (unlike the Minnesota findings), consistent with a chivalry perspective. Random coefficient models revealed that these effects were similar across the twenty‐four jurisdictions. Analyses also revealed significant postguideline reductions in sentence length disparities based on a woman's race and number of dependent children, yet increased disparities in imprisonment likelihoods postguidelines based on a woman's race and whether she was convicted on drug charges. These and other findings are discussed in the context of the Ohio legislature's implementation of a sentencing scheme that retains considerably more judicial discretion relative to Minnesota's template.