Fetal Age Determination Through Biparietal Diameter: A Simple Method of Cranial Reconstruction Using Multipurpose Silicone

In forensic medicine, gestational age of fetal remains is a crucial information in several contests, but the classic methods are inadequate when early gestational age needs to be assessed. In the author's experience, the measurement of the biparietal diameter provides more accurate information for this purpose. The status of the fetal head is therefore critical. This work describes an easy technique that allows to reconstruct the cranial volume of the fetus using multipurpose silicone given both the flexibility of the fetal head structure and the inorganic nature of the silicone itself. In conclusion, the determination of the biparietal diameter achieved through the above‐described technique permitted a more accurate estimation of the dating of pregnancy in judicial cases where the fetal remains were incomplete and disrupted.     

Comparing two analytical methods: minimal standards in forensic toxicology derived from information theory

Frequently, new instrumentation and techniques are being applied to casework without an adequate knowledge of how this new technology compares to acceptable analytical procedures. Information theory provides a mathematical method to estimate the identification power of various analytical procedures and predicts if the new method produces a better or poorer confidence in the analysis than an accepted method. This paper makes comparisons based on relative informational power and discusses methods to make those estimates. With the procedures outlined in this paper, an analyst can estimate if a novel technique has the opportunity of reaching the accepted analytical methodology and, if necessary, identify places where the greatest improvement can be made to reach this equilivalence. Even though relative information theory can dismiss some proposed techniques before any analysis starts, it cannot verify if a given technique is adequate for a particular task. For that purpose, a complete procedural verification must be undertaken.     

Digital camera identification using PRNU: A feature based approach

Source camera identification is one of the emerging field in digital image forensics, which aims at identifying the source camera used for capturing the given image. The technique uses photo response non-uniformity (PRNU) noise as a camera fingerprint, as it is found to be one of the unique characteristic which is capable of distinguishing the images even if they are captured from similar cameras. Most of the existing PRNU based approaches are very sensitive to the random noise components existing in the estimated PRNU, and also they are not robust when some simple manipulations are performed on the images. Hence a new feature based approach of PRNU is proposed for the source camera identification by choosing the features which are robust for image manipulations. The PRNU noise is extracted from the images using wavelet based denoising method and is represented by higher order wavelet statistics (HOWS), which are invariant features for image manipulations and geometric variations. The features are fed to support vector machine classifiers to identify the originating source camera for the given image and the results have been verified by performing ten-fold cross validation technique. The experiments have been carried out using the images captured from various cell phone cameras and it demonstrated that the proposed algorithm is capable of identifying the source camera of the given image with good accuracy. The developed technique can be used for differentiating the images, even if they are captured from similar cameras, which belongs to same make and model. The analysis have also showed that the proposed technique remains robust even if the images are subjected to simple manipulations or geometric variations.     

Dynamic systems simulation analysis: A planning tool for the new century

Dynamic systems simulation analysis is an analytical technique that allows for the modeling of complex, nonlinear systems. While this technique is currently not widely used in the social sciences or in criminal justice planning, the author argues that more attention should be given to these models in criminal justice. These models can be used in a variety of ways—to gain greater insight into processes of system change, to track the development of specific system populations (e.g., drug offenders, elderly offenders), and to estimate projected system growth and change over a variety of legislative and policy scenarios—making them useful tools for theoretical development and policy evaluation, as well as more pragmatic considerations such as program, facilities, and overall system planning. An overview of the methodology and some examples of analyses are presented.     

Time since discharge of shotgun shells

A technique for the estimation of time since discharge of a given class of spent shotgun shells is presented. The technique involved the use of SPME (Solid Phase Microextraction) sampling from the atmosphere inside spent shotgun shells. Compounds absorbed on the SPME fiber were desorbed and analyzed with GC-MS. The decrease in concentration of the combustion product naphthalene was monitored in all shells over a two-month period. Three conditions were examined to prevent naphthalene from escaping prior to testing the shells. A glass vial was successfully incorporated to halt the dissipation of naphthalene. At room temperature the naphthalene peak can be measured for several months and the curve-fitting data can lead to an estimation of time since discharge.     

Believing is seeing II: Beliefs and perceptions of criminal psychological profiles

This study built upon previous research by Kocsis and Hayes (2004) by investigating whether a bias exhibited by police officers in their perception of profiles would replicate in a sample of nonpolice participants. Additionally, the relationship, if any, between the degree of belief harbored by an individual concerning the merits of profiling and their perceptions of a given profile was also investigated. The findings of this study add to the contention that the biases observed in Kocsis and Hayes's previous study with regard to author label may be related to some intrinsic feature of the previously sampled police participants. Additionally, evidence was found to support the proposition that an individual's degree of belief in profiling is related to their perceptions concerning the merits of a profile. Namely, the more an individual believes in the profiling technique, the greater the merit that will be perceived in a profile.     

Estimation of time in forensic biology and pathology. An introductory review

Timing is an extremely important factor in the practice of forensic biology and pathology. This review offers an opportunity for evaluating the time at which an injury could have taken place and thus its chronologic age. Both the macroscopic and microscopic aspects of the injury are discussed. The use of histochemical techniques using the study of enzymes as a basis of the technique is discussed. Histamine and serotonin techniques are also discussed and their applications in practical cases including a traffic accident are presented. The field is discussed and references given in large numbers.     

A Nonlinear Least Squares Approach to Time of Death Estimation Via Body Cooling

The problem of time of death (TOD) estimation by body cooling is revisited by proposing a nonlinear least squares approach that takes as input a series of temperature readings only. Using a reformulation of the Marshall–Hoare double exponential formula and a technique for reducing the dimension of the state space, an error function that depends on the two cooling rates is constructed, with the aim of minimizing this function. Standard nonlinear optimization methods that are used to minimize the bivariate error function require an initial guess for these unknown rates. Hence, a systematic procedure based on the given temperature data is also proposed to determine an initial estimate for the rates. Then, an explicit formula for the TOD is given. Results of numerical simulations using both theoretical and experimental data are presented, both yielding reasonable estimates. The proposed procedure does not require knowledge of the temperature at death nor the body mass. In fact, the method allows the estimation of the temperature at death once the cooling rates and the TOD have been calculated. The procedure requires at least three temperature readings, although more measured readings could improve the estimates. With the aid of computerized recording and thermocouple detectors, temperature readings spaced 10–15 min apart, for example, can be taken. The formulas can be straightforwardly programmed and installed on a hand‐held device for field use.     

交通事故轮胎鉴定概述

轮胎鉴定是指涉及事故车辆的轮胎相关的鉴定项目,是交通事故技术鉴定中的重要项目之一,一般可分为轮胎痕迹鉴定和轮胎损坏情况及其与事故关系鉴定两种.本文着重论述了交通事故技术鉴定中上述两种轮胎鉴定的定义、鉴定步骤、鉴定方法,并通过典型案例来全面解读轮胎鉴定的具体鉴定过程.     

PARTICIPATORY MANAGEMENT Toward a Science of Correctional Management

Participatory management as an intervention technique to effect change in the prison environment requires a restructuring of the prison Incision-making process. Inmates must be given increased responsibility and be aUowed to participate meaningfully in decision-making. The inmate subculture is posited as being one of the major impediments to successful interventions within the prison setting; participatory management neutralizes its effects, replacing the traditional oppositional character of staff/ inmate relationships with a coalition of staff and inmates.     

Blind Image Steganalysis of JPEG images using feature extraction through the process of dilation

The detection of stego images, used as a carrier for secret messages for nefarious activities, forms the basis for Blind Image Steganalysis. The main issue in Blind Steganalysis is the non-availability of knowledge about the Steganographic technique applied to the image. Feature extraction approaches best suited for Blind Steganalysis, either dealt with only a few features or single domain of an image. Moreover, these approaches lead to low detection percentage. The main objective of this paper is to improve the detection percentage. In this paper, the focus is on Blind Steganalysis of JPEG images through the process of dilation that includes splitting of given image into RGB components followed by transformation of each component into three domains, viz., frequency, spatial, and wavelet. Extracted features from each domain are given to the Support Vector Machine (SVM) classifier that classified the image as steg or clean. The proposed process of dilation was tested by experiments with varying embedded text sizes and varying number of extracted features on the trained SVM classifier. Overall Success Rate (OSR) was chosen as the performance metric of the proposed solution and is found to be effective, compared with existing solutions, in detecting higher percentage of steg images.     

Sequencing of intersecting lines by combined lifting process and scanning electron microscopy

The chronological order in which two intersecting writing or typed strokes were made can be determined for several combinations of writing media by scanning electron microscope (SEM) examination, a lifting and transfer technique using Kromekote paper, or a combination of the transfer technique followed by SEM examination of the remaining material in the intersection. When non-destructive examination cannot provide unambiguous determination of sequence, judicious choice by the document examiner of which technique to use for a given combination of writing media and paper type can be made using known characteristics of the materials involved. The range of line-crossings which can be reliably sequenced is greater using a combined transfer and SEM technique than when the examination is limited to either technique alone.     

A test of the auricular surface aging technique

A recently developed technique used in the estimation of age at death is based upon the metamorphosis of the auricular surface of the ilium. This technique was designed to be used in seriation to estimate the age distribution of a skeletal sample. However, the technique has also been used in forensic science cases, which must be analyzed on a case-by-case basis. The present study examines the use of the auricular surface technique as the single aging factor. Two hypotheses are tested using a sample of 189 individuals drawn from the Terry Collection, housed at the Smithsonian Institution. The hypotheses are (1) is the method equally applicable across race and sex, and (2) how well does the method perform as the single aging factor? The results indicate that the amount of degenerative change in the auricular surface is not dependent upon race or sex in any given age category. However, the rate of degenerative change is too variable to be used as a single criterion for the estimation of age; the range of estimation error is simply too large for forensic science purposes.     

An empirical assessment of content in criminal psychological profiles

Although criminal psychological profiling has been in use by law enforcement agencies for almost three decades, there is a paucity of empirical research examining the technique. A fundamental issue that has received little attention is the empirical evaluation of information contained in profiles composed by professional profilers. In this study, a group of profilers, police officers, psychologists, college students, and self-declared psychics were given information from a solved murder investigation, after which the participants composed a written profile predicting the probable offender. Professional profilers tended to write more lengthy profiles that contained more information about the nonphysical attributes of the offender and more information about the crime scene or the offender's behavior before, during, and after the crime. These results are discussed in terms of their implication for our broader understanding of the technique of profiling and future directions for research into profiling.     

A stochastic model of the processes in PCR based amplification of STR DNA in forensic applications

In forensic DNA profiling use is made of the well-known technique of PCR. When the amount of DNA is high, generally unambiguous profiles can be obtained, but for low copy number DNA stochastic effects can play a major role. In order to shed light on these stochastic effects, we present a simple model for the amplification process. According to the model, three possible things can happen to an individual single DNA strand in each complete cycle: successful amplification, no amplification, or amplification with the introduction of stutter. The model is developed in mathematical terms using a recursive approach: given the numbers of chains at a given cycle, the numbers in the next can be described using a multinomial probability distribution. A full set of recursive relations is derived for the expectations and (co)variances of the number of amplicon chains with no, 1 or 2 stutters. The exact mathematical solutions of this set are given, revealing the development of the expectations and (co)variances as function of the cycle number. The equations reveal that the expected number of amplicon chains without stutter grows exponentially with the cycle number, but for the chains with stutter the relation is more complex. The relative standard deviation on the numbers of chains (coefficient of variation) is inversely proportional to the square root of the expected number of DNA strands entering the amplification. As such, for high copy number DNA the stochastic effects can be ignored, but they play an important role at low concentrations. For the allelic peak, the coefficient of variation rapidly stabilizes after a few cycles, but for the chains with stutter the decrease is more slowly. Further, the ratio of the expected intensity of the stutter peak over that of the allelic peak increases linearly with the number of cycles. Stochastic models, like the one developed in the current paper, can be important in further developing interpretation rules in a Bayesian context.     

Elemental analysis of bone: proton-induced X-ray emission testing in forensic cases

Proton-induced X-ray emission (PIXE) is a spectroscopic technique that provides the researcher with the elemental composition of a given target material. In this paper, we illustrate the utility of PIXE analysis in two forensic contexts: (1) case of cremation in which the nature of the remains is questioned and (2) cases of death by gunshot wound. In the first case, elemental analysis by PIXE reveals that the purported cremated remains are not bone. The last two cases show that radiopaque metallic residue embedded in bone is composed of lead from a projectile.     

Response surface methodology and improved interval analysis method-For analyzing uncertainty in accident reconstruction

Methods used to calculate intervals of accident reconstruction results are research hotspot in the word. The response surface methodology-interval analysis method (RSM-IAM) is a useful method for analyzing uncertainty of simulation results in this field, but there are two problems in this method because of the interval extension problem and inaccurate response surface models. In order to tackle these two problems, based on subinterval analysis thought and response surface methodology, an improved interval analysis method (RSM-IIAM) is proposed. In RSM-IIAM, the stepwise regression technique is used to obtain a reasonable response surface mode of the simulation model; and then, intervals of uncertain parameters are divided into several subintervals; after that, intervals of simulation results in accident reconstruction are calculated according to these subintervals. Finally, four numerical cases were given. Results showed that the RSM-IIAM is simple and high accuracy, which will be useful in analyzing uncertainty of simulation results in accident reconstruction.     

Police-Induced Confessions,Risk Factors,and Recommendations: Looking Ahead

Reviewing the literature on police-induced confessions, we identified suspect characteristics and interrogation tactics that influence confessions and their effects on juries. We concluded with a call for the mandatory electronic recording of interrogations and a consideration of other possible reforms. The preceding commentaries make important substantive points that can lead us forward—on the effects of videotaping of interrogations on case dispositions; on the study of non-custodial methods, such as the controversial Mr. Big technique; and on an analysis of why confessions, once withdrawn, elicit such intractable responses compared to statements given by child and adult victims. Toward these ends, we hope that this issue provides a platform for future research aimed at improving the diagnostic value of confession evidence.