Comparison of the Performance of Two Methods for Height Estimation

Abstract: In the case study, two methods of performing body height measurements in images are compared based on projective geometry and 3D modeling of the crime scene. Accuracy and stability of height estimations are tested using reconstruction images of test persons of known height. Given unchanged camera settings, predictions of both methods are accurate. However, as the camera had been moved in the case, new vanishing points and camera matches had to be created for the reconstruction images. 3D modeling still yielded accurate and stable estimations. Projective geometry produced incorrect predictions for test persons and unstable intervals for questioned persons. The latter is probably caused by the straight lines in the field of view being hard to discern. With the quality of material presented, which is representative for our case practice, using vanishing points may thus yield unstable results. The results underline the importance of performing validation experiments in casework.     

Advanced Framework for Digital Forensic Technologies and Procedures*

Abstract: Recent trends in global networks are leading toward service‐oriented architectures and sensor networks. On one hand of the spectrum, this means deployment of services from numerous providers to form new service composites, and on the other hand this means emergence of Internet of things. Both these kinds belong to a plethora of realms and can be deployed in many ways, which will pose serious problems in cases of abuse. Consequently, both trends increase the need for new approaches to digital forensics that would furnish admissible evidence for litigation. Because technology alone is clearly not sufficient, it has to be adequately supported by appropriate investigative procedures, which have yet become a subject of an international consensus. This paper therefore provides appropriate a holistic framework to foster an internationally agreed upon approach in digital forensics along with necessary improvements. It is based on a top‐down approach, starting with legal, continuing with organizational, and ending with technical issues. More precisely, the paper presents a new architectural technological solution that addresses the core forensic principles at its roots. It deploys so‐called leveled message authentication codes and digital signatures to provide data integrity in a way that significantly eases forensic investigations into attacked systems in their operational state. Further, using a top‐down approach a conceptual framework for forensics readiness is given, which provides levels of abstraction and procedural guides embellished with a process model that allow investigators perform routine investigations, without becoming overwhelmed by low‐level details. As low‐level details should not be left out, the framework is further evaluated to include these details to allow organizations to configure their systems for proactive collection and preservation of potential digital evidence in a structured manner. The main reason behind this approach is to stimulate efforts on an internationally agreed “template legislation,” similarly to model law in the area of electronic commerce, which would enable harmonized national implementations in the area of digital forensics.     

Measurement Uncertainty When Estimating the Velocity of an Allegedly Speeding Vehicle from Images

Abstract: Sometimes the question arises whether it is possible to estimate the velocity of a speeding car recorded by closed circuit television cameras. By estimating the travelled distance of the car between two images and the time elapsed, estimation of the velocity is rather straightforward. However, to quantify the corresponding measurement uncertainty, the data analysis becomes more involved. The article describes two approaches as to how to derive the measurement uncertainty. In the first method, distance and timing are estimated separately, and the two uncertainties are combined to derive the measurement uncertainty for the velocity. For this, a frequentist and a Bayesian approach are described. In the second method, the measurement uncertainty for the speed is derived directly using validation recordings of a car driving by at known speed. The choice which method to use depends mainly on the length of the path that the car has travelled.     

A Forensic Examination of Online Search Facility URL Record Structures

The use of search engines and associated search functions to locate content online is now common practice. As a result, a forensic examination of a suspect's online search activity can be a critical aspect in establishing whether an offense has been committed in many investigations. This article offers an analysis of online search URL structures to support law enforcement and associated digital forensics practitioners interpret acts of online searching during an investigation. Google, Bing, Yahoo!, and DuckDuckGo searching functions are examined, and key URL attribute structures and metadata have been documented. In addition, an overview of social media searching covering Twitter, Facebook, Instagram, and YouTube is offered. Results show the ability to extract embedded metadata from search engine URLs which can establish online searching behaviors and the timing of searches.     

The Effects of High Dynamic Range on Fingerprint Images Processed by Photoshop

High dynamic range (HDR) imaging is a function that combines five images with different exposures into a single image. This technique may provide fine ridge details of fingerprint images for forensic latent fingerprint examination. Therefore, viewing fingerprints under optimal conditions is of paramount importance. This paper analyzes HDR and non‐HDR photos by using the Michelson contrast formula. The Michelson formula will provide a measurement to determine whether better contrast between the background and print can be achieved using the HDR function and if the background color affects the quality of the images. Two hypothesis were tested: (i) the HDR image provides more details of fingerprints with a better tone, greater clarity, and contrast than a normally exposed image regardless of the background color; (ii) the background color does not affect the quality of HDR fingerprint images overall, but the multi‐color background may increase the contrast of HDR fingerprint images in some cases.     

An Evidence‐Based Forensic Taxonomy of Windows Phone Communication Apps

Communication apps can be an important source of evidence in a forensic investigation (e.g., in the investigation of a drug trafficking or terrorism case where the communications apps were used by the accused persons during the transactions or planning activities). This study presents the first evidence‐based forensic taxonomy of Windows Phone communication apps, using an existing two‐dimensional Android forensic taxonomy as a baseline. Specifically, 30 Windows Phone communication apps, including Instant Messaging (IM) and Voice over IP (VoIP) apps, are examined. Artifacts extracted using physical acquisition are analyzed, and seven digital evidence objects of forensic interest are identified, namely: Call Log, Chats, Contacts, Locations, Installed Applications, SMSs and User Accounts. Findings from this study would help to facilitate timely and effective forensic investigations involving Windows Phone communication apps.     

吉林省数字农业赋能乡村振兴之考量

数字农业是乡村振兴战略的重要发力点.以数字化引领农业农村现代化,能够让乡村振兴有"智"更有"质".吉林省在数字农业发展上已取得了一定的成效,但农业农村数字化发展仍总体滞后,城乡数字化发展不均衡、项目规划脱离实际、科技创新成果转化难等问题依然存在.新时期,吉林省应抓住产业数字化、数字产业化赋予的机遇,加快推进数字农业建设...     

对我国电子商务合同相关法律问题的探讨

随着互联网技术的突飞猛进,电子商务在发达国家及国内开展得十分活跃,而电子商务合同作为电子商务运转的 重要基础和工具也被人们广泛运用,极大地推动了数字经济的发展。2005年4月1日我国第一部《电子签名法》 将正式实施,对于电子商务所涉及的电子交易安全问题,法院有了一部认定和裁决的法律依据。试图从电子商务 合同的特点及其订立和履行中所涉及的法律问题进行一些探讨。     

Living in the Era of Digital Exhibitionism

Digitally mediated communication technologies have fundamentally changed the problem of child sexual abuse. Sexually explicit images of young people that can be found online range from those documenting offline abuse including adult-to-child and peer-on-peer violence, to self-generated images including those taken within the context of a coercive relationship or those that are shared online beyond the taker's control. Online availability of these images can have serious effects on victims. It is vital to identify what victims need, how youngsters are at risk online, how self-generated images may be shared online beyond the taker's control, and how children who have been traumatized by experiences of sexual abuse (offline as well as online) can be taught to stay safe online. This article summarizes the results of four different studies exploring these issues.     

Sexting girls: technological sovereignty and the digital

This essay explores the contemporary fact of girls sexting. Instead of theoretically granting girls a form of technological sovereignty while sexting as sexual empowerment, it pauses to take a selfie of the adult subjects – parents, educators, and sex-positive feminists and queers – attached to this form of agency for girls. If sexuality remains an alluring reparative trap by offering, through a reverse discourse sustained by the plasticity of girlish whiteness, a way of transforming girls as objects into subjects, this essay problematizes that gesture as a racially normative one, reading it further alongside the relation of technology to sexual difference. To speculate on how the scenography of sexting could be seen differently by adults, this essay suspends the search for authentic meaning and knowledge, following an intuition that we cannot presently see anything behind the image of the sext. After examining how criminal law breaks the tension in the definition of “the girl” between vulnerability and agency by extending objectification through child-pornography law, the essay takes a speculative turn with feminist readings of the question of modern technology to consider the analytic and pedagogical purchase of the non-sovereignty of the girl who sexts.