Visualization of Latent Blood Stains Using Visible Reflectance Hyperspectral Imaging and Chemometrics

The detection of latent traces is an important aspect of crime scene investigation. Blood stains on black backgrounds can be visualized using chemiluminescence, which is invasive and requires a darkened room, or near-infrared photography, for which investigators need to change filters manually to optimize contrast. We demonstrated the performance of visible reflectance hyperspectral imaging (400–720 nm) for this purpose. Several processing methods were evaluated: single wavelength bands, ratio images, principal component analysis (PCA), and “SIMPLe-to-use Interactive Self-modeling Mixture Analysis” (SIMPLISMA). Using these methods, we were able to enhance the contrast between blood stains and 12 different fabrics. On black cotton, blood dilutions were visible with a minimal concentration of 25% of whole blood. The hyperspectral camera system used in this study is portable and wireless, which makes it suitable for crime scene use. The described technique is noncontact and nondestructive, so all traces are preserved for further analysis.     

对当前"青春偶像剧"的危机性透视

青春偶像剧对于"青春恋情"这一大众母题的开掘落入了唯"视觉化"的误区;"抄袭"与"跟风"的弊病,暴露了当前偶像剧生产中较为落后的生产机制与方式;相对单一、封闭的文化格局,使得青春偶像剧失去了"开放性"和"大众性".所有这些既影响了青春偶像剧的"收视率",也断送了自己的艺术提升之路.     

How to Cautiously Uncover the “Black Box” of Machine Learning Models for Legislative Scholars

Machine learning models, especially ensemble and tree-based approaches, offer great promise to legislative scholars. However, they are heavily underutilized outside of narrow applications to text and networks. We believe this is because they are difficult to interpret: while the models are extremely flexible, they have been criticized as “black box” techniques due to their difficulty in visualizing the effect of predictors on the outcome of interest. In order to make these models more useful for legislative scholars, we introduce a framework integrating machine learning models with traditional parametric approaches. We then review three interpretative plotting strategies that scholars can use to bring a substantive interpretation to their machine learning models. For each, we explain the plotting strategy, when to use it, and how to interpret it. We then put these plots in action by revisiting two recent articles from Legislative Studies Quarterly.     

Can the RUVIS Reflected UV Imaging System Visualize Fingerprint Corrosion on Brass Cartridge Casings Postfiring?

Comparisons are made between the visualization of fingerprint corrosion ridge detail on fired brass cartridge casings, where fingerprint sweat was deposited prefiring, using both ultraviolet (UV) and visible (natural daylight) light sources. A reflected ultraviolet imaging system (RUVIS), normally used for visualizing latent fingerprint sweat deposits, is compared with optical interference and digital color mapping of visible light, the latter using apparatus constructed to easily enable selection of the optimum viewing angle. Results show that reflected UV, with a monochromatic UV source of 254 nm, was unable to visualize fingerprint ridge detail on any of 12 casings analyzed, whereas optical interference and digital color mapping using natural daylight yielded ridge detail on three casings. Reasons for the lack of success with RUVIS are discussed in terms of the variation in thickness of the thin film of metal oxide corrosion and absorption wavelengths for the corrosion products of brass.     

Visualizing Digital Forensic Datasets: A Proof of Concept

Digital forensic visualization is an understudied area despite its potential to achieve significant improvements in the efficiency of an investigation, criminal or civil. In this study, a three‐stage forensic data storage and visualization life cycle is presented. The first stage is the decoding of data, which involves preparing both structured and unstructured data for storage. In the storage stage, data are stored within our proposed database schema designed for ensuring data integrity and speed of storage and retrieval. The final stage is the visualization of stored data in a manner that facilitates user interaction. These functionalities are implemented in a proof of concept to demonstrate the utility of the proposed life cycle. The proof of concept demonstrates the utility of the proposed approach for the storage and visualization of digital forensic data.     

Changes in Fingerprints Depending on Physiological Factors

The aim of the study was to determine the effect of gender, body mass index, and time on the width of friction ridge impressions in fingerprints and the content of sweat and sebum forming the print. The research showed that the friction ridge impressions of women are significantly wider than those of men, and this tendency persists throughout the existence of the print. The differences may result from the anatomical structure of the skin, as well as from the use of protective products such as creams, which are used more often by women. The width of friction ridge impression is similar in underweight and overweight people, but greater than in those with normal body weight, and the amount of sweat and sebum increases with body weight. The passage of time significantly reduces both the width of the friction ridge impression and the content of sweat and sebum secretions in the print.     

Enhanced Visualization of Latent Fingermarks on Rough Aluminum Surfaces Using Sequential Au and Zn/ZnS/ZnO Depositions

Detection and visualization of fingermarks on rough and diffuse surfaces is a relatively challenging task. We succeeded in developing latent fingermarks on scratched and rough aluminum surfaces by sequential deposition of a thin layer of gold followed by one of zinc or zinc‐based compounds on the fingermarks. The best image enhancement was achieved with sequential Au and ZnS depositions. Using this combination, we could enhance the visualization of latent fingermarks aged over 65 days in normal conditions. The optical reflectance from the fingermarks with the deposited layers of metal/dielectric is analyzed as a stratified medium. Significant contrast in the reflectance from the regions of the ridges and the valleys of the fingermark would enhance the visualization. Our results show that the Au and ZnS bi‐layer combination can have a large reflection contrast and improved fingermark visualization at wavelengths corresponding to the green light for specific thickness of ZnS.     

《大学》的义理性格

经过多方求证,可以认定《大学》的单独成书是在南宋孝宗年间。通过对《大学》义理的纲要即“三纲领”和“八条目”的内涵分析,“格物”是成就工夫的起点。对“格物”,不同时期和不同儒者有不同的理解,但体现出一个发展的方向。     

Visualization of latent fingerprints using fluorescence lifetime imaging on paper emitting strong fluorescence

Latent fingerprints were successfully visualized using fluorescence lifetime imaging (FLIM) on paper which emits strong fluorescence with a lifetime close to that of fingerprints and thus from which it is difficult for time-resolved spectroscopy to visualize fingerprints. Latent fingerprint samples on paper were excited using a 450 nm or 532 nm nanosecond pulsed-laser, and time-resolved fluorescence images were obtained at a delay time of 6–16 ns in intervals of 1 ns, to the excitation pulse. The excitation beam was expanded using a lens, and the fluorescence from the fingerprints was captured using an intensified CCD camera. Because of the large fluorescence intensity of the background paper of approximately two to four orders of magnitude larger than that of the fingerprint, the fingerprint was not visualized on each fluorescence image by time-resolved spectroscopy. However, the fingerprint was visualized in a FLIM image constructed using a series of the fluorescence images for the case with the fluorescence intensity of the background paper being four orders of magnitude larger than that of the fingerprint. The difference in fluorescence lifetime in the FLIM image of the visualized fingerprint and background paper was in the order of 0.1 ns, which was an order of magnitude smaller than the inherent fluorescence lifetime of a few nanoseconds for the fingerprints and paper. It was demonstrated that, at a background fluorescence intensity with a certain order of magnitude larger than that of fingerprints, FLIM has the potential to visualize latent fingerprints which cannot be visualized by time-resolved spectroscopy.     

基于经验法则的法律论证

我国法官的裁判文书说理欲实现规范化,必须重视法律论证,为每个主张与判断提供充分的理由。最高人民法院的指导意见表明经验法则是法官进行法律论证的重要理由。经验法则作为一种实践描述能够推动法律论证填补规范缝隙。在事实认定的论证环节,经验法则既是证明规则与证据规则的形成背景,更是事实推定的直接依据。只有妥善把握经验法则的盖然性,才能规避逆谬误与后见偏差等认知陷阱,合理借助经验法则论证三段论中的小前提。在法律适用的论证环节,经验法则是类比过程中相似点与规范效果之间相关性的判断依据。法官可以借助经验法则论证立法理由与事物本质,进而根据法律目的判断相似点的相关性。基于经验法则的法律论证既能回应当下释法说理的需求,也是法律论证理论扎根中国司法土壤的尝试。