Automated bullet-identification system based on surface topography techniques

Every firearm has individual characteristics that are as unique to it as fingerprints are to human beings. When a firearm is fired, it transfers these characteristics – in the form of microscopic scratches and dents – to the fired bullets and cartridge casings. The rifling of the barrel of the firearm marks the bullets travelling through it, and the firearm's breech mechanism marks the ammunition's cartridge casing. Characterising these marks is the critical element in identifying firearms. Traditionally the comparison of ballistic evidence has been a tedious and time-consuming process requiring highly skilled examiners. In the past decade, engineers have created automated ballistics identification systems that meld traditional comparison microscopes with digital cameras, computers, huge databases, and image analysis techniques. This kind of system can help investigators to link crimes by automatically finding similarities among images of bullet but suffering significant drawbacks and minimal matching. More recently, approaches based on 3D digital representations of evidence surface topography have started to appear, both in research and industrial products. Potentially the introduction of 3D surface topography measurement can overcome the limitations of digital imaging systems by making the bullet surface measurement reproducible and reliable. A 3D quantitative approach for bullet identification is proposed in this paper. In this system the surface topography of the whole bullet can be acquired for analysis and identification. Primary researches have been done by applying advanced surface topography techniques for bullet marks’ characteristics extraction. A variety of 2D and 3D visualization graphics have also been provided to help firearm examiners to make final decisions

Transformation Model With Constraints for High Accuracy of 2D-3D Building Registration in Aerial Imagery

This paper proposes a novel rigorous transformation model for 2D-3D registration to address the difficult problem of obtaining a sufficient number of well-distributed ground control points (GCPs) in urban areas with tall buildings. The proposed model applies two types of geometric constraints, co-planarity and perpendicularity, to the conventional photogrammetric collinearity model. Both types of geometric information are directly obtained from geometric building structures, with which the geometric constraints are automatically created and combined into the conventional transformation model. A test field located in downtown Denver, Colorado, is used to evaluate the accuracy and reliability of the proposed method. The comparison analysis of the accuracy achieved by the proposed method and the conventional method is conducted. Experimental results demonstrated that: (1) the theoretical accuracy of the solved registration parameters can reach 0.47 pixels, whereas the other methods reach only 1.23 and 1.09 pixels; (2) the RMS values of 2D-3D registration achieved by the proposed model are only two pixels along the x and y directions, much smaller than the RMS values of the conventional model, which are approximately 10 pixels along the x and y directions. These results demonstrate that the proposed method is able to significantly improve the accuracy of 2D-3D registration with much fewer GCPs in urban areas with tall buildings

Response of polar regions to emerging organic pollutant organophosphorus esters (OPEs), a review

Polar regions are free from major anthropogenic impact due to their remoteness. However, certain pollutants can be transported there via atmospheric and/or oceanic circulations. Here we present an overview of current research on organophosphorus esters (OPEs) in polar regions by reviewing the literature on distribution, source and transport of OPEs. Current research on OPEs reveals significant anthropogenic influences in both polar regions. As well as the expected occurrence in the Arctic, OPEs were found on the Antarctic Ice Sheet up to 650 km from the coast, and the OPE concentrations were higher at high elevation due to cold climate retention. The immediate source of OPEs for inland Antarctica might be the Southern Ocean surrounding the continent, where OPEs in aerosols and seawater showed comparable concentrations to remote areas in the European Arctic. A positive correlation between aerosol OPEs in the open water and the surface vortex of ocean currents indicates that these compounds may be transported and accumulated in the ocean currents. The Antarctica Circumpolar Current accumulates them in the marginal seas of Antarctica

The effect of biculturalism on executive functions

Much debate in the field of bilingualism has centred around a bilingual’s advantage in Executive Functions (For a recent review, see Lehtonen et al., 2018). In light of recent conflicting evidence regarding the premise of a bilingual advantage, scholars have begun to scrutinize possible variables and confounds arising from differences in the broader social and interactional environment (de Bruin, 2019). While variables such as proficiency, immigration, and age of acquisition have received much attention over the years, there is still a paucity of research into culture as a variable exerting an effect on bilingualism. To the best of our knowledge, the few studies considering the impact of culture on bilingual’s Executives Functions group participants on the macro-level culture that is commonly associated with their nationality (e.g. Samuel, Roehr-Brackin, Pak,& Kim, 2018; Tran, Arredondo,& Yoshida, 2015). Yet, this does not capture a sufficiently nuanced perspective of the cultural diversity among bilingual populations (Grosjean, 2015). This thesis is the first to explore the effects of biculturalism on Executive Functions among bicultural-bilinguals. Study 1 surveyed 252 bilingual Singaporean young adults to provide an overview of how they viewed language and their ethnic cultural identities. The results show that the majority of Singaporean young adults (71.7%) were bicultural. The likelihood of biculturalism was predicted by their ethnic language proficiency and bilingual status (Balanced vs. Unbalanced). To augment the self-report data in the first study, Study 2 integrates self-report questionnaire data on cultural and language behaviour with a priming experiment (cultural frame switching, adapted from Hong, Morris, Chiu,& Benet-Martinez,2000) to provide empirical evidence of bilingual Singaporean young adults ability to switch between cultural frames. 233 participants from Study 1 continued with this follow up study, and the results suggest that Singaporean young adults were not only bicultural but were also able to switch between different cultures when primed with Western and ethnic cultural primes. Individuals who switched between cultural frames more frequently made a clearer distinction between Western primes than those who switched between cultural frames less frequently, suggesting that cultural primes impact cognition differentially depending on their frequency of switching between cultures. Study 3 explored the effect of cultural switching frequency on 48 young adult bicultural bilinguals’ performance on tests for interference and inhibition-control (Simon and Flanker tasks), set-shifting ability (Wisconsin Card Sort Task), and attention (Attention Network Task). Frequent cultural switchers had an advantage in resolving stimulus-response conflict significantly faster in the Flanker task, were better at maintaining set in the Wisconsin Card Sort Task, and had a smaller CONFLICT effect compared to infrequent switchers in the Attention Network Task. Taken together, this thesis has implications for future studies of bilingual populations, as the bicultural switching effects on interference and inhibition-control persists even after tightly controlling for key socio-linguistic variables including bilingual proficiency, age of acquisition, IQ, socio-economic status and age. Our research underscores the importance of considering socio-cultural variables in future studies examining a bilingual advantage in Executive Functions.Master of Art

Urban 3D Building Model Applied to True Orthoimage Generation

Three dimensional (3D) building models are increasingly necessary for urban planning, tourism, etc. How to effectively describe the architectural objects becomes a key point due to the fact that the urban buildings extremely vary in height, sizes, shapes, textures, etc. This paper presents a model for exactly describing urban 3D buildings for large-scale urban true orthoimage generation. This method is based on CSG (Constructive Solid Geometry), belonging to volumetric representation in computer graphics. This method is well suited to describing complex shapes, which can be composed by a set of primitives. Within this proposed approach the buildings are described by combining a set of basic primitives, such as box, wedge, and rectangular pyramid. This representation model is particularly useful for urban true orthoimage generation because a complex building in this model can be partitioned into many simple building parts, each of them corresponding to a basic building model. We implemented this work using the ground plan information according to digital surface model. The ground plan of a building is divided in rectangles, arcs, and circles- each of the primitives representing the ground plane of a building part. The primitives are combined by means of the Boolean operations union, intersection, and difference. So, the buildings will be described as a CSG tree. Our experimental result in Downtown, Denver, Colorado demonstrated our method can effectively and exactly represent the complex buildings, and produce high accuracy when applied in urban true orthoimage generation

Bilingualism, Culture, and Executive Functions: Is There a Relationship?

The relationship between executive functions (EF) and bilingualism has dominated debate in the field. This debate was characterised by optimism for a bilingual advantage until the last decade, when a steady stream of articles reported failure to find a consistently positive effect for bilingualism. In addition to addressing concerns about study quality, this turn of events has spurred research into other variables that may explain the conflicting findings. While recent studies have focused on sociodemographic variables and interactional contexts such as age, code-switching frequency, and socioeconomic class to account for various group and individual differences, the impact of culture is seldom scrutinised. This paper examines the possible effect of culture among bilingual studies on EF by first contextualising how bilingual EF are studied and outlining the absence of culture as a macro variable, followed by a discussion on how culture and language are often conflated. This paper directs attention to the small but emerging research that tracks the importance of culture as a separate variable from language. This review discusses why macro culture and individual monoculturalism or biculturalism need to be carefully elucidated as a factor that can interact with the bilingual experience in shaping EF