Three-dimensional surface reconstruction for cartridge cases using photometric stereo

In forensic science, automated firearms identification is an important and yet unsolved problem. On the way to the solution, one of the most important phases is data acquisition. To be able to identify firearms in a reliable way, all the striated and impressed marks on metallic surfaces of cartridge cases should be visible. But two-dimensional images of cartridge cases are very sensitive to the type and direction of the light source(s). Depending on illumination conditions, the images of marks change drastically and sometimes they simply disappear. But, if the three-dimensional (3D) topography of the surface is obtained, the geometry of the marks, which is independent of the illumination, is available. Thus, by providing illumination independent features that can be used for automated matching, 3D data have the potential to make automated matching much reliable. In the literature on data acquisition for automated firearms identification, a few different ways of three-dimensional surface extraction are described, like laser interferometry or laser profilometry. This study presents a real life application of another method, photometric stereo, for the acquisition of 3D topographic data for cartridge cases, which is the one used in BALISTIKA Ballistics Image Analysis and Recognition System. In order to construct 3D topographic data, first of all, two-dimensional images were acquired using a specially designed set-up. After the images were calibrated radiometrically, photometric stereo method was applied. In order to minimize the low-frequency errors in the final surface, a surface-fitting algorithm was used. The method uses low-cost equipment and image acquisition is not time-consuming. Results were compared to interferometric measurement values for error assessment.     

Born Weak,Growing Strong: Anti‐Government Protests as a Signal of Rebel Strength in the Context of Civil Wars

All rebel organizations start weak, but how do they grow and achieve favorable conflict outcomes? We present a theoretical model that allows for rebel organizations to gain support beyond their “core” and build their bargaining power during fighting. We highlight that rebel organizations need to win over crucial parts of society to generate the necessary support that allows them to attain favorable civil conflict outcomes. We find empirical support for the argument that low‐income individuals who initially fight the government (rebel organizations) have to convince middle‐class individuals to turn out against the government to gain government concessions. Empirically, we demonstrate that government concessions in the form of peace agreements and the onset of negotiations become more likely when protest occurs in the context of civil conflicts.

Replication Materials

The data, code, and any additional materials required to replicate all analyses in this article are available on the American Journal of Political Science Dataverse within the Harvard Dataverse Network, at: http://doi.org/10.7910/DVN/MYDZNF .

     

Alfred Kazin and Poetry

Both memoir and literary criticism, this piece by Alfred Kazin’s daughter describes her father’s relationship to poetry through the lens of musicality. She suggests that what drove Alfred Kazin’s writing on poetry was not argumentation but rather what he himself called a “terrible and pulsating musical sense,” capable of vanquishing lifelong feelings of isolation and loneliness.     

US Media and Post-9/11 Human Rights Violations in the Name of Counterterrorism

This article adds to earlier research revealing that the American news media did not discharge their responsibility as a watchdog press in the post-9/11 years by failing to scrutinize extreme and unlawful government policies and actions, most of all the decision to invade Iraq based on false information about Saddam Hussein’s alleged weapons of mass destruction arsenal. The content analyses presented here demonstrate that leading US news organizations, both television and print, did not expressly refer to human rights violations when they reported on the torturing of foreign detainees during “enhanced interrogations” in US-run prison facilities abroad and the killing of civilians, including children, in US drone strikes overseas and outside theaters of war. Moreover, by framing torture and the “collateral damage” caused by drone-launched missile attacks episodically rather than in the context of human rights, the news media failed to alert the American public to the grave humanitarian violations in the so-called war on terrorism during the George W. Bush and Barack Obama administrations.     

Self-legitimation in the face of politicization: Why international organizations centralized public communication

International organizations (I0) have centralized their public communication to a large extent over recent decades by undertaking a broader codification of communication tasks as well as a departmentalization of these tasks within units of IO bureaucracies. The paper provides the first systematic analysis of this important development in institutional design using a novel data set on the organization of public communication in 48 IOs between 1950 and 2015. It identifies self-legitimation as a key driver of centralization in the face of increased levels of politicization, that is, public awareness and activism directed at IOs. Empirically, the study suggests that the centralization of public communication significantly increases as transnational civil society organizes and gains access to IO decision-making. Further, politicization in terms of contentious activism and public scandals substantially accounts for varying levels of centralization across IOs.