Computational periscopy with an ordinary digital camera

Computing the amounts of light arriving from different directions enables a diffusely reflecting surface to play the part of a mirror in a periscope—that is, perform non-line-of-sight imaging around an obstruction. Because computational periscopy has so far depended on light-travel distances being proportional to the times of flight, it has mostly been performed with expensive, specialized ultrafast optical systems^1,2,3,4,5,6,7,8,9,10,11,12. Here we introduce a two-dimensional computational periscopy technique that requires only a single photograph captured with an ordinary digital camera. Our technique recovers the position of an opaque object and the scene behind (but not completely obscured by) the object, when both the object and scene are outside the line of sight of the camera, without requiring controlled or time-varying illumination. Such recovery is based on the visible penumbra of the opaque object having a linear dependence on the hidden scene that can be modelled through ray optics. Non-line-of-sight imaging using inexpensive, ubiquitous equipment may have considerable value in monitoring hazardous environments, navigation and detecting hidden adversaries.We thank F. Durand, W. T. Freeman, Y. Ma, J. Rapp, J. H. Shapiro, A. Torralba, F. N. C. Wong and G. W. Wornell for discussions. This work was supported by the Defense Advanced Research Projects Agency (DARPA) REVEAL Program contract number HR0011-16-C-0030. (HR0011-16-C-0030 - Defense Advanced Research Projects Agency (DARPA) REVEAL Program)Accepted manuscrip

Using evaluation to create "provisional stabilities": bridging innovation in Higher Education change process

This paper will report on the evaluation experience in two SOCRATES (European Union funding mechanism designed to support innovation in teaching and learning) projects focused on change in Higher Education. The projects were international in scope involving 6 countries and 10 institutions within the last four years. The paper reflects on change in institutions specifically, especially those introduced by the use of ICT (Information and Communication Technologies) and it suggests the hypothesis that in such a phase of transition, new rules are not yet established and a state of anomie can occur at the level of courses, departments and institutions. What happens in educational institutions in which rules and practices are well established and validated and a new event radically changes or challenges the traditional practices? Instead of the psycho-social notion of 'resistance to change', we think that the theory of Durkheim and followers which analyses human responses in times of social change may be of use to interpret situations in which change or the will to change creates conflicting systems of rules and practices. The paper will argue for a crucial role for evaluation in negotiating such periods of change.provisional stabilities ; innovation ; Higher Education ; evaluation

The vulnerability of shrimp farming income to climate change events

Purpose This paper aims to investigate shrimp income losses of farmers in the four farming systems in the research areas of Ca Mau, Vietnam, and determine the vulnerability of shrimp farming income to climate change events. Design/methodology/approach Field research interviews were conducted with 100 randomly selected households across the four farming systems to access shrimp income status and vulnerability levels to climate change events. Four focus groups, each aligned to a particular farming system, were surveyed to categorise likelihood and consequences of climate change effects based on a risk matrix worksheet to derive levels of risk, adaptive capacity and vulnerability levels. Findings Shrimp farmers in the study areas have been facing shrimp income reduction recently and shrimp farming income is vulnerable to climate change events. There are some differences between farmers’ perspectives on vulnerability levels, but some linkages are evident among shrimp farmer characteristics, ramifications for each farming system, shrimp income losses and shrimp farmers’ perspectives on vulnerability levels of shrimp incomes. From an income perspective, farmers operating in intensive shrimp farming systems appear to be less vulnerable to existing and expected climate change effects relative to those in mixed production or lower density systems. Originality/value Having identified the vulnerability level of shrimp farming income to climate change events in different farming systems based on shrimp farmers’ perspectives, the paper adds new knowledge to existing research on vulnerability of the aquaculture sector to climate change. The research findings have implications for policymakers who may choose to encourage intensive shrimp farming to enhance shrimp farmer resilience to the effects of climate change as well as improving cultivation techniques for shrimp farmers. The findings could thus guide local government decision-making on climate change responses and residents of Ca Mau as well as within the wider Mekong Delta in developing suitable practical adaption measures

The Uptake of HO₂ on Meteoric Smoke Analogues

The kinetics of heterogeneous HO2 uptake onto Meteoric Smoke Particles (MSPs) has been studied in the laboratory using analogues of MSP aerosol entrained into a flow tube. The uptake coefficient, y, was determined on synthetic amorphous olivine (MgFeSiO4) to be (6.9 ± 1.2) × 10‐2 at a relative humidity (RH) of 10%. On forsterite (Mg2SiO4), y = (4.3 ± 0.4) × 10‐3 at RH = 11.6%, and (7.3 ± 0.4) × 10‐2 at RH = 9.9% on fayalite (Fe2SiO4). These results indicate that Fe plays a more important mechanistic role than Mg in the removal of HO2 from the gas phase. Electronic structure calculations show that Fe atoms exposed at the particle surface provide a catalytic site where HO2 is converted to H2O2 via an Eley‐Rideal mechanism, but this does not occur on exposed surface Mg atoms. The impact of this heterogeneous process in the middle atmosphere was then investigated using a whole atmosphere chemistry‐climate model which incorporates a microphysical treatment of MSPs. Using a global MSP production rate from meteoric ablation of 44 tons per day, heterogeneous uptake (with y = 0.2) on MSPs significantly alters the HOx budget in the night‐time polar vortex. This impact is highly latitude dependent and thus could not be confirmed using currently available satellite measurements of HO2, which are largely unavailable at latitudes greater than 70°

Examining the impact of evaluation professionalization in Canada on the positioning, practice and employability of evaluators

This thesis presents an exploration of the impact of evaluation professionalization through credentialization, with a particular focus on the Canadian context, where the Canadian Evaluation Society (CES) has pioneered the Professional Designation Program (PDP) incorporating the 'CE' designation. Employing a mixed, multi-methods approach, this study sought to address research questions concerning the positioning, practice and employability of evaluators. The overarching research question examined the effects of evaluation professionalization in Canada, while sub-research questions compared the Canadian model to international counterparts, delved into the experiences of 'CE' designated evaluators, and drew insights from the application of a credential for evaluation in the Canadian context. Research findings revealed multifaceted impacts, highlighting that evaluation is a social construct affecting professionalization, identifying barriers to qualification-based approaches, and emphasizing the multidimensionality of professionalization's impact in Canada. The study's outcomes contribute valuable insights to the field of evaluation professionalization, providing guidance for practitioners, policymakers, and professional associations in Canada and globally. Ultimately, this research advances our understanding of the complexities surrounding evaluation professionalization and seeks to bolster the evaluation profession's development on a broader scale