Looking Around the Corner using Ultrafast Transient Imaging

We propose a novel framework called transient imaging for image formation and scene understanding through impulse illumination and time images. Using time-of-flight cameras and multi-path analysis of global light transport, we pioneer new algorithms and systems for scene understanding through time images. We demonstrate that our proposed transient imaging framework allows us to accomplish tasks that are well beyond the reach of existing imaging technology. For example, one can infer the geometry of not only the visible but also the hidden parts of a scene, enabling us to look around corners. Traditional cameras estimate intensity per pixel I(x,y). Our transient imaging camera captures a 3D time-image I(x,y,t) for each pixel and uses an ultra-short pulse laser for illumination. Emerging technologies are supporting cameras with a temporal-profile per pixel at picosecond resolution, allowing us to capture an ultra-high speed time-image. This time-image contains the time profile of irradiance incident at a sensor pixel. We experimentally corroborated our theory with free space hardware experiments using a femtosecond laser and a picosecond accurate sensing device. The ability to infer the structure of hidden scene elements, unobservable by both the camera and illumination source, will create a range of new computer vision opportunities.     

Pure and Pt-loaded gamma iron oxide as sensor for detection of sub ppm level of acetone

In this study, pure and Pt-loaded nanocrystalline γ-Fe₂O₃ have been prepared by precipitation using ultrasonic irradiation. The synthesized powders were characterized by X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), differential thermal analysis (DTA), transmission electron micrograph (TEM), selected area electron diffraction (SAED), scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Pure nanocrystallline γ-Fe₂O₃ sensors were found to show good response towards sub ppm level of acetone at 250 °C, and improves significantly on Pt loading. As an example, 1 wt% Pt loading of nanocrystallline γ-Fe₂O₃ increased its response towards acetone by 55%. The high response of γ-Fe₂O₃ holds it as a potentially promising candidate for acetone detection which may lead for the non-invasive testing of diabetics.     

Host emission from BaMgAl10O17 and SrMgAl10O17 phosphor: Effects of temperature and defect level

Abstract— Understanding the mechanism of blue‐light emission in Eu‐doped BAM phosphor as well as its sensitive degradation is required because this is a very important material in fluorescent lamps and plasma‐display panels. In this study, both theoretical and experimental investigations on the host emissions in BaMgAl¹⁰O¹⁷ and SrMgAl¹⁰O¹⁷ were performed. Host emissions from BaMgAl¹⁰O¹⁷ and SrMgAl¹⁰O¹⁷ by photoluminescence and thermoluminescence spectra were observed. Photoluminescence spectra suggested that the host emission from SrMgAl¹⁰O¹⁷ was easily quenched by thermal vibrations. The thermoluminescence spectra showed the existence of shallow and deep defect levels in BaMgAl¹⁰O¹⁷ and SrMgAl¹⁰O¹⁷ phosphors. It was shown that SrMgAl¹⁰O¹⁷ and its conduction plane could undergo degradation during irradiation of vacuum‐ultra‐violet (VUV) lights based on the calculated energy of formation of an oxygen vacancy. Moreover, the structural defects, such as oxygen vacancies, would cause localizing levels in the upper level in the valence band and in theconduction band. The results suggest the contribution of the host emission to the energy transfer to the Eu atoms would not be significant and the oxygen vacancies would act as the traps for excited carriers.     

Modeling climate change uncertainties in water resources management models

The impact of climate change on hydrologic design and management of hydrosystems could be one of the important challenges faced by future practicing hydrologists and water resources managers. Many water resources managers currently rely on the historical hydrological data and adaptive real-time operations without consideration of the impact of climate change on major inputs influencing the behavior of hydrologic systems and the operating rules. Issues such as risk, reliability and robustness of water resources systems under different climate change scenarios were addressed in the past. However, water resources management with the decision maker’s preferences attached to climate change has never been dealt with. This short paper discusses issues related to impacts of climate change on water resources management and application of a soft-computing approach, fuzzy set theory, for climate-sensitive management of hydrosystems. A real-life case study example is presented to illustrate the applicability of a soft-computing approach for handling the decision maker’s preferences in accepting or rejecting the magnitude and direction of climate change.     

A systemic approach to integrated E-maintenance of large engineering plants

Large engineering plants (LEPs) have certain unique features that necessitate a maintenance strategy that is a combination of both time and condition based maintenance. Although this requirement is appreciated to varying degrees by asset owners, applied research leading to a systematic development of such a maintenance strategy is the need of the day. Such a strategy should also adopt a wholesome ``systemic' approach so that the realization of the overall objectives of maintenance is maximized. E-maintenance has several potential benefits for large engineering plants. In this paper, a three pronged strategy is suggested for the successful implementation of e-maintenance for LEPs. Firstly, an integrated condition and time based maintenance framework is proposed for LEPs. Secondly, reference is drawn to models for condition and time based maintenance at systemic levels. As a part of the ab initio development of a condition monitoring system for a LEP, one of the characteristics of the condition monitoring system, namely, predictability, is discussed in detail as a sample for a systemic study. Thirdly, emphasis is laid on the information and expertise available in the domain of plant design, operation and maintenance and the same is tapped for incorporation in maintenance decision making.     

3D Printing of Microgel-Loaded Modular Microcages as Instructive Scaffolds for Tissue Engineering

Biomaterial scaffolds have served as the foundation of tissue engineering and regenerative medicine. However, scaffold systems are often difficult to scale in size or shape in order to fit defect-specific dimensions, and thus provide only limited spatiotemporal control of therapeutic delivery and host tissue responses. Here, a lithography-based 3D printing strategy is used to fabricate a novel miniaturized modular microcage scaffold system, which can be assembled and scaled manually with ease. Scalability is based on an intuitive concept of stacking modules, like conventional toy interlocking plastic blocks, allowing for literally thousands of potential geometric configurations, and without the need for specialized equipment. Moreover, the modular hollow-microcage design allows each unit to be loaded with biologic cargo of different compositions, thus enabling controllable and easy patterning of therapeutics within the material in 3D. In summary, the concept of miniaturized microcage designs with such straight-forward assembly and scalability, as well as controllable loading properties, is a flexible platform that can be extended to a wide range of materials for improved biological performance.     

Declarative Infrastructure Configuration Synthesis and Debugging

There is a large conceptual gap between end-to-end infrastructure requirements and detailed component configuration implementing those requirements. Today, this gap is manually bridged so large numbers of configuration errors are made. Their adverse effects on infrastructure security, availability, and cost of ownership are well documented. This paper presents ConfigAssure to help automatically bridge the above gap. It proposes solutions to four fundamental problems: specification, configuration synthesis, configuration error diagnosis, and configuration error repair. Central to ConfigAssure is a Requirement Solver. It takes as input a configuration database containing variables, and a requirement as a first-order logic constraint in finite domains. The Solver tries to compute as output, values for variables that make the requirement true of the database when instantiated with these values. If unable to do so, it computes a proof of unsolvability. The Requirement Solver is used in different ways to solve the above problems. The Requirement Solver is implemented with Kodkod, a SAT-based model finder for first-order logic. While any requirement can be directly encoded in Kodkod, parts of it can often be solved much more efficiently by non model-finding methods using information available in the configuration database. Solving these parts and simplifying can yield a reduced constraint that truly requires the power of model-finding. To implement this plan, a quantifier-free form, QFF, is defined. A QFF is a Boolean combination of simple arithmetic constraints on integers. A requirement is specified by defining a partial evaluator that transforms it into an equivalent QFF. This QFF is efficiently solved by Kodkod. The partial evaluator is implemented in Prolog. ConfigAssure is shown to be natural and scalable in the context of a realistic, secure and fault-tolerant datacenter.

Performance characterization in computer vision: A guide to best practices

It is frequently remarked that designers of computer vision algorithms and systems cannot reliably predict how algorithms will respond to new problems. A variety of reasons have been given for this situation and a variety of remedies prescribed in literature. Most of these involve, in some way, paying greater attention to the domain of the problem and to performing detailed empirical analysis. The goal of this paper is to review what we see as current best practices in these areas and also suggest refinements that may benefit the field of computer vision. A distinction is made between the historical emphasis on algorithmic novelty and the increasing importance of validation on particular data sets and problems.     

Synthesis of aluminum rich MCM-41

The synthesis of MCM-41 mesoporous compounds with Si/Al ratios as low as 2 without observing the presence of octahedral Al in²⁷AlMAS NMR is reported. FTIR spectra of chemisorbed pyridine indicated that MCM-41 materials in their protonated form exhibit both Brønsted and Lewis acid sites.