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Emerging role of machine learning in light-matter interaction
No full textMachine learning has provided a huge wave of innovation in multiple fields, including computer vision, medical diagnosis, life sciences, molecular design, and instrumental development. This perspective focuses on the implementation of machine learning in dealing with light-matter interaction, which governs those fields involving materials discovery, optical characterizations, and photonics technologies. We highlight the role of machine learning in accelerating technology development and boosting scientific innovation in the aforementioned aspects. We provide future directions for advanced computing techniques via multidisciplinary efforts that can help to transform optical materials into imaging probes, information carriers and photonics devices.LCS
Science, Democracy, and the Pursuit of Aliens
No full textIn 1902, a contributor to Popular Science affirmed that “The era of the amateur scientist is passing; science must now be advanced by the professional expert.” Throughout the twentieth century, amateurs have been increasingly excluded from the production of scientific knowledge. But since the 1990s, under the banner of “citizen science”, a growing number of initiatives have involved, once again, amateurs in science, with the goal of democratizing science, promoting scientific literacy, and solving big data problems. The creation of SETI@home at UC Berkeley in 1998 embodied all these aims. Within six month, it had attracted more than one million participants analyzing radio signals from space on their personal computer searching for signs of extraterrestrial life. The initiators of the project and the media constructed the image of the participant along the lines of an imagined amateur scientist making discoveries outside of scientific institutions, while contributing to the making of a global scientific citizenship. Infused by libertarian, countercultural, and cyber-utopian ideals, SETI@home seemed to capture the scientific aspirations of a new generation. But the tens of thousands of online biographical sketches left by the participants present a more nuanced picture. These traces offer a unique window into the self-fashioning of the participants into different kinds of “amateurs”, “volunteers”, and “hobbyists” with various views about professional science and its place in society. These sources helps us better understand the recent reconfigurations of the amateur scientist and, more generally, the struggles over the legitimacy of professional expertise.LHS
Relax and Recover: Guaranteed Range-Only Continuous Localization
No full textRange-only localization has applications as diverse as underwater navigation, drone tracking and indoor localization. While the theoretical foundations of lateration---range-only localization for static points---are well understood, there is a lack of understanding when it comes to localizing a moving device. As most interesting applications in robotics involve moving objects, we study the theory of trajectory recovery. This problem has received a lot of attention; however, state-of-the-art methods are of a probabilistic or heuristic nature and are not well suited for guaranteeing trajectory recovery. In this paper, we pose trajectory recovery as a quadratic problem and show that we can relax it to a linear form, which admits a closed-form solution. We provide necessary and sufficient recovery conditions and in particular show that trajectory recovery can be guaranteed when the number of measurements is proportional to the trajectory complexity. Finally, we apply our reconstruction algorithm to simulated and real-world data.LCAVThis work is licensed under a Creative Commons Attribution 4.0 License
280 Birds with One Stone: Inducing Multilingual Taxonomies from Wikipedia Using Character-Level Classification
No full textWe propose a novel fully-automated approach towards inducing multilingual taxonomies fromWikipedia. Given an English taxonomy, our approach first leverages the interlanguage links of Wikipedia to automatically construct training datasets for the is-a relation in the target language. Character-level classifiers are trained on the constructed datasets, and used in an optimal path discovery framework to induce high-precision, high-coverage taxonomies in other languages. Through experiments, we demonstrate that our approach significantly outperforms the state-of-the-art, heuristics-heavy approaches for six languages. As a consequence of our work, we release presumably the largest and the most accurate multilingual taxonomic resource spanning over 280 languages.LSI
Perovskite Solar Cells: 18% Efficiency Using Zn(II) and Cu(II) Octakis(diarylamine)phthalocyanines as Hole-Transporting Materials
No full textMetallophthalocyanines (MPcs) are currently emerging as alternative hole-transporting materials (HTMs) in perovskite solar cells (PSCs). However, the lack of systematic structure/photovoltaic properties investigations still hampers the rational design of MPcs that might act as efficient HTMs for PSCs. We designed and tested a series of symmetric MPcs (M = Zn(II) or Cu(II)) bearing eight diarylamino substituents of diverse type connected at the peripheral positions of the ligand through N-C bonds. The new MPcs were used as HTMs in solution-processed PSCs. The nature of the diarylamino substituents was found to play a major role in determining the photovoltaic parameters of the device. Comparison of devices fabricated using ZnPcs and their Cu analogs evidenced that the nature of the core metal cation has a more elusive influence. The highest power conversion efficiency of 18.10% was obtained using a ZnPcs bearing eight bis(p-butoxyphenyl)amino substituents.GM
Beyond Keyword Search: Semantic Indexing and Exploration of Large Collections of Historical Newspapers
No full textFor long held on library and archive shelving, historical newspapers are currently undergoing mass digitization and millions of facsimiles, along with their machine-readable content acquired via Optical Character Recognition, are becoming accessible via a variety of online portals. If this represents a major step forward in terms of preservation of and access to documents, much remains to be done in order to provide an extensive and sophisticated access to the content of these digital resources. We believe that the promise of newspaper digitization lies in their semantic indexation, closely tied with the development of co-designed interfaces that accommodate text analysis research tools and their usage by humanities scholars. How to go beyond keyword search? How to explore complex and vast amounts of data? Based on the on-going project ‘impresso - Media Monitoring of the Past’, in this talk I will present our interdisciplinary approach and share hands-on experience in going from facsimiles to enhanced search and visualization capacities supporting historical research.DHLABKeynote talk
Experimental and numerical study on wave-impact on buildings
No full textUnsteady flows such as tsunamis, impulse waves and dam-break waves can lead to damages and human losses. Hence, specific research to limit casualties and reconstruction costs is needed. The complexity of the phenomena involved suggests that a hybrid experimental-numerical approach should be used to gain a more comprehensive understanding of the process. This paper presents an explorative study on the comparison of SPH numerical simulations using a highly effective parallel computing technique with large scale experimental data for dry bed surges and wet bed bores impacting free-standing buildings with and without openings. These preliminary results showed a relatively good agreement between the two pproaches in the estimation of water depths around the buildings, which represents a key parameter for the design of vertical shelters. Nevertheless, some differences observed during the impact phase may be attributed to the incapability of the SPH numerical simulations to fully capture the turbulent nature of the process and its air-entrainment. These validation tests with detailed experimental data are a promising approach to improve the numerical models toward the development of reliable numerical tools for a safer design of resilient structures.PL-LCH[1299
The n-term Approximation of Periodic Generalized Levy Processes
No full textIn this paper, we study the compressibility of random processes and fields, called generalized Levy processes, that are solutions of stochastic differential equations driven by d-dimensional periodic Levy white noises. Our results are based on the estimation of the Besov regularity of Levy white noises and generalized Levy processes. We show in particular that non-Gaussian generalized Levy processes are more compressible in a wavelet basis than the corresponding Gaussian processes, in the sense that their n-term approximation errors decay faster. We quantify this compressibility in terms of the Blumenthal-Getoor indices of the underlying Levy white noise.LIBCSF
Shapes From Echoes: Uniqueness From Point-to-Plane Distance Matrices
No full textWe study the problem of localizing a configuration of points and planes from the collection of point-to-plane distances. This problem models simultaneous localization and mapping from acoustic echoes as well as the & x201C;structure from sound & x201D; approach to microphone localization with unknown sources. In our earlier work we proposed computational methods for localization from point-to-plane distances and noted that such localization suffers from various ambiguities beyond the usual rigid body motions; in this paper we provide a complete characterization of uniqueness. We enumerate all cases of configurations which lead to the same distance measurements as a function of the number of planes and points, and algebraically characterize the related transformations in both 2D and 3D.LCAVThis work is licensed under a Creative Commons Attribution 4.0 License
Impact of Genetic and Nongenetic Factors on Body Mass Index and Waist-Hip Ratio Change in HIV-Infected Individuals Initiating Antiretroviral Therapy
No full textObjective. There is limited data on abdominal obesity and the influence of genetics on weight change after ant iretroviral therapy (ART) initiation. We assessed body mass index (BMI) and waist hip ration (WHR) change over time in the Swiss HIV Cohort study (SHCS).Methods. Mixed-effects models characterizing BMI and WHR change over time in 1090 SHCS participants initiating ART between 2005 and 2015 were developed and used to quantify the influence of demographics, clinical factors, and genetic background.Results. Individuals with CD4 nadir = 200, and 2.8 times more WHR than individuals with >= 100 (P = 200 (OR, 1.69; 95% CI, 1.26-2.32), persisting after 10 years of ART. The risk of abdominal obesity after 2.5 years increased with CD4 nadir = 100 (OR, 1.35; 95% CI, 1.17-1.54 [in men]; OR, 1.36; 95% CI, 1.18-1.57 [in women]), persisting after 10 years of ART No significant differences were found across antiretroviral drug classes or genetic scores.Conclusions. The risk of general and abdominal obesity increased with CD4 nadir <100 cells/mu l. Based on our results, including the genetic background would not improve obesity predictions in HIV-infected individuals.UPFELLA