Scalable Semidefinite Programming using Convex Perturbations

Several important machine learning problems can be modeled and solved via semidefinite programs. Often, researchers invoke off-the-shelf software for the associated optimization, which can be inappropriate for many applications due to computational and storage requirements. In this paper, we introduce the use of convex perturbations for semidefinite programs (SDPs). Using a particular perturbation function, we arrive at an algorithm for SDPs that has several advantages over existing techniques: a) it is simple, requiring only a few lines of MATLAB, b) it is a first-order method which makes it scalable, c) it can easily exploit the structure of a particular SDP to gain efficiency (e.g., when the constraint matrices are low-rank). We demonstrate on several machine learning applications that the proposed algorithm is effective in finding fast approximations to large-scale SDPs

Design and standalone characterisation of a capacitively coupled HV-CMOS sensor chip for the CLIC vertex detector

The concept of capacitive coupling between sensors and readout chips is under study for the vertex detector at the proposed high-energy CLIC electron positron collider. The CLICpix Capacitively Coupled Pixel Detector (C3PD) is an active High-Voltage CMOS sensor, designed to be capacitively coupled to the CLICpix2 readout chip. The chip is implemented in a commercial $180$ nm HV-CMOS process and contains a matrix of $128\times128$ square pixels with $25$ $\mu$m pitch. First prototypes have been produced with a standard resistivity of $\sim20$ $\Omega$cm for the substrate and tested in standalone mode. The results show a rise time of $\sim20$ ns, charge gain of $190$ mV/ke$^{-}$ and $\sim40$ e$^{-}$ RMS noise for a power consumption of $4.8$ $\mu$W/pixel. The main design aspects, as well as standalone measurement results, are presented.Comment: 13 pages, 13 figures, 2 tables. Work carried out in the framework of the CLICdp collaboratio

Expanding the Family of Grassmannian Kernels: An Embedding Perspective

Modeling videos and image-sets as linear subspaces has proven beneficial for many visual recognition tasks. However, it also incurs challenges arising from the fact that linear subspaces do not obey Euclidean geometry, but lie on a special type of Riemannian manifolds known as Grassmannian. To leverage the techniques developed for Euclidean spaces (e.g, support vector machines) with subspaces, several recent studies have proposed to embed the Grassmannian into a Hilbert space by making use of a positive definite kernel. Unfortunately, only two Grassmannian kernels are known, none of which -as we will show- is universal, which limits their ability to approximate a target function arbitrarily well. Here, we introduce several positive definite Grassmannian kernels, including universal ones, and demonstrate their superiority over previously-known kernels in various tasks, such as classification, clustering, sparse coding and hashing

In-Space Propulsion, Logistics Reduction, and Evaluation of Steam Reformer Kinetics: Problems and Prospects

Human space missions generate waste materials. A 70-kg crewmember creates a waste stream of 1 kg per day, and a four-person crew on a deep space habitat for a 400+ day mission would create over 1600 kg of waste. Converted into methane, the carbon could be used as a fuel for propulsion or power. The NASA Advanced Exploration Systems (AES) Logistics Reduction and Repurposing (LRR) project is investing in space resource utilization with an emphasis on repurposing logistics materials for useful purposes and has selected steam reforming among many different competitive processes as the preferred method for repurposing organic waste into methane. Already demonstrated at the relevant processing rate of 5.4 kg of waste per day, high temperature oxygenated steam consumes waste and produces carbon dioxide, carbon monoxide, and hydrogen which can then be converted into methane catalytically. However, the steam reforming process has not been studied in microgravity. Data are critically needed to understand the mechanisms that allow use of steam reforming in a reduced gravity environment. This paper reviews the relevant literature, identifies gravity-dependent mechanisms within the steam gasification process, and describes an innovative experiment to acquire the crucial kinetic information in a small-scale reactor specifically designed to operate within the requirements of a reduced gravity aircraft flight. The experiment will determine if the steam reformer process is mass-transport limited, and if so, what level of forced convection will be needed to obtain performance comparable to that in 1-g

Longitudinal associations between parental support and parental knowledge on behavioral and emotional problems in adolescents.

When testing longitudinal effects of parenting practices on adolescent adjustment, an integrated consideration of externalizing and internalizing behaviors is a gap in research. This study analyzed how parental support and parental knowledge directly and indirectly influence both antisocial behavior and emotional problems. The sample had 642 adolescents aged 12-15 (mean age = 12.49; 45.4% females) from Spain, who participated in a three-year long study. The results showed longitudinal bidirectional associations between parental support and parental knowledge. Only parental knowledge, however, directly predicted antisocial behavior and emotional problems. Parental support had an indirect effect on outcomes through the mediating effect of parental knowledge. This study has practical implications by indicating that increasing parental knowledge should be the target of educational-prevention programsS

Applicability of the Theory of Planned Behavior for Predicting Alcohol Use in Spanish Early Adolescents

According to the theory of planned behavior (TPB), intentions to perform a specific behavior are the result of attitudes, norms, and perceived control, and in turn, intentions and perceived control are the main predictors of the behavior. This study aimed to test the applicability of TPB in predicting alcohol use in normative pre-adolescents. The sample was composed of 755 Spanish adolescents aged 11 to 15 (M = 12.24; SD = 0.56), 47.1% females, from 12 state secondary schools in Spain. The results of path analysis indicate that positive attitudes towards alcohol, favorable norms towards alcohol, and offer vulnerability (perceived control) are significantly positively related to intentions to use alcohol as well as negatively related to actual behavioral control (i.e., actual strategies to avoid alcohol use). In turn, intentions to use and actual control predict higher alcohol frequency and heavy drinking. Significant indirect effects of these antecedents were found on alcohol outcomes through the mediation of intentions and actual control. The findings suggest that the validity and applicability of the TPB in normative pre-adolescents depend on the severity of alcohol use and point to a need to consider negative social influence in decision making processes in early adolescenceThis research was funded by the Global Center for Applied Health Research (GCAHR; Arizona State University) and supported by the Programa de Axudas á etapa posdoutoral da Xunta de Galicia (Consellería de Cultura, Educación e Ordenación Universitaria) and by FEDER/Ministerio de Ciencia, Innovación y Universidades—Agencia Estatal de Investigación (Grant PSI2015-65766-R)—under the Axuda para a consolidación e estruturación de unidades de investigación competitivas e outras accións de fomento nas universidades do SUG (GRC, 2018)S

Robust Trajectory Planning for Autonomous Parafoils under Wind Uncertainty

A key challenge facing modern airborne delivery systems, such as parafoils, is the ability to accurately and consistently deliver supplies into di cult, complex terrain. Robustness is a primary concern, given that environmental wind disturbances are often highly uncertain and time-varying, coupled with under-actuated dynamics and potentially narrow drop zones. This paper presents a new on-line trajectory planning algorithm that enables a large, autonomous parafoil to robustly execute collision avoidance and precision landing on mapped terrain, even with signi cant wind uncertainties. This algorithm is designed to handle arbitrary initial altitudes, approach geometries, and terrain surfaces, and is robust to wind disturbances which may be highly dynamic throughout the terminal approach. Explicit, real-time wind modeling and classi cation is used to anticipate future disturbances, while a novel uncertainty-sampling technique ensures that robustness to possible future variation is e ciently maintained. The designed cost-to-go function enables selection of partial paths which intelligently trade o between current and reachable future states. Simulation results demonstrate that the proposed algorithm reduces the worst-case impact of wind disturbances relative to state-of-the-art approaches.Charles Stark Draper Laborator

Development of microsatellite markers in the toxic dinoflagellate Alexandrium minutum (Dinophyceae)

Author Posting. © Blackwell, 2006. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Molecular Ecology Notes 6 (2006): 756-758, doi:10.1111/j.1471-8286.2006.01331.x.Outbreaks of paralytic shellfish poisoning caused by the toxic dinoflagellate Alexandrium minutum (Dinophyceae) are a worldwide concern from both the economic and human health points of view. For population genetic studies of A. minutum distribution and dispersal, highly polymorphic genetic markers are of great value. We isolated 12 polymorphic microsatellites from this cosmopolitan, toxic dinoflagellate species. These loci provide one class of highly variable genetic markers, as the number of alleles ranged from 4 to 12, and the estimate of gene diversity was from 0.560 to 0.862 across the 12 microsatellites; these loci have the potential to reveal genetic structure and gene flow among A. minutum populations.Support for this research provided in part (to DMA) by U.S. National Science Foundation grants OCE-0136861 and OCE-0430724, and the National Institute of Environmental Health Sciences Grant 1 P50 ES012742-01

Effectiveness of the mantente REAL program for preventing alcohol use in spanish adolescents

Mantente REAL is a school-based universal program to prevent drug use and other problematic behaviors specifically designed to be implemented in schools at the beginning of adolescence. This program, which is a culturally adapted version of the Keepin’ it REAL intervention, focuses on skills training for resisting social pressure to use drugs and improving psychosocial development. This study aims to evaluate the effectiveness of Mantente REAL on alcohol use in the Spanish context. The sample was composed of 755 adolescents from 12 state secondary schools in Spain, aged 11 to 15 (M = 12.24, SD = 0.56), 47.1% females. The 12 schools were randomly assigned to control and experimental groups, six to each condition. Pre-test and post-test questionnaires data were collected to evaluate the effectiveness of the program. The results indicated that a culturally adapted version of Mantente REAL was effective in preventing alcohol use among youth from northern and southern Spain. Students participating in the program demonstrated changes in the desired direction on alcohol frequency and intoxication episodes. Implications of these results regarding intervention programs aimed at preventing substance use in adolescence are discussed“Mantente REAL” es un programa universal que utiliza la escuela para prevenir el consumo de drogas y otras conductas problemáticas diseñado específicamente para ser implementado en las escuelas al comienzo de la adolescencia. Este programa, que es una versión culturalmente adaptada de la intervención Keepin’ it REAL, se centra en el entrenamiento de habilidades para resistir la presión social para consumir drogas y mejorar el desarrollo psicosocial. Este estudio tiene como objetivo evaluar la eficacia de “Mantente REAL” en el consumo de alcohol en el contexto español. La muestra estuvo compuesta por 755 adolescentes de 12 escuelas secundarias públicas en España, de 11 a 15 años (M = 12.24, DT = 0.56), el 47.1% mujeres. Las 12 escuelas fueron asignadas aleatoriamente a grupo control y experimental, seis en cada condición. Los datos se recopilaron a través de cuestionarios antes y después de la intervención para evaluar la eficacia del programa. Los resultados indicaron que la versión culturalmente adaptada de “Mantente REAL” fue eficaz para prevenir el consumo de alcohol entre los jóvenes del norte y sur de España. Los estudiantes que participaron en el programa demostraron cambios en la dirección deseada en la frecuencia del alcohol y los episodios de intoxicación. Se discuten las implicaciones de estos resultados con respecto a los programas de intervención destinados a prevenir el consumo de sustancias en la adolescenciaThis study was funded by the Global Center for Applied Health Research (Arizona State University) and supported by the Programa de Axudas á etapa posdoutoral da Xunta de Galicia (Consellería de Cultura, Educación e Ordenación Universitaria) and by FEDER/Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación (Grant PSI2015-65766-R) – under the Axuda para a consolidación e estruturación de unidades de investigación competitivas e outras accións de fomento nas universidades do SUG (GRC, 2018)S