Star–galaxy classification in the Dark Energy Survey Y1 data set

We perform a comparison of different approaches to star–galaxy classification using the broadband photometric data from Year 1 of the Dark Energy Survey. This is done by performing a wide range of tests with and without external ‘truth’ information, which can be ported to other similar data sets. We make a broad evaluation of the performance of the classifiers in two science cases with DES data that are most affected by this systematic effect: large-scale structure and MilkyWay studies. In general, even though the default morphological classifiers used for DES Y1 cosmology studies are sufficient to maintain a low level of systematic contamination from stellarmisclassification, contamination can be reduced to theO(1 per cent) level by using multi-epoch and infrared information from external data sets. For Milky Way studies, the stellar sample can be augmented by ~20 per cent for a given flux limit

Star-galaxy classification in the dark energy survey Y1 data set

FINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPERJ - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIROCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOMCTIC - MINISTÉRIO DA CIÊNCIA, TECNOLOGIA, INOVAÇÕES E COMUNICAÇÕESWe perform a comparison of different approaches to star-galaxy classification using the broadband photometric data from Year 1 of the Dark Energy Survey. This is done by performing a wide range of tests with and without external 'truth' information, which can be ported to other similar data sets. We make a broad evaluation of the performance of the classifiers in two science cases with DES data that are most affected by this systematic effect: large-scale structure and Milky Way studies. In general, even though the default morphological classifiers used for DES Y1 cosmology studies are sufficient to maintain a low level of systematic contamination from stellar misclassification, contamination can be reduced to the O(1 per cent) level by using multi-epoch and infrared information from external data sets. For Milky Way studies, the stellar sample can be augmented by similar to 20 per cent for a given flux limit.481454515469FINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPERJ - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIROCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOMCTIC - MINISTÉRIO DA CIÊNCIA, TECNOLOGIA, INOVAÇÕES E COMUNICAÇÕESFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPERJ - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIROCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOMCTIC - MINISTÉRIO DA CIÊNCIA, TECNOLOGIA, INOVAÇÕES E COMUNICAÇÕESAgências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig

Crowd-based Information Organization: A Case Study of the Folk Ontologies in Wikipedia and TV Tropes

Folk ontologies are the organically created, crowd-managed ontology-like structures used to organize information in wikis. This paper takes as case studies the folk ontologies of the wikis Wikipedia and TV Tropes, performing a three-part analysis on them. The first part describes the folk ontologies and examines how they are maintained and used. The second part creates an evaluation framework based on the ontology evaluation literature and considers the folk ontologies in that light. The third part takes a random sample of pages from the wiki and performs a quantitative analysis looking at where and how the folk ontologies appear and what effects their presence has. The goal of the paper is to advance our understanding of how people, in aggregate, organize information.Master of Science in Library Scienc

Journal Staff

With the demand for more comfortable cars and reduced emissions, there is an increasing focus on model-based system engineering. Therefore, developing accurate vehicle models has become significantly important. The powertrain system, which transfers the engine torque to the driving wheels, is one of the most important parts of a vehicle. Having a reliable methodology, for modeling and parameter estimation of a powertrain structure, helps predict different kinds of behaviors such as torsional vibration which is beneficial for a number of applications in automotive industry. Examples of such cases are ride quality evaluation and model-based fault detection. This thesis uses the knowledge from the system identification field, which introduces the methods of building mathematical models for dynamical systems based on experimental data, to model the torsional vibration of an engine-load setup. It is a subsystem of the vehicular powertrain and the main source of vibration is the engine fluctuating torque. The challenges are handling a more complicated model structure with a greater number of unknown parameters as well as showing the importance of data information for acquiring better identification performance. Since the engine-load setup is modeled physically here, its state-space equations are available and a grey-box modeling approach can be applied in which the well-known prediction error method is used toestimate the unknown physical parameters. Moreover, a structural  identifiability analysis is performed which shows that all of the model parameters are identifiable assuming informative input. Two main aspects are considered to present an appropriate modeling methodology. The first is simplification of the model structure according to frequency range of interest. This is achieved by performing modal shape analysis to obtain how many degrees-of-freedom are necessary at different frequency ranges. The results show that a 7 degrees-of-freedom model can be simplified to a 2 degrees-offreedom structure and still have the desired performance for a specific application such as misfire detection. The second aspect concerns using an appropriate data set, which has the required information for estimation of the unknown parameters. By analyzing the simulation data from a known system, it is shown that the parameters of the 2 degrees-of-freedom model can not be estimated accurately using measurements from a normal combustion data set. However, all the parameters except damping coefficient converge to their true values by using a data set which has misfire in the input torque from the engine. A high estimation variance plus flat loss function indicate that the damping coefficient has no significant influence on the model output and consequently can not be estimated correctly using the available measurements. Thus, to increase the accuracy of the results during estimation on real data, the damping coefficient(s) is assumed to be known. Both the 2 and 7 degrees-of-freedom models are validated against a fresh data set and it is shown that the simulated output captures the important parts of the actual system behavior depending on the application of interest.The series name Linköping studies in science and technology Licentiate Thesis is incorrect. Correct series name is Linköping studies in science and technology. Thesis.</p

Essential guidelines for computational method benchmarking

In computational biology and other sciences, researchers are frequently faced with a choice between several computational methods for performing data analyses. Benchmarking studies aim to rigorously compare the performance of different methods using well-characterized benchmark datasets, to determine the strengths of each method or to provide recommendations regarding suitable choices of methods for an analysis. However, benchmarking studies must be carefully designed and implemented to provide accurate, unbiased, and informative results. Here, we summarize key practical guidelines and recommendations for performing high-quality benchmarking analyses, based on our experiences in computational biology.Comment: Minor update

Defining Strong State Accountability Systems: How Can Better Standards Gain Greater Traction?

This report is a pilot study intended to inform a larger analysis of the accountability systems in every state (and the District of Columbia) during the  early years of Common Core implementation. We ask that the reader treat it as  such and provide us with feedback on the accountability principles contained  herein. We plan to apply these principles, once revised, to all fifty state  accountability systems in order to appraise their quality. Our first national report  is slated for early 2013, with follow?up studies two and four years later. Tracking  systems in this manner will prove beneficial because many states will be in "flux"  over the next several years as they refine and adapt their systems based on the  demands of the Common Core and on the plans and promises outlined in their  recently approved waivers (and/or those provisions detailed by ESEA  reauthorization legislation—assuming Congress one day gets its act together).Fordham is also conducting three other studies pertinent to CCSS implementation.  The first is an analysis of Common Core implementation costs; the second, an in? depth study of district?level implementation of CCSS; and the third, a nationally  representative survey of English language arts teachers that assesses the rigor of  their reading assignments both before and after implementation of CCSS (summer  2012 and spring 2015)

Connecting British Columbia (Canada) school libraries and student achievement: A comparison of higher and lower performing schools with similar overall funding

Research over time has established associations between components of the school library and student achievement. This study was designed to investigate these associations in schools in British Columbia (Canada) where the government provides equitable funding of public schools while allowing individual school districts and schools to determine individual funding priorities. Findings replicated what numerous previous studies have shown: higher student standardized test scores were associated with a school library that is more accessible, better funded, professionally staffed, managed, stocked, integrated and used. Findings moreover pointed to higher student achievement in those schools where greater resources, from the same limited allocation were assigned to school libraries. Results of this study are of practical interest to policy makers, school and library administrators, and educators with a vested interest in student achievement and the future of school libraries. Reprinted by permission of the publisher

The case for change

"Over the past 15 years, a number of major studies have examined systematically how well students perform in literacy, mathematics and science in different countries of the world at different ages. These studies have begun to expose how well different education systems are doing – and have cast the education debate in this country [England] in a wholly new light." - Page 2