scholarly journals Fused CLEAN deconvolution for compact and diffuse emission

2018 ◽  
Vol 618 ◽  
pp. A117 ◽  
Author(s):  
L. Zhang

Context. CLEAN algorithms are excellent deconvolution solvers that remove the sidelobes of the dirty beam to clean the dirty image. From the point of view of the scale, there are two types: scale-insensitive CLEAN algorithms, and scale-sensitive CLEAN algorithms. Scale-insensitive CLEAN algorithms perform excellently well for compact emission and perform poorly for diffuse emission, while scale-sensitive CLEAN algorithms are good for both point-like emission and diffuse emission but are often computationally expensive. However, observed images often contain both compact and diffuse emission. An algorithm that can simultaneously process compact and diffuse emission well is therefore required. Aims. We propose a new deconvolution algorithm by combining a scale-insensitive CLEAN algorithm and a scale-sensitive CLEAN algorithm. The new algorithm combines the advantages of scale-insensitive algorithms for compact emission and scale-sensitive algorithms for diffuse emission. At the same time, it avoids the poor performance of scale-insensitive algorithms for diffuse emission and the great computational load of scale-sensitive algorithms for compact emission in residuals. Methods. We propose a fuse mechanism to combine two algorithms: the Asp-Clean2016 algorithm, which solves the computationally expensive problem of convolution operation in the fitting procedure, and the classical Högbom CLEAN (Hg-Clean) algorithm, which is faster and works equally well for compact emission. It is called fused CLEAN (fused-Clean) in this paper. Results. We apply the fused-Clean algorithm to simulated EVLA data and compare it to widely used algorithms: the Hg-Clean algorithm, the multi-scale CLEAN (Ms-Clean), and the Asp-Clean2016 algorithm. The results show that it performs better and is computationally effective.

2020 ◽  
Vol 2 (1) ◽  
pp. 1-24
Author(s):  
Yorgos Christidis

This article analyzes the growing impoverishment and marginalization of the Roma in Bulgarian society and the evolution of Bulgaria’s post-1989 policies towards the Roma. It examines the results of the policies so far and the reasons behind the “poor performance” of the policies implemented. It is believed that Post-communist Bulgaria has successfully re-integrated the ethnic Turkish minority given both the assimilation campaign carried out against it in the 1980s and the tragic events that took place in ex-Yugoslavia in the 1990s. This Bulgaria’s successful “ethnic model”, however, has failed to include the Roma. The “Roma issue” has emerged as one of the most serious and intractable ones facing Bulgaria since 1990. A growing part of its population has been living in circumstances of poverty and marginalization that seem only to deteriorate as years go by. State policies that have been introduced since 1999 have failed at large to produce tangible results and to reverse the socio-economic marginalization of the Roma: discrimination, poverty, and social exclusion continue to be the norm. NGOs point out to the fact that many of the measures that have been announced have not been properly implemented, and that legislation existing to tackle discrimination, hate crime, and hate speech is not implemented. Bulgaria’s political parties are averse in dealing with the Roma issue. Policies addressing the socio-economic problems of the Roma, including hate speech and crime, do not enjoy popular support and are seen as politically damaging.


2019 ◽  
Vol 21 (2) ◽  
pp. 1217-1233
Author(s):  
Filipe Maciel De Moura ◽  
Antônio Rodrigues Ximenes Neto ◽  
Adryane Gorayeb ◽  
Davis Pereira De Paula ◽  
Fábio Perdigão Vasconcelos

A planície costeira brasileira, em especial a do Nordeste do Brasil, apresenta um sistema morfológico que sofre diversas pressões do ponto de vista do uso e ocupação dos seus espaços. Logo, o entendimento da dinâmica natural e espacial desse ambiente requer a adoção de metodologias que contemplem uma abordagem em múltiplas escalas. Neste sentido, este trabalho tem o intuito de analisar as múltiplas morfologias associadas a praia das Fontes, em Beberibe-CE, em diferentes escalas taxonômicas. Esta análise auxiliou na realização de um prognostico das condições ambientais e de sua capacidade de suporte. Metodologicamente aplicou-se a proposta de Bertrand (1971), adotando-se apenas as unidades inferiores que inclui os níveis taxonômicos regionais e/ou locais, compreendendo os geossistemas, geofáciese os geótopos. Os resultados alcançados foram satisfatórios, uma vez que as unidades mapeadas foram validadas em atividades de campo para reconhecimento do produto cartográfico.Palavras-chave: Análise Multiescalar. Geomorfologia Costeira. Formação Barreiras. ABSTRACTThe Brazilian coastal plain, especially in the Northeast of Brazil, presents a morphological system that undergoes several pressures from the point of view of the use and occupation of its spaces. Therefore, the understanding of the natural and spatial dynamics of this environment requires the adoption of methodologies that contemplate a multi-scale approach. In this sense, this work has the purpose of analyzing the multiple morphologies associated to Praia das Fontes, in Beberibe-CE, at different taxonomic scales. This analysis assisted in the accomplishment of a prognosis of the environmental conditions and their support capacity. Methodologically Bertrand's (1972) proposal was applied, adopting only the lower units that includes regional and / or local taxonomic levels, including geosystems, geophysics and geo-objects. The results were satisfactory, since the mapped units were validated in field activities to recognize the cartographic product.Keywords: Multiscalar Analysis. Coastal Geomorphology. Training Barriers. RESUMENLa llanura costera brasileña, especialmente en el noreste de Brasil, tiene un sistema morfológico que sufre varias presiones desde el punto de vista del uso y la ocupación de sus espacios. Por lo tanto, comprender la dinámica natural y espacial de este entorno requiere la adopción de metodologías que incluyan un enfoque de múltiples escalas. En este sentido, este trabajo tiene como objetivo analizar las múltiples morfologías asociadas a la playa de Fontes, en Beberibe-CE, en diferentes escalas taxonómicas. Este análisis ayudó a hacer una predicción de las condiciones ambientales y su capacidad de carga. Metodológicamente, se aplicó la propuesta de Bertrand (1971), adoptando solo las unidades inferiores, que incluyen niveles taxonómicos regionales y / o locales, incluidos los geosistemas, geofacies y geotopos. Los resultados obtenidos fueron satisfactorios, ya que las unidades mapeadas fueron validadas en actividades de campo para el reconocimiento de productos cartográficos.Palabras clave: Análisis multiescala. Geomorfología costera. Barreras de entrenamiento.


1994 ◽  
Vol 29 (7) ◽  
pp. 91-100 ◽  
Author(s):  
K. C. Lindrea ◽  
S. P. Pigdon ◽  
B. Boyd ◽  
G. A. Lockwood

During commissioning and process stabilization of a NDBEPR plant at Bendigo intracellular distribution and movement of phosphorus, K+, Mg2+ and Ca2+ was followed to establish the nature of biomass development. The system was also monitored at the end of a period of breakdown of the BEPR process and during its return to phosphorus removal. Phosphorus (P) and Mg2+ distribution in the biomass were closely related during all phases of plant operation, and laboratory trials indicated that the poor performance of the full-scale plant was associated with seasonal reduction in influent Mg2+. Laboratory scale trials produced a similar effect when the influent Mg2+ was limited to concentrations much lower than those experienced in the full scale plant, but only after the Mg2+ and P reserves in the biomass were depleted. The distribution of P, K+, Mg2+ and Ca2+ in the biomass from the full scale plant was similar to that seen in the laboratory trials when cations in the feed were severely limited and recovery of the full scale plant also closely matched that of the laboratory scale system.


Mathematics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 595
Author(s):  
Huajun Song ◽  
Rui Wang

Aimed at the two problems of color deviation and poor visibility of the underwater image, this paper proposes an underwater image enhancement method based on the multi-scale fusion and global stretching of dual-model (MFGS), which does not rely on the underwater optical imaging model. The proposed method consists of three stages: Compared with other color correction algorithms, white-balancing can effectively eliminate the undesirable color deviation caused by medium attenuation, so it is selected to correct the color deviation in the first stage. Then, aimed at the problem of the poor performance of the saliency weight map in the traditional fusion processing, this paper proposed an updated strategy of saliency weight coefficient combining contrast and spatial cues to achieve high-quality fusion. Finally, by analyzing the characteristics of the results of the above steps, it is found that the brightness and clarity need to be further improved. The global stretching of the full channel in the red, green, blue (RGB) model is applied to enhance the color contrast, and the selective stretching of the L channel in the Commission International Eclairage-Lab (CIE-Lab) model is implemented to achieve a better de-hazing effect. Quantitative and qualitative assessments on the underwater image enhancement benchmark dataset (UIEBD) show that the enhanced images of the proposed approach achieve significant and sufficient improvements in color and visibility.


1964 ◽  
Vol 19 (1) ◽  
pp. 199-206 ◽  
Author(s):  
Oscar A. Parsons ◽  
Harriet I. Maslow ◽  
Freda Morris ◽  
J. Peter Denny

The Trail Making Test, previously reported highly effective in differentiating brain-damaged from non-brain-damaged Ss, was administered to 21 brain-damaged Ss and 63 non-brain-damaged Ss. Since the latter Ss performed at a level indistinguishable from that of the brain-damaged Ss, several studies were designed in an attempt to “explain” the poor performance of the non-brain-damaged Ss. The possible effects of behavioral agitation, anxiety, examiner differences, facility with letters of the alphabet, order of administration, and ego-involvement were investigated. Only anxiety was found to be significantly related to performance. However, in other analyses age, education, vocabulary, and degree of psychiatric disturbance were significantly related to performance. Until these variables are considered in the scoring system, it seems unlikely that the TMT will be effective as a general screening test for brain-damage.


2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Pedro Cavalcanti Ferreira ◽  
Leonardo Fonseca da Silva

AbstractThis article examines the effects of sectorial shifts and structural transformation on the recent productivity path of Latin America. We use a four-sector (agriculture, industry, modern services and traditional services) general equilibrium model calibrated to the main economies in the region. The model very closely replicates labor reallocations across sectors and the growth of aggregate labor productivity from 1950 to 2005. Structural transformation explains a sizeable portion of the region’s convergence in the first decades. In most cases, the poor performance of the traditional services sector is the main cause of the slowdown in productivity growth observed in the region after the mid-1970s and is a key factor in explaining the divergence during this period.


Exchange ◽  
2005 ◽  
Vol 34 (2) ◽  
pp. 149-166 ◽  
Author(s):  
Henri Gooren

AbstractThe central question of this article — why people may change their religious affiliation or become disaffiliated — is relevant from both an academic and a practical point of view. The article makes first an inventory of existing literature on religious conversion. Next I sketch the contours of the new conversion careers approach I am currently working on. I make some comparisons with a region that is not usually mentioned in the literature on conversion: Latin America. These comparisons are based on my earlier fieldwork on Roman Catholicism, Pentecostalism, and Mormonism in Costa Rica and Guatemala (H. Gooren, Rich among the Poor: Church, Firm, and Household among Small-scale Entrepreneurs in Guatemala City, Amsterdam: Thela Thesis 1999).


2019 ◽  
Vol 8 (2) ◽  
Author(s):  
Philip Ifeakachukwu Nwosa ◽  
Fasina Oluwadamilola Tosin ◽  
Ogbuagu Matthew Ikechukwu

The issue of export diversification has been contentious in Nigeria due to the country’s unstable growth pattern which is majorly associated with instability in the international oil market and the poor performance of other sectors of the economy. Therefore, this study examines the link between export diversification and economic growth in Nigeria from 1962 to 2016. The study utilizes the Auto-regressive Distributed Lag (ARDL) technique. The result of this study shows that export diversification has a positive but insignificant influence on economic growth in Nigeria. The above result implies that the oil sector still dominates the Nigerian economy while the diversification drive of the government has not been significant in other sectors of the economy. Thus, the study recommends the need for conscious economic policies that would promote the diversification of the entire non-oil sector of the economy. The study concludes that export diversification is an insignificant determinant of economic growth in Nigeria.


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