Context-Aware Hierarchical Online Learning for Performance Maximization in Mobile Crowdsourcing

In mobile crowdsourcing (MCS), mobile users accomplish outsourced human intelligence tasks. MCS requires an appropriate task assignment strategy, since different workers may have different performance in terms of acceptance rate and quality. Task assignment is challenging, since a worker's performance (i) may fluctuate, depending on both the worker's current personal context and the task context, (ii) is not known a priori, but has to be learned over time. Moreover, learning context-specific worker performance requires access to context information, which may not be available at a central entity due to communication overhead or privacy concerns. Additionally, evaluating worker performance might require costly quality assessments. In this paper, we propose a context-aware hierarchical online learning algorithm addressing the problem of performance maximization in MCS. In our algorithm, a local controller (LC) in the mobile device of a worker regularly observes the worker's context, her/his decisions to accept or decline tasks and the quality in completing tasks. Based on these observations, the LC regularly estimates the worker's context-specific performance. The mobile crowdsourcing platform (MCSP) then selects workers based on performance estimates received from the LCs. This hierarchical approach enables the LCs to learn context-specific worker performance and it enables the MCSP to select suitable workers. In addition, our algorithm preserves worker context locally, and it keeps the number of required quality assessments low. We prove that our algorithm converges to the optimal task assignment strategy. Moreover, the algorithm outperforms simpler task assignment strategies in experiments based on synthetic and real data.Comment: 18 pages, 10 figure

Little Boxes: A Dynamic Optimization Approach for Enhanced Cloud Infrastructures

The increasing demand for diverse, mobile applications with various degrees of Quality of Service requirements meets the increasing elasticity of on-demand resource provisioning in virtualized cloud computing infrastructures. This paper provides a dynamic optimization approach for enhanced cloud infrastructures, based on the concept of cloudlets, which are located at hotspot areas throughout a metropolitan area. In conjunction, we consider classical remote data centers that are rigid with respect to QoS but provide nearly abundant computation resources. Given fluctuating user demands, we optimize the cloudlet placement over a finite time horizon from a cloud infrastructure provider's perspective. By the means of a custom tailed heuristic approach, we are able to reduce the computational effort compared to the exact approach by at least three orders of magnitude, while maintaining a high solution quality with a moderate cost increase of 5.8% or less

The Phosphorylation of PDX-1 by Protein Kinase CK2 Is Crucial for Its Stability

The homeodomain protein PDX-1 is a critical regulator of pancreatic development and insulin production in pancreatic β-cells. We have recently shown that PDX-1 is a substrate of protein kinase CK2; a multifunctional protein kinase which is implicated in the regulation of various cellular aspects, such as differentiation, proliferation, and survival. The CK2 phosphorylation site of PDX-1 is located within the binding region of the E3 ubiquitin ligase adaptor protein PCIF1. To study the interaction between PDX-1 and PCIF1 we used immunofluorescence analysis, co-immunoprecipitation, GST-pull-down studies, and proximity ligation assay (PLA). For the analysis of the stability of PDX-1 we performed a cycloheximide chase. We used PDX-1 in its wild-type form as well as phosphomutants of the CK2 phosphorylation site. In pancreatic β-cells PDX-1 binds to PCIF1. The phosphorylation of PDX-1 by CK2 increases the ratio of PCIF1 bound to PDX-1. The stability of PDX-1 is extended in the absence of CK2 phosphorylation. Our results identified protein kinase CK2 as new important modulator of the stability of PDX-1

Thematic approach as research object: what has been investigated?

O presente trabalho busca, por meio de uma revisão bibliográfica, analisar as pesquisas referentes à perspectiva curricular da Abordagem Temática. Para isso, realizou-se um levantamento de teses e dissertações com foco em Abordagem Temática e por meio das publicações um olhar para dados concernentes aos anos, orientações e locais de publicação das pesquisas; classificou-se as pesquisas quanto sua natureza e foco e categorizou-se de acordo com seus objetivos e problemas. Os dados demonstram a crescente disseminação dessa proposta curricular, principalmente na região sul e sudeste do país. Além disso, evidenciam uma maior produção em trabalhos de natureza prática e com foco na formação de professores. As pesquisas puderam, a partir da Análise Textual Discursiva, ser agrupadas em 5 categorias: Compreensão de visões docentes; Influências para prática pedagógica; Desafios e potencialidades; Características teóricas ou metodológicas e Contribuições para o conhecimento, sendo a maior parte das produções relacionadas à essa última, que expressa as pesquisas que buscam as contribuições da Abordagem Temática para o conhecimento científico.The present work aims, through a literature review, to analyze the researches regarding the curricular perspective of the Thematic Approach. For this, a survey of theses and dissertations with focus on Thematic Approach was carried out and by means of publications a look at data concerning the years, guidelines and places of research publication; the studies were classified according to their nature and focus and categorized according to their objectives and problems. The data demonstrate the growing dissemination of this curricular proposal, especially in the south and southeast of the country. Furthermore, a greater production in works of a practical nature and focusing on teacher education was evidenced. The researches could, from the Discursive Textual Analysis, be grouped into 5 categories: Understanding of teachers’ perspectives; Influences for pedagogical practice; Challenges and potentialities; Theoretical or methodological characteristics and Contributions to knowledge, being most of the productions related to the latter, which expresses the researches that seek the contributions of the Thematic Approach to scientific knowledge

A DESCONSIDERAÇÃO INVERSA DA PERSONALIDADE JURÍDICA: UMA ANÁLISE DA APLICABILIDADE DA LEI DA LIBERDADE ECONÔMICA NO CASO DO DEVEDOR DE ALIMENTOS

O presente trabalho analisa a Lei 13.874/2019, chamada de Declaração de Direitos da Liberdade Econômica, sob o viés da desconsideração da personalidade jurídica inversa, especificamente identificando sua aplicabilidade no caso de obrigações alimentares, em que o devedor pratica atos de ocultação patrimonial. A Lei da Liberdade Econômica, inicialmente concebida pela Medida Provisória de nº 881, proclama ideais neoliberais de mercado, temas tidos como centrais pelo atual governo. Por sua vez, a desconsideração da personalidade jurídica inversa, prevista na mencionada lei, constava unicamente de construção jurisprudencial e agora é regulamentada pelo artigo 50, §3º, do Código Civil. Por meio do presente artigo, verificou-se ser possível a desconsideração da personalidade jurídica inversa, na hipótese do devedor de alimentos que utiliza da pesssoa jurídica para tornar-se inadimplente com seus deveres alimentares. Assim, tal medida é necessária para efetivar o direito do alimentando. Para isso, qualifica-se a pesquisa como quantitativa e qualitativa e de método indutivo. A pesquisa caracteriza-se quanto seus objetivos, como descritiva.&nbsp

Wet chemical polishing for industrial type PERC solar cells

Industrial PERC cell process flows typically apply the polishing of the rear side after texturing as well as the edge isolation after POCl3 diffusion. In this paper, we present a novel single step polishing process which we apply post double sided texturing and diffusion in order to remove the rear emitter and to reduce the rear surface roughness. One challenge is to minimize the etch back of the front side emitter during rear side polishing due to the reactive gas phase of the polishing process. By optimizing the polishing process, we are able to limit the increase of the emitter sheet resistance below 5 Ω/sq. However, the wet cleaning post polishing contributes an additional 20 Ω/sq emitter sheet resistance increase which is subject to further optimization. We compensate the emitter sheet resistance increase due to wet cleaning by applying a 45 Ω/sq POCl3 diffusion instead of a 60 Ω/sq diffusion. The resulting PERC solar cells with polished rear surface post texture and diffusion show conversion efficiencies up to 19.6% which is comparable to the reference PERC cells which apply a rear protection layer instead of a polishing process.German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety/0325296Heraeus Precious MetalsRenaSingulus TechnologiesSolar Worl

CONSERVAÇÃO PÓS-COLHEITA DE MELÃO SUBMETIDO A DIFERENTES CORTES: RELATO DE AULA PRÁTICA

O melão é um fruto muito promissor no mercado de produtos minimamente processado. O processamento mínimo envolve várias operações e vem ganhando destaque no mercado, pois oferece um produto com características semelhantes ao fruto intacto e facilita o consumo imediato. O trabalho teve por objetivo avaliar a conservação pós-colheita de melão minimamente processado e refrigerado em um período de armazenamento. Os frutos foram lavados em água corrente, desinfectados, secados ao ar, cortados manualmente, embalados e armazenados na geladeira. Aos 0 e 7 dias foram realizadas as análises de perda de massa, sólidos solúveis totais, pH, acidez titulável e relação de sólidos solúveis e acidez titulável.As análises evidenciaram perda de massa em ambos os tratamentos, sendo que a perda máxima foi de 1,88%, considerada uma perda não suficiente para apresentar sintomas de murcha; os sólidos solúveis totais, não apresentou diferença significativa; o pH médio encontrado foi 6,245. A acidez títulável apresentou aumento significativo em função do tempo para ambos os tratamentos. A relação de sólidos solúveis e acidez titulável teve redução significativa em função do tempo para ambos os tratamentos

A Magnetosome-Based Platform for Flow Biocatalysis

Biocatalysis in flow reactor systems is of increasing importance for the transformation of the chemical industry. However, the necessary immobilization of biocatalysts remains a challenge. We here demonstrate that biogenic magnetic nanoparticles, so-called magnetosomes, represent an attractive alternative for the development of nanoscale particle formulations to enable high and stable conversion rates in biocatalytic flow processes. In addition to their intriguing material characteristics, such as high crystallinity, stable magnetic moments, and narrow particle size distribution, magnetosomes offer the unbeatable advantage over chemically synthesized nanoparticles that foreign protein “cargo” can be immobilized on the enveloping membrane via genetic engineering and thus, stably presented on the particle surface. To exploit these advantages, we develop a modular connector system in which abundant magnetosome membrane anchors are genetically fused with SpyCatcher coupling groups, allowing efficient covalent coupling with complementary SpyTag-functionalized proteins. The versatility of this approach is demonstrated by immobilizing a dimeric phenolic acid decarboxylase to SpyCatcher magnetosomes. The functionalized magnetosomes outperform similarly functionalized commercial particles by exhibiting stable substrate conversion during a 60 h period, with an average space–time yield of 49.2 mmol L–1 h–1. Overall, our results demonstrate that SpyCatcher magnetosomes significantly expand the genetic toolbox for particle surface functionalization and increase their application potential as nano-biocatalysts