A Framework for Verifiable and Auditable Collaborative Anomaly Detection

Collaborative and Federated Leaning are emerging approaches to manage cooperation between a group of agents for the solution of Machine Learning tasks, with the goal of improving each agent's performance without disclosing any data. In this paper we present a novel algorithmic architecture that tackle this problem in the particular case of Anomaly Detection (or classification of rare events), a setting where typical applications often comprise data with sensible information, but where the scarcity of anomalous examples encourages collaboration. We show how Random Forests can be used as a tool for the development of accurate classifiers with an effective insight-sharing mechanism that does not break the data integrity. Moreover, we explain how the new architecture can be readily integrated in a blockchain infrastructure to ensure the verifiable and auditable execution of the algorithm. Furthermore, we discuss how this work may set the basis for a more general approach for the design of collaborative ensemble-learning methods beyond the specific task and architecture discussed in this paper

5-th Dolomites Workshop on Constructive Approximation and Applications – Special Issue dedicated to Robert Schaback on the occasion of his 75th birthday

The guest editors discuss the highlights of the 5-th Dolomites Workshop on Constructive Approximation and Applications, and briefly introduce the papers included in this special issue

Effects of eight months of whole body vibration training on hip bone mass in older women

Objective: The aim of this study was to examine the effect of 8 months of whole-body vibration training on bone mass in octogenarian women. Method: Thirty-seven women (aged 82.4 [SD=5.7] years) voluntarily participated in this study. The vibration group (n=19) trained on a vibration platform twice a week (20 Hz and 2 mm) whereas controls (n=18) did not participate in any training program. Bone mass was measured by dual-energy X-ray absorptiometry at the hip region. General linear repeated measures ANOVA (group by time) was used to examine the effect of whole body vibration on bone mass changes. Results: After the intervention, in all the hip regions (total hip, femoral neck, trochanter, intertrochanter, Ward’s area), no statistically significant changes in bone mass were found. Conclusion: Eight months of whole body vibration training (twice a week) in elderly women do not produce osteogenic effects

Interpolation with the polynomial kernels

The polynomial kernels are widely used in machine learning and they are one of the default choices to develop kernel-based classification and regression models. However, they are rarely used and considered in numerical analysis due to their lack of strict positive definiteness. In particular they do not enjoy the usual property of unisolvency for arbitrary point sets, which is one of the key properties used to build kernel-based interpolation methods. This paper is devoted to establish some initial results for the study of these kernels, and their related interpolation algorithms, in the context of approximation theory. We will first prove necessary and sufficient conditions on point sets which guarantee the existence and uniqueness of an interpolant. We will then study the Reproducing Kernel Hilbert Spaces (or native spaces) of these kernels and their norms, and provide inclusion relations between spaces corresponding to different kernel parameters. With these spaces at hand, it will be further possible to derive generic error estimates which apply to sufficiently smooth functions, thus escaping the native space. Finally, we will show how to employ an efficient stable algorithm to these kernels to obtain accurate interpolants, and we will test them in some numerical experiment. After this analysis several computational and theoretical aspects remain open, and we will outline possible further research directions in a concluding section. This work builds some bridges between kernel and polynomial interpolation, two topics to which the authors, to different extents, have been introduced under the supervision or through the work of Stefano De Marchi. For this reason, they wish to dedicate this work to him in the occasion of his 60th birthday

Ilex paraguariensis consorciada com Mimosa scabrella: produtividade e aspectos nutricionais.

Resumo

Boro no crescimento de mudas de erva-mate em solução nutritiva.

A maioria das soluções nutritivas indicam a dose de 0,5 mg L-1 de boro (B) como ideal, mas para erva-mate não há informações sobre sua necessidade em B. Avaliou-se o crescimento de mudas clonais de erva-mate em solução nutritiva, submetidas a doses de: 0,0; 1,0; 2,5 e 5,0 mg L-1 de B. O experimento foi conduzido em Viçosa-MG e após 80 dias, através de análise de regressão, avaliou-se características de crescimento das mudas onde obteve-se que doses de B próximas de 2,90 mg L-1 favoreceram o melhor crescimento em altura, diâmetro do colo e comprimento do sistema radicular. Já para maximizar a produção de matéria seca, volume do sistema radicular, área foliar e espessura foliar a erva-mate necessita de doses próximas a 3,00 mg L-1 de B. Conclui-se que mudas de erva-mate, conduzidas em solução nutritiva, necessitam de 2,5 a 3,1 mg L-1 de B para um bom crescimento

Calagem melhora a disponibilidade de cálcio no solo e a produtividade de Ilex paraguariensis St. Hil.

Avaliou-se a influência da calagem na disponibilidade de Ca2+ no solo, produtividade e teor foliar de Ca e Al em erva-mate. Instalaram-se experimentos em três locais, avaliando-se cinco doses superficiais de calcário dolomítico para atingir 50 % das seguintes saturações por bases: 0, 30, 60, 90 e 120 %. Após 18 meses, avaliou-se: teor de Ca2+ no solo em três profundidades; teor foliar de Ca e Al e produtividade de erva-mate comercial (ECOM). A calagem, não alterou o teor foliar de Ca, mas, reduziu o de Al. A calagem, aumentou o teor de Ca 2+ no solo e, a produtividade de ECOM entre 21 e 27 %. Em solos com baixa disponibilidade natural de Ca 2+, a calagem deve disponibilizá-lo entre 4,0-4,5 cmol c dm-3 na profundidade de 0-5 cm, já em solos com alta disponibilidade de Ca 2+, a calagem deve disponibilizar o nutriente até 6,0 cmolc dm-3 para o cultivo da erva-mate

Adubação potássica e intervalos de colheita influenciam o potássio do solo e a produtividade de cultivos de erva-mate.

O trabalho objetivou avaliar a adubação potássica e intervalos de colheita na disponibilidade de potássio, produtividade e distribuição do conteúdo de potássio na massa colhida da erva-mate. Avaliaram-se doses de 0, 20, 40, 80, 160 e 320 kg ha-1 de K2O para colheitas com intervalos de 12, 18 e 24 meses. Quantificou-se a disponibilidade de potássio em duas profundidades do solo e a produtividade de erva-mate comercial (ECOM) e galho grosso (GG) e distribuição do conteúdo de K nesses componentes. A adubação potássica aumentou a disponibilidade de potássio no solo e aumentou a produtividade da erva-mate. Para cultivos em solos com disponibilidade em nível baixo de potássio, recomenda-se doses próximas a 190, 270 e 320 kg ha-1 de K2O, respectivamente, para colheitas com intervalos de 12, 18 e 24 meses. Na retirada do GG da área, requer adubação de reposição do potássio adicional entre 20 a 30 %

Special Issue dedicated to Stefano De Marchi on the occasion of his 60th birthday

As colleagues and friends we dedicate this issue to Stefano De Marchi on the occasion of his 60th birthday, publishing works of some of his collaborators. Stefano has made many important contributions to approximation theory and beyond and is one of the “founding fathers” of this journal. Here we briefly reminisce and recount some of our experiences with Stefano in the spirit of the occasion

Malnutrition and Sarcopenia Combined Increases the Risk for Mortality in Older Adults on Hemodialysis

Aim: Sarcopenia and malnutrition are highly prevalent in older adults undergoing hemodialysis (HD) and are associated with negative outcomes. This study aimed to evaluate the role of sarcopenia and malnutrition combined on the nutritional markers, quality of life, and survival in a cohort of older adults on chronic HD. Methods: This was an observational, longitudinal, and multicenter study including 170 patients on HD aged >60 years. Nutritional status was assessed by 7-point-subjective global assessment (7p-SGA), body composition (anthropometry and bioelectrical impedance), and appendicular skeletal muscle mass (Baumgartner's prediction equation). Quality of life was assessed by KDQoL-SF. The cutoffs for low muscle mass and low muscle strength established by the 2019 European Working group on sarcopenia for Older People (EWGSOP) were used for the diagnosis of sarcopenia. Individuals with a 7p-SGA score 5 were considered malnourished, individuals with low strength or low muscle mass were pre-sarcopenic, and those with low muscle mass and low muscle strength combined as sarcopenic. The sample was divided into four groups: sarcopenia and malnutrition; sarcopenia and no-malnutrition; no-sarcopenia with malnutrition; and no-sarcopenia and no-malnutrition. Follow-up for survival lasted 23.5 (12.2; 34.4) months. Results: Pre-sarcopenia, sarcopenia, and malnutrition were present in 35.3, 14.1, and 58.8% of the patients, respectively. The frequency of malnutrition in the group of patients with sarcopenia was not significantly higher than in the patients without sarcopenia (66.7 vs. 51.2%; p = 0.12). When comparing groups according to the occurrence of sarcopenia and malnutrition, the sarcopenia and malnutrition group were older and presented significantly lower BMI, calf circumference, body fat, phase angle, body cell mass, and mid-arm muscle circumference. In the survival analysis, the group with sarcopenia and malnutrition showed a higher hazard ratio 2.99 (95% CI: 1.23: 7.25) for mortality when compared to a group with no-sarcopenia and no-malnutrition. Conclusion: Older adults on HD with sarcopenia and malnutrition combined showed worse nutritional parameters, quality of life, and higher mortality risk. In addition, malnutrition can be present even in patients without sarcopenia. These findings highlight the importance of complete nutritional assessment in patients on dialysis. (c) Copyright (c) 2021 Macedo, Amaral, Rodrigues, Santin and Avesani