Rossella Berni

• Ph.D in Applied Statistics
• Professor (Full) at University of Florence

In this paper, we deal with statistical modeling and a related case study for reliability when multiple failure causes are present. At first, we present in detail two main approaches for competing risk modeling, e.g. the Cox Proportional Hazards model, and the Fine & Gray model. In both models, we consider the inclusion of random effects, a no-triv...

In this manuscript, we propose an innovative approach to studying consumers’ preferences for coffee, which integrates a choice experiment with consumer sensory tests and chemical analyses (caffeine contents obtained through a High-Performance Liquid Chromatography (HPLC) method). The same choice experiment is administered on two consecutive occasio...

This study proposes an innovative approach for analysing consumer preferences for coffee by integrating a choice experiment with a guided tasting and chemical analysis. Firstly, two types of coffee were chosen from the mass market retailers with different sensorial profiles (100% Arabica, and Arabica and Robusta blends); subsequently, a guided tast...

This work deals with consumers' preferences about coffee. Firstly, a choice experiment is performed on a sample of potential consumers. Following this, a sensory test involving the tasting of two varieties of coffee is carried out with the respondents, after which the same choice experiment is supplied to them again. An innovative approach for buil...

Complex engineering and technological processes typically generate data with a non-trivial hierarchical structure. To this end, in this article we propose a full procedure for optimizing such processes through optimal experimental designs and modeling. In order to study a hierarchical structure, several types of experimental factors may arise, maki...

This paper deals with a proposal for joint modeling and process optimization for split-plot designs analyzed through mixed response surface models. It addresses the following main issues: i) the building of a joint mixed responsesurface model for a multiple response situation, by defining only one response through which specific coefficients areinc...

The European Union has fixed the 2020 renewable energy targets on 20% of energy obtained by renewable energy, and it posed limitation to the biofuel production by agriculture. Photovoltaic electricity may represent a clean method for generating electricity for agriculture. This paper focuses on a multi-functional full electric battery tractor; the...

Featured Application This research represents a key-study devoted to the continuous improvement of manufacturing processes leading to a concrete advantage for companies. The proposed guideline allows to enhance the process capability and the product quality, including the achievement of a robust process by limiting the variability and the scraps. T...

This paper proposes an innovative method for estimating brand association matching and strength. It is based on a dual analytical perspective as it compares consumer-perceived with company-defined brand associations, thereby filling a research gap in the offline and online brand studies. In order to build this method, we investigate online communit...

Nowadays, computer experiments are used increasingly more to solve complex engineering and technological issues. Computer experiments are analysed through suitable metamodels acting as statistical interpolators of the simulated input-output data: Kriging is the most appropriate and widely used one. We optimise the braking performance of freight tra...

The number of spots to monitor to evaluate soil respiration (Rs) is often chosen on an empirical or conventional basis. To obtain an insight into the necessary number of spots to account for Rs variability in a Mediterranean pine-dominated mixed forest, we measured Rs all year long on sixteen dates with a portable gas-analyser in 50 spots per date...

This paper studies the impact when the experimenter does not randomize the design for split-plot experiments when there is a linear trend. The paper uses both simulation and basic theory to explain the bias if we do not randomize the design and the inflation in variance if we do. The paper shows proper residual plots can detect the trend if the des...

This paper deals with the planning and modeling of a split-plot experiment to improve novel gas sensing materials based on Perovskite, a nano-structured, semi-conductor material that is sensitive to changes in the concentration of hazardous gas in the ambient air. The study addresses both applied and theoretical issues. More precisely, it focuses o...

Introduction This paper introduces a fast method to evaluate the effect of payload distribution on in-train forces. Methods The method is based on Strong Orthogonal Arrays (SOA) and the excellent space-filling properties of Latin Hypercube Design (LHD): SOA-based-LHD is proved to be very efficient in spanning the range of in-train forces for diffe...

This paper deals with Kriging modeling applied for optimizing the braking performances for freight trains. In particular, it focuses on mass distribution optimization to reduce the effects of in-train forces among vehicles, e.g. compression and tensile forces, in-train emergency braking. Kriging models are applied with covariance structure based on...

In this paper we present the Interuniversity Research Center STEERING, formed in June 2017. The Research Center has been founded by three Italian Universities through five Departments. It represents the connection between Statistics and Engineering. The five Departments promoting it are the following: Department of Innovation and Information Engine...

Eight different types of nanostructured perovskites based on YCoO 3 with different chemical compositions are prepared as gas sensor materials, and they are studied with two target gases NO 2 and CO. Moreover, a statistical approach is adopted to optimize their performance. The innovative contribution is carried out through a split-plot design plann...

This paper deals with Kriging models applied to optimise braking performances for freight trains. More precisely, it is focused on mass distribution optimisation aimed at reducing the effects of in-train forces among vehicles, e.g. compression and tensile forces, in-train emergency braking. To this end, Kriging models are applied with covariance st...

The livestock sector has a high impact in terms of carbon footprint. Lowering GHG emission from the livestock sector deals with implementing climate neutral production techniques in a cost effectiveness way and with developing market communication to make carbon free diary products competitive with alternative products. This study aimed at analyzin...

Test laboratories with International Organization for Standardization/International Electrotechnical Commission 17025:2005 accreditation are obliged to calculate measurement uncertainty and declare the calculated value. Furthermore, they have to ensure the quality of the test results, and their participation in interlaboratory comparisons is mandat...

Reliability specifications for solder joints, as well as for all electronic components, have become a fundamental feature in the qualification of an electronic product. The relevance of these reliability features increases if new components or materials are considered. In this research activity, an accelerated thermal test on customized electronic...

This paper proposes a multiresponse process optimization through mixed response surface models. The robust design approach is used by involving noise effects in the optimization step. In order to illustrate our proposal, a prototype of an energy meter, based on an open source concept, is studied. The proposed device architecture assures easy develo...

In this paper, an innovative methodology aimed at improving the development of novel gas sensors through a process optimization is carried out by applying mixed response surface (RS) models. High accuracy measurements of new conductometric metal oxide gas sensors, obtained by an efficient control of the working conditions, are gathered. The respons...

This article deals with process optimization for a centrifugal compressor. More precisely, the technological problem concerns the reduction of the surface roughness of centrifugal compressor impellers through a new technology implemented by GE Oil & Gas called superfinishing. The new technology is studied through statistical methods in order to ach...

This paper presents a study focused on potential demand for agricultural multi-functional electric tractor. In this context, the willingness-to-pay is investigated in order to establish the potential diffusion of an electrical solar tractor, by considering different levels of key attributes related to environmental, technical and economical charact...

Objectives: Sex steroids are important regulators of bone physiology and play an essential role in the maintenance of bone health throughout the life. Hormonal replacement therapy (HRT) is a treatment commonly used to relieve symptoms and some undesirable consequences of menopause such as osteoporosis. Osteoporosis, characterized by the loss of bo...

This paper deals with optimal experimental design criteria and neural networks in the aim of building experimental designs from observational data. It addresses the following three main issues: (i) the introduction of two radically different approaches, namely T‐optimal designs extended to Generalized Linear Models and Evolutionary Neural Networks...

This paper deals with optimal experimental design criteria and neural networks in the aim of building experimental designs from observational data. It addresses the following three main issues: (i) the introduction of two radically different approaches, namely T-optimal designs extended to Generalized Linear Models and Evolutionary Neural Networks...

This paper deals with an analysis of random effects for microelectronic data. More precisely, by considering the technical challenges related to the use of electrically conductive adhesives such as soldering material in electronics, the sources of variabilities related to different electrically conductive adhesive characteristics and working proces...

Understanding the ageing of materials for electronic application is a complex challenge, in par- ticular for composite material as electrically conductive adhesive consisting of a nonconductive polymer binder and conductive filler particles. This research involves a large amount of parameters related to both operating conditions and material struct...

This article deals with the quantitative Fault Tree Analysis (FTA) and the estimation method of the top-event in case of dependent events. It aims at addressing two main issues: (1) the decomposition of variability for the top-event according to several error components linked to the estimation of the top-event and sources of internal and external...

With the introduction of the European Directives restrictions of hazardous substances, electrically conductive adhesives (ECAs) have received great attention in the field of electronics as a possible replacement of the traditional tin-lead soldering technology. So, in this new context, the analysis and the characterization of these alternative mate...

This paper deals with experimental planning and optimization in response surface methodology. It aims at addressing two main issues: i) the optimization of a split-plot design in the multiple response case by the use of a robust-design approach and ii) the related problem of weighting the responses according to the actual importance of these variab...

Objective: To explore the influence of end-of-life decisions (EoL-D) on survival and mortality data in the light of differences reported among European countries. Design: We collected the published data of several epidemiological studies: Epicure, Epipage, Epibel and the Norwegian study performed in the UK, France, Belgium and Norway, respective...

In the literature, a large number of researchers and practitioners are dealing with preference measurements which are considered as one of the most general methods in order to study and improve the consumer’s behaviour intended as the consumer’s decision about improving his/her utility in changing a service or a product. Nevertheless, a wide range...

This paper focuses on a specific case of experimental planning and optimization in a multiresponse case. Particularly, our attention is dedicated to a numerical control machine and our final goal is to improve this machine's measurement accuracy for a general dental implant. This work substantially aims at addressing two issues: the optimization me...

This paper is focused on observational data and on the use of large data sets to implement an experimental design without additional runs, for an efficient use of these data. More specifically, the proposed procedure is based on several steps, aimed at avoiding some problems, such as lack of randomization and efficiency, obtaining a final experimen...

This paper deals with the application of binary response choice models to study four food products of the Val d'Orcia area. It aims at addressing two main issues: i) the analysis of food products of high quality by planning a combined study of choice and conjoint designs in the presence of certiÞcation criteria and quality characteristics; (ii) the...