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A rejoinder to the comments of Benedetto et al. on the paper "Critical remarks on the Italian research assessment exercise VQR 2011-2014" (Journal of Informetrics, 11(2): 337-357)
No full textThe paper "Critical remarks on the Italian research assessment exercise VQR 2011-2014" (Franceschini & Maisano, 2017) analyzed some vulnerabilities of the recently concluded Italian assessment exercise. Some apical (former and current)members of ANVUR promptly commented on our criticisms through a letter to the editor (Benedetto, Checchi, Graziosi, & Malgarini, 2017). We believe that this letter is not very convincing. In the following, we provide a rejoinder to the comments directed to our paper
Analysis of HEVC transform throughput requirements for hardware implementations
No full textHardware implementations can provide significant speedup and saving for video compression applications. In this work we focus on the transform coding sub-module analyzing the performance required by actual encoder implementations. We show that the throughput assumption about the transform sub-module in most research works is overly optimistic since it does not consider the complexity of a rate-distortion optimized video coding process. Many HEVC coding options are compared in terms of impact on quality and throughput, so to recommend the most efficient settings without excessively penalizing quality. Moreover, comparisons with the AVC standard show that, in general, HEVC presents much higher complexity to deliver its claimed compression advantages. Finally, a practical case study is shown to highlight how the proposed transform throughput analysis could be used to determine the throughput for a transform sub-module hardware design
Power-performance assessment of different DVFS control policies in NoCs
No full textWe analyze the power-delay trade-off in a Network-on-Chip (NoC) under three Dynamic Voltage and Frequency Scaling (DVFS) policies. The first rate-based policy sets frequency and voltage of the NoC to the minimum value that allows to sustain the injection rate without reaching saturation. The second queue-based policy uses a feedback-loop approach to throttle the NoC frequency and voltage such that the average backlog of the injection queues tracks a target value. The third delay-based policy uses a closed- loop strategy that targets a given NoC end-to-end average delay. We first show that, despite the different mechanism and implementation, both rate-based and queue-based policies obtain very similar results in terms of power and delay, and we propose a theoretical interpretation of this similarity. Then, we show that delay-based policy generally offers a better power-delay trade-off. We obtained our results with an extensive set of experiments on synthetic traffic, as well as multimedia, communications and PARSEC benchmarks. For all the experiments, we report both cycle-accurate simulation results for the analysis of NoC delay and accurate power results obtained targeting a standard-cell library in an advanced 28-nm FDSOI CMOS technology
Investigation of food waste valorization through sequential lactic acid fermentative production and anaerobic digestion of fermentation residues
No full textThis work concerns the investigation of the sequential production of lactic acid (LA) and biogas from food waste (FW). LA was produced from FW using a Streptococcus sp. strain via simultaneous saccharification and fermentation (SSF), and separate enzymatic hydrolysis and fermentation (SHF). Via SHF a yield of 0.33 gLA/gFW (productivity 3.38 gLA/L.h) and via SSF 0.29 gLA/gFW (productivity 2.08 gLA/L.h) was obtained. Fermentation residues and FW underwent anaerobic digestion (3 wt% TS). Biogas yields were 0.71, 0.74 and 0.90 Nm3/kgVS for FW and residues from SSF and SHF respectively. The innovation of the approach consists of considering the conversion of FW into two different high value products through a biorefinery chain, therefore making economically feasible LA production and valorising its fermentative residues. Finally, a mass balance involved three different process outlines with the aim to assess the amount of LA and biogas that may be generated within different scenarios
The museum of errors/horrors in Scopus
No full textRecent studies have shown that the Scopus bibliometric databases is probably less accurate than one thinks. As a further evidence of this fact, this paper presents a structured collection of several weird typologies of database errors, which can therefore be classified as horrors. Some of them concern the incorrect indexing of so-called Online-First paper, duplicate publications, and the missing/incorrect indexing of references. A crucial point is that most of these errors could probably be avoided by adopting some basic data checking systems. Although this paper does not provide a quantitative and systematic analysis (which will be provided in a future publication), it can be easily understood that these errors can have serious consequences such as: (i) making it difficult or even impossible to retrieve some documents, and (ii) distorting bibliometric indicators/metrics relating to journals, individual scientists or research institutions. Our attention is focused on the Scopus database, although preliminary data show that the Web of Science database is far from being free from these errors. The tone of the paper is deliberately provocative, in order to emphasize the seriousness of these error
A STUDY OF RELATIONSHIPS BETWEEN TRAFFIC NOISE AND ANNOYANCE FOR DIFFERENT URBAN SITE TYPOLOGIES
No full textThe paper intends to analyse the different attitudes of residents in urban areas in regard to annoyance induced by traffic noise, account taken of the effects of the street configuration and of the presence of specific public transport modes in the definition of the dose-response curves. People's annoyance was investigated through a campaign of noise and traffic measurements and an epidemiological survey, administered to a sample of 830 residents in the buildings close to the measurement points. An ordinal regression model taking into account environmental and urban characteristics was used to identify a dose-response relationship. The cumulative probabilities allowed to define two cut points on the dose-response curves (60 and 75 dB(A)), grouping people in three classes and making the representation of the dose-response relationships different from those traditionally defined that use only the percentage of highly annoyed people. The results show different people's attitudes towards the annoyance in the urban sites while the dose-response relationship shows that the correlation between annoyance and noise is low. For the same value of day equivalent level, 10% more people are annoyed in L sections (broad streets) than in U sections (narrow streets). Furthermore, all the dose-response curves show a higher sensitivity of people living in L sections; this difference can be measured as a shift of about 4 dB(A). Noise levels are, arguably, a useful indicator, but they are not reliable enough to define the discomfort of the residents, while the site characteristics could shed light on annoyance variabilit
Simulation of Local Effects, Energy Absorption and Failure Mechanism in Multilayered and Sandwich Structures
No full textThe present dissertation describes the research work carried out towards: I. developing of analytical and numerical models for accurate and efficient analysis of laminates and sandwiches under different loading conditions (static analyses, impulsive loading and low velocity impacts); II. developing of techniques to improve structural performances of composites structures by tuning their energy absorption mechanism; A higher order theory (AD-ZZ) including zig-zag effects, transverse shear continuity, variable transverse displacement and layerwise representation is presented for analysis of laminates and sandwiches. This theory is cast in such a way that the unknowns in the model will involve only five variables like equivalent single layer models: the three displacement components and the two shear rotations of the normals on the reference surface. It is advantageous to formulate the theory in this way, as it provides the opportunity to refine its through-the-thickness representation by adding computational layers in the thickness direction without increasing the number of unknowns. After extensive evaluation of the accuracy obtained by the above mentioned theory for a variety of structures, the AD-ZZ model is enriched by adding a set of continuity functions in order to treat laminates and structures with in-plane discontinuities (e.g. bonded joints, two material wedge) under a unified approach without adding new unknowns. Speaking of techniques to improve structural performances, two approaches are presented: variable stiffness composites and stitching. The former tool works on the strain energy of the structure computing fibre distributions that minimize unwanted energy contributions and maximize the wanted ones. The latter prescribes the insertions of transverse reinforcements in sandwich structures. The homogenized mechanical properties of this structure, required by the AD-ZZ model to perform the analysis, are evaluated through virtual material tests using a 3D FE model. The results obtained applying these techniques demonstrate that both are effective in reducing transverse stresses at critical interfaces and, in certain cases, in improving bending stiffness. New C0 displacement-based and stress-based finite elements for analysis of laminated and sandwich plates based on the AD-ZZ model are developed. To achieve this goal, a new technique that converts derivatives of functional degrees of freedom contained in the AD-ZZ is presented. Both the elements satisfy all the requirements of computationally efficient finite element models for analysis of multilayered structures, namely 1) the number of degrees of freedom is independent from the number of layers; 2) no shear correction factors or penalty number are added in the formulation. Consistent shear fields are obtained for the present finite element formulations. Numerical results demonstrate that these new elements are robust, accurate and computationally efficient for analysis of multilayered structures. In order to study structures subjected to impact loading a new simulation procedure is developed. It is based on the AD-ZZ model and considers the crushing behaviour of soft-like media without performing each time a detailed 3D finite element analysis. Numerical results show that the response of composites undergoing low velocity impact is very accurately predicted with low computational effort. Overall, the present procedure holds great promise for analysis of laminated and sandwich structures undergoing low velocity impac
Distributed In-network Processing and Resource Optimization over Mobile-Health Systems
No full textAdvances in wireless and mobile communication technologies has promoted the development of Mobile-health (m-health) systems to find new ways to acquire, pro- cess, transport, and secure the medical data. M-health systems provide the scal- ability needed to cope with the increasing number of elderly and chronic disease patients requiring constant monitoring. However, the design and operation of such systems with Body Area Sensor Networks (BASNs) is challenging in twofold. First, limited energy, computational and storage resources of the sensor nodes. Second, the need to guarantee application level Quality of Service (QoS). In this paper, we inte- grate wireless network components, and application-layer characteristics to provide sustainable, energy-efficient and high-quality services for m-health systems. In par- ticular, we propose an Energy-Cost-Distortion (E-C-D) solution, which exploits the benefits of in-network processing and medical data adaptation to optimize the trans- mission energy consumption and the cost of using network services. Moreover, we present a distributed cross-layer solution, which is suitable for heterogeneous wire- less m-health systems with variable network size. Our scheme leverages Lagrangian duality theory to find efficient trade-off among energy consumption, network cost, and vital signs distortion, for delay sensitive transmission of medical data. Simula- tion results show that the proposed scheme achieves the optimal trade-off between energy efficiency and QoS requirements, while providing 15% savings in the objec- tive function (i.e., E-C-D utility function), compared to solutions based on equal bandwidth allocation
