3,759 research outputs found
In search for theories: polyphony, polysemy and semiotic mediation in the mathematics classroom.
No full textThis theoretical report addresses the theme of the PME Conference (“In search for theories in Mathematics Education”). The history of two interlaced research programs (Mathematical Discussion and Mathematical Machines) headed by the author is outlined, together with the merging of both, combined with studies on information and communication technologies. They are the roots of the theoretical framework of semiotic mediation after a Vygotskian approach (Bartolini Bussi & Mariotti, 2008). May this framework answer the present needs of focusing cultural historical issues and the teacher'
Pac post-2020 e innovazione tecnologica: il caso degli investimenti in tecnologie conservative del suolo in Toscana
No full textLa promozione di sistemi agricoli sostenibili e resilienti passa necessariamente attraverso il processo di ammodernamento produttivo e tecnologico dei sistemi stessi (Tilman, 2002; Vagnozzi, 2015). Diverse tecnologie attualmente disponibili sono in grado di migliorare in modo congiunto le performance ambientali ed economiche delle aziende agricole, come ad esempio l’agricoltura di precisione e le tecniche di non lavorazione del suolo. Queste tecnologie rappresentano innovazioni chiave per promuovere il processo di intensificazione sostenibile e per migliorare la resilienza del settore agricolo di fronte alle principali sfide future (Buckwell et al., 2014). In particolare, la diffusione di tecnologie di no-tillage possono apportare diversi benefici per l’ambiente come ad esempio la riduzione dell’erosione del suolo, il sequestro del carbonio e la lisciviazione dei nutrienti (Soileau et al., (1994); Holland (2004); Abdalla et al., (2013)). Pertanto la diffusione di tecnologie conservative di gestione dei suoli può coniugare un ottimo privato con un ottimo sociale (Lankoski et al., 2006).
L’analisi dell’adozione dell’innovazione e delle nuove tecnologie in agricoltura è un tema ampiamente trattato nella letteratura scientifica. La comprensione delle determinanti e dei enebling factors del processo di innovazione tecnologica nelle aziende agricole è stato affrontato sia nella letteratura economico agraria sia negli studi sullo sviluppo rurale. Diversi articoli hanno evidenziato il ruolo centrale nel processo di adozione delle tecnologie delle aspettative legate ai futuri flussi di costi e benefici, le incertezze e attitudini al rischio, la qualità delle informazioni e delle conoscenze nel determinare costi di accesso alla tecnologia (Sauer and Zilberman, 2012; Klerkx et al., 2012; Esposti 2012). Adrews et al. (2013) ha identificato tre diversi frames coi quali esprimere la propensione ad investire in tecnologie conservative del suolo: a) motivi legati alla redditività dell’investimento; b) esistenza di incentivi che modificano i rapporti tra i costi ed i benefici; c) esperienze e attitudini soggettive.
Un’ampia letteratura ha evidenziato effetti positivi della politica agricola comune (ed in particolare i pagamenti diretti) nel ridurre il processo di abbandono nelle aree rurali e la disattivazione delle aziende agricole (Raggi et al., 2013; Bartolini e Viaggi, 2013; Olper et al., 2014) nel promuovere il processo di ammodernamento dei sistemi agricoli, nell’incentivare l’innovazione tecnologica in condizioni di strette creditizie o di incertezza (Esposti, 2014) e nel migliorare l’ efficienza e la produttività (Rizov et al., 2013). L’adozione di no-tillage può risentire dell’influenzata di diverse fonti di incertezza tra cui le rese, i prezzi dei prodotti agricoli, il costo degli input (Loughrey et al. 2016). Alti livelli di incertezza possono ridurre la propensione ad investire (Loughrey et al. 2016) o ritardare il processo di ammodernamento tecnologico (Bartolini e Viaggi, 2012).
Le simulazioni micro-economiche degli investimenti rappresentato un tema di crescente interesse nella letteratura economico agraria e sono un valido strumento di supporto ai decisori pubblici o privati per supportare la valutazione degli interventi pubblici nel settore (Ramilan et al. 2011; O’ Dongue 2013).
Mediante l’applicazione di simulazioni micro-economiche, in questo lavoro, sono stati simulati gli effetti di diversi scenari di politica sulla propensione ad adottare innovazioni tecnologiche in condizioni di incertezza. La rimanete parte dell’articolo introdurrà la metodologia e successivamente principali risultati ed infine verranno presentate le considerazioni conclusive
Business-driven IT Management
No full textBusiness-driven IT management (BDIM) aims at ensuring successful alignment of business and IT through thorough understanding of the impact of IT on business results, and vice versa.
In this dissertation, we review the state of the art of BDIM research and we position our intended contribution within the BDIM research space along the dimensions of decision support (as opposed of automation) and its application to IT service management processes.
Within these research dimensions, we advance the state of the art by 1) contributing a decision theoretical framework for BDIM and 2) presenting two novel BDIM solutions in the IT service management space. First we present a simpler BDIM solution for prioritizing incidents, which can be used as a template for creating BDIM solutions in other IT service management processes. Then, we present a more comprehensive solution for optimizing the business-related performance of an IT support organization in dealing with incidents.
Our decision theoretical framework and models for BDIM bring the concepts of business impact and risk to the fore, and are able to cope with both monetizable and intangible aspects of business impact. We start from a constructive and quantitative re-definition of some terms that are widely used in IT service management but for which was never given a rigorous decision: business impact, cost, benefit, risk and urgency.
On top of that, we build a coherent methodology for linking IT-level metrics with business level metrics and make progress toward solving the business-IT alignment problem. Our methodology uses a constructive and quantitative definition of alignment with business objectives, taken as the likelihood – to the best of one’s knowledge – that such objectives will be met. That is used as the basis for building an engine for business impact calculation that is in fact an alignment computation engine. We show a sample BDIM solution for incident prioritization that is built using the decision theoretical framework, the methodology and the tools developed. We show how the sample BDIM solution could be used as a blueprint to build BDIM solutions for decision support in other IT service management processes, such as change management for example.
However, the full power of BDIM can be best understood by studying the second fully fledged BDIM application that we present in this thesis. While incident management is used as a scenario for this second application as well, the main contribution that it brings about is really to provide a solution for business-driven organizational redesign to optimize the performance of an IT support organization. The solution is quite rich, and features components that orchestrate together advanced techniques in visualization, simulation, data mining and operations research. We show that the techniques we use - in particular the simulation of an IT organization enacting the incident management process – bring considerable benefits both when the performance is measured in terms of traditional IT metrics (mean time to resolution of incidents), and even more so when business impact metrics are brought into the picture, thereby providing a justification for investing time and effort in creating BDIM solutions.
In terms of impact, the work presented in this thesis produced about twenty conference and journal publications, and resulted so far in three patent applications. Moreover this work has greatly influenced the design and implementation of Business Impact Optimization module of HP DecisionCenter™: a leading commercial software product for IT optimization, whose core has been re-designed to work as described here
FLUORESCENCE BASED STUDIES ON BETA-AMYLOID MISFOLDING AND AGGREGATION
No full textRecent findings about the relationship between amyloid b-peptide (Ab) accumulation and cognitive decline in Alzheimer's disease (AD) suggest a complex role for Ab in this neurodegenerative process. The transition of Ab soluble monomers to toxic small oligomers involves an initial transition from a non organized/a-helix monomer to a b-sheet rich conformer. This early step represents a suitable target to design new potent inhibitors and obtain effective therapeutics for AD. Moreover, several chaperone molecules are though to accelerate amyloid aggregation, i.e., the enzyme acetylcholinesterase (AChE). Since most of the marketed drugs for AD are AChE inhibitors, the investigation of the inhibitory potency against the AChE-induced amyloid aggregation exerted by anti-cholinesterase agents definitively represents an interesting area of investigation for drug discovery. The in vitro Ab aggregation can be evaluated by a fluorescence-based assay by using Thioflavin T (ThT) as fluorescent dye. More in details, ThT specifically binds to amyloid fibrils (in the beta-sheet conformation) giving rise to an intense specific emission band (lem = 490 nm) in its fluorescent spectrum (1-3). Therefore the increase in the specific fluorescence emission was used to monitor amyloid fibrils formation. Two fluorescence-based assays specifically developed (4,5) for the evaluation of beta-amyloid self- and AChE-induced aggregation were applied to follow the aggregation process as well as to screen for potential inhibitors. The concomitant use of circular dichroism spectroscopy was helpful to set up the optimal experimental conditions and to draw some hypotheses on the mechanism of action of known and new inhibitors.
(1) H. Naiki, K. Higuchi, K. Nakakuki, T. Takeda, Lab. Invest. 1991, 65, 104.
(2) H. LeVine, Protein Sci. 1993, 2, 404.
(3) H. LeVine 3rd, Methods Enzymol. 1999, 309, 274.
(4) M. Bartolini, C. Bertucci, M.L. Bolognesi, A. Cavalli, C. Melchiorre, V. Andrisano, Chembiochem 2007, 8, 2152.
(5) M. Bartolini, C. Bertucci, V. Cavrini, V. Andrisano, Biochem. Pharmacol. 2003, 65, 407
Single-source library for enabling seamless assignment of data-parallel task-DAGs to CPUs and GPUs in heterogeneous architectures
No full textCurrently, the majority of devices is heterogeneous and comprises at least a multi-core CPU and a GPU. Exploiting these modules requires programmers to a) assign parallel activities to the different hardware resources, and b) code each activity through target-specific approaches x(e.g., multi-core CPUs and GPUs). Current frameworks do not provide high-productivity while guaranteeing performance comparable to low-level ones. Also, they often lack the easy exploration of possible task assignments to the heterogeneous resources, mainly because the assignment needs to be done in advance and the targets have software incompatibilities. This paper introduces task-DAGs (Directed Acyclic Graph) concepts into PHAST, a single-source data-parallel library that supports multi-core CPUs and NVIDIA GPUs. The resulting framework allows postponing the task-to-target assignment to the testing or runtime phase. In fact, each task is coded in a target-agnostic fashion and can be automatically optimized for a specific platform. The consequent productivity effects are shown for a computer-vision benchmark comparing to a SYCL implementation and performing an automatic task assignment for maximum resources utilization
Il personale
No full textCon il contributo sul personale viene offerta una ricognizione completa del quadro normativo e giurisprudenziale in materia. Il metodo prescelto tende a far emergere le problematiche di carattere pratico derivate dalla c.d. privatizzazione del pubblico impiego. Vengono evidenziati i nodi irrisolti di una riforma incompiuta, in cui il sistema della responsabilità dirigenziale è sostanzialmente fallito. Si evidenzia altresì che è il medesimo interesse pubblico sotteso alla disciplina esaminata a non essere tutelato, poiché, da un lato, il controllo sull’atto è venuto meno con le recenti riforme, ma, dall’altro, il sistema sul controllo dei risultati non funziona. La privatizzazione non ha portato ad un miglioramento dell’efficienza della pubblica amministrazione (anzi, forse, è peggiorata), poiché è la logica di fondo ad essere sbagliata: si è pensato che introducendo la disciplina del rapporto di lavoro di diritto comune si sarebbero conferiti ai dirigenti i medesimi poteri dell’imprenditore privato, dimenticandosi, peraltro, che l’amministrazione non è un’azienda di servizi e che non agisce secondo logiche aziendali, ma politiche(amministrative)
Flexible task-DAG management in PHAST library: Data-parallel tasks and orchestration support for heterogeneous systems
No full textHeterogeneous architectures proved successful in achieving unprecedented performance and energy-efficiency. However, taking advantage of these diverse processing elements is still hard. Programmers need to code through the different approaches suitable for each target architecture and need to decide the distribution of activities on the different resources. The majority of current frameworks focuses on either performance or productivity. The former mainly provides low-level target-specific programming interfaces, and the latter offers high-level tools that often fail in achieving high-performance. In both cases, the design is usually data-parallel, as task-parallelism is not supported. In this work, we propose a task-based solution within the data-parallel heterogeneous single-source PHAST library. Tasks can be coded in a target-agnostic fashion, can be compiled and parallelized on multi-core CPUs and NVIDIA GPUs automatically and support the choice of the execution platform at runtime. We evaluate the capabilities of the proposed task-directed acyclic graph support in case of an extensive set of randomly generated task-based applications with different sizes and characteristics. We compare it against a SYCL implementation in terms of performance and complexity metrics, highlighting that PHAST achieves about 1.56× and 2.60× speedup over SYCL for multi-core CPU and GPU, respectively, while improving also code complexity metrics
Task-DAG support in single-source PHAST library: Enabling flexible assignment of tasks to CPUs and GPUs in heterogeneous architectures
No full textNowadays, the majority of desktop, mobile, and embedded devices in the consumer and industrial markets are heterogeneous, as they contain at least multi-core CPU and GPU resources in the same system. However, exploiting the performance and energy-efficiency of these diverse processing elements does not come for free from a software point of view: programmers need to a) code each activity through the specific approaches, libraries, and frameworks suitable for their target architecture (e.g., CPUs and GPUs) along with the orchestration of such heterogeneous execution, and b) decide the distribution of sequential and parallel activities towards the different parallel hardware resources available. Current frameworks typically provide either low-abstraction-level target-specific and/or generic but not high-performance interfaces, which complicate the exploration of different task assignments, with DAG1 precedence relationship, to the available heterogeneous resources. To enable this, tasks would typically need to be coded one time for each target architecture due to the profound differences in their programming. In this work, we include the support of tasks and DAGs of data-parallel tasks within the single-source PHAST library, which currently supports both multi-core CPUs and NVIDIA GPUs, so that tasks are coded in a target-agnostic fashion and their targeting to multi-core or GPU architectures is automatic and efficient. The integration of this coding approach with tasks can help to postpone the choice of the execution platform for each task up to the testing, or even to the runtime, phase. Finally, we demonstrate the effects of this approach in the case of a sample image pipeline benchmark from the computer vision domain. We compare our implementation to a SYCL implementation from a productivity point of view. Also, we show that various task assignments can be seamlessly explored by implementing both the PEFT2 mapping technique along with an exhaustive search in the mapping space
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