1,721,392 research outputs found
Estimation of Tail Probability via the Maximum Lq-Likelihood method
Full text link1 online resource (PDF, 36 pages)Ferrari, Davide; Yang, Yuhong. (2007). Estimation of Tail Probability via the Maximum Lq-Likelihood method. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/199669
A novel hardware-in-the-loop device for floating offshore wind turbines and sailing boats
Full text linkEstimation of Tail Probability via the Maximum Lq-Likelihood Method
No full textEstimation of tail probability is of interest in various applications. Given a parametric model, a natural approach is maximum likelihood estimationAlthough the resulting estimator is asymptotically efficient, the large sam-ple property is often not trustworthy for estimating small tail probabilities.We introduce a new estimator for the parameters, the Maximum Lq-Like-lihood Estimator (MLqE), based on Havrda and Charv·t entropy function
Strategie di Comunicazione Proattive per Migliorare Sicurezza e Efficienza durante la Collaborazione Uomo-Robot
No full textL'avanzamento della tecnologia ha aumentato significativamente la presenza di sistemi automatizzati nella società moderna, portando allo sviluppo di nuovi sistemi robotici che consentono un'integrazione più semplice e sicura in vari settori. I robot collaborativi, o cobot, sono progettati per lavorare in ambienti condivisi insieme agli esseri umani, offrendo maggiore flessibilità, adattabilità ed efficienza operativa rispetto ai sistemi robotici tradizionali. Nonostante la loro crescente diffusione, in particolare tra le piccole e medie imprese, la robotica collaborativa deve ancora affrontare diverse sfide che ne limitano il pieno potenziale. Due degli aspetti più critici in questo contesto sono la comunicazione e la sicurezza, entrambi essenziali per ottenere una collaborazione ottimale tra uomo-robot (HRC).
La comunicazione è fondamentale quando si lavora a stretto contatto con un operatore, in quanto facilita la cooperazione nel completamento dei compiti assegnati. Un sistema di comunicazione semplice e naturale che emuli la collaborazione tra esseri umani (HHC) favorisce l'integrazione dei cobot all'interno dei team, migliorando la qualità dell'interazione, la fiducia e riducendo lo stress nel lavorare accanto ai robot. La sicurezza è un altro aspetto cruciale nella HRC, in particolare negli ambienti in cui esseri umani e robot operano in stretta prossimità senza barriere fisiche. È obbligatorio che i robot rispettino le normative ISO, che garantiscono la sicurezza dei lavoratori per prevenire e mitigare possibili danni o infortuni. Gli approcci tradizionali alla sicurezza spesso impongono restrizioni severe, come fermare o rallentare il robot quando un essere umano entra nello spazio di lavoro per evitare collisioni o limitare lo scambio di energia durante un contatto. Sebbene questi metodi prevengano efficacemente gli incidenti, possono anche ridurre l'efficienza complessiva.
Questa tesi esplora l'integrazione tra sicurezza e comunicazione, concentrandosi su come creare un sistema di comunicazione che sia allo stesso tempo semplice e naturale, ma anche capace di affrontare o prevenire problemi o rallentamenti, incorporando discussioni sulla sicurezza all'interno di conversazioni preventive con l'operatore. Per raggiungere questo obiettivo, sono stati esplorati diversi canali di comunicazione, in particolare voce e gesti, portando allo sviluppo di un'architettura di comunicazione multimodale. Questa architettura consente uno scambio bidirezionale di informazioni tra esseri umani e robot, con l'obiettivo di replicare la struttura conversativa delle interazioni tra esseri umani. Ciò permette ai robot non solo di eseguire comandi, ma anche di fornire feedback e proporre soluzioni alternative. Utilizzando simulazioni in tempo reale di un modello di robot in un ambiente virtuale, è possibile prevedere potenziali rallentamenti causati da preoccupazioni legate alla sicurezza. Questo consente al sistema di utilizzare la comunicazione per anticipare tali problemi e proporre soluzioni alternative, garantendo la sicurezza senza compromettere l'efficienza.
I sistemi di comunicazione proposti sono stati testati e validati in vari casi di studio, dimostrando come un quadro di comunicazione bidirezionale ben progettato possa migliorare sia la collaborazione che la sicurezza. I risultati mostrano che, con strategie di comunicazione efficaci, i robot possono anticipare problemi e offrire soluzioni alternative, portando a operazioni più efficienti e sicure in ambienti condivisi. Questo lavoro contribuisce allo sviluppo continuo della robotica collaborativa, avvicinandola sempre di più a eguagliare le prestazioni dei sistemi automatizzati tradizionali, garantendo al contempo la sicurezza dei lavoratori.The advancement of technology has significantly increased the presence of automated systems in modern society, leading to the development of new robotic systems that enable easier and safer integration across various sectors. Collaborative robots, or cobots, are designed to work in shared environments alongside humans, offering greater flexibility, adaptability, and operational efficiency compared to traditional robotic systems. Despite their growing adoption, particularly by small and medium-sized enterprises, collaborative robotics still face several challenges that limit their full potential. Two of the most critical issues in this context are communication and safety, both of which are essential for achieving optimal human-robot collaboration (HRC).
Communication is fundamental when working closely with human operators, as it facilitates cooperation in completing assigned tasks. A simple and natural communication system that emulates human-human collaboration (HHC) promotes the integration of cobots within teams, improving interaction quality, trust, and reducing stress when working alongside robots. Safety is another crucial aspect in HRC, particularly in environments where humans and robots operate in close proximity without physical barriers. It is mandatory that robots comply with ISO regulations, which ensure the worker's safety to prevent and mitigate potential harm or injuries. Traditional safety approaches often impose strict constraints, such as stopping or slowing down the robot when a human enters the workspace to avoid collisions or limiting the energy exchange during a contact. While these methods effectively prevent accidents, they can also reduce overall efficiency.
This thesis explores the integration of safety and communication, focusing on how to create a communication system that is both simple and natural, while also capable of addressing or preventing problems or slowdowns by incorporating safety discussions into proactive conversations with the operator. To achieve this, various communication channels, particularly voice and gestures, were explored, leading to the development of a multimodal communication architecture. This architecture enables bidirectional information exchange between humans and robots, aiming to replicate the conversational structure of human-human interactions. It allows robots not only to execute commands but also to provide feedback and suggest alternative solutions. By using real-time simulations of a robot model within a virtual environment, potential slowdowns caused by safety concerns can be predicted. This allows the system to use communication to anticipate such issues and propose alternative solutions, ensuring safety without compromising efficiency.
The proposed communication systems were tested and validated in various case studies, demonstrating how a well-designed bidirectional communication framework can enhance both collaboration and safety. The results show that with effective communication strategies, robots can anticipate potential problems and offer alternative solutions, leading to more efficient and safer operations in shared environments. This work contributes to the ongoing development of collaborative robotics, bringing them closer to matching the performance of traditional automated systems while ensuring the safety of human workers
Web-based versus paper-based data collection for the evaluation of teaching activity: empirical evidence from a case study
No full textThe collection of teaching evaluation questionnaires in the traditional paper-and-pencil format is a costly and time consuming process and yet it is a common assessment practice in many university systems. Web-based data collection would reduce costs and significantly increase the efficiency of the overall evaluation process in numerous ways. Results for both types of surveys are reported from two years of progressive introduction of the Web-based survey by the University of Modena and Reggio Emilia, Italy. In the first year, two faculties representing scientific and humanistic fields were selected for a Web-based survey. In the second year, eight out of twelve faculties took part in the Web survey. This data collection strategy allowed for responses from non-attending students and facilitated a comparison of attitudes between attending and non-attending students
The Maximum Lq-Likelihood Estimator in Extreme Value Theory, Italian
No full textIn questo lavoro, si propone di utilizzare lo stimatore MLqE di Massima Lq-Verosimiglianza, introdotto da Ferrari e Yang (2007), per la stima dei parametri della distribuzione del Valore Estremo generalizzata e della distribuzione di Pareto generaliz- zata. L’analisi empirica, condotta mediante simulazioni Monte Carlo, mostra che lo sti- matore MLqE e ́ piu ́ efficiente dello stimatore di Massima Verosimiglianza nel caso in cui si voglia stimare la probabilita ́ di un evento estremo, avendo a disposizione un campione di dimensioni limitate
Evaluation of Teaching Activity through the Internet and Non-Attending Students: The Experience of the University of Modena and Reggio Emilia
No full textThe collection of the evaluation questionnaires is costly and time consuming process. The use of internet in data collection, rather than completion on paper, will produce a cheaper and more efficient process. The two modes of administration were described through the results of two years of experimentation in the university of Modena and Reggio Emilia. In the first year, two faculties, representing the scientific and humanistic field, were selected: biosciences and biotechnologies, Economic and Communication Sciences. In the second year, eight faculties out of twelve participated to the experimentation. The adopted strategy allowed gathering information also about non-attending students. The different behaviours of the attending and non-attending student groups will be described in some details
A continuous kinetic assay for RNA-cleaving deoxyribozymes, exploiting ethidium bromide as an extrinsic fluorescent probe
Full text linkWe describe a rapid and inexpensive method to monitor the kinetics of small RNA-cleaving deoxyribozymes, based on the exogenous fluorophore ethidium bromide. Ethidium binds preferentially to double-stranded nucleic acids, and its fluorescence emission increases dramatically upon intercalation. Thus, ethidium can be used in single-turnover experiments to measure both annealing of the deoxyribozyme to its substrate and release of the products. Under conditions in which dissociation of the product is fast compared with cleavage, the apparent rate of product release reflects the cleavage step. The method was developed for characterizing the so-called 8-17 catalytic DNA, but its general applicability in the deoxyribozyme field was verified using the 10-23 RNA-cleaving construct. Catalysis by both deoxyribozymes was not inhibited in the presence of substoichiometric amounts of ethidium, and the rates obtained through the ethidium assay were virtually identical to the rates determined using radiolabeled substrates. In contrast, the assay cannot be applied to the large, structured ribozymes, and its use to study the kinetics of the small hammerhead ribozyme was hampered by the presence on the catalyst of at least one high-affinity ethidium binding site
Maximum Lq-Likelihood Method
Full text linkIn this paper, the maximum Lq-likelihood estimator (MLqE), a new parameter estimator based on nonextensive entropy [Kibernetika 3 (1967) 30–35] is introduced. The properties of the MLqE are studied via asymptotic analysis and computer simulations. The behavior of the MLqE is characterized by the degree of distortion q applied to the assumed model. When q is properly chosen for small and moderate sample sizes, the MLqE can successfully trade bias for precision, resulting in a substantial reduction of the mean squared error. When the sample size is large and q tends to 1, a necessary and sufficient condition to ensure a proper asymptotic normality and efficiency of MLqE is established
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