933 resultados para Concurrent exception handling
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Background: Cervicocephalic kinesthetic deficiencies have been demonstrated in patients with chronic neck pain (NP). On the other hand, authors emphasized the use of different motion speeds for assessing functional impairment of the cervical spine. Purpose: The objectives of this study were (1) to investigate the head repositioning accuracy in NP patients and control subjects and (2) to assess the influence of target distance, motion speed, motion direction and pain. Materials and methods: Seventy-one subjects (36 healthy subjects and 35 NP patients; age 30–55 years) performed the head repositioning test (HRT) at two different speeds for horizontal and vertical movements and at two different distances. For each condition, six consecutive trials were sampled. Results: The study showed the validity and reproducibility of the HRT, confirming a dysfunctional threshold of 4.5°. Normative values of head repositioning error up to 3.6° and 7.1° were identified for healthy and NP subjects, respectively. A distance of 180 cm from the target and a natural motion speed increased HRT accuracy. Repositioning after extension movement showed a significantly larger error in both groups. Intensity, duration of pain as well as pain level did not significantly alter head repositioning error. Conclusions: The assessment of proprioceptive performance in healthy and NP subjects allowed the validation of the HRT. The HRT is a simple, not expensive and fast test, easily implementable in daily practice to assess and monitor treatment and evolution of proprioceptive cervical deficits.
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Visando obter subsídios para um estudo da qualidade da água em tanques de piscicultura, realizou-se um experimento de 166 dias com uma espécie nativa, pacu (Piaractus mesopotamicus). Nos tanques foram testados dois níveis diferentes de proteína na dieta (16% e 34% de proteína bruta) e três densidades de estocagem (0,25; 0,50 e 0,77 peixes/m²). Dos resultados obtidos foi observado que a interação entre a densidade de estocagem e a duração do experimento interferiram nas variáveis bicarbonato e alcalinidade e a interação entre a densidade de estocagem e a porcentagem de proteína interferiram nas concentrações de CO2 livre e total, condutividade e pH (P < 0,05). A temperatura da água nos tanques variou significativamente ao longo do período estudado (P < 0,05), diminuindo gradativamente do verão para o inverno. Não houve diferença significativa no tempo de residência da água nos tanques (P > 0,05) durante a duração do experimento. Os demais parâmetros não sofreram interferência dos tratamentos ao longo do período de estudo.
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Iron ore concentrate pellets have the potential to fracture and abrade during transportation and handling, which produces unwanted fine particulates and dust. Consequently, pellet producers characterize the abrasion resistance of their pellets, using an Abrasion Index (AI), to indicate whether their products will produce unacceptable levels of fines. However, no one has ever investigated whether the AI correlates to pellet dustiness. During the course of this research, we investigated the relationship between AI and iron ore concentrate pellet dustiness using a wide range of industrial and laboratory pellet samples. The results showed that, in general, AI can be used to indicate high levels of dust. However, for good-quality pellets, there was no correlation between the two. Thus, dust generation from shipping and handling pellets will depend on the quantity of pellets handled and how much they are handled. These results also showed that the type of industrial furnace used to harden iron ore concentrate pellets may affect their fines generation and potential dustiness.
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Concurrent software executes multiple threads or processes to achieve high performance. However, concurrency results in a huge number of different system behaviors that are difficult to test and verify. The aim of this dissertation is to develop new methods and tools for modeling and analyzing concurrent software systems at design and code levels. This dissertation consists of several related results. First, a formal model of Mondex, an electronic purse system, is built using Petri nets from user requirements, which is formally verified using model checking. Second, Petri nets models are automatically mined from the event traces generated from scientific workflows. Third, partial order models are automatically extracted from some instrumented concurrent program execution, and potential atomicity violation bugs are automatically verified based on the partial order models using model checking. Our formal specification and verification of Mondex have contributed to the world wide effort in developing a verified software repository. Our method to mine Petri net models automatically from provenance offers a new approach to build scientific workflows. Our dynamic prediction tool, named McPatom, can predict several known bugs in real world systems including one that evades several other existing tools. McPatom is efficient and scalable as it takes advantage of the nature of atomicity violations and considers only a pair of threads and accesses to a single shared variable at one time. However, predictive tools need to consider the tradeoffs between precision and coverage. Based on McPatom, this dissertation presents two methods for improving the coverage and precision of atomicity violation predictions: 1) a post-prediction analysis method to increase coverage while ensuring precision; 2) a follow-up replaying method to further increase coverage. Both methods are implemented in a completely automatic tool.
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We analyzed six apiaries in several natural environments with a Mediterranean ecosystem in Madrid, central Spain, in order to understand how landscape and management characteristics may influence apiary health and bee production in the long term. We focused on five criteria (habitat quality, landscape heterogeneity, climate, management and health), as well as 30 subcriteria, and we used the analytic hierarchy process (AHP) to rank them according to relevance. Habitat quality proved to have the highest relevance, followed by beehive management. Within habitat quality, the following subcriteria proved to be most relevant: orographic diversity, elevation range and important plant species located 1.5 km from the apiary. The most important subcriteria under beehive management were honey production, movement of the apiary to a location with a higher altitude and wax renewal. Temperature was the most important subcriterion under climate, while pathogen and Varroa loads were the most significant under health. Two of the six apiaries showed the best values in the AHP analysis and showed annual honey production of 70 and 28 kg/colony. This high productivity was due primarily to high elevation range and high orographic diversity, which favored high habitat quality. In addition, one of these apiaries showed the best value for beehive management, while the other showed the best value for health, reflected in the low pathogen load and low average number of viruses. These results highlight the importance of environmental factors and good sanitary practices to maximize apiary health and honey productivity.
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Power distance can produce contextual effects that surpass the cultural level of analysis, allowing predicting how the assimilation of these cultural values impacts individuals motivations to attain power positions and behaviors towards authorities. Power distance value can be conceived both at a micro and macro level of analysis. However existing measures used at a cultural level have been the object of several critics, and others applied at the individual level need further study in terms of their psychometric properties. This article presents the main psychometric properties of the Earley and Erez (1997) Power Differential Scale. This scale measures the acceptability of power and status differences both at micro and macro level. Two studies analyse the scale’s construct validity and its factorial invariance across groups of participants (Study 1); and its predictive validity at an individual level (Study 2). The results obtained support the proposed unidimensionality of the scale. Furthermore, it demonstrated predictive power by showing the role of power distance in the prediction of individual motivations to attain power and to respond to power situations using withdrawal or confrontational strategies. Future research is discussed, specifically the impact of power differential construct in individual attitudes and behavior.
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BACKGROUND: The Life-Space Assessment (LSA), developed in the USA, is an instrument focusing on mobility with respect to reaching different areas defined as life-spaces, extending from the room where the person sleeps to mobility outside one's hometown. A newly translated Swedish version of the LSA (LSA-S) has been tested for test-retest reliability, but the validity remains to be tested. The purpose of the present study was to examine the concurrent validity of the LSA-S, by comparing and correlating the LSA scores to other measures of mobility. METHOD: The LSA was included in a population-based study of health, functioning and mobility among older persons in Sweden, and the present analysis comprised 312 community-dwelling participants. To test the concurrent validity, the LSA scores were compared to a number of other mobility-related variables, including the Short Physical Performance Battery (SPPB) as well as "stair climbing", "transfers", "transportation", "food shopping", "travel for pleasure" and "community activities". The LSA total mean scores for different levels of the other mobility-related variables, and measures of correlation were calculated. RESULTS: Higher LSA total mean scores were observed with higher levels of all the other mobility related variables. Most of the correlations between the LSA and the other mobility variables were large (r = 0.5-1.0) and significant at the 0.01 level. The LSA total score, as well as independent life-space and assistive life-space correlated with transportation (0.63, 0.66, 0.64) and food shopping (0.55, 0.58, 0.55). Assistive life-space also correlated with SPPB (0.47). With respect to maximal life-space, the correlations with the mobility-related variables were generally lower (below 0.5), probably since this aspect of life-space mobility is highly influenced by social support and is not so dependent on the individual's own physical function. CONCLUSION: LSA was shown to be a valid measure of mobility when using the LSA total, independent LS or assistive LSA.
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The aim of this thesis is to contribute to deeper knowledge about the writing practices of teachers in upper secondary school. Schools are under constant pressure to respond to the needs and expectations of an ever-changing society and political intentions. A major factor in this change which is taking place in schools is digitalization. Another factor is the adoption of new governing principles for schools involving management by goals and results, which brings increased demands for written documentation of teachers' work. In order to describe and problematize this development the thesis is based on a combination of Critical Discourse Analysis and New Literacy (Clark and Ivanič, 1997). The theoretical framework rests upon an understanding of writing as social action and the idea that texts both affect and are affected by the social environment. The empirical study focuses on twelve teachers and their writing practices, analyzed during week-long field visits over three years. The teachers' talk about their writing is used together with analyses of texts and images to investigate parts of teachers' writing which, according to the teachers, are considered complex and problematic. The findings indicate significant differences between the writing practices of the individual teachers, where each teacher has his or her own system of texts fulfilling different purposes. Despite these differences it is still possible to identify recurrent themes in the discursive conditions for teachers' writing: efficiency, reuse, authority, audit, relationships to addressees, and room to maneuver. The study illustrates possible dilemmas for teachers' writing at the intersection of teachers' professional responsibility and demands for accountability.
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This study aimed to identify the parameters related to the expression of the reactivity in horses during handling and based on that proposed and validated a scale of composite measure reactivity score to characterize horse's reactivity. To this end, the first stage (S1) proposed the scale and the second (S2) validated it. In S1, 364 Lusitano horses were evaluated, 188 were adult breeding mares (4–12 years old), and 176 were foals (males/females, aged from 2 months to 2 years). During hooves trimming, vermifuge application, palpation scores were assigned to behaviors of movement, ears and eyes position, breathing, vocalization, and urination. A response parameter called reactivity was attributed to each animal, ranging from score 1 (nonreactive/calm) to score 4 (very reactive/aggressive). The verification of the possible parameters (age, behavior), which explains the response parameter (reactivity), was taken using ordinal proportional odds model. Movement, breathing, ears and eyes position, vocalization, and age appear to explain the reactivity of horses during handling (P < .01). Therefore, based on these parameters, it was possible to propose two scales of composite measure reactivity score: one to characterize the mares and another the foals. On S2, the proposed scale was validated by the simultaneous application of Forced Human Approach Test, another commonly used test to evaluate the reactivity in horses, with a correlation of 0.97 (P < .05). The assessment of the reactivity of horses during handling by a composite measure reactivity score scale is valid, and easy to apply, without disrupting daily routine and override the impact of individual differences.
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Dyscalculia is usually perceived of as a specific learning difficulty for mathematics or, more appropriately, arithmetic. Because definitions and diagnoses of dyscalculia are in their infancy and sometimes are contradictory. However, mathematical learning difficulties are certainly not in their infancy and are very prevalent and often devastating in their impact. Co-occurrence of learning disorders appears to be the rule rather than the exception. Co-occurrence is generally assumed to be a consequence of risk factors that are shared between disorders, for example, working memory. However, it should not be assumed that all dyslexics have problems with mathematics, although the percentage may be very high, or that all dyscalculics have problems with reading and writing. Because mathematics is very developmental, any insecurity or uncertainty in early topics will impact on later topics, hence to need to take intervention back to basics. However, it may be worked out in order to decrease its degree of severity. For example, disMAT, an app developed for android may help children to apply mathematical concepts, without much effort, that is turning in itself, a promising tool to dyscalculia treatment. Thus, this work will focus on the development of a Decision Support System to estimate children evidences of dyscalculia, based on data obtained on-the-fly with disMAT. The computational framework is built on top of a Logic Programming approach to Knowledge Representation and Reasoning, grounded on a Case-based approach to computing, that allows for the handling of incomplete, unknown, or even self-contradictory information.
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What do international non-governmental organisations (INGOs) do before and during the escalation of conflicts? The academic literature primarily focuses on these organisations' behaviour during an evident crisis rather than on how they anticipate the escalation of conflicts, assess the situation in which they find themselves, and decide on strategies to cope with the possibility of upcoming violence. Such lopsided focus persists despite calls for INGOs to become more proactive in managing their programmes and their staff members' safety. Mindful of this imbalance, the present study provides a causal explanation of how decision-makers in INGOs anticipate and react to the risk of low-level violence escalating into full-blown conflicts. This thesis aims to explain these actors' behaviour by presenting it as a two�step process involving how INGOs conduct risk assessments and how they turn these assessments into decisions. The study performs a structured, focused comparison of seven INGOs operating in South Sudan before the so-called Juba Clashes of 7 July 2016. Based on an analytical framework of INGO decision�making stemming from political risk analysis, organisational decision-making theory and conflict studies literature, the study reconstructs decision-making via process-tracing combined with mixed methods of data collection.
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This Thesis studies the optimal control problem of single-arm and dual-arm serial robots to achieve the time-optimal handling of liquids and objects. The first topic deals with the planning of time-optimal anti-sloshing trajectories of an industrial robot carrying a cylindrical container filled with a liquid, considering 1-dimensional and 2-dimensional planar motions. A technique for the estimation of the sloshing height is presented, together with its extension to 3-dimensional motions. An experimental validation campaign is provided and discussed to assess the thoroughness of such a technique. As far as anti-sloshing trajectories are concerned, 2-dimensional paths are considered and, for each one of them, three constrained optimizations with different values of the sloshing-height thresholds are solved. Experimental results are presented to compare optimized and non-optimized motions. The second part focuses on the time-optimal trajectory planning for dual-arm object handling, employing two collaborative robots (cobots) and adopting an admittance-control strategy. The chosen manipulation approach, known as cooperative grasping, is based on unilateral contact between the cobots and the object, and it may lead to slipping during motion if an internal prestress along the contact-normal direction is not prescribed. Thus, a virtual penetration is considered, aimed at generating the necessary internal prestress. The stability of cooperative grasping is ensured as long as the exerted forces on the object remain inside the static-friction cone. Constrained-optimization problems are solved for 3-dimensional paths: the virtual penetration is chosen among the control inputs of the problem and friction-cone conditions are treated as inequality constraints. Also in this case experiments are presented in order to prove evidence of the firm handling of the object, even for fast motions.
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L’elaborato descrive le fasi di progettazione, programmazione e validazione di un programma sviluppato in ambiente Java per il Vehicle Routing Problem. L’algoritmo implementato è di tipo euristico costruttivo primal e presenta funzionalità specifiche per la gestione di un elevato numero di vincoli e l’applicazione a casistiche reali. La validazione è stata effettuata su una base dati reale e in confronto a dataset di cui è nota la soluzione ottima. Il programma è stato progettato per risultare flessibile alle richieste dell’utente e utilizzabile per valutazioni economiche in ambito consulenziale.
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Questa tesi si propone di analizzare due macchinari della linea di “Handling” della divisione Active di IMA S.p.A., ovvero la macchina “Cyclops” e la macchina “Hercules”. Per entrambe le macchine si vuole svolgere un’analisi completa dei rischi strutturali: si vogliono individuare, infatti, i componenti strutturalmente critici al fine di proporre migliorie e soluzioni per evitare problematiche o danneggiamenti alle macchine. Per l’individuazione delle criticità strutturali, la prima cosa effettuata è stata un’analisi del funzionamento dei macchinari, attraverso uno studio dei singoli componenti e dei loro montaggi, a cui è seguita un’analisi dei carichi e delle sollecitazioni agenti su entrambe le macchine in condizioni di lavoro standard. A valle di queste analisi è stato possibile, quindi, individuare i componenti maggiormente sollecitati e, con l’ausilio di un software di nome Creo Simulate, ovvero un’estensione del software PTC Creo, molto diffuso nell’ambito della progettazione 3D di componenti industriali, sono state eseguite delle simulazioni virtuali di calcolo agli elementi finiti. Dall’analisi dei risultati delle simulazioni eseguite al calcolatore si sono evidenziate le eventuali criticità di ogni componente proponendo modifiche di progettazione, sia in termini di modifica della geometria del componente, sia riguardo a possibili modifiche nella scelta dei materiali. In aggiunta alle simulazioni virtuali, per completezza d’analisi, sono state svolte anche analisi strutturali di tipo analitico per la verifica di collegamenti bullonati e collegamenti saldati e per la verifica a fatica di alberi in rotazione.
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L’elaborato si è sviluppato all'interno dell’azienda System Logistics S.p.A. di Fiorano Modenese, leader nel settore del material handling e dell’intralogistica. Il focus dell'elaborato è sulla progettazione di un piano di campionamento indicizzato secondo il livello di qualità accettabile. Successivamente ad una presentazione più approfondita dell’azienda e dei prodotti offerti, si passa all’introduzione teorica dei temi dell’intralogistica e della qualità. Questo permette di comprendere il contesto operativo più generale in cui si inserisce il progetto. Infatti, la parte centrale è dedicata alla presentazione delle origini, degli obiettivi e della metodologia del progetto, in particolare, anticipando le procedure che si sono poste come basi strutturali della progettazione. La parte finale descrive il processo statistico che ha portato all’ottenimento del nuovo piano di campionamento e la sua applicazione empirica ai componenti più critici della navetta del LogiMate, il più recente prodotto dell’azienda. In quest’ultima fase si pone il focus sul processo di raccolta e analisi dei dati presentando, in particolare, un’analisi comparativa rispetto alla situazione iniziale dal punto di vista del rischio e un’analisi effettuata con le Carte di Controllo sul processo produttivo di un fornitore. L’esposizione è realizzata anche mediante grafici, ottenuti principalmente attraverso il supporto di Excel e Minitab, al fine illustrare in modo più agevole ed esplicito i risultati ottenuti.