679 research outputs found

    A User-Centered Perspective for the blockchain Development

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    Blockchain technology is regarded as one of the most important digital innovations in the last two decades. Its applicability beyond cryptocurrencies has been a growing topic of research interest not only in computer science but also in other areas, such as marketing, finance, law, healthcare, etc. However blockchain is far from reaching the population on a larger scale. The dissertation evaluates the causes that are preventing successful implementation and adoption of blockchain technology at a larger scale, supporting infrastructure for public and private companies. The latest academic research suggests that the blockchain services are still in an early stage, and standards for developing blockchain-based applications have not been defined yet. Moreover the interaction with the blockchain technology is still complex, especially for non expert users, because it requires many technical skills. The dissertation focuses on this knowledge gap as a cause for the blockchain missing reach on society at a larger scale. This work aims to fill the gap by presenting innovative methodologies and user-centered models that could help the adoption of the blockchain technology by a larger number of private/public companies and individuals. Based on these models, specific tools for both expert and non-expert users are developed and discussed in the dissertation. First, tools for expert users, i.e., software developers, are proposed to analyze the smart contracts’ source code, to collect the smart contracts in a reasoned repository, and to identify code clones and boost the use of open source libraries for a better collective practice in developing and maintaining the blockchain. Second, tools for non-expert users, i.e. people with no technical knowledge, are proposed to suggest them the fairest fees to pay to have their transactions executed according to the price and waiting times they are willing to spend, and to identify malicious smart contracts that can deceive them, thus preventing them to trust the blockchain and use it again. Finally, visualization models for users with expertise in different disciplines are proposed to provide them with graphical representations that can foster the understanding of the blockchain underlying mechanisms

    An Organized Repository of Ethereum Smart Contracts’ Source Codes and Metrics

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    International audienceMany empirical software engineering studies show that there is a need for repositories where source codes are acquired, filtered and classified. During the last few years, Ethereum block explorer services have emerged as a popular project to explore and search for Ethereum blockchain data such as transactions, addresses, tokens, smart contracts’ source codes, prices and other activities taking place on the Ethereum blockchain. Despite the availability of this kind of service, retrieving specific information useful to empirical software engineering studies, such as the study of smart contracts’ software metrics, might require many subtasks, such as searching for specific transactions in a block, parsing files in HTML format, and filtering the smart contracts to remove duplicated code or unused smart contracts. In this paper, we afford this problem by creating Smart Corpus, a corpus of smart contracts in an organized, reasoned and up-to-date repository where Solidity source code and other metadata about Ethereum smart contracts can easily and systematically be retrieved. We present Smart Corpus’s design and its initial implementation, and we show how the data set of smart contracts’ source codes in a variety of programming languages can be queried and processed to get useful information on smart contracts and their software metrics. Smart Corpus aims to create a smart-contract repository where smart-contract data (source code, application binary interface (ABI) and byte code) are freely and immediately available and are classified based on the main software metrics identified in the scientific literature. Smart contracts’ source codes have been validated by EtherScan, and each contract comes with its own associated software metrics as computed by the freely available software PASO. Moreover, Smart Corpus can be easily extended as the number of new smart contracts increases day by day

    Qualitative assessment of contrast-enhanced ultrasound in differentiating clear cell renal cell carcinoma and oncocytoma

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    Background: We aimed to assess whether clear cell renal cell carcinoma (ccRCC) can be differentiated from renal oncocytoma (RO) on a contrast-enhanced ultrasound (CEUS). Methods: Between January 2021 and October 2022, we retrospectively queried and analyzed our prospectively maintained dataset. Renal mass features were scrutinized with conventional ultrasound imaging (CUS) and CEUS. All lesions were confirmed by histopathologic diagnoses after nephron-sparing surgery (NSS). A multivariable analysis was performed to identify the potential predictors of ccRCC. The area under the curve (AUC) was depicted in order to assess the diagnostic accuracy of the multivariable model. Results: A total of 126 renal masses, including 103 (81.7%) ccRCC and 23 (18.3%) RO, matched our inclusion criteria. Among these two groups, we found significant differences in terms of enhancement (homogeneous vs. heterogeneous) (p < 0.001), wash-in (fast vs. synchronous/slow) (p = 0.004), wash-out (fast vs. synchronous/slow) (p = 0.001), and rim-like enhancement (p < 0.001). On the multivariate logistic regression, heterogeneous enhancement (OR: 19.37; p = <0.001) and rim-like enhancement (OR: 3.73; p = 0.049) were independent predictors of ccRCC. Finally, these two variables had an AUC of 82.5% and 75.3%, respectively. Conclusions: Diagnostic imaging for presurgical planning is crucial in the choice of either conservative or radical management. CEUS, with its unique features, revealed its usefulness in differentiating ccRCC from RO

    Macrostructural Alterations of Subcortical Grey Matter in Psychogenic Erectile Dysfunction

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    Psychogenic erectile dysfunction (ED) has been defined as the persistent inability to attain and maintain an erection sufficient to permit sexual performance. It shows a high incidence and prevalence among men, with a significant impact on the quality of life. Few neuroimaging studies have investigated the cerebral basis of erectile dysfunctions observing the role played by prefrontal, cingulate, and parietal cortices during erotic stimulation. In spite of the well-known involvement of subcortical regions such as hypothalamus and caudate nucleus in male sexual response, and the key role of nucleus accumbens in pleasure and reward, poor attention was paid to their role in male sexual dysfunction. In this study, we determined the presence of grey matter (GM) atrophy patterns in subcortical structures such as amygdala, hippocampus, nucleus accumbens, caudate nucleus, putamen, pallidum, thalamus, and hypothalamus in patients with psychogenic ED and healthy men. After Rigiscan evaluation, urological, general medical, metabolic and hormonal, psychological and psychiatric assessment, 17 outpatients with psychogenic ED and 25 healthy controls were recruited for structural MRI session. Significant GM atrophy of nucleus accumbens was observed bilaterally in patients with respect to controls. Shape analysis showed that this atrophy was located in the left medial-anterior and posterior portion of accumbens. Left nucleus accumbens volumes in patients correlated with low erectile functioning as measured by IIEF-5 (International Index of Erectile Function). In addition, a GM atrophy of left hypothalamus was also observed. Our results suggest that atrophy of nucleus accumbens plays an important role in psychogenic erectile dysfunction. We believe that this change can influence the motivation-related component of sexual behavior. Our findings help to elucidate a neural basis of psychogenic erectile dysfunction

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation