Comparação de Metodologias de Migração de Bancos de Dados Relacionais para Bancos Orientados a Documentos

Companies have migrated data from relational databases to NoSQLdatabases to improve their business through more active services ata lower operating cost, especially by the adoption of cloud services.This process is called Data Migration and is considered by someauthors one of the biggest challenges in systems engineering today.Although it is advantageous, the process of migrating data fromthe relational model to NoSQL models is not trivial and has led tothe development of different methodologies for this purpose. Theobjective of this work was to analyze and compare three differentmigration methodologies between Relational and NoSQL DocumentOriented databases under the following aspects: algorithminput, method documentation, migration process and generateddocuments. For that, different relational models were empiricallymigrated using such methodologies, allowing the analysis of theevaluated aspects. The results show that there is no consolidatedway to perform the migration and that the method to be chosendepends on the context of the application. So, scenarios that showwhen to use each method are presented. Although not performingcomputational tests, this work provides suggestions and insightsthrough the evaluation of the migration processes under the theoreticalmodels. It expected that the results presented here will helpIT managers decide on the best data model migration methodologyto follow in their actual projects.

Migration of Atlantic salmon (Salmo salar) smolts in a large hydropower reservoir

Migration rates, delay, timing, and success of acoustic-tagged Atlantic salmon (Salmo salar) presmolts (n = 120) and smolts (n = 57) are reported as they moved through the large Mactaquac Generating Station (MGS) reservoir and subsequently the lower Saint John River (SJR). The potential relationship between fish movements and the MGS operations was examined directly and via a hydrodynamic model. Migration rates were 15.4–29.3 km·day−1 within the river sections and 5.0–13.3 km·day−1 through the reservoir, a significant reduction of 32%–57%. Migratory timing was temporally mismatched with dam operations such that only a few (n = 3) smolts had the option of dam passage via spill. Migration success estimated as apparent survival was high through the reservoir (81%–100%), declined by 8%–32% during passage at the MGS, and additional losses (27%–55%) occurred during the migration to the lower SJR, such that overall survival to the estuary for the groups tagged as autumn presmolts was 61%–65%, and survival for those tagged as spring smolts was 6%–10%.

Model migration and rough edges: British actuaries and the ontologies of modelling

The existing literature on modelling provides two main ways of viewing model migration: a modular view, which seeks to decompose models in their constitutive elements, and thus provides a view on what it is that migrates; and a practice-based view, which focuses on modelling as an activity, and understands a model as intricately entangled with its context of use. This article brings together these two sensitivities by focusing on ontologies of modelling. The paper presents a case study of the appropriation of modern finance theory’s ‘no-arbitrage’ models by British actuaries – a process that gradually unfolded at around the turn of the century and led to significant friction within the UK’s insurance industry. We can distinguish two main modelling ontologies: a ‘risk-neutral ontology’, which underpins no-arbitrage models and holds that the value of financial instruments is determined by ‘arbitrage’; and, a ‘real-world ontology’, which assumes that the economic world consists of real probabilities that may be approximated through a combination of archival-statistical methods and expert judgment. The appropriation of the risk-neutral modelling ontology was made possible by the declining legitimacy of actuarial expertise as ‘financial stewards’ of life insurance companies. The risk-neutral modelling ontology provided an ‘objective’ alternative to the traditional actuarial models, which explicitly required actuaries to make ‘prudent’ judgments. Despite the fact that the no-arbitrage modelling was considered an ‘objective’ affair, the valuation models that insurers use today are strongly shaped by political compromises, a result of the ‘rough edges’ of models.

Modeling of Scramjet Combustors Based on Model Migration and Process Similarity

Contributed by the low cost, the simulation method is considered an attractive option for the optimization and design of the supersonic combustor. Unfortunately, accurate and satisfactory modeling is time-consuming and cost-consuming because of the complex processes and various working conditions. To address this issue, a mathematical modeling for the combustor on the basis of the clustering algorithm, machine learning algorithm, and model migration strategy is developed in this paper. A general framework for the migration strategy of the combustor model is proposed among the similar combustors, and the base model, which is developed by training the machine learning model with data from the existing combustion processes, is amended to fit the unexampled combustor using the model migration strategy with a few data. The simulation results validate the effectiveness of the development strategy, and the migrated model is proved to be suitable for the new combustor in higher accuracy with less time and calculation.