1,927 research outputs found
Hybrid Evolutionary Shape Manipulation for Efficient Hull Form Design Optimisation
‘Eco-friendly shipping’ and fuel efficiency are gaining much attention in the maritime industry due to increasingly stringent environmental regulations and volatile fuel prices. The shape of hull affects the overall performance in efficiency and stability of ships. Despite the advantages of simulation-based design, the application of a formal optimisation process in actual ship design work is limited. A hybrid approach which integrates a morphing technique into a multi-objective genetic algorithm to automate and optimise the hull form design is developed. It is envisioned that the proposed hybrid approach will improve the hydrodynamic performance as well as overall efficiency of the design process
Approximating Cross-validatory Predictive P-values with Integrated IS for Disease Mapping Models
An important statistical task in disease mapping problems is to identify out-
lier/divergent regions with unusually high or low residual risk of disease.
Leave-one-out cross-validatory (LOOCV) model assessment is a gold standard for
computing predictive p-value that can flag such outliers. However, actual LOOCV
is time-consuming because one needs to re-simulate a Markov chain for each
posterior distribution in which an observation is held out as a test case. This
paper introduces a new method, called iIS, for approximating LOOCV with only
Markov chain samples simulated from a posterior based on a full data set. iIS
is based on importance sampling (IS). iIS integrates the p-value and the
likelihood of the test observation with respect to the distribution of the
latent variable without reference to the actual observation. The predictive
p-values computed with iIS can be proved to be equivalent to the LOOCV
predictive p-values, following the general theory for IS. We com- pare iIS and
other three existing methods in the literature with a lip cancer dataset
collected in Scotland. Our empirical results show that iIS provides predictive
p-values that are al- most identical to the actual LOOCV predictive p-values
and outperforms the existing three methods, including the recently proposed
ghosting method by Marshall and Spiegelhalter (2007).Comment: 21 page
Grey-Box Modeling for Photo-Voltaic Power Systems Using Dynamic Neural-Networks
There exists various ways of modeling and forecasting photo-voltaic (PV) systems. These methods can be categorized, in board-way, under either definite equations models (white or clear-box) or heuristic data-driven artificial intelligence models (black-box). The two directions of modeling pose a number of drawbacks. To benefit from both worlds, this paper proposes a novel method where clear-box model is extended to a grey-box model by modeling uncertainities using focused time-delay neural network models. The grey-box or semi-definite model was shown to exhibit enhanced forecasting capabilities
Generalized Hybrid Evolutionary Algorithm Framework with a Mutation Operator Requiring no Adaptation
This paper presents a generalized hybrid evolutionary optimization structure that not only combines both nondeterministic and deterministic algorithms on their individual merits and distinct advantages, but also offers behaviors of the three originating classes of evolutionary algorithms (EAs). In addition, a robust mutation operator is developed in place of the necessity of mutation adaptation, based on the mutation properties of binary-coded individuals in a genetic algorithm. The behaviour of this mutation operator is examined in full and its performance is compared with adaptive mutations. The results show that the new mutation operator outperforms adaptive mutation operators while reducing complications of extra adaptive parameters in an EA representation
Evaluation of the Students' Learning Experience and Competency Gain with YACRS
No abstract available
The Practicality of Cloud Computing
Since its inception, cloud computing has become the current paradigm. Organizations of different size and type have embraced the concept because of its both technological and economic advantages. Sacred Heart University Library has recently published its newly designed website on the cloud. For a small academic library, what does it mean to put their online data on the cloud? This paper will analyze and discuss the advantages of cloud computing, and some potential obstacles created by it through the author’s observations. This paper hopes the uniqueness of the case will contribute to the improvement of cloud computing experience of other libraries
Micromechanics model for predicting effective elastic moduli of porous ceramic matrices with randomly oriented carbon nanotube reinforcements
Multi-step micromechanics-based models are developed to predict the overall effective elastic moduli of porous ceramic with randomly oriented carbon nanotube (CNT) reinforcements. The presence of porosity in the ceramic matrix that has been previously neglected in the literature is considered in present analysis. The ceramic matrix with porosity is first homogenized using a classical Mori-Tanaka model. Then, the homogenized porous ceramic matrix with randomly oriented CNTs is analysed using two micromechanics models. The results predicted by the present models are compared with experimental and analytical results that have been reported in literature. The comparison shows that the discrepancies between the present analytical results and experimental data are about 10% for 4 wt% of CNTs and about 0.5% for 8 wt% CNTs, both substantially lower than the discrepancies currently reported in the literature
What Would be the Future of the Integrated Library Systems?
Since the advent of Integrated Library Systems (ILSs) in 1970s, they have gone from being innovative to stagnant. In recent years, the rapid advancement of web technologies and the exponential growth of electronic resources and digital contents have increasingly exposed the weakness of traditional ILSs. The lack of flexibility, interoperability, and efficiency makes the ILSs hardly meet the needs of both internal and external library users. Meanwhile Content Management Systems (CMS) such as Drupal and open source ILSs have gotten much attention due to their technological and economic advantages, and cloud computing has allowed libraries to focus on bigger pictures. Facing the unprecedented challenges, major ILS vendors are pressed to develop the next generation ILS; nonetheless, the concrete ideas of the future ILSs are still being investigated. The paper will reference the developmental history of ILSs to discuss the limitations of the current ILSs, the unavoidable transformation these systems are facing, and some aspects or features that the next-generation ILSs are expected to contain
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