822 research outputs found

    Multi-Objective Evolutionary Neural Network to Predict Graduation Success at the United States Military Academy

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    This paper presents an evolutionary neural network approach to classify student graduation status based upon selected academic, demographic, and other indicators. A pareto-based, multi-objective evolutionary algorithm utilizing the Strength Pareto Evolutionary Algorithm (SPEA2) fitness evaluation scheme simultaneously evolves connection weights and identifies the neural network topology using network complexity and classification accuracy as objective functions. A combined vector-matrix representation scheme and differential evolution recombination operators are employed. The model is trained, tested, and validated using 5100 student samples with data compiled from admissions records and institutional research databases. The inputs to the evolutionary neural network model are used to classify students as: graduates, late graduates, or non-graduates. Results of the hybrid method show higher mean classification rates (88%) than the current methodology (80%) with a potential savings of $130M. Additionally, the proposed method is more efficient in that a less complex neural network topology is identified by the algorithm

    Application of computational intelligence to explore and analyze system architecture and design alternatives

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    Systems Engineering involves the development or improvement of a system or process from effective need to a final value-added solution. Rapid advances in technology have led to development of sophisticated and complex sensor-enabled, remote, and highly networked cyber-technical systems. These complex modern systems present several challenges for systems engineers including: increased complexity associated with integration and emergent behavior, multiple and competing design metrics, and an expansive design parameter solution space. This research extends the existing knowledge base on multi-objective system design through the creation of a framework to explore and analyze system design alternatives employing computational intelligence. The first research contribution is a hybrid fuzzy-EA model that facilitates the exploration and analysis of possible SoS configurations. The second contribution is a hybrid neural network-EA in which the EA explores, analyzes, and evolves the neural network architecture and weights. The third contribution is a multi-objective EA that examines potential installation (i.e. system) infrastructure repair strategies. The final contribution is the introduction of a hierarchical multi-objective evolutionary algorithm (MOEA) framework with a feedback mechanism to evolve and simultaneously evaluate competing subsystem and system level performance objectives. Systems architects and engineers can utilize the frameworks and approaches developed in this research to more efficiently explore and analyze complex system design alternatives --Abstract, page iv

    Development and validation of in silico tools for efficient library design and data analysis in high throughput screening campaigns

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    My PhD project findings have their major application in the early phase of the drug discovery process, in particular we have developed and validated two computational tools (Molecular Assembles and LiGen) to support the hit finding and the hit to lead phases. I have reported here novel methods to first design chemical libraries optimized for HTS and then profile them for a specific target receptor or enzyme. I also analyzed the generated bio-chemical data in order to obtain robust SARs and to select the most promising hits for the follow up. The described methods support the iterative process of validated hit series optimization up to the identification of a lead. In chapter 3, Ligand generator (LiGen), a de novo tool for structure based virtual screening, is presented. The development of LiGen is a project based on a collaboration among Dompé Farmaceutici SpA, CINECA and the University of Parma. In this multidisciplinary group, the integration of different skills has allowed the development, from scratch, of a virtual screening tool, able to compete in terms of performance with long standing, well-established molecular docking tools such as Glide, Autodock and PLANTS. LiGen, using a novel docking algorithm, is able to perform ligand flexible docking without performing a conformational sampling. LiGen also has other distinctive features with respect to other molecular docking programs: • LiGen uses the inverse pharmacophore derived from the binding site to identify the putative bioactive conformation of the molecules, thus avoiding the evaluation of molecular conformations which do not match the key features of the binding site. • LiGen implemenst a de novo molecule builder based on the accurate definition of chemical rules taking account of building block (reagents) reactivity. • LiGen is natively a multi-platform C++ portable code designed for HPC applications and optimized for the most recent hardware architectures like the Xeon Phi Accelerators. Chapter 3 also reports the further development and optimization of the software starting from the results obtained in the first optimization step performed to validate the software and to derive the default parameters. In chapter 4, the application of LiGen in the discovery and optimization of novel inhibitors of the complement factor 5 receptor (C5aR) is reported. Briefly, the C5a anaphylatoxin acting on its cognate G protein-coupled receptor C5aR is a potent pronociceptive mediator in several models of inflammatory and neuropathic pain. Although there has long been interest in the identification of C5aR inhibitors, their development has been complicated, as is the case with many peptidomimetic drugs, mostly due to the poor drug-like properties of these molecules. Herein, we report the de novo design of a potent and selective C5aR noncompetitive allosteric inhibitor, DF2593A. DF2593A design was guided by the hypothesis that an allosteric site, the “minor pocket”, previously characterized in CXCR1 and CXCR2, could be functionally conserved in the GPCR class.DF2593A potently inhibited C5a-induced migration of human and rodent neutrophils in vitro. Moreover, oral administration of DF2593A effectively reduced mechanical hyperalgesia in several models of acute and chronic inflammatory and neuropathic pain in vivo, without any apparent side effects. Chapter 5 describes another tool: Molecular Assemblies (MA), a novel metrics based on a hierarchical representation of the molecule based on different representations of the scaffold of the molecule and pruning rules. The algorithm used by MA, defining a priori a metrics (a set of rules), creates a representation of the chemical structure through hierarchical decomposition of the scaffold in fragments, in a pathway invariant way (this feature is novel with respect to the other algorithms reported in literature). Such structure decomposition is applied to nine hierarchical representation of the scaffold of the reference molecule, differing for the content of structural information: atom typing and bond order (this feature is novel with respect to the other algorithms reported in literature) The algorithm (metrics) generates a multi-dimensional hierarchical representation of the molecule. This descriptor applied to a library of compounds is able to extract structural (molecule having the same scaffold, wireframe or framework) and sub structural (molecule having the same fragments in common) relations among all the molecules. At least, this method generates relations among molecules based on identities (scaffolds or fragments). Such an approach produces a unique representation of the reference chemical space not biased by the threshold used to define the similarity cut-off between two molecules. This is in contrast to other methods which generate representations based in similarities. MA procedure, retrieving all scaffold representation, fragments and fragmentation’s patterns (according to the predefined rules) from a molecule, creates a molecular descriptor useful for several cheminformatics applications: • Visualization of the chemical space. The scaffold relations (Figure 7) and the fragmentation patterns can be plotted using a network representation. The obtained graphs are useful depictions of the chemical space highlighting the relations that occur among the molecule in a two dimensional space. • Clustering of the chemical space. The relations among the molecules are based on identities. This means that the scaffold representations and their fragments can be used as a hierarchical clustering method. This descriptor produces clusters that are independent from the number and similarity among closest neighbors because belonging to a cluster is a property of the single molecule (Figure 8). This intrinsic feature makes the scaffold based clustering much faster than other methods in producing “stable” clusters in fact, adding and removing molecules increases and decreases the number of clusters while adding or removing relations among the clusters. However these changes do not affect the cluster number and the relation of the other molecules in dataset. • Generate scaffold-based fingerprints. The descriptor can be used as a fingerprint of the molecule and to generate a similarity index able to compare single molecules or also to compare the diversity of two libraries as a whole. Chapter 6 reports an application of MA in the design of a diverse drug-like scaffold based library optimized for HTS campaigns. A well designed, sizeable and properly organized chemical library is a fundamental prerequisite for any HTS project. To build a collection of chemical compounds with high chemical diversity was the aim of the Italian Drug Discovery Network (IDDN) initiative. A structurally diverse collection of about 200,000 chemical molecules was designed and built taking into account practical aspects related to experimental HTS procedures. Algorithms and procedures were developed and implemented to address compound filtering, selection, clusterization and plating. Chapter 7 collects concluding remarks and plans for the further development of the tools

    Use of Multivariate Techniques to Validate and Improved the Current USAF Pilot Candidate Selection Model

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    The Pilot Candidate Selection Method (PCSM) seeks to ensure the highest possible probability of success at UPT. PCSM applies regression weights to a candidate\u27s Air Force Officer Qualification Test (AFOQT) Pilot composite score, self-reported flying hours, and five Basic Attributes Test (BAT) score composites. PCSM scores range between 0 and 99 and is interpreted as a candidate\u27s probability of passing UPT. The goal of this study is to apply multivariate data analysis techniques to validate PCSM and determine appropriate changes to the model\u27s weights. Performance of the updated weights is compared to the current PCSM model via Receiver Operating Curves (ROC). In addition, two independent models are developed using multi-layer perceptron neural networks and discriminant analysis. Both linear and logistic regression is used to investigate possible updates to PCSM\u27s current linear regression weights. An independent test set is used to estimate the generalized performance of the regressions and independent models. Validation of the current PCSM model demonstrated in the first phase of this research is enhanced by the fact that PCSM outperforms all other models developed in the research

    Exploring the spectroscopic diversity of type Ia supernovae with DRACULA: a machine learning approach

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    The existence of multiple subclasses of type Ia supernovae (SNeIa) has been the subject of great debate in the last decade. One major challenge inevitably met when trying to infer the existence of one or more subclasses is the time consuming, and subjective, process of subclass definition. In this work, we show how machine learning tools facilitate identification of subtypes of SNeIa through the establishment of a hierarchical group structure in the continuous space of spectral diversity formed by these objects. Using Deep Learning, we were capable of performing such identification in a 4 dimensional feature space (+1 for time evolution), while the standard Principal Component Analysis barely achieves similar results using 15 principal components. This is evidence that the progenitor system and the explosion mechanism can be described by a small number of initial physical parameters. As a proof of concept, we show that our results are in close agreement with a previously suggested classification scheme and that our proposed method can grasp the main spectral features behind the definition of such subtypes. This allows the confirmation of the velocity of lines as a first order effect in the determination of SNIa subtypes, followed by 91bg-like events. Given the expected data deluge in the forthcoming years, our proposed approach is essential to allow a quick and statistically coherent identification of SNeIa subtypes (and outliers). All tools used in this work were made publicly available in the Python package Dimensionality Reduction And Clustering for Unsupervised Learning in Astronomy (DRACULA) and can be found within COINtoolbox (https://github.com/COINtoolbox/DRACULA).Comment: 16 pages, 12 figures, accepted for publication in MNRA

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    http://archive.org/details/intel432670ada00rogeNAN

    “I Can See the Forest for the Trees”: Examining Personality Traits with Trasformers

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    Our understanding of Personality and its structure is rooted in linguistic studies operating under the assumptions made by the Lexical Hypothesis: personality characteristics that are important to a group of people will at some point be codified in their language, with the number of encoded representations of a personality characteristic indicating their importance. Qualitative and quantitative efforts in the dimension reduction of our lexicon throughout the mid-20th century have played a vital role in the field’s eventual arrival at the widely accepted Five Factor Model (FFM). However, there are a number of presently unresolved conflicts regarding the breadth and structure of this model (c.f., Hough, Oswald, & Ock, 2015). The present study sought to address such issues through previously unavailable language modeling techniques. The Distributional Semantic Hypothesis (DSH) argues that the meaning of words may be formed through some function of their co-occurrence with other words. There is evidence that DSH-based techniques are cognitively valid, serving as a proxy for learned associations between stimuli (Günther et al., 2019). Given that Personality is often measured through self-report surveys, the present study proposed that a Personality measure be created directly from this source data, using large pre-trained Transformers (a type of neural network that is adept at encoding and decoding semantic representations from natural language). An inventory was constructed, administered, and response data was analyzed using partial correlation networks. This exploratory study identifies differences in the internal structure of trait-domains, while simultaneously demonstrating a quantitative approach to item creation and survey development

    Influence of big-data based digital media on spiritual goal strivings and well-being: a media richness theory perspective

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    A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements for the degree of Doctor of PhilosophyBig-Data characteristics and spirituality are seldom discussed together in the context of assistances provided by big-data based digital media on spiritual goal strivings (SGS). This study’s main aim is to investigate the significance of this relationship between big-data based digital media characteristics and SGS outcomes, and its impact on well-being. A theoretical integrated framework was developed underpinned by Media Richness Theory (MRT) to capture the influence of big-data based digital media characteristics on SGS outcomes. The research design of this epistemological study adopted positivism type of scientific enquiry; employing a deductive approach confining under quantitative research methods and used survey data collection technique. Non-probability self-selection sampling was used and a total of 987 valid responses were analysed by applying statistical tests and techniques following rigorous statistical Structural Equation Modelling (SEM) techniques using IBM AMOS. The results revealed the existence of significant relationship between the big-data based digital media characteristics and SGS outcomes. The study also reveals that digital media characteristics influences successes in SGS outcomes where certain aspects of digital media characteristics are shown to assist SGS towards accomplishments while some have shown to cause hindrances for SGS to be accomplished. The results also confirmed that success in SGS accomplishments increased vitality aspect of well-being. This information is vital for decision making, implementing and planning for various spiritual stakeholders mainly spiritual seekers, spiritual organisations and user experience (UX) - user interface (UI) designers of big-data based digital media developers. With this knowledge contribution, the stakeholders are able to make informed decisions and look for efficient strategies that would provide effective, reliable and sustainable assistances towards SGS accomplishments. The study provides theoretical contribution to the body of IS literature with an integrated and extended MRT conceptual framework providing the foundation for exploring the extended MRT instrument for future studies in similar thematic contexts by other researchers. Further, this study’s empirically validated evidence provides practical contribution in its effort to spiritual stakeholders with the confidence to adopt and develop effective strategies to implement big-data based digital systems in organisations with selective configuring and tuning to utilise the accelerating aspects of the medium for effective SGS accomplishments. UX and UI stakeholders will benefit significantly to be able to design and develop digital systems supporting SGS based on a deeper understanding of the certain factors from this study which indicates significant influence on SGS and to look for effective strategies in their development phase to accommodate the revealed concerns and assistances that would provide efficient, consistent and sustainable spiritual goal outcomes. Overall the findings in this study provide optimistic future for utilising the assistances provided by big-data based digital media capabilities for SGS accomplishments. Overall statistical results reveal that the advantages of assistances provided towards SGS outcomes outweighed the disadvantages of hindrances towards SGS outcomes
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