Application of Machine Learning Techniques in Credit Card Fraud Detection

Credit card fraud is an ever-growing problem in today’s financial market. There has been a rapid increase in the rate of fraudulent activities in recent years causing a substantial financial loss to many organizations, companies, and government agencies. The numbers are expected to increase in the future, because of which, many researchers in this field have focused on detecting fraudulent behaviors early using advanced machine learning techniques. However, the credit card fraud detection is not a straightforward task mainly because of two reasons: (i) the fraudulent behaviors usually differ for each attempt and (ii) the dataset is highly imbalanced, i.e., the frequency of majority samples (genuine cases) outnumbers the minority samples (fraudulent cases). When providing input data of a highly unbalanced class distribution to the predictive model, the model tends to be biased towards the majority samples. As a result, it tends to misrepresent a fraudulent transaction as a genuine transaction. To tackle this problem, data-level approach, where different resampling methods such as undersampling, oversampling, and hybrid strategies, have been implemented along with an algorithmic approach where ensemble models such as bagging and boosting have been applied to a highly skewed dataset containing 284807 transactions. Out of these transactions, only 492 transactions are labeled as fraudulent. Predictive models such as logistic regression, random forest, and XGBoost in combination with different resampling techniques have been applied to predict if a transaction is fraudulent or genuine. The performance of the model is evaluated based on recall, precision, f1-score, precision-recall (PR) curve, and receiver operating characteristics (ROC) curve. The experimental results showed that random forest in combination with a hybrid resampling approach of Synthetic Minority Over-sampling Technique (SMOTE) and Tomek Links removal performed better than other models

Ultrasound-Assisted Post-Pyrolysis Magnetization of Microporous Biochar for Effective Removal of Heavy Metals

Low cost and efficient adsorption of heavy metals from wastewater and thorough removal of adsorbent after water treatment have become the two essential needs for the commercial use of any adsorbent. Biochar (BC), the solid byproduct of pyrolysis with microporous carbonaceous structure, has been increasingly recognized as an efficient adsorbent for a vast number of pollutants. Magnetization, though eases the separation and reuse of BC, significantly reduces its adsorption capacity to a comparatively much higher extent. In this study, a hybrid post-pyrolysis magnetization was developed which sustained and even significantly increased the adsorption capacity of biochar. The process included i) structural modification of biochar under ultrasound waves, ii) magnetization with magnetite (Fe3O4) nanoparticles and iii) functionalization with 3-aminopropyl triethoxysilane. Ultrasound irradiation exfoliates and breaks apart the irregular graphite layers of biochar, and creates new/opens the blocked microspores, thus enhancing the BC’s porosity. On the other hand, 3-aminopropyl triethoxysilane stabilizes the magnetic nanoparticles on the biochar surface, while it participates in water treatment through the strong chelation ability of its amino groups toward metal ions. Scanning electron microscope image demonstrated the stable and uniform distribution of Fe3O4 nanoparticles on the surface of microporous biochar and Fourier-transform infrared spectroscopy suggested effective surface functionalization. In addition, although magnetization usually reduces the porosity of carbonaceous adsorbents, acoustic activation prior to magnetization increased the microporosity of biochar (from 123 for Raw-BC to 155 m2/g for acoustic-based magnetic biochar). Preliminary results of Ultraviolet–visible spectroscopy showed that acoustic-based magnetic biochar exhibited a much greater ability to remove Ni and Pb, with 139% and 38% higher adsorption compared to raw biochar. Almost complete removal of Pb (91%) was observed by magnetic-BC

Perceptions of Enrollment Employees in Community College: An Exploration of Organizational Climate and Organizational Effectiveness

This study investigated the type of organization climate and extent of organization effectiveness perceived by the enrollment division employees at a community college in the northeast United States, as well as the potential relationship(s) between and among descriptive categories and organizational climate, in relation to organizational effectiveness. Using a quantitative survey research design, this study applied field theory and used two instruments; the Work Group Climate Assessment (WCA) and the Organizational Effectiveness Index (OEI). The WCA identified enrollment employees\u27 perceptions of their department and division\u27s organizational climate, also known as work environment, collecting two sets of data on actual performance and importance. The OEI identified enrollment employees\u27 perceptions of their departments and division\u27s organizational effectiveness, also known as operational productivity and goal achievement. This study focused on enrollment management employees from four interconnected departments: admissions, advisement, testing, and registrar. The study found significant differences in the way employees view the organizational climate and organizational effectiveness between descriptive categories, particularly in job titles. Additionally within the job title category, there were significant differences in climate perceptions among the directors and administrative support groups. The organizational effectiveness and organizational climate both varied, specifically and significantly within the category of job title, in the enrollment division at this particular college. Moreover the findings indicate that the organizational climate of this division predicts its organizational effectiveness, when controlling for job title at 65% variance consistently. Thus, job titles and organizational climate were explanatory variables for the variance found between and among groups\u27 perceptions of organizational effectiveness in the enrollment division

The Feasibility of Requiring Presentation of Purely Contingent Claims in Probate

The Feasibility of Requiring Presentation of Purely Contingent Claims in Probat

Recognition of extracellular DNA by type IV pili promotes biofilm formation by \u3ci\u3eClostridioides difficile\u3c/i\u3e

Clostridioides difficile is a Gram-positive bacillus, which is a frequent cause of gastrointestinal infections triggered by the depletion of the gut microbiome. Because of the frequent recurrence of these infections after antibiotic treatment, mechanisms of C. difficile persistence and recurrence, including biofilm formation, are of increasing interest. Previously, our group and others found that type IV pili, filamentous helical appendages polymerized from protein subunits, promoted microcolony and biofilm formation in C. difficile. In Gram-negative bacteria, the ability of type IV pili to mediate bacterial self-association has been explained through interactions between the pili of adjacent cells, but type IV pili from several Gram-negative species are also required for natural competence through DNA uptake. Here, we report the ability of two C. difficile pilin subunits, PilJ and PilW, to bind to DNA in vitro, as well as the defects in biofilm formation in the pilJ and pilW gene-interruption mutants. Additionally, we have resolved the X-ray crystal structure of PilW, which we use to model possible structural mechanisms for the formation of C. difficile biofilm through interactions between type IV pili and the DNA of the extracellular matrix. Taken together, our results provide further insight into the relationship between type IV pilus function and biofilm formation in C. difficile and, more broadly, suggest that DNA recognition by type IV pili and related structures may have functional importance beyond DNA uptake for natural competence

Ubiquitination screen using protein microarrays for comprehensive identification of Rsp5 substrates in yeast

Ubiquitin-protein ligases (E3s) are responsible for target recognition and regulate stability, localization or function of their substrates. However, the substrates of most E3 enzymes remain unknown. Here, we describe the development of a novel proteomic in vitro ubiquitination screen using a protein microarray platform that can be utilized for the discovery of substrates for E3 ligases on a global scale. Using the yeast E3 Rsp5 as a test system to identify its substrates on a yeast protein microarray that covers most of the yeast (Saccharomyces cerevisiae) proteome, we identified numerous known and novel ubiquitinated substrates of this E3 ligase. Our enzymatic approach was complemented by a parallel protein microarray protein interaction study. Examination of the substrates identified in the analysis combined with phage display screening allowed exploration of binding mechanisms and substrate specificity of Rsp5. The development of a platform for global discovery of E3 substrates is invaluable for understanding the cellular pathways in which they participate, and could be utilized for the identification of drug targets

Clinical Significance of Bronchodilator Responsiveness Evaluated by Forced Vital Capacity in COPD: SPIROMICS Cohort Analysis.

ObjectiveBronchodilator responsiveness (BDR) is prevalent in COPD, but its clinical implications remain unclear. We explored the significance of BDR, defined by post-bronchodilator change in FEV1 (BDRFEV1) as a measure reflecting the change in flow and in FVC (BDRFVC) reflecting the change in volume.MethodsWe analyzed 2974 participants from a multicenter observational study designed to identify varying COPD phenotypes (SPIROMICS). We evaluated the association of BDR with baseline clinical characteristics, rate of prospective exacerbations and mortality using negative binomial regression and Cox proportional hazards models.ResultsA majority of COPD participants exhibited BDR (52.7%). BDRFEV1 occurred more often in earlier stages of COPD, while BDRFVC occurred more frequently in more advanced disease. When defined by increases in either FEV1 or FVC, BDR was associated with a self-reported history of asthma, but not with blood eosinophil counts. BDRFVC was more prevalent in subjects with greater emphysema and small airway disease on CT. In a univariate analysis, BDRFVC was associated with increased exacerbations and mortality, although no significance was found in a model adjusted for post-bronchodilator FEV1.ConclusionWith advanced airflow obstruction in COPD, BDRFVC is more prevalent in comparison to BDRFEV1 and correlates with the extent of emphysema and degree of small airway disease. Since these associations appear to be related to the impairment of FEV1, BDRFVC itself does not define a distinct phenotype nor can it be more predictive of outcomes, but it can offer additional insights into the pathophysiologic mechanism in advanced COPD.Clinical trials registrationClinicalTrials.gov: NCT01969344T4

Water interaction differences determine the relative energetic stability of the polyproline II conformation of the alanine dipeptide in aqueous environments

Although subsequent studies have provided extensive support for the 1968 Tiffany and Krimm proposal (Biopolymers 6, 1379) that the polyproline II (PPII) conformation is a significant component of the structure of unordered polypeptide chains, two issues are still not fully resolved: the PPII persistence length in a chain and the source of its relative stability with respect to the β‐conformation. We examine the latter question by studying the B97‐D/6‐31++G ** energy, in the absence and presence of a reaction field, of the alanine dipeptide hydrated by various amounts of explicit waters and resolving this into its three components: the energies of the individual solvated peptides and water structures plus the interaction energy involving them. We find that the relative stability of the PPII conformation is determined mainly by the difference in the interaction energies of the water structures in the near‐peptide layers. © 2012 Wiley Periodicals, Inc. Biopolymers 97: 789–794, 2012.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92429/1/22064_ftp.pd

Theoretical calculation of the circular dichroism of unordered polypeptide chains

A calculation has been done of the circular dichroism (CD) spectrum of an unordered polypeptide chain. This has been based on a Boltzmann averaging over a dipeptide conformational CD map. This is shown to be valid by comparing the CD spectra of 28-mer oligopeptides with those generated by summing dipeptide CD spectra. The calculated CD spectrum of an unordered polypeptide chain is found to agree with the assignment proposed by Tiffany and Krimm from experimental studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37833/1/360110912_ftp.pd