Predicting Customer Retention of an App-Based Business Using Supervised Machine Learning

Identification of retainable customers is very essential for the functioning and growth of any business. An effective identification of retainable customers can help the business to identify the reasons of retention and plan their marketing strategies accordingly. This research is aimed at developing a machine learning model that can precisely predict the retainable customers from the total customer data of an e-learning business. Building predictive models that can efficiently classify imbalanced data is a major challenge in data mining and machine learning. Most of the machine learning algorithms deliver a suboptimal performance when introduced to an imbalanced dataset. A variety of algorithm level (cost sensitive learning, one class learning, ensemble methods ) and data level methods (sampling, feature selection) are widely used to address the class imbalance in the retention prediction problems. This research employs a quantitative and inductive approach to build a supervised machine learning model that addresses the class imbalance problem and efficiently predict the customer retention. The retention Precision is used as the evaluation metrics for this research. The research evaluates the performance of different sampling methods (Random Under – Sampling, Random Over – Sampling, SMOTE) on different single and ensemble machine learning models. The results show that Random Under-Sampling used along with XGBoost classifier yields the best precision in identifying the retention class. The best model evolved in the research was also used to predict retainable customers from the recent unknown customer data, and could attain a retention precision of 57.5%

Re-evaluating the need for universal iron supplementation in pregnant Indian women in the light of gestational age specific low hemoglobin prevalence

Background: Anemia prevalence among Indian pregnant women in 2015-16 was 50.4% and has not declined from 49.7% in 1998-99 despite the national policies on iron-folic acid supplementation. New gestational age-specific cut-offs (INTERGROWTH cut-off) for risk of low Hemoglobin (Hb) have been identified. Aims and objectives: Compare prevalences of low Hb  based on WHO and INTERGROWTH cut-offs Methods: The prevalence of anemia/low Hb among pregnant women in trimesters 2 and 3 from NFHS-4 data were estimated using the current WHO recommendations and the INTERGROWTH cut-offs. Results: Prevalence of low Hb by the INTERGROWTH cut-off was 28.1%(95% CI:26.9-29.4) and 21.7%(95% CI:20.6-22.9) in trimesters 2 and 3. Anemia prevalence by WHO cut-off was much higher at 41.2%(95% CI:39.8-42.5) and 54.8%(95 CI:53.2-56.3) in trimesters 2 and 3. The prevalence of low-Hb was similar between ANC and no-ANC reported groups in both trimesters (26.1% and 28.9% in trimester-2; 20.1% and 22.4% in trimester-3). Conclusion: The  prevalence of low-Hb with gestational age specific cut-offs is much lower compared to earlier estimates using WHO cut-off. The universal iron supplementation program for pregnant women in India need to be re-examined in this light and a tragetter Hb testing based supplementation may be more beneficial in reducing anemia prevalence

High-performance sparse matrix-vector multiplication on GPUs for structured grid computations

ABSTRACT In this paper, we address efficient sparse matrix-vector multiplication for matrices arising from structured grid problems with high degrees of freedom at each grid node. Sparse matrix-vector multiplication is a critical step in the iterative solution of sparse linear systems of equations arising in the solution of partial differential equations using uniform grids for discretization. With uniform grids, the resulting linear system A x = b has a matrix A that is sparse with a very regular structure. The specific focus of this paper is on sparse matrices that have a block structure due to the large number of unknowns at each grid point. Sparse matrix storage formats such as Compressed Sparse Row (CSR) and Diagonal format (DIA) are not the most effective for such matrices. In this work, we present a new sparse matrix storage format that takes advantage of the diagonal structure of matrices for stencil operations on structured grids. Unlike other formats such as the Diagonal storage format (DIA), we specifically optimize for the case of higher degrees of freedom, where formats such as DIA are forced to explicitly represent many zero elements in the sparse matrix. We develop efficient sparse matrix-vector multiplication for structured grid computations on GPU architectures using CUD

A rare and independent association of Right Atrial Myxoma with Immune Thrombocytopenic Purpura

Primary tumours of the heart are rare and the most common benign ones are myxomas.  The clinical features are varied and include a myriad of presenting symptoms like embolic, constitutional, cardiac and also symptoms due to obstruction. Right atrial myxomas are very rarely seen when compared with left atrium. Such myxomas independently co existing with Immune Thrombocytopenic Purpura (ITP) is even rarer and we now present one such case in with right atrial myxoma was associated with ITP and was managed surgically. This case emphasises the fact that ITP can co-exist with myxoma and should be borne in mind when treating such patients surgically

Molecular cloning, characterization and expression analysis of cytoplasmic Cu/Zn-superoxid dismutase (SOD) from pearl oyster Pinctada fucata

Because of its capacity to rapidly convert superoxide to hydrogen peroxide, superoxide dismutase (SOD) is crucial in both intracellular signalling and regulation of oxidative stress. In this paper we report the cloning of a Cu/Zn SOD (designated as pfSOD) from the pearl oyster (Pinctada fucata) using rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA of this Cu/Zn SOD contains an open reading frame (ORF) of 471 bp coding for 156 amino acids. No signal peptide was identified at the N-terminal amino acid sequence of Cu/Zn SOD indicating that this pfSOD encodes a cytoplasmic Cu/Zn SOD. This is supported by the presence of conserved amino acids required for binding copper and zinc. Semi-quantitative analysis in adult tissues showed that the pfSOD mRNA was abundantly expressed in haemocytes and gill and scarcely expressed in other tissues tested. After challenge with lipopolysaccharide (LPS), expression of pfSOD mRNA in haemocytes was increased, reaching the highest level at 8 h, then dropping to basal levels at 36 h. These results suggest that Cu/Zn SOD might be used as a bioindicator of the aquatic environmental pollution and cellular stress in pearl oyster

Messenger RNA expression of pattern recognition receptor proteins in the pearl oyster Pinctada fucata (Gould, 1850) in response to lipopolysaccharide stimulation

Pattern recognition receptor proteins (PRP) are capable of binding specifically to conserved portion of microbial cell wall components and they are involved in the recognition of different immune modulators. Proteins such as F-type lectin, galectin and LGBP play protective role in innate immunity of invertebrates. The time dependent expression of F-type lectin gene as well as galectin and LGBP genes was determined after lipopolysaccharide (LPS) challenge in the pearl oyster Pinctada fucata. A significant increase of mRNA expression levels of all the three genes under study was observed in haemocytes, reaching a maximum level at 8 h post-challenge and then declined to basal levels at 36 h. These results suggest that PRPs play a critical role in the innate immune system of the pearl oyster P. fucata

Differential and additional expression of proteins in the subcellular organelles of Penaeus monodon (Fabricus) in response to white spot syndrome virus (WSSV) infection

Currently the most common and devastating disease of shrimp is caused by the white spot syndrome virus (WSSV), which has spread throughout the world mainly by different species of crustaceans carrying the virus. Penaeus monodon were challenged with WSSV and the protein expression variation studied over a period of time. The gills, one of the main target organs of WSSV, showed upregulation of 24 proteins and expression of three novel proteins after infection. In the hepatopancreas, 20 upregulated proteins and six novel proteins were observed. The muscle showed upregulation of 11 proteins and one new protein. Subcellular organelles like nuclear and mitochondrial proteins of each tissue showed different profiles with either increased/decreased expression of few proteins or additional expression of novel proteins. The protein profiles resolved in the study provide a rich source of information on proteins in shrimp which may be involved in antiviral response

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Biomechanical analysis of assisted sit to stand

A significant number of non-institutionalized older adults have difficulty rising from a chair. Although there exist several assistive devices to aid with sit to stand, there is a lack of research that compares and analyzes various modes of assisted sit to stand to characterize their relative effectiveness in terms of biomechanical metrics. In addition, few existing assistive devices have been designed specifically to share between the user and the device the force required to rise, an approach that has the benefit of maintaining both the mobility and muscular strength of the user. This thesis advances our understanding of different modes of load-sharing sit to stand through empirical quantification. A specially-designed sit-to-stand test bed with load sharing capabilities was fabricated for human-subjects experiments. In addition to an unassisted rise and a static assist using a grab bar, three mechatronic modes of assist, at the seat, waist and arms, were implemented. The test bed employs a closed-loop load-sharing control scheme to require a user to provide a portion of the effort needed for a successful rise motion. Experiments were performed with 17 healthy older adults using the five aforementioned modes of rise. Force and kinematic sensor measurements obtained during the rise were used as inputs into a biomechanical model of each subject, and each mode of rise was evaluated based on key biomechanical metrics extracted from this model relating to stability, knee effort reduction, and rise trajectory. In addition, a questionnaire was administered to determine subjective response to and preference for each rise type. Results show that the seat and waist assists provide statistically significant improvements in terms of stability and knee effort reduction, while the arm and bar assists do not provide any biomechanical improvement from the unassisted rise. The assists most preferred by the subject were the seat and bar assists. Because of subject preference and biomechanical improvements, of the modes tested, the seat assist was determined to be the best mode of providing assistance with sit to stand.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat