Building Classification Models from Imbalanced Fraud Detection Data

Many real-world data sets exhibit imbalanced class distributions in which almost all instances are assigned to one class and far fewer instances to a smaller, yet usually interesting class. Building classification models from such imbalanced data sets is a relatively new challenge in the machine learning and data mining community because many traditional classification algorithms assume similar proportions of majority and minority classes. When the data is imbalanced, these algorithms generate models that achieve good classification accuracy for the majority class, but poor accuracy for the minority class. This paper reports our experience in applying data balancing techniques to develop a classifier for an imbalanced real-world fraud detection data set. We evaluated the models generated from seven classification algorithms with two simple data balancing techniques. Despite many ideas floating in the literature to tackle the imbalanced issue, our study shows the simplest data balancing technique is all that is required to significantly improve the accuracy in identifying the primary class of interest (i.e., the minority class) in all the seven algorithms tested. Our results also show that precision and recall are useful and effective measures for evaluating models created from artificially balanced data. Hence, we advise data mining practitioners to try simple data balancing first before exploring more sophisticated techniques to tackle the class imbalance problem

Cytotoxic effects of commercial wheatgrass and fiber towards human acute promyelocytic leukemia cells (HL60).

Cytotoxicity, the possible selective activity upon HL60 as well as the anti-proliferation effect of local health supplement wheatgrass and mixture of fibers were investigated in vitro using various cancerous cell line and normal blood cell culture. The IC(50) of wheatgrass-treated HL60 (17.5 ± 1.1, 12.5 ± 0.3, and 16 ± 0.5 microgram/ml for 24, 48 and 72 h, respectively) and fibers-treated HL60 (86.0 ± 5.5, 35.0 ± 2.5, and 52.5 ± 4.5 microgram/ml for 24, 48 and 72 h, respectively) showed that both extracts possessed optimum effect after 48 hours of treatment. No significant cytotoxic effect was observed on other type of cells. For trypan blue dye exclusion method, wheatgrass reduced the number of viable cells by 13.5% (±1.5), 47.1% (±3.6), and 64.9% (±2.7) after 24, 48 and 72 h exposure, respectively. Mixture of fibers reduced the number of viable cells by 36.4% (±2.3), 57.1% (±3.1), and 89.0% (±3.4) after 24, 48 and 72 h exposure, respectively, indicated that necrosis is also an alternative to the apoptotic mechanism of cell death. Annexin-V/propidium iodide staining revealed that both extracts induced apoptosis where early apoptosis had been detected concurrently with the reduction of percentage of cell viability. Cell cycle analysis revealed that in HL60, the percentage of apoptosis increased with time (wheatgrass: 16.0% ± 2.4, 45.3% ± 3.4 and 39.6% ± 4.1; mixture of fibers: 14.6% ± 1.8, 45.4% ± 2.3 and 45.9% ± 1.2) after exposure for 24, 48 and 72 h, respectively at the concentration of 100 microgram/ml and showed optimum effect at 48 hours. Thus, these health products can be a potential alternative supplement for leukaemia patients

Optimal conditions for hepatitis B core antigen production in shaked flask fermentation

The effects of various environmental factors such as pH (5, 6, 7, 8 and 9), temperature (30, 37 and 40°C) and rotational speed (150, 200 and 250 rpm) on the growth and the hepatitis B core antigen (HBcAg) production of Escherichia coli W3110IQ were examined in the present study. The highest growth rate is achieved at PH 7, 37°C and at a rotational speed of 250 rpm which is 0.927 h−1. The effect of pH on cell growth is more substantial compared to other parameters; it recorded a 123% different between the highest growth rate (0.927 h−1) at pH 7 and lowest growth at pH 5. The highest protein yield is achieved at pH 9, rotational speed of 250 rpm and 40°C. The yield of protein at pH 7 is 154% higher compared to the lowest yield achieved at pH 5. There is about 28% different of the protein yield for theE. coli cultivated at 250 rpm compared to that at 150 rpm which has the lowest HBcAg yield. The yield of protein at 40°C is 38% higher compared to the lowest yield achieved, at 30°C

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Social construction of knowledge in a problem-based learning setting / Tan Swee Chuan

Tujuan kajian ini ialah untuk (1) menyiasat proses pembinaan pengetahuan secara sosial dalam konteks PBL, (2) menyiasat impak unsur-unsur utama PBL dalam menyokong dan menghalang proses pembinaan pengetahuan secara sosial. Kajian ini menggunakan pendekatan kajian kes (Merriam, 2009) and menganalisa wacana tiga peserta PBL yang belajar dalam program sarjana di sebuah universiti awam. Melalui proses lelaran, model analisa interaksi Gunawardena et al., (1997) diubah suai (mIAM) untuk mengkaji datadata yang muncul dalam bentuk fasa-fasa interaksi proses pembinaan pengetahuan secara sosial. Kesemua enam fasa mIAM muncul dalam wacana antara peserta-peserta PBL. Ini menunjukkan bahawa pembinaan pengetahuan sacara sosial berlaku dan peserta-peserta tersebut telah mengalami satu pembelajaran konstruktivis yang mendalam. Pemeriksaan terperinci wacana PBL membawa pemahaman yang lebih mendalam tentang unsur-unsur PBL (Dolmans et al., 2005) yang menyokong atau menghalang pembinaan pengetahuan secara sosial. Kepentingan kajian ini terletak pada model analisis yang muncul iaitu mIAM. Fasa-fasa interaksi mIAM boleh digunakan untuk menyiasat proses and takat pembinaan pengetahuan sacara sosial. Ia juga boleh digunakan sebagai kerangka asas untuk pembimbing PBL untuk memajukan wacana PBL ke fasa-fasa yang lebih lanjut dalam pembinaan pengetahuan secara sosial

Monash University

I would like to express a sincere appreciation to my supervisor, Mr. Ken Harris, for his trust and support on this project. I would like to thank Dr. Ting Kai Ming, who allowed me to extend the project, and he gave me advice and encouragement along the way. Special thanks go to my superior, Mr. Soh Chee Hiang, who sponsors me to present this work at the First International Conference on Optimization Methods and Software in December 2002. In addition, special thanks to my wife, Siew Foong, and my Dad and Mum, for their love and support throughout all these years. Most of all, I praise my LORD Jesus Christ, HIS everlasting Love give me the strength, every single day. ii PRELIMINARY PAGES PAG

The role of chemoattractants in modulating neutrophil-endothelial adhesion

This study aimed to define the role of IL-8 and other chemoattractants in neutrophil recruitment to sites of inflammation, and in particular, to characterise the mechanisms by which chemoattractants, when present in the luminal compartment, may modulate neutrophil--endothelial adhesion under conditions of flow.In vitro models of inflammation were employed including a flow chamber which stimulated the pathophysiological conditions of flow at the apical endothelial surface in vivo and a Boyden-type chemotaxis assay. The effect of chemoattractants when presented in different ways to neutrophils on the dynamics of their adhesion under flow, adhesion molecule expression and chemotaxis, were examined.Activated endothelium secreted soluble IL-8 but neither IL-8 nor platelet-activating factor (PAF) was necessary for neutrophil rolling, adhesion and transmigration on activated endothelium. Prior exposure of neutrophils to nanomolar concentrations of IL-8 or PAF induced L-selectin shedding and reduced ability to tether and roll on activated endothelium. IL-8 and other peptide chemoattractants but not PAF, induced detachment of neutrophils stably adherent to activated endothelium. Furthermore, nanomolar concentrations of IL-8 and other peptide chemoattractants in the apical compartment totally inhibited neutrophil transmigration.Therefore, chemoattractants appeared to modulate neutrophil-endothelial adhesion in different ways depending on how they were presented to neutrophils. The environment in the sub-endothelial compartment allows chemoattractants to accumulate and to generate a chemotactic gradient which may promote neutrophil recruitment. However, a high concentration of IL-8 in the apical compartment does not appear to be an appropriate physiological signal for neutrophil recruitment at sites of inflammation and may inhibit neutrophil-endothelial adhesion and transmigration by a number of mechanisms.</p