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1.
PLoS One ; 19(3): e0294537, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38446831

RESUMO

Credit card fraud is a significant problem that costs billions of dollars annually. Detecting fraudulent transactions is challenging due to the imbalance in class distribution, where the majority of transactions are legitimate. While pre-processing techniques such as oversampling of minority classes are commonly used to address this issue, they often generate unrealistic or overgeneralized samples. This paper proposes a method called autoencoder with probabilistic xgboost based on SMOTE and CGAN(AE-XGB-SMOTE-CGAN) for detecting credit card frauds.AE-XGB-SMOTE-CGAN is a novel method proposed for credit card fraud detection problems. The credit card fraud dataset comes from a real dataset anonymized by a bank and is highly imbalanced, with normal data far greater than fraud data. Autoencoder (AE) is used to extract relevant features from the dataset, enhancing the ability of feature representation learning, and are then fed into xgboost for classification according to the threshold. Additionally, in this study, we propose a novel approach that hybridizes Generative Adversarial Network (GAN) and Synthetic Minority Over-Sampling Technique (SMOTE) to tackle class imbalance problems. Our two-phase oversampling approach involves knowledge transfer and leverages the synergies of SMOTE and GAN. Specifically, GAN transforms the unrealistic or overgeneralized samples generated by SMOTE into realistic data distributions where there is not enough minority class data available for GAN to process effectively on its own. SMOTE is used to address class imbalance issues and CGAN is used to generate new, realistic data to supplement the original dataset. The AE-XGB-SMOTE-CGAN algorithm is also compared to other commonly used machine learning algorithms, such as KNN and Light GBM, and shows an overall improvement of 2% in terms of the ACC index compared to these algorithms. The AE-XGB-SMOTE-CGAN algorithm also outperforms KNN in terms of the MCC index by 30% when the threshold is set to 0.35. This indicates that the AE-XGB-SMOTE-CGAN algorithm has higher accuracy, true positive rate, true negative rate, and Matthew's correlation coefficient, making it a promising method for detecting credit card fraud.


Assuntos
Algoritmos , Suplementos Nutricionais , Fraude/prevenção & controle , Conhecimento , Aprendizado de Máquina
3.
Huan Jing Ke Xue ; 32(2): 428-36, 2011 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-21528564

RESUMO

Field in-situ rainfall simulation tests with two rainfall intensities (40 mm x h(-1) and 70 mm x h(-1)), which were conducted at typical sloping cropland in Yimeng mountainous area, were designed to analyze the output characteristics of dissolved inorganic nitrogen, Inorganic-N (NO3(-)-N, NH4(+) -N) and dissolved phosphorus (DP) in runoff water, as well as to compare the eutrophication risk in this water by calculating three ratios of Inorganic-N/DP, NO3(-) -N/DP, and NH4(+)-N/DP, respectively, in cross ridge and longitudinal ridge tillage methods. Results showed that, under the same rainfall intensity, the DP level in runoff water was higher in cross ridge than longitudinal ridge, while the change of different Inorganic-N level between the two tillage methods were not consistent. Cross ridge could effectively reduce runoff and the output rate of Inorganic-N and DP when compared to the longitudinal ridge tillage, which would be more outstanding with the increases of rainfall intensities. The losses of Inorganic-N and DP in runoff water were 43% and 5% less, respectively, in cross ridge than longitudinal ridge at the 40 mm x h(-1) rainfall intensity, and were 68% and 55%, respectively, at 70 mm x h(-1). The higher Inorganic-N/DP and NO3(-) -N/DP ratios suggest that runoff water from either cross ridge or longitudinal ridge tillage have a certain eutrophication risk, which present an increasing trend during the precipitation-runoff process. Compared with longitudinal ridge, cross ridge can not only hinder the increasing trend of eutrophication risk, but also can significantly lower it, and thus effectively reduce the effect of sloping cropland runoff on the eutrophication processes of receiving waters.


Assuntos
Agricultura/métodos , Eutrofização , Nitrogênio/análise , Fósforo/análise , Poluição da Água/prevenção & controle , China , Simulação por Computador , Fertilizantes , Poluição da Água/análise
4.
Zhonghua Shao Shang Za Zhi ; 26(1): 3-5, 2010 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-20510025

RESUMO

The prevention and treatment of complications are very important aspects in burn treatment. We should pay attention to the fundamental research, clinical prevention and treatment of complications. We have had good grasp of the subjects by fundamental research such as MODS. We must keep complications in mind when signs, symptoms, monitoring index and laboratory reports are inconsistent to the usual course of the injury, and we must guard against the occurrence of complications in the whole course of burn treatment. Consideration must be given to the treatment of both complications and the primary disease in order to slow down deterioration of patient, and guarantee the curative effect. There are still many unknown areas of burn complications for us to explore and discover.


Assuntos
Queimaduras/complicações , Insuficiência de Múltiplos Órgãos/prevenção & controle , Insuficiência de Múltiplos Órgãos/etiologia
5.
Nan Fang Yi Ke Da Xue Xue Bao ; 29(3): 504-5, 2009 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-19304537

RESUMO

OBJECTIVE: To study the efficacy of laparoscopic placement of total peritoneum intraperitoneal onlay mesh (TPIPOM) for treatment of inguinal hernia. METHODS: TPIPOM was placed laparoscopically in 125 cases of inguinal hernia, and the clinical outcomes of the patients were observed and compared with 64 patients receiving transabdominal preperitoneal laparoscopic mesh repair (TAPP) and 53 with total extraperitoneal laparoscopic hernioplasty (TEP). RESULTS: The laparoscopic operations were successfully performed in all the patients. In TPIPOM, TAPP and TEP groups, the operating time was 30.8-/+10.3 min, 68.4-/+22.4 min and 69.5-/+23.4 min (P<0.05), the mean hospital stay was 3.8-/+1.3 days, 4.3-/+1.5 days and 4.5-/+1.6 days (P<0.05), the average time to ambulation was 1.2-/+0.5 days, 1.8-/+0.7 days and 2.2-/+0.8 days (P<0.05), the duration of pain was 1.0-/+0.5 days, 1.6-/+0.9 days and 1.9-/+0.8 days (P<0.05), and the cost was 5000.8-/+800.5 yuan, 8000.5-/+950.6 yuan and 8900.2-/+750.3 yuan (P<0.05), respectively. No scrotum edema occurred in these patients. The patients were followed up for 59.9-/+6.5 months and recurrence was found. CONCLUSION: TPIPOM is safe and effective for management of inguinal hernia with such advantages as minimal invasion, simple procedures, shorter operation time, reduced relapse and quick recovery.


Assuntos
Hérnia Inguinal/cirurgia , Laparoscopia/métodos , Implantação de Prótese , Telas Cirúrgicas , Adolescente , Adulto , Idoso , Feminino , Humanos , Laparoscopia/economia , Masculino , Pessoa de Meia-Idade , Peritônio/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Resultado do Tratamento , Adulto Jovem
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