Improved Weighted Random Forest for Classification Problems

Several studies have shown that combining machine learning models in an appropriate way will introduce improvements in the individual predictions made by the base models. The key to make well-performing ensemble model is in the diversity of the base models. Of the most common solutions for introducing diversity into the decision trees are bagging and random forest. Bagging enhances the diversity by sampling with replacement and generating many training data sets, while random forest adds selecting a random number of features as well. This has made the random forest a winning candidate for many machine learning applications. However, assuming equal weights for all base decision trees does not seem reasonable as the randomization of sampling and input feature selection may lead to different levels of decision-making abilities across base decision trees. Therefore, we propose several algorithms that intend to modify the weighting strategy of regular random forest and consequently make better predictions. The designed weighting frameworks include optimal weighted random forest based on ac-curacy, optimal weighted random forest based on the area under the curve (AUC), performance-based weighted random forest, and several stacking-based weighted random forest models. The numerical results show that the proposed models are able to introduce significant improvements compared to regular random forest

Study of executive function in women with breast cancer undergoing chemotherapy

Background: Chemotherapy as one of the main methods of cancer treatment has many side effects that one of them is the impact of this treatment on the brain. Objective: The aim of this study was to compare the executive functions in women diagnosed with breast cancer undergoing chemotherapy and healthy counterparts. Methods: In this case-control study, women with breast cancer (n=40) undergoing chemotherapy along with healthy women (n=40) with no history of chronic diseases using available sampling method and were selected from Tehran Shohada Tajrish Hospital (2015-2016). Data was collected using demographic characteristics questionnaire, anxiety and depression test, continuous performance test, and Wisconsin card category collected and was analyzed by the independent t test. Findings: In the continuous performance test, omission and commission errors, with weaknesses in speed tests in patients with breast cancer were higher than those in the control group and this difference was statistically significant. There was a significant difference between the two groups in which reflects the low number of correct answers and cluster with higher preservation in breast cancer patients compared to healthy counterparts. Conclusion: According to the results, deficits in executive functions caused by chemotherapy in cancer patients that require therapeutic measures in this field. Keyword: Executive function, Breast cancer, Chemotherapy, Wome

Evaluation on Water Resources and Determining the Values of Exported and Imported Virtual Water in Hashtgerd Region

Abstract The concept of virtual water in recent years has been proposed with the world's water resource consumption management approach. Hashtgerd study area is one of 609 study areas of the country that is located entirely in Alborz Province. Average annual rainfall in this region was about 200 to 340 mm and the average agricultural production per year was more than one million tons and had more than 16 million cubic meters surplus recovery from underground water resources. The aim of this study is to evaluate resources and amounts of virtual water in the agricultural sector of the study area and its impact on the area water resources balance and ultimately provide solutions to reduce water consumption by the agricultural sector. The most important exported water products in Hashtgerd area in order of importance are peaches and nectarines (33% of water exports), plums (15% of water exports), vegetables (5.14 percent of water exports), cherry (4.7% of water exports) and wheat (6.5 percent of water exports). Virtual water trade balance of agricultural and horticultural products in the digital range is equal to 260+ million cubic meters. Density of agricultural lands can be mentioned as the main reasons for positive balance of virtual water trade in this area