Mathematical modelling of burr height of the drilling process using a statistical-based multi-gene genetic programming approach

Drilling is one of the important machining processes performed extensively in production industry. Literature emphasises that the output process parameters such as burr height, surface roughness, strength, etc. are related to and can be improved by the appropriate settings of the input process parameters. Recently, researchers have applied well-known computational intelligence methods such as regression analysis, artificial neural networks (ANNs), support vector regression (SVR), etc. in the prediction of performance characteristics of the drilling process. Alternatively, an evolutionary approach of multi-gene genetic programming (MGGP) that evolves the model structure and its coefficients automatically can be applied. Despite of being widely applied, MGGP has the limitation for producing models that over-fit on the testing data. One of the reasons attributed for this behaviour is the over-size of the evolved models. Therefore, a statistical-based MGGP (S-MGGP) approach is proposed and applied to the burr height data obtained from the drilling of AISI 316L stainless steel. In this proposed approach, Bayesian information criterion is embedded in its paradigm, which punishes the fitness of larger size models. The performance of S-MGGP and ANN models is found to be better than those of the standardised MGGP and SVR. Further, the parametric and sensitivity analysis conducted validates the robustness of our proposed model and is proved to capture the dynamics of the drilling phenomenon by unveiling dominant input process parameters and the hidden non-linear relationships.     

Weight loss and metabolic profiles in obese individuals using two different approaches

Intentional weight loss with a reduction in adipose tissue is associated with an improvement in medical complications linked to obesity. The aim of this study was to compare the effect of two different weight loss diets on obese individuals (BMI 30-40 kg m(-2)) for improvements in anthropometric measurements and blood biomarkers. Study 1 comprised a low energy diet (LED) of 5000-6000 kJ d(-1) for a slow but steady weight loss over 12 weeks. Study 2 comprised a very low energy diet (VLED) of 3000 kJ d(-1) using meal replacements for rapid weight loss over a shorter period of 4 weeks followed by 10 weeks of weight stabilisation to prevent rebound after rapid weight loss. Nutrition information sessions were given to both groups. Fasting blood samples, anthropometric measurements and 3-day food diaries were collected at baseline and again at completion of weight loss, at 12 weeks for LED group and 4 weeks for VLED group. Mean weight loss in the LED group (n = 18) was -3.17 kg (-3.7%) compared to a -6.54 kg (-7%) loss in the VLED group (n = 14) (p < 0.001). The VLED group experienced significantly greater reductions in fat mass, -13.9% compared to -8.9% for the LED group (p < 0.05). Significantly greater reductions in blood glucose (p < 0.05), cholesterol and LDL-C (p < 0.01 for both), and waist circumference (p≤ 0.05) were noted in VLED compared to those for LED diet. Short-term, rapid weight loss produced the desired ≥5% weight loss suggested to substantially reduce metabolic abnormalities associated with obesity, and to reduce health risks.     

Performance calculations for closed-loop air-to-water solar hybrid heating systems with and without a rock bed in the solar air heater

A transient analysis has been carried out on a hybrid solar water heater which comprises a rock bed air heater with optimum design parameters in conjunction with an air-to-water transverse fin shell-and-tube heat exchanger (mixed air and unmixed water type) in which cold water from the storage tank receives heat from the hot air coming out of the air heater which flows in the shell at right angles to the water flowing in the tubes. The system's performance has been evaluated for typical winter weather conditions in Delhi for different combinations of flow rates of air and water for different volumes of the water storage tank. No hot water is assumed to be withdrawn from the tank to serve the load. A comparative analysis of the system's performance with and without a rock bed in the air heater reveals about 11°C higher temperature of storage tank in the former at 50 kg/h m² air flow rate. With both the air heater types, although the system performance was observed to increase with the rates of air and water flow, no significant improvement in system performance was achieved at .     

KAGO: an approximate adaptive grid-based outlier detection approach using kernel density estimate

Pattern Analysis and Applications - Outlier detection approaches show their efficacy while extracting unforeseen knowledge in domains such as intrusion detection, e-commerce, and fraudulent...     

A novel hybrid artificial neural network technique for the early skin cancer diagnosis using color space conversions of original images

In this study, an innovative hybrid machine learning-technique is used for the early skin cancer diagnosis fusing Convolutional Neural Network and Multilayer Perceptron to analyze images and information related to the skin cancer. This information is extracted manually after applying different color space conversions on the original images for better screening of the lesions. The proposed architecture is compared with standalone architecture in addition to some other techniques by commonly used evaluation metrics. HAM10000 dataset is used for training and testing as this data contain seven different skin lesions. The novelty of the proposed hybrid model is the structure of the network which handles structured data (patients' metadata and other useful features from different color spaces related to the illumination, energy, darkness, etc.) and unstructured data (images). The results show an overall 86%, 95% top-1 and top-2 accuracy respectively, and 96% area under the curve for the seven classes. The study demonstrates the superiority of the proposed hybrid model with a 2% improvement in the accuracy over the standalone model and a promising behavior as compared to the ensemble techniques. The follow-up research will include more patient data to develop a skin cancer detection device.     

Performance evaluation of agro-waste (sugarcane bagasse ash) for MB dye effluents removal under UV and dark environmental conditions: A cost-effective approach

Clean Technologies and Environmental Policy - The current work presents a relatively simple, cost-effective, and environmentally friendly solution for the removal of dye effluents from wastewater....     

An efficient two phase approach for solving reliability–redundancy allocation problem using artificial bee colony technique

The main goal of the present paper is to present a two phase approach for solving the reliability–redundancy allocation problems (RRAP) with nonlinear resource constraints. In the first phase of the proposed approach, an algorithm based on artificial bee colony (ABC) is developed to solve the allocation problem while in the second phase an improvement of the solution as obtained by this algorithm is made. Four benchmark problems in the reliability–redundancy allocation and two reliability optimization problems have been taken to demonstrate the approach and it is shown by comparison that the solutions by the new proposed approach are better than the solutions available in the literature.     

Studies on the oxidation behavior of Inconel 625 between 873 and 1523 K

The oxidation behavior of Inconel 625 during the early stages (<150 min) has been studied at oxygen pressures (P_{O 2}) of 0.12 kPa (0.9 torr) and 101.3 kPa (760 torr) in the temperature range of 1323 K to 1523 K by using TGA and between 873 and 1523 K by using XPS, AES, and EDS. The TGA results correlated well with those obtained by surface analysis of the oxide films. The results of XPS and AES analysis suggested that two distinctly different oxidation mechanisms operate, depending on the temperature of oxidation. Enrichment of the oxide films with respect to Cr₂O₃ occurs above 873 K, the degree of enrichment peaking at about 1200 K such that the oxide films formed at temperatures close to this consist almost exclusively of Cr₂O₃. At temperatures above 1300 K, the oxides of two minor alloying components, Nb and Ti, have been found to be present in the oxide films in significant proportions. The results have been discussed on the basis of the relative thermodynamic stabilities of the competing oxide phases and the diffusivities of the alloying elements in Inconel 625.