Non-Intrusive Monitoring of Everyday Behavioral Activities in an Indoor Environment

A non-intrusive design for monitoring everyday activities of an elderly person is presented. The proposed system is intended to be used in the bedroom, allowing the elders to stay at home in a safe environment. The required hardware design is simple in structure and cost effective. The sensor design is implemented by using capacitive sensors and an Arduino microcontroller unit. And a real time graphical user interface is implemented to monitor the elderly person. The performance analysis shows that the sensor design is able to differentiate between a human body and a house pet.     

Systematic skin segmentation: merging spatial and non-spatial data

Skin detection is used in applications ranging from face detection, tracking of body parts, hand gesture analysis, to retrieval and blocking objectionable content. We present a systematic approach for robust skin segmentation using graph cuts. The skin segmentation process starts by exploiting the local skin information of detected faces. The detected faces are used as foreground seeds for calculating the foreground weights of the graph. If local skin information is not available, we opt for the universal seed. To increase the robustness, the decision tree based classifier is used to augment the universal seed weights when no local information is available in the image. With this setup, we achieve robust skin segmentation, outperforming off-line trained classifiers. The setup also provides a generic skin detection system, using positive training data only. With face detection, we take advantage of the contextual information present in the scene. With the weight augmentation, we provide a setup for merging spatial and non-spatial data. Experiments on two datasets with annotated pixel-level ground truth show that the systematic skin segmentation approach outperforms other approaches and provides robust skin detection.     

Effect of Prior Oxidation on Tensile Properties of Bare and Al3Ti Diffusion Aluminide Coated Near α Titanium Alloy Titan 29A

The effect of prior oxidation, for various durations up to 2,000 h in air at 650 °C, on the room temperature tensile properties of uncoated and Al₃Ti diffusion aluminide coated near α Ti alloy, Titan 29A, has been evaluated. The tensile properties of the uncoated alloy deteriorated with oxidation. Oxidation for just 100 h caused 11–13 % decrease in yield strength (YS) and ultimate tensile strength (UTS) of the alloy. The uncoated alloy exhibited brittle fracture within the elastic regime at significantly lower stress after oxidation for 2,000 h. On the other hand, the strength of the coated alloy remained unaffected even after 2,000 h of oxidation and the YS and UTS was similar to that of the un-oxidized alloy. The ductility of the coated alloy, however, decreased with the increase in oxidation duration. Such differences in the tensile behavior of the uncoated and coated alloy can be ascribed to the beneficial effect of the Al₃Ti diffusion aluminide coating in preventing surface embrittlement in the alloy during oxidation.     

Potential and viability of grid-connected solar PV system in Bangladesh

The potential of grid-connected solar PV system in Bangladesh was estimated utilizing GeoSpatial toolkit, NASA SSE solar radiation data and HOMER optimization software. Financial viability of solar photovoltaic as an electricity generation source for Bangladesh was also assessed utilizing a proposed 1-MW grid-connected solar PV system using RETScreen simulation software for 14 widespread locations in Bangladesh. The technical potential of gird-connected solar PV in Bangladesh was calculated as about 50174 MW. The annual electricity generation of the proposed system varied depending on the location between 1653 MWh and 1854 MWh, with a mean value of 1729 MWh. Several different economic and financial indicators were calculated, such as the internal rate of return, net present value, benefit-cost ratio, cost of energy production and simple payback. All indicators – for all sites – showed favorable condition for development of the proposed solar PV system in Bangladesh. The results also showed that a minimum of 1423 tons of greenhouse gas emissions can be avoided annually utilizing the proposed system at any part of the country.     

Strand Current Distribution Modeling in Turbo-generators Using Finite-element Method Based on Proposed Dual Method

Abstract—The necessity of using a 3D model is one of the main problems for modeling Roebel bar transposition in turbo-generators by the finite-element method. This article proposes a 2D dual model for computing strand current distribution in the Roebel bar of turbo-generators. Considering the leakage and mutual inductances for each strand and the coupling inductances between them, the end winding region is modeled in this 2D dual model. In this article, the Roebel bar structure including 16 strands was considered, and these distributions are calculated for different transpositions using the finite-element method. In the finite-element method model, the circulating currents are calculated by subtracting a load current at each strand from the total of strand current. Also, for different transpositions, such as 90°, 180°, 360°, and 540°, the circulating currents are calculated using an analytical method. The obtained strand current distributions from the 2D dual model have good agreement with the obtained results from the analytical method for the 180° and 360° transposed coil models.     

An ambipolar polymer additive for enhanced open circuit voltage in a bulk heterojunction solar cells

Open circuit voltage (V_OC) of organic bulk heterojunction solar cell is extended by the addition of a 20 wt % of F8TBT, an ambipolar polymer in the active layer matrixes (P3HT:PCBM) and then spin casted (1000 rpm/30 s) in the optimized devices on the PEDOT:PSS layer of the ITO glass. A substantial increase in the open circuit voltage from approximately 0.61–0.88 V (44.26%) has been observed with slight increase in efficiency up to 1.91% in the fabricated devices. However, further increment of F8TBT content to 40 wt % reduces the photovoltaic efficiency and affects the J_SC values remarkably, possibly due the excess amount of resistance developed. The enhancement of V_OC is attributed to the ambipolar nature of F8TBT polymer which facilitates the generated electron and hole transfer at the respective electrodes, enhanced π–π* conjugation in polymer matrix, a superior nanoscale separation, and better molecular conformation at the film interface, thus giving an ample opportunities to explore the impact of blending of materials rather than depositing a thin buffer layer by expensive vapor phase technologies. The details of electrical and microstructure characterization of the film were analyzed by AFM, SEM, UV–Vis, J–V characteristics, and EQE techniques. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43042.