Articles

In today s data driven technical world, decisions are made by proper analysis of the real time data obtained from different sensors attached in the premises. The field of agriculture is also not an exception. To process these huge data, they need to be transferred to respective data processing units situated in the same premises or at remote end. In both of the cases, data transfer mechanism is performed by wirelessly interconnected specialized nodes having integrated sensors, controllers, wireless connectivity modules and portable energy sources. These nodes are popularly known as sensor nodes and the arrangement of wirelessly interconnected nodes is called Wireless Sensor Network (WSN). When WSN nodes are connected with processing units and other WSNs at remote end through internet, they constitute a networked ecosystem called Internet of Things (IoT). In this paper, we have attempted to survey the wireless protocols for IoT and their challenges while used in the field of Agriculture. Also a comparative analysis of the protocols has been provided to facilitate the researchers and farmers to choose suitable protocols for their application.

Metal-Oxide Semiconductor (MOS)nanostructures have a potential future prospect large number of novel phenomena at the nanoscale and investigating size and dimensionality dependence of nanostructure properties for potential applications. The fabrication and design of photodetectors or optical switches based on nanostructures with different morphology, suitable choice of substrate with different growth techniques have shown rapid advancement in past few years. Nanostructure photodetector can be designed in different ways either based on the device structure or based on mechanism of photoconduction. Possibly the most simple type of device structure is metal semiconductor metal (MSM) type which can be operated based on resistive nature of the materials whose conductions are modulated by generation of electron-hole pairs in presence of excitation by suitable frequency of photon and its transportation in external circuit. Photodiodes, avalanche photodiodes (APD), phototransistors and Photo multiplier tube(PMT) type complex device architecture with high end fabrication techniques are being used for high speed applications in communication systems. Apart from high end fabrication techniques like chemical vapour deposition (CVD), atomic layer deposition (ALD), physical vapor deposition (PVD) and use of different substrates, techniques like design of hetero structure devices, doping the active material with suitable elements, surface modification of the active materials and integration of closely spaced inter-digtated electrodes have been employed for the enhancement of the performance of the device.