An efficient modulation technique to mitigate nonlinearities in optical OFDM

The optical OFDM (O-OFDM) system is a growing technology for next generation high-speed optical communication. Two types of O-OFDM; CO-OFDM (Coherent- Optical OFDM) and Direct-current-based optical OFDM (DCOFDM) are discussed. Mach–Zehnder modulators (MZMs) are used in up-converter part of CO-OFDM system to convert the RF signal to optical signal when the light cannot directly modulate for higher speed. The MZM has a cosine behavior with high nonlinear characteristic that affects the system performance. This paper aims to investigate an efficient pulse modulation technique for mitigating nonlinearity effect in the Mach-Zehnder modulator of CO-OFDM system. It also highlights the proposed method, an efficient CO-OFDM system to solve the existing nonlinearity issue. This technique influences positively on OSNR to reduce non linearity over different distances of optical channel and improve the system performance in terms of power consumption and bandwidth efficiency

Effect of modulation technique in Mach-Zehnder Modulator (MZM) in optical OFDM system

This paper highlights the bit error rate (BER) performance of a radio-over-fiber system utilizing binary phase shift keying (BPSK), M-QAM, QPSK in the external modulator which is the Mach-Zehnder modulator (MZM). The results have been obtained from the RoF link over 8, 30, 60 90 and 120 km distance to study the effect of nonlinear dispersion and attenuation of signal and compare the results other modulation. Furthermore, the chromatic dispersion has no effect on MZM whereas it has distinct effect on OOK modulation scheme without optical dispersion compensation, the performances of different modulation schemes such as OOK, PPM and PAM are analyzed. Comparisons of transmission distance, transmission capacity, bandwidth efficiency in coherent optical orthogonal frequency division multiplexing (CO-OFDM) system are included. Simulation results are given using Matlab, Simulink and Optisystem software. The results also show the importance of upconverter to reduce the nonlinearity effect in the transmission channel

Effect of rotary blade design modification on residue retention into conservation agriculture practice

Conservation Agriculture (CA) has been a promising technique for better crop production. Manual seeding with conventional tillage practice is laborious and time consuming. However, Strip tillage (ST) method incorporating seeding machines minimizes human drudgery and optimizes the crop yield. Many problems associated with ST have been rectified e.g. tiny furrow backfill, inaccuracy of seed and fertilizer placement, leading to poor germination and curtailed outcomes. This article focused on the effects of residue retention for the rotary blades design on a versatile multi-crop planter (VMP). Four types of rotary blades of VMP differed by 15o increment of tip angles were designed, fabricated, and experimented with a constant speed 350 RPM for ST operation targeting wheat and maize cultivation. Technical aspects related to the quality of strip i.e. width of furrow, depth of seed placement, moisture content, bulk density etc. were observed. Furthermore, the percentage of straw cut and seed emergence were visualized. From the observation, straw clogging was almost dissolved due to rotating action with the sharp edge of the new designed blades in front of the furrow openers. Soil cutting depth of strips and seed placement depth was consistent all over the field by the modified blades during wheat and maize sowing. The set of tip angle blades at 15 cm anchored rice residue shown the improved seed germination rate of 95.89% for wheat and 78.65% for maize. The investigation enables scope for adopting modified blade for better performance into CA practice

Characterization of Tea (\u3ci\u3eCamellia sinensis\u3c/i\u3e) Granules for Quality Grading Using Computer Vision System

Tea (Camellia sinensis) has been found as an important medicinal beverage for human which is consumed all over the world. Primarily, the majority of tea is being cultivated in Asia and Africa, however it is commercially produced by more than 60 countries. Though substantial amount is produced, its processing system is still underdeveloped which leads to decrease in export opportunity as well as low monetary value. Moreover, the traditional method of tea grading and sorting is laborious, inefficient, and costly which ultimately produces the low-quality heterogeneous products. Processing and grading of tea granules after drying is very important task for maintaining quality. Computer vision (CV) applications in processing unit especially in grading and sorting of agro-products is very popular and reliable option to improve quality of produce. In this study, an attempt was taken to develop a machine vision system for quality grading of tea granules based on physical parameters of four standard tea grades namely BOP, GBOP, CD and PF. An image acquisition system with suitable illumination arrangement was developed to obtain high resolution image of tea granules. The images were analyzed to extract physical features like projected area, circularity, roundness, ferret diameter, aspect ratio and solidity. Tea granules (BOP, CD, PF and GBOP grade) were found significantly different for the textural features area, perimeter, circularity, roundness and ferret diameter. Projected area, perimeter, and feret diameter treated as a good indicator of the extracted features as the system has been able to significantly (p \u3c 0.01) differentiate among the grade of tea. The developed characterization attributes based on physical features prior to an automatic sorting technology will improve the efficiency and enhance the cost-effectiveness which ultimately led to energize the international export market

Energy-Efficient Wireless Sensor Network with an Unequal Clustering Protocol Based on a Balanced Energy Method (EEUCB)

A hot spot problem is a problem where cluster nodes near to the base station (BS) tend to drain their energy much faster than other nodes due to the need to perform more communication. Unequal clustering methods such as unequal clustering routing (UDCH) and energy-efficient fuzzy logic for unequal clustering (EEFUC) have been proposed to address this problem. However, these methods only concentrate on utilizing residual energy and the distance of sensor nodes to the base station, while limited attention is given to enhancing the data transmission process. Therefore, this paper proposes an energy-efficient unequal clustering scheme based on a balanced energy method (EEUCB) that utilizes minimum and maximum distance to reduce energy wastage. Apart from that, the proposed EEUCB also utilizes the maximum capacity of node energy and double cluster head technique with a sleep-awake mechanism. Furthermore, EEUCB has devised a clustering rotation strategy based on two sub-phases, namely intra- and inter-clustering techniques, that considers the average energy threshold, average distance threshold, and BS layering node. The performance of the proposed EEUCB protocol is then compared with various prior techniques. From the result, it can be observed that the proposed EEUCB protocol shows lifetime improvements of 57.75%, 19.63%, 14.7%, and 13.06% against low-energy adaptive clustering hierarchy (LEACH), factor-based LEACH FLEACH, EEFUC, and UDCH, respectively