North Eastern Regional Institute of Science and Technology

About: North Eastern Regional Institute of Science and Technology is a education organization based out in Itanagar, India. It is known for research contribution in the topics: Population & Raman spectroscopy. The organization has 813 authors who have published 1429 publications receiving 16122 citations.

Sum-Rate Performance of Massive MIMO Systems in Highly Scattering Channel with Semi-Orthogonal and Random User Selection

Abstract: The sum-rate performance of a massive MIMO system is dependent on the adequate user and antenna selection techniques. It is best when all the selected users are mutually orthogonal (MOU) and antennas are selected based on maximum channel gain. In the case, when number of antennas in massive MIMO is approximately hundreds, the computational complexity cost in joint user and antenna selection is very high. Semi-orthogonal user selection (SUS) is preferred to reduce interference and complexity cost. In highly scattering Rayleigh fading channel random user selection (RUS) technique can be used because of small loss of system sum-rate compared toSUSandMOUtechniques. In this paper we propose a joint user and antenna selection algorithm where users are scheduled using semi-orthogonality measure and antenna selection is based on maximum channel gain. In addition, an algorithm for joint user and antenna selection is reported here with RUS for user selection and maximum channel gain for antenna selection. We explore the system sum-rate performance of a massive MIMO system using these algorithms for the case of a highly scattering Rayleigh fading channel. We consider various precoding techniques MMSE, ZFBF, and MRT and a range of SNR. We also explore the effect of spatial and multiuser diversity on system sum-rates using proposed algorithms. The sum-rate obtained by algorithms-1 is greater than the algorithm-2 about 1–3% but second one is much simpler.

Development of artificial neural network models for the performance prediction of an inclined plate seed metering device

Abstract: Seed planting equipment with inclined plate seed metering devices is the most commonly used equipment for planting of peanut crop in India. For obtaining the high yield, it is very essential to drop the peanut seeds in rows maintaining accurate seed rate and seed spacing with minimum damage to seeds during metering. This mainly depends on the forward speed of the planting equipment, rotary speed of the metering plate and the area of cells on the plate. The relationship between these factors and the performance parameters viz., seed rate, seed spacing and percent seed damage can be established using regression analysis. But they may not be very accurate and consistent throughout the solution space. Hence, an attempt has been made in this paper to develop the feed forward artificial neural network (ANN) models for the prediction of the performance parameters of an inclined plate seed metering device. The data were generated in the laboratory by conducting experiments on a sticky belt test stand provided with a seed metering device and an opto-electronic seed counter. The generated data was used to develop both statistical and neural network models. The optimum architecture of the neural network models was determined using genetic algorithm (GA) as a single objective constrained optimization problem. The performance of the developed models was compared among themselves for 4 randomly generated test cases. The results show that the ANN model predicted the performance parameters of the seed metering device better than the statistical models. It is possible to determine the optimum levels of the input parameters to obtain the desired performance parameters of the seed metering device by performing reverse mapping of the developed ANN models.

A Rare Feeding Observation on Water Lilies (Nymphaea alba) by the Capped Langur (Trachypithecus pileatus)

Abstract: The capped langur (Trachypithecus pileatus, Blyth 1843) inhabits a variety of forest types including tropical dry deciduous, subtropical, broad-leaf and dense evergreen hill forest with many streams, bamboo forest up to 2,000 m and teak and sal plantation forest areas [Srivastava, 1999; Majupuria, 1990]. The capped langur is diurnal and almost entirely arboreal, eating young and mature leaves, ripe and unripe fruits, flowers, seeds, bark and gum [Solanki and Kumar, 2002]. Stanford [1991, 1992], in his studies on feeding behaviours in Bangladesh, observed that, in the dry season, capped langurs survive on mature leaves, some seeds and bamboo shoots, occasionally feeding on gum and termite soil trails. We observed the feeding behaviour of this little known langur in Pakhui Wildlife Sanctuary, Arunachal Pradesh. The Sanctuary (26°54′–27°16′ N and 92°36′–93°09′ E) is located in the south-west of Arunachal Pradesh and is 861.95 km in area. The general vegetation type of the entire tract is classified as Assam Valley tropical semi-evergreen forest (2B/C1 of Champion and Seth [1968]). During a 1-year study on feeding and food preference of this langur, a rare feeding behaviour was observed in September 2002. A troop of capped langurs (consisting of 1 adult male, 4 females and two 9-month-old infants) was observed feeding on the stalks, leaves and flowers of the water lily Nymphaea alba. The monkeys spent most time feeding on the stalks, followed by the leaves of the lilies. Another interesting observation was that the 2 lactating females (who had infants) entered the water to feed on the water lilies so that their bodies were immersed in

Experimental study on drilling micro-hole through micro-EDM and optimization of multiple performance characteristics

Abstract: Drilling of micro-hole with fine edges and smooth internal surfaces finds numerous applications in manufacturing industries; holes drilled in injection nozzles, drug delivery orifices and spinneret holes are some of examples. This work carries out an experimental investigation and parametric optimization on micro-hole drilling using micro-electrical discharge machining (µ-EDM) process. The machining experiments are conducted employing Taguchi L16 orthogonal array for evaluating machining time (t) average overcut (AOV), taper angle (TA), entry overcut (EnOV), exit overcut (ExOV) and material removal rate (MRR) as process performances, while voltage (V), capacitance (pF) and feed rate (µm/s) are considered as process parameters. The influence of process parameters on the responses is studied at different cutting conditions. The drilled micro-holes profile is studied in terms of burrs, craters, spots on the edges and internal surfaces using micrographs obtained with optical and scanning electron microscopes. The ANOVA result reveals that capacitance is the most significant parameter for t, AOV, TA, MRR, EnOV and ExOV. For simultaneous optimization of three performance measures (i.e., t, AOV and TA), an overall evaluation criterion has been evaluated and optimum cutting conditions such as voltage: 80 V, capacitance: 100 pF and feed rate: 15 µm/s are obtained. The expected outcome obtained at the optimum condition is improved by 10.57% (36.934 to 40.839) over the grand average of performance. The confirmation experimental result at optimum cutting condition (i.e., 39.378) is comparable with the expected result (i.e., 40.839).

A novel partial image encryption using chaotic logistic map

Abstract: Transmitted images may have many different applications like commercial, military, medical etc. To protect the information from unauthorized access secure image transfer is required and this can be achieved by image data encryption. But the encryption of whole image is time consuming. This paper proposed a selective encryption techniques using spatial or DCT domain. The result of the several experimental, statistical analysis and sensitivity test shows that the proposed image encryption scheme provides an efficient and secure way for real-time image encryption and transmission. A chaotic logistic map is used to perform different encryption/decryption operation in this proposed method.