K. Venkata Lakshmi Narayana

Bio: K. Venkata Lakshmi Narayana is an academic researcher from VIT University. The author has contributed to research in topics: Wireless sensor network & Network performance. The author has an hindex of 3, co-authored 7 publications receiving 17 citations.

Cross-layer multi channel MAC protocol for wireless sensor networks in 2.4-GHz ISM band

Abstract: In a smart grid environment, wireless sensor networks (WSNs) perform a significant role in supervising and taking control decisions based on the data transferred from source to destination. The work in this paper is aimed to develop a cross-layer multi-channel MAC (CMCMAC) protocol for interference mitigation between ZigBee and WiFi operating in common 2.4GHz frequency band. In this protocol, to avoid the interference between the channels, the future interference is predicted using the Hidden Markov Model (HMM), based on the prediction a channel with the minimum interference is selected for data transmission to enhance the network performance. The results obtained show the enriched network performance.

Design and development of improved linearized network based liquid level transmitter

Abstract: In this paper, a liquid level transmitter using cylindrical capacitive sensor and an improved linearized network for capacitance measurement has been proposed to measure the liquid level and to convert level changes into an electrical current which can be transmitted to a remote indicator. The change in capacitance of cylindrical capacitive sensor due to change in liquid level is measured by an improved linearized capacitance measuring network. The offset capacitance of the cylindrical capacitive sensor and the stray capacitances that exist between sensor electrodes & metallic tank are measured before the liquid level measurement. The measured capacitances are used in the proposed capacitance measuring network to minimize the effects of offset capacitance and stray capacitances on liquid level measurement using dc control voltage and operational amplifiers with high input impedance. The experimental investigations have been performed to sense water level of metallic tank in both increased and decreased level conditions. In the first phase of experiment, a linearized network has been simulated using LabVIEW (Laboratory Virtual Instrument Engineering Workbench) and studied with the test capacitance, and in the second phase, the experimentation was done by replacing the test capacitance with a cylindrical capacitive sensor for the measurement of liquid level. As a result of investigations conducted, it has been observed that the variation in liquid level from 0 to 25cm having linear relationship with output dc voltage in the range of 0 to 5.5V. Corresponding to liquid level variations, the dc output voltage further converted into an electric current of 4 to 20mA for remote indication and control purpose. The experimental results of liquid level transmitter are found to have good linearity of about ± 0.2% and a resolution of about 1 cm. The sensitivities of the capacitance measuring circuit and level transmitter have been found about 6.5 mV/pF and 250mV/cm respectively.

Cross-layer multi channel MAC protocol for interference mitigation

Abstract: In a smart grid environment, wireless sensor networks (WSNs) perform a significant role in supervising and taking control decisions based on the data transferred from source to destination. The work in this paper is aimed to develop a cross-layer multi-channel MAC (CMCMAC) protocol for interference mitigation between ZigBee and WiFi operating in common 2.4GHz frequency band. In this protocol, to avoid the interference between the channels, the future interference is predicted using the hidden Markov model, based on the prediction a channel with the minimum interference is selected for data transmission to enhance the network performance. The results obtained show the enriched network performance.

A low-cost capacitive sensor for water level monitoring in large-scale storage tanks

Abstract: Water-level sensors are indispensable for monitoring the level of water in storage tanks, which are used in drinking water distribution networks. In this paper, a long-range capacitive-type water-level sensor is presented. The proposed sensor is constructed using widely-available multilayer tubes, which are used for building drinking water systems. Thus, both the manufacturing cost of the sensor and the cost of the associated electronic circuits, which are used for interfacing the sensor to a digital data-acquisition unit, are low. The performance of the proposed sensor has been evaluated in a water storage tank of a city-scale water distribution network. The experimental results indicate that the accuracy of the proposed experimental prototype sensor is equivalent to that of a commercially available ultrasound water level sensor, while, additionally, its manufacturing cost is significantly lower.

Review on Liquid-level Measurement and Level Transmitter Using Conventional and Optical Techniques

Abstract: Liquid-level measurement in storage tank system play an important role in industrial application such as in food processing, pharmaceutical industry, chemical industry, water purification system, p...

Hybrid dual-loop control method for dead-time second-order unstable inverse response plants with a case study on CSTR

Abstract: Abstract Unstable processes are hard to stabilize as they contain one or more positive poles which result in unbounded dynamic behavior. The occurrence of the delay and positive zeros often creates more difficulty in controlling such unstable plants. Most control strategies meant for first-order unstable processes fail to stabilize and control the higher-order unstable processes. Hence, a new dual-loop hybrid control structure is suggested for dead-time unbounded second-order processes with positive/negative zeros. Inner-loop has a stabilizing PID controller. The PID controller parameters are derived by comparing the numerator and characteristic polynomial coefficients in the transfer function for internal-loop servo action. A fractional-order internal model controller (FOIMC) is used in the external-loop. Methods for the selection of outer-loop tuning parameter and fractional-order are also discussed. By comparing the simulation results with a contemporary single-loop scheme, the usefulness of the suggested scheme is proved. The suggested scheme is capable of minimizing the overshoot and improving the overall dynamic performance. Finally, the usefulness of the suggested scheme is also demonstrated by a case study on temperature control of a continuous stirred tank reactor (CSTR) during a first-order irrevocable exothermic reaction.

Survey and Comparative Study of LoRa-Enabled Simulators for Internet of Things and Wireless Sensor Networks

Abstract: The Internet of Things (IoT) is one of the most important emerging technologies, spanning a myriad of possible applications, especially with the increasing number and variety of connected devices. Several network simulation tools have been developed with widely varying focuses and used in many research fields. Thus, it is critical to simulate the work of such systems and applications before actual deployment. This paper explores the landscape of available IoT and wireless sensor networks (WSNs) simulators and compares their performance using the Low Power Wide Area Network (LPWAN) communication technology called LoRa (Long Range), which has recently gained a lot of interest. Using a systematic approach, we present a chronological survey of available IoT and WSNs simulation tools. With this, we categorized and content-analyzed published scientific papers in the IoT and WSNs simulation tools research domain by highlighting the simulation tools, study type, scope of study and performance measures of the studies. Next, we present an overview of LoRa/LoRaWAN technology by considering its architecture, transmission parameters, device classes and available simulation tools. Furthermore, we discussed three popular open-source simulation tools/frameworks, namely, NS-3, OMNeT++ (FLoRa) and LoRaSim, for the simulation of LoRa/LoRaWAN networks. Finally, we evaluate their performance in terms of Packet Delivery Ratio (PDR), CPU utilization, memory usage, execution time and the number of collisions.