Vignan University

About: Vignan University is a education organization based out in Guntur, Andhra Pradesh, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

Scheduling latency comparison of two open-source RTOSs on CORTEX-M3

Abstract: In hard real time systems, determinism and predictability of time are important aspects that need to be considered in the execution of a given task. It is a well-known fact that the task execution time depends on scheduling latency which in turn depends on the capability of Real Time Operating Systems (RTOS) scheduler. Hence it is clear that scheduling latency is an important parameter of RTOS that specifies its performance. Thus keeping an eye on recently available Real Time Operating Systems, an effort is made in this work to carry out performance comparisons of two real-time operating systems, based on their scheduling latencies. FreeRTOS and ChibiOS/RT deployed onto CORTEX-M3 processors are chosen for this purpose.

An Optimization Strategy to Improve Performance in Electrochemical Discharge Machining of Borosilicate Glass Using Graph Theory Algorithm and Desirability Index

Abstract: Electrochemical discharge machining (ECDM) a combined version of electrical discharge machining (EDM) and electrochemical machining (ECM), is an emerging alternative method to shape low machinability material like borosilicate glass. Since the material removal rate (MRR) decreases with the machining depth due to insufficient electrolyte at the tool tip, the radial over cut (ROC) is found at the entrance due to accumulation of electrolyte. To overcome these issues, a hybrid electrolyte (HE) of NaOH+5% KOH is proposed in the present study, because the HE has low viscosity and high electrical conductivity compared to individual conventional electrolyte (CE). Experiments are conducted with an in-hose developed ECDM set-up integrated with metal oxide semiconductor field effect transistor (MOSFET) assisted power module. Experimental plan developed based on L9 orthogonal array with three process variables, electrolyte concentration, applied voltage, and duty factor at three levels, taper angle (TA) and ROC considered as quality characteristics and MRR is considered as performance characteristics. In this paper, a novel simultaneous multi-response optimization technique by combining Graph theory algorithm (GTA) and desirability function approach (DFA) is presented. Weights for the responses are calculated using the GTA and are used to evaluate overall (composite) desirability index (ODI) and it is treated as the multi response performance index (MRPI) to determine optimum levels for the process variables. ANOVA test indicated that DF has more influence on machining performance with 47.16% for CE and 57.06% for hybrid electrolyte. An increased MRR, and a reduction in OC and TA was noticed with HE compared to CE. In addition, SEM images revealed a smooth machined surface texture with CE and a feathery-like machined surface texture with HE. The average of the response values from the confirmation tests were found to be within the ±5% of predicted mean value, and the optimal values obtained from the proposed optimisation technique are confirmed.

Phytochemical library of Caralluma genus

Abstract: Caralluma is one of the prominent genus out of 200 genera and 2500 species of Asclepiadaceae family. Caralluma genus belongs to Asclepiadaceae and is widely distributed in Asia countries, Africa, Arabian Peninsula, Canary Islands and Southeast Europe. In folkloric medicine, as well as in Unani and Ayurvedic systems of medicine, the plants of Caralluma are being used for the treatment of diabetic patients and rheumatism. Tribals consider some of them as food during famines and also as a part of the traditional medicinal system. In India and Pakistan, Caralluma species have been used as emergency foods for the last few centuries. As allopathic medicines possess toxic nature and side effects, the use of plant-based medicine is becoming popular. This lead to a sudden enhancement in the production of herbal drugs. At present Caralluma is gaining much importance from researchers because it possesses array immunostimulating activities due to presence flavonoids and saponins and pregnane glycosides as active components. The present article thoroughly reviewed about various phytochemicals present in different species of Caralluma. Tabulated a list of phytochemicals isolated by various researchers from different plants of the Caralluma genus. Further, listed out the species on which enthusiastic researchers of this field can extend their investigation.

Functional characterization of late embryogenesis abundant genes and promoters in pearl millet (Pennisetum glaucum L.) for abiotic stress tolerance

Abstract: Late embryogenesis abundant (LEA) genes display distinct functions in response to abiotic stresses in plants. In pearl millet (Pennisetum glaucum L.), a total of 21 PgLEA genes were identified and classified into six groups including LEA1, LEA2, LEA3, LEA5, LEA7, and dehydrins (DHN). Open reading frames (ORFs) of PgLEAs range from 291 bp (PgLEA1-1) to 945 bp (PgLEA2-11) and distributed randomly among the seven chromosomes. Phylogenetic analysis revealed that all PgLEA proteins are closely related to sorghum LEA proteins. The PgLEAs were found to be expressed differentially under high progressive vapor pressure deficit (VPD), PgLEA7 was significantly expressed under high VPD and was selected for functional validation. In silico analysis of the PgLEA promoter regions revealed abiotic stress-specific cis-acting elements such as ABRE, CCAAT, MYBS, and LTRE. Based on the type of motifs, PgLEAPC promoter (758 bp), its deletion 1 (PgLpd1, 349 bp) and deletion 2 (PgLpd2, 125 bp) were cloned into the plant expression vector pMDC164 having the promoter-less uidA gene. All the three plant expression vectors were introduced into tobacco through Agrobacterium tumefaciens-mediated transformation to obtain T1 and T2 generations of transgenic plants. Based on expression of the uidA gene, tissue-specific expression was observed in mature stems, roots and seedlings of PgLEAPC and PgLpd1 carrying transgenics only. While the transgenic PgLEAPC plants displayed significantly higher uidA expression in the stem and root tissues under salt, drought, heat, and cold stresses, very low or no expression was observed in PgLpd1 and PgLpd2 transgenics under the tested stress conditions. The results of this study indicate that the complete promoter of PgLEAPC plays a role in developing abiotic stress tolerance in plants.

Design and Performance Evaluation of Energy Efficient 8-Bit ALU At Ultra Low Supply Voltages Using FinFET With 20nm Technology

Abstract: ince last few years, the tiny size of MOSFET, that is less than tens of nanometers, created some operational problems such as increased gate-oxide leakage, amplified junction leakage, high sub-threshold conduction, and reduced output resistance. To overcome the above challenges, FinFET has the advantages of an increase in the operating speed, reduced power consumption, decreased static leakage current is used to realize the majority of the applications by replacing MOSFET. By considering the attractive features of the FinFET, an ALU is designed as an application. In the digital processor, the arithmetic and logical operations are executed using the Arithmetic logic unit (ALU). In this paper, power efficient 8-bit ALU is designed with Full adder (FA) and multiplexers composed of Gate diffusion input (GDI) which gained designer's choice for digital combinational circuit realization at minimum power consumption. The design is simulated using Cadence virtuoso with 20nm technology. Comparative performance analysis is carried out in contrast to the other standard circuits by taking the critical performance metrics such as delay, power, and power delay product (PDP), energy-delay product (EDP) metrics into consideration.