Power Rate Exponential Reaching Law for Enhanced Performance of Sliding Mode Control

Devika K. B.,Susy Thomas 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.6

In Sliding Mode Control (SMC), the control action can be split into two regions- the reaching phaseand the sliding phase. Considerable research attention has been given to improve the reaching time so as to bestutilize the benefit of robustness property of sliding mode motion. Attention has also been on alleviating and/oreliminating chattering during sliding mode motion so that smooth control is obtained which will not hinder practicalapplications. Exponential Reaching Law (ERL) is one of the methods reported in the literature for alleviatingchattering in sliding mode. This paper proposes a Power Rate Exponential Reaching Law (PRERL) wherebysubstantial improvement both in reaching time and chattering alleviation are achieved compared to ERL. WithERL, the states do not settle at its desired position due to high frequency low magnitude chattering, thus limitingits practical utility. This drawback has been overcome in the PRERL method. Thus the benefits of the proposedmethod is many fold: reducing reaching time, improving chattering alleviation and ensuring settling of the states atits final position with considerable improvement in speed of response.

Monetary & fiscal policy implications for rising government debt under labor endogeneity

Devika Hazra 한양대학교 경제연구소 2017 JOURNAL OF ECONOMIC RESEARCH Vol.22 No.3

Several advanced economies are heading towards a period of fiscal stress; aging population raises government transfers which in turn increases nominal government debt. Existing literature studies how alternative combinations of monetary and fiscal policies can stabilize real debt in the face of exponentially rising transfers. This paper develops an overlapping generations (OG) model with endogenous labor to study the implications of labor supply decisions on the path of real government debt under alternative monetary and fiscal policy combinations and finds that adopting a policy regime where the monetary authority passively targets inflation in the face of rising transfers, even before the economy is at the fiscal limit, might stabilize inflation better than an active monetary regime. The model in the paper has been calibrated to the US economy to demonstrate dynamic effects.

An Exploratory Study

Devika Cassandra Gooptar 한국라틴아메리카학회 2017 라틴아메리카연구 Vol.30 No.2

This study explores the topics of human rights violations, persons with disabilities (pwds) and the criminal justice system of Trinidad and Tobago. The goal of this research is to discover whether human rights violations exist against pwds in the justice system and if so, how and why they may be violated. The various means by which these rights can be protected and enhanced is also critical to this research. This study encompasses three components of the justice system: the police, courts and prison systems as well as inculcated legislation as a key constituent. I adopted a qualitative methodology, with semi-structured interviews representing the main data collection medium accompanied by secondary sources. I found evidence that the human rights of pwds are possibly violated within the police, courts and legislative aspect of the system, with less clarity shed on the reality within the nation’s correctional facilities. I identified numerous multifaceted and interlocked themes which assisted in explaining how and why the rights of pwds may be violated in the justice system.Based upon these findings, I provide multiple suggestions for ways in which the rights of pwds can be enforced and protected within the individualized sectors as well as overall justice system. In terms of accessing and maneuvering within the criminal justice system of Trinidad and Tobago, pwds are increasingly marginalised and susceptible to conscious as well as unintentional human rights violations in a number of ways due to a multitude of reasons.

The other side of the coin: Towards a narrative analysis of Dogri folk tales

Devika Sharma,Amitabh Vikram Dwivedi 국립민속박물관 2022 International Journal of Intangible Heritage Vol.17 No.-

Discourse coherence involves a multistrand phenomenon that is perpetually aided with connective elements to build a narrative. The paper explores the cohesive units that help in the formation of narrative context, thereby making them compelling and worth reading or listening to. Folk narratives consist of inclusive information that builds up the social identity of a community. In this, the cultural knowledge and community wisdom of natives play an important role in the decoding and meaning-making tales to inquire about the cohesive formation at sentence and process. The study analyses extracts collected from Dogri folk discourse level. To find out the importance of language creativity and contextual signals, the proposals of T. Givón, Bruce Fraser and George Yule are taken into consideration. The findings illustrate the active use of cohesive binders in Dogri tales. Also, the mechanisms work in varied forms to build a lucid discourse. This case study of regional tales can help popularise the culture of vulnerable societies and share the Indigenous wisdom embedded in their folk tales globally.

Electrical properties of polycrystalline and single crystalline nickel layer capped ZnO nanowires

Devika Mudusu,Koteeswara Reddy Nandanapalli,레디,강장원,박성하,CharlesW. Tu 한국물리학회 2017 Current Applied Physics Vol.17 No.12

This article reports the electrical characteristics of pristine, polycrystalline and single crystalline nickel (Ni) layer capped zinc oxide (ZnO) nanowires. Core/shell ZnO/Ni nanostructures were developed using chemical vapor deposition and e-beam evaporation, and the structures were annealed at different temperatures. Field effect transistor (FET) devices were fabricated using photolithography and investigated their characteristics at room temperature. All FET devices exhibited depletion-mode characteristics with n-type conductivity. However, single-crystalline Ni shelled ZnO nanowires based FET devices showed a high on/off ratio and transconductance, as compared to other devices. The overall measurements show that though the ZnO nanowires capped with Ni layer, their electrical properties remain same as pristine ZnO nanowires.

Escaping the Shadow Zone : The Constitutive Contexts of Discipline-centered Knowledge and Research on Women in Kerala, India

J. Devika Ewha Womans University Press 2007 Asian Journal of Women's Studies(AJWS) Vol.13 No.2

This paper interrogates the historical contexts in which knowledge on 'women' has been produced in Kerala state, India, where the radical questioning of patriarchal knowledge-production has begun to acquire unmistakable momentum in the 1990s. Asking whether this indicates an occasion for unqualified celebration, it approaches an answer through critically examining two specific histories, those of discipline-centered, university based academic knowledge in Kerala, which goes back to the early twentieth century, and the emergence of 'women' as a topic for critical discussion in the public sphere. In general, it tries to trace the shaping of the social science and humanities as instruments of state-led developmentalism and cultural nationalism in the early twentieth century and the consequences of this for 'women' as objects of knowledge production. Further, it also examines the context of the emergence of feminist scholarship on Kerala.

On the origin and evolution of SARS-CoV-2

Singh Devika,Yi Soojin V. 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the ongoing global outbreak of a coronavirus disease (herein referred to as COVID-19). Other viruses in the same phylogenetic group have been responsible for previous regional outbreaks, including SARS and MERS. SARS-CoV-2 has a zoonotic origin, similar to the causative viruses of these previous outbreaks. The repetitive introduction of animal viruses into human populations resulting in disease outbreaks suggests that similar future epidemics are inevitable. Therefore, understanding the molecular origin and ongoing evolution of SARS-CoV-2 will provide critical insights for preparing for and preventing future outbreaks. A key feature of SARS-CoV-2 is its propensity for genetic recombination across host species boundaries. Consequently, the genome of SARS-CoV-2 harbors signatures of multiple recombination events, likely encompassing multiple species and broad geographic regions. Other regions of the SARS-CoV-2 genome show the impact of purifying selection. The spike (S) protein of SARS-CoV-2, which enables the virus to enter host cells, exhibits signatures of both purifying selection and ancestral recombination events, leading to an effective S protein capable of infecting human and many other mammalian cells. The global spread and explosive growth of the SARS-CoV-2 population (within human hosts) has contributed additional mutational variability into this genome, increasing opportunities for future recombination.

Excellent enhancement in the device performance of nitrogen plasma treated ZnO nanorods based diodes

Reddy Nandanapalli Koteeswara,Devika Mudusu,한윤봉 나노기술연구협의회 2014 Nano Convergence Vol.1 No.26

Impact of the plasma exposure time on the physical properties of homo-epitaxial ZnO nanorods (NRs) and their devices was investigated. Here, ZnO NRs were synthesized by chemical solution method on glass substrates and treated under high intensity nitrogen plasma at different exposure timings. The as-grown as well as treated ZnO NRs exhibited hexagonal crystal structure and (001) as a preferential orientation. While increasing the plasma exposure time from 1 to 15 min, the structural and optical quality of ZnO NRs gradually improved and above this exposure time, both the properties degraded. The devices fabricated with 15 min plasma treated ZnO NRs showed excellent diode performance than the untreated nanostructures based devices. The diodes developed with treated ZnO NRs showed a low turn-on voltage (3.3 V) than the devices developed with untreated NRs.

Functionalization of graphene layers and advancements in device applications

Nandanapalli, Koteeswara Reddy,Mudusu, Devika,Lee, Sungwon Elsevier 2019 Carbon Vol.152 No.-

<P><B>Abstract</B></P> <P>The invention of graphene, as a two-dimensional (2D) atomic layered material, has created enormous scientific revolutions in materials science. As a result, there are a variety of 2D materials came into limelight and intervening the existing technology. Today, one of the focusing issues in graphene technology is the development of functionalized (doped) graphene monolayers since the pristine graphene is chemically inert, hydrophobic and zero band gap material. As a result, the potential applications of graphene are limited to a few fields of science and technology. Surface functionalization, one of the typical approaches, is well-adopted for the development of functionalized graphene layers. In this scenario, we reviewed the latest advancements exclusively in the development of functionalized graphene layers, and exciting breakthroughs in graphene's science and technology. A brief history along with intrinsic properties of graphene is discussed in the introduction. Then, the methods adopted for the realization of functionalized graphene layers, and the impact of surface modification on their physical and chemical properties along with device performances are elaborately discussed. Finally, the review is summarized and outlined the perspectives of functionalized graphene layers in view of the development of multifunctional high-quality graphene layers for next-generation device applications.</P> <P><B>Graphical abstract</B></P> <P>This review discusses the importance of graphene functionalization, typical methodologies adopted for functionalizing the graphene layers or sheets, and advancements in the performance of graphene-based devices.</P> <P>[DISPLAY OMISSION]</P>

Development of tin (II) sulfide nanostructured films with uniform surface morphology by two-step growth process

Nandanapalli, Koteeswara Reddy,Mudusu, Devika,Lingandhinne, Raja Mohan Reddy,Mitta, Sekhar Babu,K. Reddy, Gunasekhar,Karuppannan, Ramesh,Whang, Dongmok Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.770 No.-

<P><B>Abstract</B></P> <P>Tin (II) sulfide (SnS), one of the most abundant materials, is being considered as an absorber material for the development of low-cost and nontoxic solar cell devices. In this direction, we have developed nanocrystalline films of SnS with uniform morphology on different substrates by adopting two-step thermal evaporation process. The surface studies show that irrespective of substrate nature, the as-grown SnS films possess uniform surface-morphology with well-defined facets. Structural studies reveal that SnS films grown on various substrates possess an orthorhombic crystal structure. However, as compared to other substrates, the structures developed on sapphire and copper exhibit ⟨010⟩ as preferential growth direction. From the electrical measurements, it is noticed that the films deposited on highly-conductive substrates consist of low electrical resistance, whereas the films are slightly resistive on insulating substrates. Based on these investigations it is emphasized that high-quality SnS films can be developed with uniform morphology on any substrates by adopting our two-step process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SnS films were developed with uniform morphology by using two-step process. </LI> <LI> The films grown on different substrates possess nanocrystallites with well-defined facets. </LI> <LI> These films consist of excellent chemical stoichiometry and phase purity. </LI> <LI> SnS films grown on different substrates have either ⟨111⟩ or ⟨010⟩ growth direction. </LI> </UL> </P>