Amita Kapoor | University of Delhi (original) (raw)

Papers by Amita Kapoor

Procedia Computer Science

2016 International Conference on Advances in Computing, Communications and Informatics (ICACCI), 2016

International Journal of Information Technology and Management, 2015

Journal of the Optical Society of America B Optical Physics, 2009

2016 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2016

An approach for the recognition of low resolution grey scale facial images using cloud Hopfield n... more An approach for the recognition of low resolution grey scale facial images using cloud Hopfield neural network (CHNN) is presented. This approach consists of three steps: first we transform the grey scale facial images into binary facial images using Otsu's method, second Hebb rule is employed to store binary faces in the weight matrix of the network and finally correct face is retrieved from distorted face using CHNN retrieval algorithm. CHNN consists of clouds each with r number of unique neurons, these clouds are updated asynchronously unlike conventional asynchronous retrieval in which only one neuron is updated at a time. We compare our results with that of conventional HNN and other face recognition methods. Our results show that even when the distortion in the presented face is 45%, the CHNN is able to give at least 82.8% successful retrieval as compared to only 63% by conventional HNN for the same amount of distortion. This is much greater than previous reported claims to the best of our knowledge.

Bodhi Path ISSN 2347-8004, January 2016, Page No.52, 2016

Freedom from transmigration is the ultimate goal of all seekers. According to Buddhist scriptures... more Freedom from transmigration is the ultimate goal of all seekers. According to Buddhist scriptures, philosophy and psychology Āsava is the kernel of transmigration. Liberation from āsava has been declared again and again in Pali canon as a necessary condition for being an 'Arahat', the one who has attained Nibbana, the one who no longer transmigrates. This paper elaborates upon the concept of transmigration, how āsava is the kernel of transmigration, the root cause of the cycle of life and death, and how can one get free from āsava?

Advances in Intelligent Systems and ComputingPublisher: Springer, 2019

Autonomous vehicles (AVs) have received testing permits in many countries but according to AVRI-2... more Autonomous vehicles (AVs) have received testing permits in many countries but according to AVRI-2018 India is not prepared for AVs. In this paper, we will investigate the need of AVs on Indian roads and up to which level of automation they can be implemented? Approximately 0.15 million deaths occur on the Indian roads every year, this number can be drastically reduced with the introduction of AVs on Indian roads. We propose an assistance system (AS), embedded in the existing vehicles that require minimal hardware addition. The AS can detect lanes, nearby vehicles, and indicate driver attentiveness. We tested the system on real road images of Delhi, the capital of India. The AS provides an additional perception to the driver that can help in the reduction of accidents and thus reduce the loss of precious human resource without any major policies changes or supplementary hardware requirement.

2016 International Conference on Advances in Computing, Communications and Informatics (ICACCI), 2016

2015 International Conference on Advances in Computing, Communications and Informatics (ICACCI), 2015

Employing the quantum interference among one- and two-photon excitations induced by ultrashort tw... more Employing the quantum interference among one- and two-photon excitations induced by ultrashort two-color laser pulses it is possible to generate charge and spin currents in semiconductors and semiconductor nanostructures on femtosecond time scales. Here, it is reviewed how the excitation process and the dynamics of such photocurrents can be described on the basis of a microscopic many-body theory. Numerical solutions of the semiconductor Bloch equations (SBE) provide a detailed description of the time-dependent material excitations. Applied to the case of photocurrents, numerical solutions of the SBE for a two-band model including many-body correlations on the second-Born Markov level predict an enhanced damping of the spin current relative to that of the charge current. Interesting effects are obtained when the scattering processes are computed beyond the Markovian limit. Whereas the overall decay of the currents is basically correctly described already within the Markov approximat...

Physics and Simulation of Optoelectronic Devices XV, 2007

Advancements in information technology today have made a paradigm shift in teaching as well as le... more Advancements in information technology today have made a paradigm shift in teaching as well as learning process. Technology supports both teaching and learning and thus infuses classrooms with various learning tools, such as computers and hand held devices and learning materials developed in form of animations, videos, manuals and presentations. Technology has made learning a very easy process which is available to the students for round the clock. Being knowledge partners it is our obligation not only to guide the students to correct resources but also contribute towards evolution & development of such resources. In the present work, an e-learning based model has been developed for effective teaching of basic electronics experiments. The work includes demonstration of various electronics experiments based on digital and analog electronics by developing various e-manuals, power point presentations, descriptive animations and videos shot in the practical laboratories of the college. These resources would act as a handy tool for anyone who wishes to perform these experiments and will be a stepping stone in the realm of practical based learning for forthcoming students of science.

Erbium doped fibre amplifier is a key device in WDM/DWDM technology. The task of modelling EDFA i... more Erbium doped fibre amplifier is a key device in WDM/DWDM technology. The task of modelling EDFA is computationally expensive. In this paper we investigate the application of multilayered feed-forward neural network to model an EDFA.

This paper presents the development, use and impact of e-learning resources on undergraduate girl... more This paper presents the development, use and impact of e-learning resources on undergraduate girl students. The paper compares the conventional method of teaching vs the use of ICT tools for teaching. An interesting component of our study is that the ICT tools have been developed by students themselves under the guidance of a teacher.

Procedia Computer Science

2016 International Conference on Advances in Computing, Communications and Informatics (ICACCI), 2016

International Journal of Information Technology and Management, 2015

Journal of the Optical Society of America B Optical Physics, 2009

2016 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2016

Bodhi Path ISSN 2347-8004, January 2016, Page No.52, 2016

Advances in Intelligent Systems and ComputingPublisher: Springer, 2019

2016 International Conference on Advances in Computing, Communications and Informatics (ICACCI), 2016

2015 International Conference on Advances in Computing, Communications and Informatics (ICACCI), 2015

Physics and Simulation of Optoelectronic Devices XV, 2007

The scope of this thesis is modeling, design and application of optical amplifiers and long perio... more The scope of this thesis is modeling, design and application of optical amplifiers and long period gratings (LPGs). Typically, we concentrate on erbium doped fiber amplifiers, erbium doped lithium niobate waveguide optical amplifiers (EDWAs), and semiconductor optical amplifiers (SOAs). These three devices besides being employed as optical amplifiers also promise their feasibility to be used as optical signal processors. Modeling and simulation of these amplifiers is thus an important tool in the understanding and designing of these amplifiers. This can further aid in the development on structural modifications which can help in implementing new technologies and look for novel applications of the same structure. The salient features of the underlying work can be summarized as below:
The thesis is structured as follows: After a brief introduction to the state of art in Chapter 1, Chapter 2 provides a review of the concepts used in subsequent chapters. Confinement and guidance of electromagnetic waves through waveguides and fibers is presented. Specifically, we discuss the variational method for channel waveguides and analysis for optical fibers taking into account the core, cladding and ambient refractive index regions. The basic characteristics of long period gratings are presented along with the coupled mode theory for determining the coupling between the fundament core mode and co-propagating cladding mode. Finally, the general principle of optical amplification is presented and some common optical amplifiers are discussed.
In Chapter 3 power coupled equations for modeling of EDFA’s are discussed. Recently, researchers have proposed EDF's with LPG written in them for better gain flattening. These structures are analyzed using modified coupled mode analysis. We have evolved a methodology to incorporate ASE taking into consideration the random phase of spontaneous emission. Our results show that LPG written in EDF itself, not only brings about gain flattening, but also suppresses the ASE.
Chapter 4 looks into the analysis of erbium doped titanium in-diffused lithium niobate waveguide optical amplifiers. The gain coupled differential equations involve integrals and depend explicitly on the modal fields, making it time consuming to solve. In this chapter we approximate the Hermite-Gaussian modal field obtained from the variational analysis by suitably chosen approximations. These approximations reduce the integrals to analytical forms. This results in a computationally efficient solution.
In Chapters 5-7, we focus on semiconductor optical amplifiers. Chapter 5 discusses the basic semiconductor physics controlling the behavior of an SOA. The chapter also discusses the widely accepted Connelly model, to model an SOA in steady state. Chapter 6 investigates the possibility of using ATLAS, a Silvaco’s physics based simulator tool, to model the behavior of SOA. The results obtained by ATLAS are compared with the experimental data, validating the use of ATLAS to simulate SOAs. In Chapter 7 we further investigate using ATLAS, the effect of modification in SOA design on gain saturation and alpha factor. Specifically, we look into the effects of doping the active layer of the SOA, changing the depth of the active layer and changing the width of ridge. Our results show that it is possible to engineer the gain saturation and alpha factor of an SOA.
During our study of the transmission spectra of LPG written in it, we observed that at a certain wavelength greater than the resonance wavelength, the transmitted core power varies significantly from 0 (no transmission) to 1 (full transmission) as the ambient index is varied. This motivated us to investigate the possibility of intensity based refractive index sensor using LPG. Hence, in Chapter 8, we look into the application of LPGs as refractive index sensors. We propose a design recipe to tailor a refractive index sensor with maximum sensitivity in the desired refractive index range.
Finally we present an outlook on future research.

In this report we present the results obtained by two-dimensional simulation of bulk SOAs using A... more In this report we present the results obtained by two-dimensional simulation of bulk SOAs using ATLAS simulation tool. The results of our work are presented below:
• We successfully modeled the optical gain of the SOA by using radiative recombination parameter B as the fitting parameter (Section 2.3.1).
• We developed a model to implement a virtual optical source. This helped us to model the gain saturation behavior of an SOA. Using this technique, we successfully modeled gain saturation. We found that temperature plays an important role at high currents (Section 2.1.2, 2.1.3 and 2.3.3).
We further investigated the effect of modification in the device design on the performance of the SOA. First, we investigated what effect the doping of the active layer has on the saturation behavior of the SOA. We considered both p and n doping of the active layer. We limited ourselves to practical doping levels possible for InGaAsP (maximum 2x108 cm-3). We investigated the influence of varying dopant concentrations.
It was observed that:
• For acceptor doping of active layer, the effective carrier time is almost insensitive to the applied injection current. Moreover, doping the active layer with acceptor impurities reduces the effective carrier life time, as a result p-doping should improve the gain recovery of the SOA (Figure 3.5).
• Acceptor doping of the active layer increases the small signal amplifier gain (Figure 3.2).
• Keeping the operating current density constant, we considered two cases:
o First, the length of the SOA is kept constant. Under these conditions, p-doping in the active layer enhances the small signal gain, but saturation power becomes low. An n-doped active layer, on the other hand leads to low gain but
high saturation power (Figure 3.6).
o Second, the small signal gain is kept constant (11.8 dB) by varying the device
length. In this case, our results demonstrate that a p-doped active layer with a small device length (~160μm) has high saturation power. An n-doped active layer on the other hand needs a large device length (~258μm) and leads to low input saturation power (Figure 3.8).
Next, we investigated the effect of changing the ridge width. We varied the width from 1.6 μm to 11.6 μm. It was observed that:
• A very small ridge width, results in low resistance and therefore the band edges in the InP regions droop (Figure 3.9 b). Thus, it is important to have a minimum ridge width.
1
Synopsis
• An increase in the ridge width results in increase in the saturation power, but at the same time the effective carrier lifetime is also increased (Figure 3.12 and Figure 3.14). Thus, we need to optimize between the need of high saturation power and fast recovery.
Finally, we considered the effect of changing the depth of the active layer. We varied the depth from 300 nm to 80 nm. We choose this range to ensure both single mode operation by the waveguide and bulk behavior by the active region. Our simulations show that:
• Change in the depth of the active layer causes fluctuation in the dominant mechanism for the confinement of light in growth axis. It fluctuates between index guided and gain guided (Figure 3.18, Figure 3.19 and Figure 3.20).
• It was observed that index guided SOAs had relatively high saturation power as compared to gain guided SOAs (Figure 3.23).
• A decrease in the depth of the active layer increases the saturation power in general and reduces the effective carrier lifetime (Figure 3.22a).
As a future work, it will be interesting to see the combined effect of these modifications and implement an SOA based on them.

15th Annual Conference of Indian Society for Buddhist StudiesAt: Jain Vishwa Bharati University, Ladnun-341306, Rajasthan, 2015

Āsava is an important component of Buddhist scriptures, philosophy and psychology. Freedom from ā... more Āsava is an important component of Buddhist scriptures, philosophy and psychology. Freedom from āsava has been mentioned at many places as a necessary condition for being an 'Arahat', the one who has attained Nibbana. Arahat is used as synonym with anāsava that is the one who has conquered his āsava. The question naturally, then arises, what is āsava, what is the origin of āsava, why one is bounded by āsava and how can one get free from āsava? Early Buddhist literature talks of āsava in Tipiṭaka (Sutta Pitaka, Vinaya Piṭaka and Abhidhamma Piṭaka) at many places. Saṃyutta Nikāya's, Āsavasutta (SN 45.13.163) describes that there are three āsava, viz.: kāmāsava, bhavāsava, and avijjāsava, it further adds that by following the eightfold path one can get free from āsava. According to Manjim Nikaya's Mahāsaccaka (MN 36), Tathagata Gautama tells Saccaka, the Nigaṇṭha's son, how on attaining Nibbana he could see what are āsava, what are the types of āsava, what is there origin, and how one can conquer āsava. Here Budha calls this knowledge as third true knowledge that he attained (tatiyā vijjā adhigatā). Dhamapada talks of āsava in verses 93, 226, 253, 292 and 293. According to Dhamapada again there are three types of āsava, it elaborates what actions free or bound a being to āsava. In Abhidhamma's Dhammasangini (verse 1096-1100) for the first time we see the mention of four āsava, kāmāsava, bhavāsava, diṭṭhāsava and avijjāsava. Abhidhamma goes further and explains these four types of āsava. According to Abhidhamma desire, passion, craving, thirst, fever, languishing, intoxication etc. of kāmā, bhavā, presence of diṭṭhā and avijjā are āsava. Mahathera Narada, in his translation of Abhidhammattha Sangaha speaks that āsava are latent in all worldlings and may rise to the surface in any plane of existence. Exact meaning of āsava has confounded the western philosophers and seekers alike, as there do not exist an English word that can do justice to the meaning of āsava. David Rhys has used the word intoxicant, relating āsava to alcoholic drinks. According to him just as after drinking one starts behaving like a madman, people under the bound of āsava filled with pride act like mad, i.e. are not aware of what can be the consequences of their actions. Other authors have used words like cankers, defilements and even taint for āsava. These words though still not accurate try to describe the property, the affect of āsava. According to Bhikhu Bodhi āsava sustain the forward movement of the process of birth and death. As long as a person is bounded by āsava he goes on in the cycle of life and death, the wheel of life (cyclic existence). Thus, the significance of āsava in the Buddhist philosophy cannot be neglected. In this paper we attempt to explore the various aspects of āsava as given by different scholars, understand the phenomenon/concept/thing called āsava and its catalytic effect in the continuation of samsara.

INDIAN SOCIETY FOR BUDDHIST STUDIESAt: Sanchi University of Buddhist- Indic Studies, Sanchi, Barla, Dist-Raisen (M. P.), India, 2017

According to the Theravada, Mettā or maitrī (Sanskrit) is the first of the four Brahmavihāras and... more According to the Theravada, Mettā or maitrī (Sanskrit) is the first of the four Brahmavihāras and one of the ten pāramīs. Research in the nascent field of positive psychology provides empirical evidence that positive emotion like loving-kindness broadens a person’s attention and thinking; builds the quality of their interpersonal relationship; increases optimism and tranquility and strengthens cognitive and learning abilities. World since time immemorial has been inflicted upon by hate, jealousy, wars, and conflicts. Many great persons have tried to reduce them, some succeeded to a certain level. In this paper, we explore that can mettā be a way to achieve Global Peace, effectively and in a more permanent way. We extrapolate the experiential work by Fowler and Christakis. Their 20-year experimental research proved that happiness, like health is a contagious phenomenon. We propose that like happiness, mettā too is contagious. If more and more people are inducted into mettā through the practice of meditation, those people and their immediate family members too will develop mettā, and once a critical number of individuals develop mettā the world can become a better place and Global Peace can be achieved. We explore the suttas of Tipitika and experiential results of positive Psychology to prove our proposition. Buddha himself had said to his disciples: “Go forth for the good of the many, for the happiness of the many, out of compassion for the world, for the welfare, the good and the happiness of gods and men. Let no two of you go in the same direction.”

Avijjā (Ignorance) is the principal cause of all malevolence, misery and pain in the world. It cl... more Avijjā (Ignorance) is the principal cause of all malevolence, misery and pain in the world. It cloaks being's mental eyes and mind, thus prevent them from seeing the true nature of things. According to Avijjāsutta in Pali canon (Samyutta Nikāya V.429)