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Effect of varying spatial orientations on build time requirements for FDM process: A case study

Defence technology（防务技术） 2017年第2期13卷 92-100页

作者： Sandeep Rathee Manu Srivastava Sachin Maheshwari Arshad Noor Siddiquee Division of Manufacturing Processes and Automation Engineering Netaji Subhas Institute of Technology Department of Mechanical Engineering Jamia Millia Islamia A Central University

In this research, effect of varying spatial orientations on the build time requirements for fused deposition modelling process is studied. Constructive solid geometry cylindrical primitive is taken as work piece and modeling is accomplished for it. Response surface methodology is used to design the experiments and obtain statistical models for build time requirements corresponding to different orientations of the given primitive in modeller build volume. Contour width, air gap, slice height, raster width, raster angle and angle of orientation are treated as process parameters. Percentage contribution of individual process parameter is found to change for build time corresponding to different spatial orientations. Also, the average of build time requirement changes with spatial orientation. This paper attempts to clearly discuss and describe the observations with an aim to develop a clear understanding of effect of spatial variations on the build time for Fused Deposition Modelling process. This work is an integral part of process layout optimization and these results can effectively aid designers specially while tackling nesting issues.

关键词： Fused deposition modeling Spatial orientation Process parameters Response Surface Methodology Build time

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Opinion of computer Science Instructors and Students on MOOCs in an Indian University

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Journal of Educational technology Systems 2018年第2期47卷 205 - 212页

作者： Pushp Sra Pinaki Chakraborty School of Computer and Systems Sciences Jawaharlal Nehru University New Delhi India Division of Computer Engineering Netaji Subhas Institute of Technology New Delhi India

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Optimal nonlinear system identification using fractional delay second-order volterra system

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IEEE/CAA Journal of Automatica Sinica 2018年

作者： Kumar, Manjeet Aggarwal, Apoorva Rawat, Tarun Parthasarathy, Harish Department of Electronics and Communication Engineering Division Netaji Subhas Institute of Technology New Delhi 110078 India India

The aim of this work is to design a fractional delay second order Volterra filter that takes a discrete time sequence as input and its output is as close as possible to the output of a given nonlinear unknown system which may have higher degree nonlinearities in the least square sense. The basic reason for such a design is that rather than including higher than second degree nonlinearities in the designed system, we use the fractional delay degrees of freedom to approximate the given system. The advantage is in terms of obtaining a better approximation of the given nonlinear system than is possible by using only integer delays ( since we are giving more degrees of freedom via the fractional delays ) and simultaneously it does not require to incorporate higher degree nonlinearities than two. This work hinges around the fact that if the input signal is a decimated version of another signal by a factor of M, then fractional delays can be regarded as delays by integers less than M. Using the well known formula for calculating the discrete time Fourier transform ( TFT ) of a decimated signal, we then arrive at an expression for the DTFT of the output of a fractional delay system in terms of the unknown first and second order Volterra system coefficients and the fractional delays. The final energy function to be minimized is the norm square of the difference between the DTFT of the given output and the DTFT of the output of the fractional delay system. Minimization over the filter coefficients is a linear problem and thus the final problem is to minimize a highly nonlinear function of the fractional delays which is accomplished using search techniques like the gradient-search and nature inspired optimization algorithms. The effectiveness of the proposed method is demonstrated using two nonlinear benchmark systems tested with five different input signals. The accuracy of the stated models using the globally convergent metaheuristic, cuckoo-search al

关键词： Linear systems

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Content Based Image Retrieval using Gabor Filters and Color Coherence Vector

Content Based Image Retrieval using Gabor Filters and Color ...

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IEEE International Advance Computing Conference, IACC

作者： Jyotsna Singh Ahsaas Bajaj Anirudh Mittal Ansh Khanna Rishabh Karwayun Department of Electronics and Communications Engineering Netaji Subhas Institute of Technology New Delhi India

ISBN: (纸本)9781538666791;9781538666784

Images have become a standard for information consumption and storage, far replacing text in various domains such as museums, news stations, medicine and remote sensing. Such images constitute of the majority of data being consumed on the Internet today and the volume is constantly increasing day by day. Most of these images are unlabeled and devoid of any keywords. The swift and continuous increase in the use of images and their unlabeled characteristics have demanded the need for efficient and accurate content-based image retrieval systems. A considerable number of such systems have been designed for the task that derive features from a query image and show the most similar images. One such efficient and accurate system is attempted in this paper which makes use of color and texture information of the images and retrieves the best possible results based on this information. The proposed method makes use of Color Coherence Vector (CCV) for color feature extraction and Gabor Filters for texture features. The results were found to be significantly higher and easily exceeded a few popular studies as well.

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An educational laboratory virtual instrumentation suite assisted experiment for studying fundamentals of series resistance-inductance-capacitance circuit

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EUROPEAN JOURNAL OF engineering EDUCATION 2017年第6期42卷 1220-1239页

作者： Rana, K. P. S. Kumar, Vineet Mendiratta, Jatin Instrumentation and Control Engineering Department Netaji Subhas Institute of Technology Dwarka New-Delhi India Instrumentation and Control Engineering Department Netaji Subhas Institute of Technology Dwarka New-Delhi India Deloitte Digital Deloitte Consulting US India Bangalore Karnataka India

One of the most elementary concepts in freshmen Electrical engineering subject comprises the Resistance-Inductance-Capacitance (RLC) circuit fundamentals, that is, their time and frequency domain responses. For a beginner, generally, it is difficult to understand and appreciate the step and the frequency responses, particularly the resonance. This paper proposes a student-friendly teaching and learning approach by inculcating the multifaceted versatile software LabVIEW (TM) along with the educational laboratory virtual instrumentation suite hardware, for studying the RLC circuit time and frequency domain responses. The proposed approach has offered an interactive laboratory experiment where students can model circuits in simulation and hardware circuits on prototype board, and then compare their performances. The theoretical simulations and the obtained experimental data are found to be in very close agreement, thereby enhancing the conviction of students. Finally, the proposed methodology was also subjected to the assessment of learning outcomes based on student feedback, and an average score of 8.05 out of 10 with a standard deviation of 0.471 was received, indicating the overall satisfaction of the students.

关键词： Electrical engineering resistance-inductance-capacitance circuit frequency response step response circuit simulation

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Effect of tool plunge depth on reinforcement particles distribution in surface composite fabrication via friction stir processing

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Defence technology（防务技术） 2017年第2期13卷 86-91页

作者： Sandeep Rathee Sachin Maheshwari Arshad Noor Siddiquee Manu Srivastava Division of Manufacturing Processes and Automation Engineering(MPAE) Netaji Subhas Institute of Technology Department of Mechanical Engineering Jamia Millia Islamia A Central University

Aluminium matrix surface composites are gaining alluring role especially in aerospace, defence, and marine industries. Friction stir processing(FSP) is a promising novel solid state technique for surface composites fabrication. In this study, AA6061/SiC surface composites were fabricated and the effect of tool plunge depth on pattern of reinforcement particles dispersion in metal matrix was investigated. Six varying tool plunge depths were chosen at constant levels of shoulder diameter and tool tilt angle to observe the exclusive effect of plunge variation. Process parameters chosen for the experimentation are speed of rotation, travel speed and tool tilt angle which were taken as 1400 rpm, 40 mm/min, and 2.5 °respectively. Macro and the microstructural study were performed using stereo zoom and optical microscope respectively. Results reflected that lower plunge depth levels lead to insufficient heat generation and cavity formation towards the stir zone center. On the other hand, higher levels of plunge depth result in ejection of reinforcement particles and even sticking of material to tool shoulder. Thus, an optimal plunge depth is needed in developing defect free surface composites.

关键词： Metal matrix composites Friction stir processing Tool plunge depth Microstructural characterization

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CRPO: Cognitive routing protocol for opportunistic networks 2017

CRPO: Cognitive routing protocol for opportunistic networks

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2017 International Conference on High Performance Compilation, Computing and Communications, HP3C 2017

作者： Gupta, Apoorv Bansal, Aman Naryani, Deepika Sharma, Deepak Kr. Division of Information Technology Netaji Subhas Institute of Technology University of Delhi India Division of Computer Engineering Netaji Subhas Institute of Technology University of Delhi India

ISBN: (纸本)9781450348683

Opportunistic networks (OppNets) provide an infrastructure-less environment for delivering messages from source to destination. However, random nature of network topologies, unstable node connections and many other factors make routing of messages difficult. Transfer of a message from source to destination depends on the opportunity available to the carrier node for its encounter with the destination. Hence, an intelligent store-carryforward paradigm needs to be defined which judicially transfers the message from source to the intermediate node till it reaches its destination. In this paper, a new routing protocol called Cognitive Routing Protocol for Opportunistic networks (CRPO) is proposed which makes intelligent decisions based on its past experiences and sensory inputs. It defines a neural network at each node and learns about the simulating environment with time for the successful delivery of messages. From simulation results, the authors observed that the proposed routing protocol outperforms traditional routing protocols such as Epidemic and PRoPHET, and an advanced routing protocol HBPR in terms of message delivery ratio, overhead ratio and number of messages getting dropped. © 2017 ACM.

关键词： Routing protocols

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An energy efficient routing protocol for wireless internet-of-things sensor networks

arXiv

引用

arXiv 2018年

作者： Vashishth, Vidushi Chhabra, Anshuman Khanna, Anirudh Sharma, Deepak Kumar Singh, Jyotsna Division of Electronics and Communication Engineering Netaji Subhas Institute of Technology University of Delhi New Delhi India Division of Information Technology Netaji Subhas Institute of Technology University of Delhi New Delhi India Department of Computer Science University of California Davis New Delhi India

Internet of Things (IoT) are increasingly being adopted into practical applications such as security systems, smart infrastructure, traffic management, weather systems, among others. While the scale of these applications is enormous, device capabilities, particularly in terms of battery life and energy efficiency are limited. Despite research being done to ameliorate these shortcomings, wireless IoT networks still cannot guarantee satisfactory network lifetimes and prolonged sensing coverage. Moreover, proposed schemes in literature are convoluted and cannot be easily implemented in real-world scenarios. This necessitates the development of a simple yet energy efficient routing scheme for wireless IoT sensor networks. This paper models the energy constraint problem of devices in IoT applications as an optimization problem. To conserve energy of devices the proposed protocol makes use of clustering, cluster head election and least energy-expensive path computation for efficient and realtime routing. The path computation involves using a formulated equation which characterizes communication intent between transmitter and receiver devices. The features selected for the clustering algorithm contribute towards optimizing the energy conservation effort. This paper also utilizes an evolutionary sleep scheduling technique which can be optionally used to further boost network efficiency. This technique combines the benefits of Particle Swarm Optimization (PSO) and Genetic Algorithm (GA). The proposed routing protocol has been simulated and compared with two existing routing protocols in terms of metrics such as number of active nodes, energy dynamics and network coverage. The simulation results prove that the proposed protocol outperforms LEACH and FCM. Copyright © 2018, The Authors. All rights reserved.

关键词： Energy efficiency

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An Efficient and Secure Authentication Scheme using Markov Chain for Wireless Sensor Networks

An Efficient and Secure Authentication Scheme using Markov C...

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IEEE International Advance Computing Conference, IACC

作者： Deepti Singh Bijendra Kumar Samayveer Singh Satish Chand Computer Engineering Department Netaji Subhas Institute of Technology New Delhi Department of Computer Science Engineering Bennett University Greater Noida School of computer and system sciences Jawaharlal Nehru University New Delhi

ISBN: (纸本)9781538666791;9781538666784

Due to varied applications of wireless sensor networks (WSNs), data is required by any user when and wherever they require. Usually, base station gathers all information from the sensor and sends it periodically to the user. But for real-time application, mutual authentication among the communicating nodes is required. During user authentication base station checks that the user is authorized to gather the collected information from the sensor node through an insecure channel. In this paper, we propose an efficient authentication scheme which provides anonymity of user in WSNs that uses Markov chain. The Markov chain is a stochastic process that can be used for a system in which it follows a chain of linked events but next event depends only on the current state of the system. Stationary limit distribution of matrix is created by the base station to help the user to keep their password and identity safe. The security analysis verifies that the proposed scheme is safe against various attacks like forgery, parallel session attacks, user impersonation, etc.

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PLCC System Performance with Complex Channel-Gain and QPSK Signaling

PLCC System Performance with Complex Channel-Gain and QPSK S...

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International Conference on Signal Processing and Integrated Networks (SPIN)

作者： Kamal Agrawal Ankur Bansal Department of Electrical Engineering Indian Institute of Technology Delhi New Delhi Division of ECE Netaji Subhas Institute of Technology New Delhi

This paper analyzes the performance of a power line carrier communication (PLCC) system under the effect of complex channel gain and additive background noise utilizing quadrature phase shift keying (QPSK) transmission scheme. The background noise considered here is complex in nature whose envelope is Nakagami-m distributed while phase follows uniform distribution. The magnitude and phase of complex channel gain coefficients are assumed to have Rayleigh and uniform distribution, respectively. Utilizing the sub-optimal decision rule for the real and imaginary parts of the complex data, and after deriving the expressions for the conditional probability density function (PDF) of the decision variables, we obtain a closed from expression for the conditional symbol error rate (SER) of the QPSK data for the considered system. Further, we analyze the outage performance of the considered PLCC system and derive the expression for conditional outage probability. The derived expressions of SER and outage probability are conditioned on the phase of the complex channel gain and the noise, which has been numerically averaged to get the analytical values for average SER and average outage probability. The analytical results presented in this paper have been verified by the simulations.

关键词： Phase shift keying Power system reliability Probability Probability density function Noise measurement Data communication Fading channels

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