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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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A Low Power Hybrid CMOS-Memristor based Ring Oscillator for Hardware Security Applications

A Low Power Hybrid CMOS-Memristor based Ring Oscillator for ...

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IEEE International Conference on Recent Trends in Electronics, Information & Communication technology (RTEICT)

作者： Abhinav Sharma Kunwar Singh Puneet Singh Khurana Division of Electronics and Communication Engineering Netaji Subhas Institute of Technology New Delhi India

ISBN: (数字)9781538624401

ISBN: (纸本)9781538624418

This paper proposes implementation of a low power hybrid CMOS-Memristor Ring Oscillator (RO), with a higher randomness value compared to existing technologies. A comparison of conventional CMOS inverter, memristive load inverter and a two memristor inverter based RO is done in terms of frequency of oscillation, power consumption and the randomness in oscillation frequency. Memristors because of their non-volatile nature, compatibility with CMOS technology and low area and power consumption are being widely used for low power VLSI design. This concept is well supported with the simulation results. Randomness for the proposed two memristor based RO is found to be 51.16μ which is 2.065x and 1.596x of the CMOS based RO and memristive load based RO respectively. The power consumption of the circuit is highly improved. Maximum power of the design is reported as 270μW which is 86.4% and 35.25% lesser than that of the CMOS and memristive load based designs respectively.

关键词： Memristors Inverters Delays Ring oscillators Security Power demand Jitter

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A Hybrid CMOS-Memristor based Programmable Wien Bridge Oscillator

A Hybrid CMOS-Memristor based Programmable Wien Bridge Oscil...

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IEEE International Conference on Recent Trends in Electronics, Information & Communication technology

作者： Puneet Singh Khurana Kunwar Singh Abhinav Sharma Division of Electronics and Communication Engineering Netaji Subhas Institute of Technology New Delhi India

ISBN: (数字)9781538624401

ISBN: (纸本)9781538624418

This paper presents a novel programmable Wien Bridge Oscillator (WBO) using hybrid CMOS-Memristor circuit to generate required frequency based on memristor programmability. The memristor consumes very small area at nanoscale level and it offers the programmability of its resistance, the memristance. For these reasons, memristors are being extensively used in several electronic circuits for e.g., oscillators. This kind of programmability feature offered by the memristors enables their utilization in programmable circuits controlled by digital pulses. The programmable memristors used in the proposed WBO at the non-inverting side provide variation of frequency at various values of memresistance whereas programmable memristors at the inverting end vary the gain of the oscillator. The frequency variation achieved is 50 kHz to 6 kHz by varying the memristors from 10 kΩ to 80 kΩ, which is in close agreement to the theoretical frequency with an error of less than ±1%. The circuit simulations are performed using 180 nm CMOS technology.

关键词： Memristors Oscillators Resonant frequency Mathematical model Threshold voltage Integrated circuit modeling

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Frequency band implementation of non-integer order functions

Frequency band implementation of non-integer order functions

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International Conference on Signal Processing and Integrated Networks (SPIN)

作者： Nitisha Shrivastava Pragya Varshney Division of Instrumentation & Control Engineering Netaji Subhas Institute of Technology New Delhi India

The role of non-integer calculus in the fields of signal processing, control and automation is gradually gaining high importance due to its additional degree of freedom. In this paper we focus on frequency band approximations of non-integer order differentiators and integrators in s-domain. The implementation of non-integer order proportional plus integral plus derivative (PID) controller to control a plant model is presented. This is done by first approximating the non-integer order terms to a finite value using different approximation techniques and then decomposing the finite model to obtain the circuit elements. The frequency response analysis of the approximated model is presented and it is shown that the number of circuit elements depends on the approximation technique. The time domain analysis of the closed loop system is presented by plotting the step response. The simulations have been performed using MATLAB and OrCAD Capture CIS simulator.

关键词： Mathematical model Frequency control Integrated circuit modeling Finite element analysis Signal processing Poles and zeros

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Redaction of Protected Health Information in EHRs using CRFs and Bi-directional LSTMs

Redaction of Protected Health Information in EHRs using CRFs...

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International Conference on Reliability, Infocom Technologies and Optimization (ICRITO) (Trends and Future Directions)

作者： Apar Madan Ann Mary George Apurva Singh M.P.S. Bhatia Divison of Computer Engineering Netaji Subhas Institute of Technology University of Delhi New Delhi India

ISBN: (纸本)9781538646939

This paper describes the de-identification of personally identifiable information (PIIs) in electronic health records (EHRs) using two models of conditional random fields (CRFs) and bidirectional long short term memory networks (LSTMs). Most medical records store private information such as PATIENT NAME, HOSPITAL NAME, LOCATION, etc. that needs to be de-identified or redacted before being passed on for further medical research. The process of removing such information using machine learning techniques is started with pre-processing of raw data by tokenization and detection of sentences. On comparing the techniques, it is noted that CRFs require manual feature engineering to train the model whereas LSTM is capable of handling long term dependencies without much insight about the dataset. Bi-directional LSTM network was used to generate context information from suitable word representations. Finally, a predictive layer was applied to predict the protected health information (PHI) terms having maximum probability. Evaluated with the i2b2 gold data set of clinical narratives of patients of 2014 De-identification challenge, we propose an efficient solution for redaction using two models, both of which achieve good F-scores for PHIs of all types. The LSTM-based model achieved a micro-F1 measure of 0.9592, which performs better than the CRF-based model.

关键词： Hidden Markov models Labeling Task analysis Logic gates Tagging Feature extraction Microsoft Windows

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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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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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Control of a two link planar electrically-driven rigid robotic manipulator using fractional order SOFC 3rd

Control of a two link planar electrically-driven rigid robot...

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3rd International Conference on Advanced Intelligent Systems and Informatics, AISI 2017

作者： Azar, Ahmad Taher Kumar, Jitendra Kumar, Vineet Rana, K.P.S. Faculty of Computers and Information Benha University Banha Egypt Nile University 6th of October City Egypt Division of instrumentation and control Engineering Netaji Subhas Institute of Technology DwarkaNew Delhi110078 India

ISBN: (纸本)9783319648606

An intelligent adaptive fuzzy logic control technique, Fractional Order Self Organizing Fuzzy Controller (FOSOFC) is presented and applied to control a two link planar electrically-driven rigid robotic (EDRR) manipulator system. As EDRR is a multi-input multi-output complex nonlinear system, an intelligent adaptive controller, FOSOFC is considered to control it perfectly. To show the efficacy of the FOSOFC controller, the obtained performance is compared with fractional order fuzzy proportional integral and derivative (FOFPID) controller for study in servo as well as the regulatory problems. Gains of the controllers are tuned by a meta-heuristic bio-inspired algorithm namely Cuckoo Search Algorithm. Based on the trajectory tracking and disturbance rejection (DR) performances, efficiency of controllers has been accessed and it has been found that FOSOFC outperforms on FOFPID controller. © 2018, Springer International Publishing AG.

关键词： Controllers

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

arXiv

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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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Leveraging polarity switches and domain ontologies for sentiment analysis in text 1

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1st International Conference on Computational Intelligence, Communications, and Business Analytics, CICBA 2017

作者： Sharma, Srishti Chakraverty, Shampa Jauhari, Anisha Department of Computer Engineering Netaji Subhas Institute of Technology New Delhi India

ISBN: (数字)9789811064272

ISBN: (纸本)9789811064265

This paper proposes an approach for Sentiment Analysis on online textual reviews that leverages polarity switches and domain ontologies to first perform Aspect Based Sentiment Analysis and uses it to then refine the overall sentiment scores. It segregates the review text into different fragments using sentiment polarity switching information. Then, it maps each of these fragments with the domain ontology to determine the aspect each fragment refers to and carries out corresponding Aspect Based Sentiment Analysis. Finally, the sentiments from all the aspects are clubbed together taking into account the hierarchical level of aspects in the domain ontology to refine the overall review polarity. Hontology was used to map the textual fragments to different aspects in the hotel domain like service, room, etc. Experiments carried out in the hotel domain on 800 hotel reviews extracted from Tripadvisor, Yelp, Expedia, Orbitz, *** and Priceline show that Aspect Based SA and domain ontologies together can indeed be used to refine SA. The macro level F1 score for the proposed approach is 3.96% higher than the baseline approach. © Springer Nature Singapore Pte Ltd 2017.

关键词： Sentiment analysis

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