Najeeb-ud-din Hakim

@nitsri.ac.in

Professor, Electronics and Communication Engineering
National Institute of Technology Srinagar



        

https://researchid.co/najeebuddin

RESEARCH, TEACHING, or OTHER INTERESTS

Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials

45

Scopus Publications

Scopus Publications

  • Analog-to-digital converters: a review of existing architectures and a new proposal for high resolution sensors
    Saima Bashir, Najeeb-ud-din Hakim, and G.M. Rather
    Emerald
    Purpose As technology advances the demand for an analog-to digital converter has increased, as every application demands a converter as per its parameters. Currently, work is done on improvement of data converters at three levels of design – architectural, circuit and physical level. This paper aims to review the work done in the field of analog-to-digital converters (ADCs) at architectural and circuit level and discusses the achievements in this field. Furthermore, a new architecture is proposed, which works at higher resolution and provides optimum design parameters at low power consumption. Design/methodology/approach A hybrid architecture combining the features of synthetic approximation register and sigma-delta ADC is presented. The validity of the proposed design at architectural level is verified using MATLAB SIMULINK simulations. Findings The design simulation was tested for a sinusoidal wave of 1 V at the test frequency of 60 Hz. The design consumes least power, and is found to yield an error of the order less than 10–3 V, thus providing highly accurate digital output. Originality/value The design is applicable in many applications including biomedical systems, Internet-of-Things and earthquake engineering. This architecture can be further optimized to obtain better performance parameters.


  • Prime turn model and first last turn model: An adaptive deadlock free routing for network-on-chips
    Misbah Manzoor, Roohie Naaz Mir, and Najeeb-ud-din Hakim
    Elsevier BV

  • Analytical Modeling of the Effect of Silver Nanoparticle Incorporation in Active Layer of an Organic Solar Cell
    Sakshi Koul and Najeeb-ud-din Hakim
    Institute of Electrical and Electronics Engineers (IEEE)
    The incomplete absorption of the incoming light radiation in the absorber layer of the organic solar cell (OSC) is a major issue in OSC technology. Persistent research is being carried out to address this issue and the incorporation of metallic nanoparticles (MNPs) has been considered a viable option. The presence of MNPs in the active layer of the cell enhances the absorption of light, thereby leading to increased cell efficiencies. An effort has been made to critically evaluate the incorporation of spherical silver nanoparticles in the active layer of a Poly (3-hexylthiophene): phenyl-C61-butyric acid methyl ester (P3HT:PCBM) based OSC. The optical properties of the active layer are affected by the incorporated MNPs. The MNPs with their characteristic absorption and scattering cross section affect the absorption capabilities of the active layer absorber material. The absorption coefficient of the active layer also gets modified because of the presence of the MNPs in it. An analytical model is proposed to describe the effect of the changing sizes of the incorporated MNPs on the absorption coefficient and the ensuing generation of charge carriers in the OSC. The generation to recombination rate ratio (G/R) has been coined as a performance parameter for the quantification of the effect of the introduction of MNPs in OSCs. This parameter has not been used earlier for the performance analysis of the MNP-incorporated OSCs.

  • A REVIEW OF DESIGN APPROACHES FOR ENHANCING THE PERFORMANCE OF NOCS AT COMMUNICATION CENTRIC LEVEL
    Misbah Manzoor, Roohie Naaz Mir, and Najeeb-ud-Din Hakim
    Scalable Computing: Practice and Experience
    As the trend of technology shrinking continues a vast amount of processors are being incorporated in a limited space. Due to this almost half of the chip area in Multi-Processor Systems-on-Chips (MPSoCs) is under interconnections, which pose a big problem for communication. Network-on-Chips (NoCs) evolved as a significant scalable solution for removing wiring congestion and communication problem in MPSoCs. NoCs provide the advantage of customized architecture, increased scalability and bandwidth. NoC is a structured framework where communication is the prime concern. In this review paper we present an overview of research and design approaches in the communication centric areas of NoCs. Here we have tried to discuss and iterate most of the available work done for communication in 2D NoCs. This paper gives the insight of different attributes and performance parameters of NoCs. Further it gives a detailed description of how topology, flow control and routing mechanisms can affect the qualitative aspects (performance) of NoCs. It then explains how various attributes of routing can help in increasing the efficacy of NoCs. Subsequently a brief review of different simulators used for NoCs is given. All of this is provided based on the survey of academic, theoretical and experimental approaches presented in the past. Finally some suggestions for future work are also given.

  • A simple analytical model for the resonant tunneling diode based on the transmission peak and scattering effect
    Sneh Lata Yadav and Hakim Najeeb-ud-din
    Springer Science and Business Media LLC




  • Fault-tolerant buffer aware round robin arbiter design for NoC architectures
    Afshan Khan et. al.
    Deanship of Scientific Research
    An arbiter is identified as one of the critical components of the NoC router. Among various arbitration schemes, Round-Robin arbiter is one among the popular arbitration schemes. In this work we have proposed an arbitration scheme that will be able to solve the problem of constant wait time of a conventional Round-Robin arbiter and will provided some additional features as well. The superiority of the proposed design is its ability to overcome this constant wait time, by identifying the real-time requirements of each port, based on information from respective buffers. The additional feature of the proposed algorithm is its fault-tolerant behavior for the errors related to buffer information. The proposed design is implemented using Vivado IDE and is verified on Zed-board Zynq-7000 FPGA platform. Simulation results reveal that the proposed algorithm has completely eradicated the drawback of constant wait time by performing arbitration dynamically. More importantly, it was observed that the proposed algorithm is tolerant to any temporary or permanent fault for deciding priorities. These major improvements in a Conventional round robin arbiter are achieved at the cost of 36% increase in area and a bonus 8% and 2% improvement in delay and operating frequency respectively.

  • Analytical model for the effects of the variation of ferrolectric material parameters on the minimum subthreshold swing in negative capacitance capacitor
    Raheela Rasool, Najeeb-ud-Din, and G. M. Rather
    IOP Publishing
    Abstract In this paper, we analytically study the relationship between the coercive field, remnant polarization and the thickness of a ferroelectric material, required for the minimum subthreshold swing in a negative capacitance capacitor. The interdependence of the ferroelectric material properties shown in this study is defined by the capacitance matching conditions in the subthreshold region in an NC capacitor. In this paper, we propose an analytical model to find the optimal ferroelectric thickness and channel doping to achieve a minimum subthreshold swing, due to a particular ferroelectric material. Our results have been validated against the numerical and experimental results already available in the literature. Furthermore, we obtain the minimum possible subthreshold swing for different ferroelectric materials used in the gate stack of an NC-FET in the context of a manufacturable semiconductor technology. Our results are presented in the form of a table, which shows the calculated channel doping, ferroelectric thickness and minimum subthreshold for five different ferroelectric materials.

  • A novel hardware-efficient spatial orientation tree-based image compression algorithm and its field programmable gate array implementation
    Mohd Rafi LONE and Najeeb-ud-Din HAKIM
    The Scientific and Technological Research Council of Turkey (TUBITAK-ULAKBIM) - DIGITAL COMMONS JOURNALS


  • The Effect of Shallow Trench Isolation and Sinker on the Performance of Dual-Gate LDMOS Device
    Suman Chahar, G. M. Rather, and Najeeb-ud-din Hakim
    Institute of Electrical and Electronics Engineers (IEEE)
    In this paper, a dual-gate laterally double-diffused metal–oxide–semiconductor (DG-LDMOS) device with shallow trench isolation (STI) and sinker at the source side has been proposed. STI and sinker help to provide isolation and reduce the leakage current, respectively, in the device. This is an improvement over a single-gate (SG) LDMOS device when only one gate is used and no STI and sinker are there. The study of both the devices has been carried out using the ATLAS SILVACO simulator. In the simulation studies, all the dimensions and doping parameters of both devices have been kept the same except gate length and channel doping. The distance between two gates of DG-LDMOS device has been kept smaller. This has been done to overcome the island and overlapping issues. The simulation studies have shown a significant improvement in DG-LDMOS device parameters in comparison to the SG-LDMOS device. The DG-LDMOS device provides high breakdown voltage, low ON-resistance, high <inline-formula> <tex-math notation="LaTeX">$f_{\\sf {T}}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$f_{\\sf {max}}$ </tex-math></inline-formula>, low drain-induced barrier lowering, and better output conductance as compared to conventional SG-LDMOS device. These features make the DG-LDMOS device an excellent candidate for RF applications.

  • Investigation on Chirping induced performance degradation in Single Mode Directly modulated 1.55um DFB laser
    Abida Yousuf and Hakim Najeeb-ud-din
    Walter de Gruyter GmbH
    Abstract Dynamic characteristics of directly modulated laser are investigated by simulating the single mode laser rate equations, emphasized on the effect of the gain compression for the two laser models: one adiabatic chirp dominated and another with a combination of adiabatic and transient chirp-dominated laser. The influence of laser adiabatic and transient chirp on system performance in normal and anomalous propagation regime is investigated by simulation. It is shown that in the anomalous propagation regime, the presence of fiber nonlinearity can be beneficial, improving the system performance by opening the eye diagram at system output. Contrarily, in the normal propagation regime, presence of high gain compression coefficient (ε &gt; 4 × 10–17 cm3) can strongly degrade the system performance by closing the eye diagram at system output. Finally, it is shown that the laser model with a combination of adiabatic and transient chirp with anomalous dispersion coefficient shows much better result in the saturated regime. This can be used to extend the transmission distance in optical communication.

  • Investigation on chirping characteristics of a 1.55-µm directly modulated distributed feedback laser
    Abida Yousuf and Hakim Najeeb-ud-din
    Springer Science and Business Media LLC



  • FPGA implementation of a low-power and area-efficient state-table-based compression algorithm for DSLR cameras
    Mohd Rafi LONE and Najeeb-ud-Din HAKIM
    The Scientific and Technological Research Council of Turkey (TUBITAK-ULAKBIM) - DIGITAL COMMONS JOURNALS
    Small image acquisition devices like digital single lens reflex (DSLR) cameras most commonly use Joint Photographic Expects Group (JPEG) coding standard for lossy compression. Although JPEG is a simple coding standard, its compression efficiency is very low as compared to any typical state-of-the-art image coding standards like set partitioning in hierarchical trees (SPIHT). In this paper, a novel state-table-based SPIHT (STS) algorithm and its field programmable gate array (FPGA) implementation is proposed. The STS uses two small state-tables and two extremely small lists. The STS not only provides better compression efficiency than the state-of-the-art JPEG 2000 at high bit rates but also requires very small memory to hold the state-tables and lists in comparison to SPIHT. On average STS requires 0.86\\% of the memory needed by SPIHT when evaluated for image sizes ranging from 4 Mpixels to 40 Mpixels. The implementation results show that STS consumes very less FPGA area in comparison to SPIHT-based architectures. The dynamic power dissipation of STS is also less than that of JPEG-like compression standards. This makes our proposed algorithm a better candidate for compression in low-power, low-memory digital image acquisition devices.

  • Buffer aware arbiter design to achieve improved QoS for NoC
    Afshan Amin Khan, Roohie Naaz Mir, and Najeeb-ud-din
    IEEE
    In order to meet the need for high-speed data processing, system designers have adopted Multi-Processor System-on-Chip (MPSoC) design. Network-on-chip (NoC) promises to be a viable solution as the basic communication fabric for such designs. A router is the basic component of NoC and using efficient internal blocks to design a router is expected to improve the performance of a router as a whole. One such block of prime importance is an arbitration unit. The commonly used arbitration logics include Fixed Priority, Lottery and Round Robin algorithm. However, they lack the capability of dynamically changing the priority according to data flit rates of specific ports. Thus a requester sending more requests can suffer from starvation and ultimately loss of data if not served within due course of time. In this work, we propose an improved Round Robin algorithm, for increasing Quality-of-Service (QoS) of a router. This is achieved by making use of an additional control signal from the buffer of each input port named as Buffer full (b_f). This addition will help us avoid the starvation condition of input ports which have more data flits to send than the lightly loaded input ports. The superiority of the proposed method than the conventional one is its feasibility for non-uniform traffic applications. All the circuits are implemented using Vivado 2016.2, with Zed-board as the target board. The proposed design is expected to find its application in areas where the traffic pattern is not certain and can vary from uniform to hot-spot traffic.

  • Effect of chirp characteristics of directly modulated laser on the signal transmission performance
    Abida Yousuf, Hakim Najeeb-ud-din, and Gausia Qazi
    IEEE
    The effect of chirp characteristics of directly modulated laser on the signal transmission performance is investigated by simulation. We have identified that negative dispersion shifted fiber shows performance improvement for both adiabatic and transient dominated laser. However, much better performance is observed in case of transient dominated laser. Finally equalizing fibers are inserted to compensate the further distortion induced by laser chirp and fiber nonlinearities. The simulation results suggest that by optimizing transmission fiber parameters and utilizing the repeaters after certain intervals, the performance will be further improved.

  • Comparison of parallel image scanning methods for achieving better throughput
    Mohammad Rafi and Najeeb-ud-Din
    IEEE
    Higher throughput is always desired in real time image processing applications. There are many ways to achieve higher throughput. However, if we have additional resources and memory bandwidth available, parallelism can be applied to achieve it. In this work, we have presented two image scanning methods that carry out parallelism to double the throughput of any architecture. Partitioned image scanning method divides the input image into two or more sub-images and then applies the desired filter function on each sub-image in parallel. Adjacent row scanning method provides the input to each filter alternatively, one accessing odd rows and the other even rows of the input image. From the results, it is evident that the resources utilized by partitioned image scanning method are more than that of adjacent row scanning method. The results show that adjacent row scanning method require approximately 20% lesser resources than that required by partitioned image scanning method.

  • Effect of mobility degradation on the device performance of organic thin-film transistor's
    Farkhanda Ana and Najeeb-ud-Din
    IEEE
    The quest for alternative materials to Silicon has lead the technological industry to introduce a new class of materials i.e. ‘organics’. The semiconducting properties of organic materials has made possible the realization of organic thin-film transistor (OTFT) which provides a major area of research in the device design technology. It is a well-known fact that OTFT's exhibit the Poole-Frenkel mobility mechanism wherein the material mobility increases with the increase in gate voltage. In this paper, an attempt is made to investigate the mobility behaviour of pentacene (intrinsic) based OTFT in bottom-contact configuration. The device characteristics are studied based on two-dimensional numerical simulation and analysis. Due to the grain structure of pentacene and interface charges, the material mobility degrades due to surface roughness and scattering phenomenon. These mobility degradation effects have been incorporated into the numerical analysis and it has been found that the device characteristics show a significant deviation from the linear trend at high gate voltages. The influence of mobility degradation on device performance parameter metrics i.e. VTH, GM and ION/IOFF has been studied and it has been found that there is substantial change in these parameters.


  • The effect of gain compression on the modulation characteristics of 1.55μm distributed feedback laser
    Abida Yousuf, Hakim Najeeb-ud-din, and Gausia Qazi
    IEEE
    The influence of gain compression on the modulation characteristics of a distributed feedback (DFB) laser is investigated. We simulate the single mode 1.55μm distributed feedback laser and the results show that the resonance frequency is reduced by gain compression. This limits the laser bandwidth to frequencies well below the relaxation oscillation frequency. It is shown that higher the maximum gain, lower the effects of gain compression. Therefore, by optimizing the parameters that control the maximum gain, the maximum laser bandwidth can be increased.