Mehboob Alam

RLC Ladder Model for Scattering in Single Metallic Nanoparticles

In this paper, we present a new modeling technique for plasmon-based metallic nanoparticles under the influence of an electromagnetic field. The model approximates the coefficients of the admittance rational function. The proposed model utilizes spherical wave functions to describe the field and it provides an equivalent ladder-form RLC realization. Simulation results show that our model matches very closely with the exact solution. Our newly developed model can be used as a basic building block to develop an equivalent circuit model for metallic nanoparticle-based plasmonic waveguides

A closed-form analytical model for single nanoshells

In this paper, we develop an accurate analytical closed-form model for the frequency resonance and scattering characteristics of single nanoshells. Nanoshells, dielectric spheres that are coated with noble metal, possess excellent tunability of their resonance frequency as a function of the relative sizes of the core and the thickness of the shell. Consequently, nanoshells offer much improved sensitivity, specificity, and cost-effectiveness in their applications. Simulation results show that our new closed-form model matches very closely with the exact solution for typical nanoshell configurations used in near-infrared applications.

Efficient distributed arithmetic based DWT architecture for multimedia applications

This paper presents a novel architecture for 9/ Discrete Wavelet Transform (DWT) based on Distributed Arithmetic (DA). The proposed architecture optimizes the performance by exploiting the computational redundancy. The DWT inner product of coefficient matrix is distributed over the input by careful analysis of input, output and coefficients word lengths. In the coefficient matrix, linear maps are used to assign the necessary computation processing elements in space domain. The result is a low hardware complexity DWT processor for 9/7 transforms, which allows two times faster clock than the direct implementation. In the proposed architecture reducing the clock frequency by two or the supply voltage and maintaining the same throughput as of other architecture achieve the low power by a factor of four. The proposed architecture is therefore scalable and can operate at high speed / consumes low power and has reduced computational complexity (improvement of 77.6% over filter based and 40.27% over lifted based architectures) as compared to already published 9/7 biorthogonal wavelet architectures.

Wavelet-Based Passivity Preserving Model Order Reduction for Wideband Interconnect Characterization

Model order reduction plays a key role in determining VLSI system performance and the optimization of interconnects. In this paper, the authors develop an accurate and provably passive method for model order reduction using adaptive wavelet-based frequency selective projection. The wavelet-based approach provides an automated means to generate low order models that are accurate in a particular range of frequencies. The results indicate that our approach provides more accurate reduced order models than the spectral zero method with uniform interpolation points and the zero-shift and multi-shift Block Arnoldi-based techniques

An accurate closed-form analytical model of single nanoshells for cancer treatment

Recently, there have been significant experimental advances in cancer treatment using metallic nanoshells, which are silica spheres coated with gold. Nanoshells posses an excellent tunability of their resonance frequency as a function of the relative sizes of the core and the thickness of the shell, consequently offering much improved sensitivity, specificity, and cost-effectiveness in cancer treatment. In this paper, we develop an accurate analytical closed-form model for the frequency resonance and scattering characteristics of single nanoshells. The closed-form model helps to intuitively explain the optical properties of the nanoshells. Simulation results show that the new model matches very closely with the exact solution for typical nanoshell configurations used in cancer treatment. The developed model ultimately allows for the real-time detection, monitoring and treatment of cancer using nanoshells.

On the Selection of Spectral Zeros for Generating Passive Reduced Order Models

As process technology continues to scale into the nanoscale regime, passive components and interconnect plays an ever increasing role in realization of mixed-signal systems. In this paper, the authors develop a new method for the model order reduction of passive components and interconnect using frequency selective projection methods with interpolation points based on the spectral-zeros of the RLC interconnect models transfer function. The methodology uses imaginary part of the spectral zeros for frequency selective adaptive projection and provides stable as well as passive reduced order models. The results indicate that our method provides more accurate approximations than techniques based on balanced truncation and moment matching

An RLC Ladder Model for the Equivalent Impedance of Single Metal Nanoparticles in Electromagnetic Field

In this paper, we present a new modeling technique for plasmon-based metal single nanoparticles under the influence of electromagnetic field. A model based on continued fractions is derived to approximate the coefficients of the admittance rational function. The proposed model utilizes spherical wave functions to describe the field and it provides an equivalent ladder-form RLC realization. Simulation results show that our model matches very closely with the exact solution

A novel pipelined threads architecture for AES encryption algorithm

This paper presents a single-chip parallel architecture for advanced encryption standard (AES). The proposed architecture uses the thread approach, which integrates fully pipelined parallel units, that process 128 bits/cycle and quadruples the data throughput. The threads architecture allows a reduction of the clock rate by a factor of four, while maintaining the data throughput, and consumes less power. The prototype runs at a data rate of 7.68 Gbps on a Xilinx xc2V1500 Virtex-II FPGA. The data rate shows that the proposed thread approach produces one of the fastest single-chip FPGA implementations currently available. In addition, the proposed architecture is scalable to 192, 256 and higher bits.

A new time distributed DCT architecture for MPEG-4 hardware reference model

This paper presents the design of a new time distributed architecture (TDA) which outlines the architecture (ISO/IEC JTC1/SC29/WG11 MPEG2002/M8565) submitted to MPEG4 Part9 committee and included in the ISO/IEC JTC1/SC29/WG11 MPEG2002/9115N document. The proposed TDA optimizes the two-dimensional discrete cosine transform (2-D-DCT) architecture performance. It uses a time distribution mechanism to exploit the computational redundancy within the inner product computation module. The application specific requirements of input, output and coefficients word length are met by scheduling the input data. The coefficient matrix uses linear mappings to assign necessary computation to processor elements in both space and time domains. The performance analysis shows performance savings in excess of 96% as compared to the direct implementation and more than 71% as compared to other optimized application specific architectures for DCT.

Frequency Selective Model Order Reduction via Spectral Zero Projection

As process technology continues to scale into the nanoscale regime, interconnect plays an ever increasing role in determining VLSI system performance. As the complexity of these systems increases, reduced order modeling becomes critical. In this paper, we develop a new method for the model order reduction of interconnect using frequency restrictive selection of interpolation points based on the spectral-zeros of the RLC interconnect models transfer function. The methodology uses the imaginary part of spectral zeros for frequency selective projection and provides stable as well as passive reduced order models for interconnect in VLSI systems. For large order interconnect models with realistic RLC parameters, the results indicate that our method provides more accurate approximations than techniques based on balanced truncation and moment matching with excellent agreement with the original systems transfer function.