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    Power efficient nanophotonic on-chip network for future large scale multiprocessor architectures

    , Article Proceedings of the 2011 IEEE/ACM International Symposium on Nanoscale Architectures, NANOARCH 2011, 8 June 2011 through 9 June 2011, San Diego, CA ; 2011 , Pages 114-121 ; 9781457709944 (ISBN) Koohi, S ; Hessabi, S ; Sharif University of Technology
    2011
    Abstract
    This paper proposes new architectures for data and control planes in a nanophotonic networks-on-chip (NoC) with the key advantages of scalability to large scale networks, constant node degree, and simplicity. Moreover, we propose a minimal deterministic routing algorithm for the data network which leads to small and simple photonic switches. Built upon the proposed novel topology, we present a scalable all-optical NoC, referred to as 2D-HERT, which offers passive routing of optical data streams based on their wavelengths. Utilizing wavelength routing method, Wavelength Division Multiplexing (WDM) technique, and a new all-optical control architecture, our proposed optical NoC eliminates the... 

    Hierarchical opto-electrical on-chip network for future multiprocessor architectures

    , Article Journal of Systems Architecture ; Volume 57, Issue 1 , 2011 , Pages 4-23 ; 13837621 (ISSN) Koohi, S ; Hessabi, S ; Sharif University of Technology
    2011
    Abstract
    Importance of power dissipation in NoCs, along with power reduction capability of on-chip optical interconnects, offers optical network-on-chip as a new technology solution for on-chip interconnects. In this paper, we extract analytical models for data transmission delay, power consumption, and energy dissipation of optical and traditional NoCs. Utilizing extracted models, we compare optical NoC with electrical one and calculate lower bound limit on the optical link length below which optical on-chip network loses its efficiency. Based on this constraint, we propose a novel hierarchical on-chip network architecture, named as H2NoC, which benefits from optical transmissions in large scale... 

    Scalable architecture for a contention-free optical network on-chip

    , Article Journal of Parallel and Distributed Computing ; Volume 72, Issue 11 , 2012 , Pages 1493-1506 ; 07437315 (ISSN) Koohi, S ; Hessabi, S ; Sharif University of Technology
    2012
    Abstract
    This paper proposes CoNoC (Contention-free optical NoC) as a new architecture for on-chip routing of optical packets. CoNoC is built upon all-optical switches (AOSs) which passively route optical data streams based on their wavelengths. The key idea of the proposed architecture is the utilization of per-receiver wavelength in the data network to prevent optical contention at the intermediate nodes. Routing optical packets according to their wavelength eliminates the need for resource reservation at the intermediate nodes and the corresponding latency, power, and area overheads. Since passive architecture of the AOS confines the optical contention to the end-points, we propose an electrical... 

    Hierarchical on-chip routing of optical packets in large scale MPSoCs

    , Article Proceedings of the 18th Euromicro Conference on Parallel, Distributed and Network-Based Processing, PDP 2010, 17 February 2010 through 19 February 2010, Pisa ; 2010 , Pages 515-524 ; 9780769539393 (ISBN) Koohi, S ; Hessabi, S ; Sharif University of Technology
    2010
    Abstract
    In this paper, we extract analytical models for data transmission delay, power consumption, and energy dissipation of optical and traditional NoCs. Utilizing extracted models, we compare optical NoC with electrical one for varying values of link length and degree of multiplexing and calculate lower bound limit on the optical link length below which optical on-chip network loses its efficiency. Based on this constraint, we propose a novel hierarchical on-chip network architecture, named as H2NoC, which benefits from optical transmissions in large scale SoCs and overcomes the scalability problem resulted from lower bound limit on the optical link length. Performing a series of simulation-based... 

    All-optical wavelength-routed architecture for a power-efficient network on chip

    , Article IEEE Transactions on Computers ; Vol. 63, issue. 3 , 2014 , p. 777-792 Koohi, S ; Hessabi, S ; Sharif University of Technology
    2014
    Abstract
    In this paper, we propose a new architecture for nanophotonic Networks on Chip (NoC), named 2D-HERT, which consists of optical data and control planes. The proposed data plane is built upon a new topology and all-optical switches that passively route optical data streams based on their wavelengths. Utilizing wavelength routing method, the proposed deterministic routing algorithm, and Wavelength Division Multiplexing (WDM) technique, the proposed data plane eliminates the need for optical resource reservation at the intermediate nodes. For resolving end-point contention, we propose an all-optical request-grant arbitration architecture which reduces optical losses compared to the alternative... 

    Topology exploration of a thermally resilient wavelength-based ONoC

    , Article Journal of Parallel and Distributed Computing ; Volume 100 , 2017 , Pages 140-156 ; 07437315 (ISSN) Tinati, M ; Karimi, R ; Koohi, S ; Hessabi, S ; Sharif University of Technology
    Academic Press Inc  2017
    Abstract
    With the growing number of cores, high-performance systems face power challenges due to dominating communication power. Thus, attaining energy efficient high-bandwidth inter-core communication nominates photonic network-on chip as the most promising interconnection paradigm. Although photonic networks pave the way for extremely higher performance communications, their intrinsic susceptibility to thermal fluctuations intimidates reliability of system. This necessitates the development of methodologies to analyze and model thermal effects on network behavior. In this paper, we model temperature fluctuations of optical chips and analyze photonic networks in a holistic approach. We present a... 

    HELIOS: High-speed sequence alignment in optics

    , Article PLoS Computational Biology ; Volume 18, Issue 11 , 2022 ; 1553734X (ISSN) Maleki, E ; Akbari Rokn Abadi, S ; Koohi, S ; Sharif University of Technology
    Public Library of Science  2022
    Abstract
    In response to the imperfections of current sequence alignment methods, originated from the inherent serialism within their corresponding electrical systems, a few optical approaches for biological data comparison have been proposed recently. However, due to their low performance, raised from their inefficient coding scheme, this paper presents a novel all-optical high-throughput method for aligning DNA, RNA, and protein sequences, named HELIOS. The HELIOS method employs highly sophisticated operations to locate character matches, single or multiple mutations, and single or multiple indels within various biological sequences. On the other hand, the HELIOS optical architecture exploits... 

    All-optical wavelength-routed NoC based on a novel hierarchical topology

    , Article NOCS 2011: The 5th ACM/IEEE International Symposium on Networks-on-Chip, 1 May 2011 through 4 May 2011 ; May , 2011 , Pages 97-104 ; 9781450307208 (ISBN) Koohi, S ; Abdollahi, M ; Hessabi, S ; Sharif University of Technology
    2011
    Abstract
    This paper proposes a novel topology for optical Network on Chip (NoC) architectures with the key advantages of regularity, vertex symmetry, scalability to large scale networks, constant node degree, and simplicity. Moreover, we propose a minimal deterministic routing algorithm for the proposed topology which leads to small and simple photonic routers. Built upon our novel network topology, we present a scalable all-optical NoC, referred to as 2D-HERT, which offers passive routing of optical data streams based on their wavelengths. Utilizing wavelength routing method along with Wavelength Division Multiplexing technique, our proposed optical NoC eliminates the need for electrical resource... 

    An optical wavelength switching architecture for a high-performance low-power photonic NoC

    , Article Proceedings - 25th IEEE International Conference on Advanced Information Networking and Applications Workshops, WAINA 2011, 22 March 2011 through 25 March 2011 ; March , 2011 , Pages 1-6 ; 9780769543383 (ISBN) Koohi, S ; Shafaei, A ; Hessabi, S ; Sharif University of Technology
    2011
    Abstract
    The paper proposes a scalable wavelength-switched optical NoC, named as SWS-ONoC. The proposed architecture is built upon a novel all-optical router which passively routes optical data streams based on their wavelengths. Utilizing wavelength routing method, SWS-ONoC eliminates electrical transactions for optical resource reservation and hence, reduces latency and area overheads of the electrical units. The proposed architecture benefits from Wavelength Division Multiplexing (WDM) scheme to efficiently route multicast optical packets concurrent with unicast data streams. Performing a series of simulation-based experiments, we study efficiency of the proposed architecture, its power and energy... 

    Scalable architecture for wavelength-switched optical NoC with multicasting capability

    , Article Proceedings - 13th Euromicro Conference on Digital System Design: Architectures, Methods and Tools, DSD 2010, 1 September 2010 through 3 September 2010, Lille ; 2010 , Pages 398-403 ; 9780769541716 (ISBN) Koohi, S ; Shafaei, A ; Hessabi, S ; Sharif University of Technology
    2010
    Abstract
    This paper proposes a novel all-optical router as a building block for a scalable wavelength-switched optical NoC. The proposed optical router, named as AOR, performs passive routing of optical data streams based on their wavelengths. Utilizing wavelength routing method, AOR eliminates the need for electrical resource reservation and the corresponding latency and area overheads. Taking advantage of Wavelength Division Multiplexing (WDM) technique, the proposed architecture is capable of data multicasting, concurrent with unicast data transmission, with high bandwidth and low power dissipation, without imposing noticeable area and latency overheads. Comparing AOR against previously proposed... 

    ONC3: All-optical NoC based on cube-connected cycles with quasi-DOR algorithm

    , Article Proceedings - 15th Euromicro Conference on Digital System Design, DSD 2012 ; 2012 , Pages 296-303 ; 9780769547985 (ISBN) Abdollahi, M ; Tavana, M. K ; Koohi, S ; Hessabi, S ; Sharif University of Technology
    2012
    Abstract
    This paper proposes a nanophotonic Network-on-Chip architecture based on the traditional Cube-Connected Cycles topology (CCC), which is named as ONC3. We also suggest a contention-free quasi-Dimension-Order-Routing algorithm for the proposed structure. Compared to the previous 2D layouts, our novel scheme lessens the crosstalk parameter of the insertion loss and consequently, the power consumption. Besides, the router structure is area-efficient. On the other hand, optical destination checking supersedes electrical resource reservation, with utilizing passive wavelength routing method and Wavelength Division Multiplexing scheme, simultaneously. The efficiency of the proposed architecture, in... 

    Evaluation of traffic pattern effect on power consumption in mesh and torus network-on-chips

    , Article 2007 International Symposium on Integrated Circuits, ISIC, Singapore, 26 September 2007 through 28 September 2007 ; 2007 , Pages 512-515 ; 1424407974 (ISBN); 9781424407972 (ISBN) Koohi, S ; Mirza Aghatabar, M ; Hessabi, S ; Sharif University of Technology
    2007
    Abstract
    Technology scaling increases clock rates and die sizes; therefore, power dissipation is predicted to soon become the key limiting factor on the performance of single-chip designs. NoC as an efficient and scalable on-chip communication architecture for SoC architectures, enables integration of a large number of computational and storage blocks on a single chip. Since different applications impose different traffic models to the network, in this paper we will analyze the power and energy consumption of the most popular traffic models, i.e., Uniform, Local, HotSpot and First Matrix Transpose, in two famous and well designed topologies, mesh and torus. We will also compare these topologies with... 

    Energy efficient all-optical arbitration in optical network-on-chip

    , Article 2012 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2012 ; 2012 ; 9781467302623 (ISBN) Koohi, S ; Yin, Y ; Hessabi, S ; Yoo, S. J. B ; Sharif University of Technology
    2012
    Abstract
    We propose an all-optical arbitration architecture to resolve end-point contention in the optical networks-on-chip. The proposed architecture reduces on-chip optical power and energy losses by 37% and 21%, respectively, compared to Corona's token-based control plane  

    HFOS L : hyper scale fast optical switch-based data center network with L-level sub-network

    , Article Telecommunication Systems ; Volume 80, Issue 3 , 2022 , Pages 397-411 ; 10184864 (ISSN) Khani, E ; Hessabi, S ; Koohi, S ; Yan, F ; Calabretta, N ; Sharif University of Technology
    Springer  2022
    Abstract
    The ever-expanding growth of internet traffic enforces deployment of massive Data Center Networks (DCNs) supporting high performance communications. Optical switching is being studied as a promising approach to fulfill the surging requirements of large scale data centers. The tree-based optical topology limits the scalability of the interconnected network due to the limitations in the port count of optical switches and the lack of optical buffers. Alternatively, buffer-less Fast Optical Switch (FOS) was proposed to realize the nanosecond switching of optical DCNs. Although FOSs provide nanosecond optical switching, they still suffer from port count limitations to scale the DCN. To address... 

    All-optical DNA variant discovery utilizing extended DV-curve-based wavelength modulation

    , Article Journal of the Optical Society of America A: Optics and Image Science, and Vision ; Volume 35, Issue 11 , 2018 , Pages 1929-1940 ; 10847529 (ISSN) Maleki, E ; Babashah, H ; Koohi, S ; Kavehvash, Z ; Sharif University of Technology
    OSA - The Optical Society  2018
    Abstract
    This paper presents a novel optical processing approach for exploring genome sequences built upon an optical correlator for global alignment and the extended dual-vector-curve-curve (DV-curve) method for local alignment. To overcome the problem of the traditional DV-curve method for presenting an accurate and simplified output, we propose the hybrid amplitude wavelength polarization optical DV-curve (HAWPOD) method, built upon the DV-curve method, to analyze genome sequences in three steps: DNA coding, alignment, and post-Analysis. For this purpose, a tunable graphene-based color filter is designed for wavelength modulation of optical signals. Moreover, all-optical implementation of the... 

    Speeding up DNA sequence alignment by optical correlator

    , Article Optics and Laser Technology ; Volume 108 , 2018 , Pages 124-135 ; 00303992 (ISSN) Mozafari, F ; Babashah, H ; Koohi, S ; Kavehvash, Z ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    In electronic computers, extensive amount of computations required for searching biological sequences in big databases leads to vast amount of energy consumption for electrical processing and cooling. On the other hand, optical processing is much faster than electrical counterpart, due to its parallel processing capability, at a fraction of energy consumption level and cost. In this regard, this paper proposes a correlation-based optical algorithm using metamaterial, taking advantages of optical parallel processing, to efficiently locate the edits as a means of DNA sequence comparison. Specifically, the proposed algorithm partitions the read DNA sequence into multiple overlapping intervals,... 

    High-speed all-optical DNA local sequence alignment based on a three-dimensional artificial neural network

    , Article Journal of the Optical Society of America A: Optics and Image Science, and Vision ; Volume 34, Issue 7 , 2017 , Pages 1173-1186 ; 10847529 (ISSN) Maleki, E ; Babashah, H ; Koohi, S ; Kavehvash, Z ; Sharif University of Technology
    OSA - The Optical Society  2017
    Abstract
    This paper presents an optical processing approach for exploring a large number of genome sequences. Specifically, we propose an optical correlator for global alignment and an extended moiré matching technique for local analysis of spatially coded DNA, whose output is fed to a novel three-dimensional artificial neural network for local DNA alignment. All-optical implementation of the proposed 3D artificial neural network is developed and its accuracy is verified in Zemax. Thanks to its parallel processing capability, the proposed structure performs local alignment of 4 million sequences of 150 base pairs in a few seconds, which is much faster than its electrical counterparts, such as the... 

    Integration in analog optical computing using metasurfaces revisited: toward ideal optical integration

    , Article Journal of the Optical Society of America B: Optical Physics ; Volume 34, Issue 6 , 2017 , Pages 1270-1279 ; 07403224 (ISSN) Babashah, H ; Kavehvash, Z ; Koohi, S ; Khavasi, A ; Sharif University of Technology
    OSA - The Optical Society  2017
    Abstract
    In this paper, we introduce a modified optical integrator based on suitably designed metamaterial blocks. The integration is performed on an impinging wave pattern as it propagates through these blocks. So far, various metamaterial-based optical integrators have been implemented with appropriate performance in the case of zero- DC input signals. However, these integrators suffer from low accuracy when fed by signals rich in low-frequency contents. The latter property arises from truncation of low-frequency contents of the input wave in the Fourier domain. To solve this shortcoming, we propose a new metasurface-based structure which reflects low-frequency parts of the input signal in the... 

    Temporal analog optical computing using an on-chip fully reconfigurable photonic signal processor

    , Article Optics and Laser Technology ; Volume 111 , 2019 , Pages 66-74 ; 00303992 (ISSN) Babashah, H ; Kavehvash, Z ; Khavasi, A ; Koohi, S ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    This paper introduces the concept of on-chip temporal optical computing, based on dispersive Fourier transform and suitably designed modulation module, to perform mathematical operations of interest, such as differentiation, integration, or convolution in time domain. The desired mathematical operation is performed as signal propagates through a fully reconfigurable on-chip photonic signal processor. Although a few numbers of photonic temporal signal processors have been introduced recently, they are usually bulky or they suffer from limited reconfigurability which is of great importance to implement large-scale general-purpose photonic signal processors. To address these limitations, this... 

    Video cut detection in E-learning applications

    , Article 2007 9th International Symposium on Signal Processing and its Applications, ISSPA 2007, Sharjah, 12 February 2007 through 15 February 2007 ; 2007 ; 1424407796 (ISBN); 9781424407798 (ISBN) Koohi, S ; Babagoli, M ; Lotfi, T ; Kasaei, S ; Sharif University of Technology
    2007
    Abstract
    Real-time video transmission is considered as an important means for information distribution. One major application of it is E-learning, which requires real-time video processing and transmission. On the other hand, the process of cut detection is a fundamental component in automatic video browsing, indexing, searching, retrieval, and archiving. This paper introduces a new video cut detection technique that uses dominant lines and angles extracted from edge information of the video contents. To the best of our knowledge, it is the first works done for cut detection in E-learning application. This method is compatible with our application's requirements and has a low complexity and high...