scholarly journals Design Space of Flexible Multigigabit LDPC Decoders

VLSI Design ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Philipp Schläfer ◽  
Christian Weis ◽  
Norbert Wehn ◽  
Matthias Alles
Keyword(s):  
Design Space ◽  
State Of The Art ◽  
Cmos Technology ◽  
Systematic Investigation ◽  
Design Parameters ◽  
Ldpc Decoder ◽  
The Past ◽  
Ieee 802.11Ad ◽  
Decoder Design ◽  
First Time

Multigigabit LDPC decoders are demanded by standards like IEEE 802.15.3c and IEEE 802.11ad. To achieve the high throughput while supporting the needed flexibility, sophisticated architectures are mandatory. This paper comprehensively presents the design space for flexible multigigabit LDPC applications for the first time. The influence of various design parameters on the hardware is investigated in depth. Two new decoder architectures in a 65 nm CMOS technology are presented to further explore the design space. In the past, the memory domination was the bottleneck for throughputs of up to 1 Gbit/s. Our systematic investigation of column- versus row-based partially parallel decoders shows that this is no more a bottleneck for multigigabit architectures. The evolutionary progress in flexible multigigabit LDPC decoder design is highlighted in an extensive comparison of state-of-the-art decoders.

scholarly journals High Throughput and Resource Efficient Pipelined Decoder Designs for Projective Geometry LDPC Codes

2019 ◽  
Vol 64 (2) ◽  
pp. 179-191
Author(s):  
Ved Mitra ◽  
Mahesh C. Govil ◽  
Girdhari Singh ◽  
Sanjeev Agrawal
Keyword(s):  
Projective Geometry ◽  
Critical Path ◽  
Ldpc Codes ◽  
Cmos Technology ◽  
Quantization Scheme ◽  
Path Delay ◽  
Bit Rate ◽  
Error Performance ◽  
Ldpc Decoder ◽  
Decoder Design

Projective geometry (PG) based low-density parity-check (LDPC) decoder design using iterative sum-product decoding algorithm (SPA) is a big challenge due to higher interconnection and computational complexity, and larger memory requirement caused by relatively higher node degrees. PG-LDPC codes using SPA exhibits the best error performance and faster convergence. This paper presents an efficient novel decoding method, modified SPA (MSPA) that not only shortens the critical-path delay but also improves the hardware utilization and throughput of the decoder while maintaining the error performance of SPA. Three fully-parallel LDPC decoder designs based on PG structure, PG(2,GF( 2s )) of LDPC codes are introduced. These designs differ in their bit-node (BN) and check-node (CN) architectures. Fixed-point, 9-bit quantization scheme is used to achieve better error performance. Another significant contribution of this work is the pipelining of the proposed decoder architectures to further enhance the overall throughput. These parallel and pipelined designs are implemented for 73-bit (rate 0.616) and 1057-bit (rate 0.769) regular-structured PG-LDPC codes, on Xilinx Virtex-6 LX760 FPGA and on 0.18 μm CMOS technology for ASIC. Synthesis and simulation results have shown the better performance, throughput and effectiveness of the proposed designs.

A Systematic Investigation of State-of-the-Art SystemC Verification

2020 ◽  
Vol 29 (15) ◽  
pp. 2030013
Author(s):  
Bin Lin ◽  
Fei Xie
Keyword(s):  
Design Process ◽  
State Of The Art ◽  
Electronic System ◽  
Systematic Investigation ◽  
System Level ◽  
Data Types ◽  
Time To Market ◽  
The Past ◽  
Electronic System Level ◽  
Functional Correctness

The growing complexity of System-on-a-Chips (SoCs) and rapidly decreasing time-to-market have pushed the design abstraction to the electronic system level in order to increase design productivity. SystemC is a widely used electronic system level modeling language that enables quick prototyping and early verification in the SoC design process. The functional correctness of SystemC designs is often one of the greatest concerns in the SoC design process, since undetected design errors may propagate to low-level implementations or even final silicon products, which are costly to fix. However, SystemC verification is a challenging task due to its complex language features such as object-oriented constructs, hardware-oriented data types and concurrency. A variety of approaches have been proposed for SystemC verification in the past two decades. This work systematically investigates the state-of-the-art SystemC verification approaches by discussing their methodologies, advantages, and limitations, as well as presenting comparison among various approaches.

Surrogate-Based Optimisation for a Mixed-Variable Design Space: Proof of Concept and Opportunities for Turbomachinery Applications

2015 ◽  
Author(s):  
Lieven Baert ◽  
Charlotte Beauthier ◽  
Michaël Leborgne ◽  
Ingrid Lepot
Keyword(s):  
Design Space ◽  
State Of The Art ◽  
Design Parameters ◽  
High Fidelity ◽  
Proof Of Concept ◽  
Conceptual Design Phase ◽  
Interesting Approach ◽  
Turbomachinery Design ◽  
Mixed Variable ◽  
Mixed Nature

State-of-the-art turbomachinery design processes rely more and more on the extensive use of numerical simulations. To deal with expensive high-fidelity computations, surrogate-based optimisation (SBO) has become a very interesting approach. In order to cope with industrial cases, the capability to handle variables of a mixed nature appears key. Innovative and auto-adaptive surrogates have been implemented within Minamo that are capable of natively handling the different natures of the design parameters. The present work discusses this mixed-variable SBO framework applied to a multi-profile combinational problem inside the bypass duct. A proof of concept is given followed by a more advanced application. It is demonstrated that the proposed mixed-variable SBO efficiently delivers reliable results and that it offers many opportunities during a conceptual design phase.

scholarly journals Anomeric stereoauxiliary strategy enables efficient synthesis of wide-ranging imidazo[1,5-α]pyridines

2021 ◽  
Author(s):  
Kui Zeng ◽  
Jin Ye ◽  
Xintong Meng ◽  
Sebastian Dechert ◽  
Martin Simon ◽  
...  
Keyword(s):  
Heterocyclic Compounds ◽  
State Of The Art ◽  
Biomass Conversion ◽  
Synthetic Approach ◽  
Efficient Synthesis ◽  
The Past ◽  
Tremendous Progress ◽  
First Time ◽  
Structure Calculations ◽  
Ring Transition State

Abstract Imidazo[1,5-α]pyridines are one of the most important groups of N-heterocyclic compounds, with wide applications in pharmaceutics, chemical science and material science. Despite tremendous progress in their synthesis over the past decade, a number of important imidazo[1,5-α]pyridines as intermediate products remain inaccessible, such as 1-alkylimidazo[1,5-α]pyridines. Herein, we report a novel anomeric stereoauxiliary approach for the preparation of this important class of compounds. It strongly expands the scope of readily accessible imidazo[1,5-α]pyridines well beyond the existing state-of-the-art methods. More than 80 products with a substantial number of deemed unattainable ones were synthesized. With the first time accessibility to alkyl(pyridine-2-yl)methanone substrates, a group of important deuterated imidazo[1,5-α]pyridines derivatives were also efficiently achieved. The mechanism containing a key seven-membered ring transition state via α-anomeric stereoauxiliary for this new synthetic pathway is provided in great detail and supported by electronic structure calculations. In total, this novel synthetic approach for a broad range of imidazo[1,5-α]pyridines involving the native stereochemistry will open a new window for research endeavors in diverse fields, encompassing organic synthesis, biomass conversion via cleavage of C-N bonds and medicinal chemistry.

Optical Properties of HVEM Accelerators

1975 ◽  
Vol 33 ◽  
pp. 180-181
Author(s):  
A. Strojnik ◽  
J.W. Scholl ◽  
V. Bevc
Keyword(s):  
Optical Properties ◽  
Electron Accelerator ◽  
Systematic Investigation ◽  
Electron Source ◽  
High Brightness ◽  
The Past ◽  
Wide Range ◽  
Optical Behavior

The electron accelerator, as inserted between the electron source (injector) and the imaging column of the HVEM, is usually a strong lens and should be optimized in order to ensure high brightness over a wide range of accelerating voltages and illuminating conditions. This is especially true in the case of the STEM where the brightness directly determines the highest resolution attainable. In the past, the optical behavior of accelerators was usually determined for a particular configuration. During the development of the accelerator for the Arizona 1 MEV STEM, systematic investigation was made of the major optical properties for a variety of electrode configurations, number of stages N, accelerating voltages, 1 and 10 MEV, and a range of injection voltages ϕ0 = 1, 3, 10, 30, 100, 300 kV).

A Macintosh Interface for the Cameca Camebax-Micro Electron Microprobe

1990 ◽  
Vol 48 (1) ◽  
pp. 438-439
Author(s):  
Carl E. Henderson
Keyword(s):  
Electron Microprobe ◽  
Processing Speed ◽  
Word Processing ◽  
State Of The Art ◽  
Computer Control ◽  
Third Party ◽  
Disk Storage ◽  
The Past ◽  
User Facility ◽  
Instrument Control

Over the past few years it has become apparent in our multi-user facility that the computer system and software supplied in 1985 with our CAMECA CAMEBAX-MICRO electron microprobe analyzer has the greatest potential for improvement and updating of any component of the instrument. While the standard CAMECA software running on a DEC PDP-11/23+ computer under the RSX-11M operating system can perform almost any task required of the instrument, the commands are not always intuitive and can be difficult to remember for the casual user (of which our laboratory has many). Given the widespread and growing use of other microcomputers (such as PC’s and Macintoshes) by users of the microprobe, the PDP has become the “oddball” and has also fallen behind the state-of-the-art in terms of processing speed and disk storage capabilities. Upgrade paths within products available from DEC are considered to be too expensive for the benefits received. After using a Macintosh for other tasks in the laboratory, such as instrument use and billing records, word processing, and graphics display, its unique and “friendly” user interface suggested an easier-to-use system for computer control of the electron microprobe automation. Specifically a Macintosh IIx was chosen for its capacity for third-party add-on cards used in instrument control.

Towards the Design of Cost-efficient Generic Register Using Quantum-dot Cellular Automata

2020 ◽  
Vol 10 (4) ◽  
pp. 534-547
Author(s):  
Chiradeep Mukherjee ◽  
Saradindu Panda ◽  
Asish K. Mukhopadhyay ◽  
Bansibadan Maji
Keyword(s):  
Cellular Automata ◽  
Quantum Dot ◽  
Power Dissipation ◽  
Cmos Technology ◽  
Oxide Semiconductor ◽  
Digital Data ◽  
Design Parameters ◽  
Flip Flop ◽  
Quantum Dot Cellular Automata ◽  
Cost Efficient

Background: The advancement of VLSI in the application of emerging nanotechnology explores quantum-dot cellular automata (QCA) which has got wide acceptance owing to its ultra-high operating speed, extremely low power dissipation with a considerable reduction in feature size. The QCA architectures are emerging as a potential alternative to the conventional complementary metal oxide semiconductor (CMOS) technology. Experimental: Since the register unit has a crucial role in digital data transfer between the electronic devices, such study leading to the design of cost-efficient and highly reliable QCA register is expected to be a prudent area of research. A thorough survey on the existing literature shows that the generic models of Serial-in Serial Out (SISO), Serial-in-Parallel-Out (SIPO), Parallel-In- Serial-Out (PISO) and Parallel-in-Parallel-Out (PIPO) registers are inadequate in terms of design parameters like effective area, delay, O-Cost, Costα, etc. Results: This work introduces a layered T gate for the design of the D flip flop (LTD unit), which can be broadly used in SISO, SIPO, PISO, and PIPO register designs. For detection and reporting of high susceptible errors and defects at the nanoscale, the reliability and defect tolerant analysis of LTD unit are also carried out in this work. The QCA design metrics for the general register layouts using LTD unit is modeled. Conclusion: Moreover, the cost metrics for the proposed LTD layouts are thoroughly studied to check the functional complexity, fabrication difficulty and irreversible power dissipation of QCA register layouts.

scholarly journals State-of-the-Art Char Production with a Focus on Bark Feedstocks: Processes, Design, and Applications

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 87
Author(s):  
Ali Umut Şen ◽  
Helena Pereira
Keyword(s):  
State Of The Art ◽  
Lignocellulosic Materials ◽  
Heating Rates ◽  
Production Methods ◽  
Slow Pyrolysis ◽  
Production Studies ◽  
Lignocellulosic Feedstocks ◽  
Thermochemical Method ◽  
Superior Surface ◽  
First Time

In recent years, there has been a surge of interest in char production from lignocellulosic biomass due to the fact of char’s interesting technological properties. Global char production in 2019 reached 53.6 million tons. Barks are among the most important and understudied lignocellulosic feedstocks that have a large potential for exploitation, given bark global production which is estimated to be as high as 400 million cubic meters per year. Chars can be produced from barks; however, in order to obtain the desired char yields and for simulation of the pyrolysis process, it is important to understand the differences between barks and woods and other lignocellulosic materials in addition to selecting a proper thermochemical method for bark-based char production. In this state-of-the-art review, after analyzing the main char production methods, barks were characterized for their chemical composition and compared with other important lignocellulosic materials. Following these steps, previous bark-based char production studies were analyzed, and different barks and process types were evaluated for the first time to guide future char production process designs based on bark feedstock. The dry and wet pyrolysis and gasification results of barks revealed that application of different particle sizes, heating rates, and solid residence times resulted in highly variable char yields between the temperature range of 220 °C and 600 °C. Bark-based char production should be primarily performed via a slow pyrolysis route, considering the superior surface properties of slow pyrolysis chars.

scholarly journals UV Inscription and Pressure Induced Long-Period Gratings through 3D Printed Amplitude Masks

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1977
Author(s):  
Ricardo Oliveira ◽  
Liliana M. Sousa ◽  
Ana M. Rocha ◽  
Rogério Nogueira ◽  
Lúcia Bilro
Keyword(s):  
State Of The Art ◽  
Low Cost ◽  
Resonance Wavelength ◽  
Complex Structures ◽  
Pressing Method ◽  
Long Period ◽  
Long Period Gratings ◽  
3D Printed ◽  
Mechanical Pressing ◽  
First Time

In this work, we demonstrate for the first time the capability to inscribe long-period gratings (LPGs) with UV radiation using simple and low cost amplitude masks fabricated with a consumer grade 3D printer. The spectrum obtained for a grating with 690 µm period and 38 mm length presented good quality, showing sharp resonances (i.e., 3 dB bandwidth < 3 nm), low out-of-band loss (~0.2 dB), and dip losses up to 18 dB. Furthermore, the capability to select the resonance wavelength has been demonstrated using different amplitude mask periods. The customization of the masks makes it possible to fabricate gratings with complex structures. Additionally, the simplicity in 3D printing an amplitude mask solves the problem of the lack of amplitude masks on the market and avoids the use of high resolution motorized stages, as is the case of the point-by-point technique. Finally, the 3D printed masks were also used to induce LPGs using the mechanical pressing method. Due to the better resolution of these masks compared to ones described on the state of the art, we were able to induce gratings with higher quality, such as low out-of-band loss (0.6 dB), reduced spectral ripples, and narrow bandwidths (~3 nm).

scholarly journals Electro-Quasistatic Animal Body Communication for Untethered Rodent Biopotential Recording

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shreeya Sriram ◽  
Shitij Avlani ◽  
Matthew P. Ward ◽  
Shreyas Sen
Keyword(s):  
Lower Energy ◽  
Sensor Node ◽  
State Of The Art ◽  
The Body ◽  
Animal Body ◽  
Current State ◽  
Communication Modalities ◽  
First Time ◽  
Biopotential Recording

AbstractContinuous multi-channel monitoring of biopotential signals is vital in understanding the body as a whole, facilitating accurate models and predictions in neural research. The current state of the art in wireless technologies for untethered biopotential recordings rely on radiative electromagnetic (EM) fields. In such transmissions, only a small fraction of this energy is received since the EM fields are widely radiated resulting in lossy inefficient systems. Using the body as a communication medium (similar to a ’wire’) allows for the containment of the energy within the body, yielding order(s) of magnitude lower energy than radiative EM communication. In this work, we introduce Animal Body Communication (ABC), which utilizes the concept of using the body as a medium into the domain of untethered animal biopotential recording. This work, for the first time, develops the theory and models for animal body communication circuitry and channel loss. Using this theoretical model, a sub-inch$$^3$$ 3 [1″ × 1″ × 0.4″], custom-designed sensor node is built using off the shelf components which is capable of sensing and transmitting biopotential signals, through the body of the rat at significantly lower powers compared to traditional wireless transmissions. In-vivo experimental analysis proves that ABC successfully transmits acquired electrocardiogram (EKG) signals through the body with correlation $$>99\%$$ > 99 % when compared to traditional wireless communication modalities, with a 50$$\times$$ × reduction in power consumption.

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