Design Automation Environment Research Articles

Nonvolatile Logic-in-Memory LSI Using Cycle-Based Power Gating and its Application to Motion-Vector Prediction

A magnetic tunnel junction (MTJ)-based logic-in-memory hardware accelerator LSI with cycle-based power gating is fabricated using a 90 nm MTJ/MOS process on a 300 mm wafer fabrication line for practical-scale, fully parallel motion-vector prediction, without wasted power dissipation. The proposed nonvolatile LSI is designed by establishing an automated design environment with MTJ-based logic-circuit IPs and peripheral assistant tools, as well as a precise MTJ device model produced by the fabricated test chips. Through the measurement results of the fabricated LSI, this study shows both the impact of the power-gating technique in a fine temporal granularity utilizing the non-volatility of the MTJ device and the effectiveness of the established automated design environment for designing random logic LSI using nonvolatile logic-in-memory.

EVOLUTIONARY DESIGN OF WIND TURBINE BLADES

An automatic design environment is implemented for the aerodynamic design of wind turbine blades. This tool involves the integration of evolutionary techniques and a simple, fast, and robust aerodynamic simulator which was developed for the prediction of the performance of any turbine blade produced by the evolutionary process. The aerodynamic simulator is based on blade element theory in which a panel method is combined with an integral boundary layer code to calculate the blade airfoils’ characteristics. In order to reduce computations some simplifications have been applied and the results corrected by means of the application of neural network based approximations. Results of the simulations obtained using this technique, of the application of the automatic design procedure and of the operation of the wind turbines thus obtained are presented.

Hardware-Accelerated Simulation Environment for CT Sigma–Delta Modulators Using an FPGA

In this brief, a hardware-accelerated simulation environment for continuous-time (CT) $\Sigma\Delta$ modulators is presented. Due to the presence of the nonlinear quantizer, simulating $\Sigma\Delta$ modulators is a complicated task in general. The simulation of CT modulators is even more time consuming than that of their discrete-time counterparts, due to the analog loop filter. In particular, in an automated design environment, a large number of simulations have to be performed during the design process of $ \Sigma\Delta$ modulators. In this brief, it is shown for the first time that the system-level emulation of CT $\Sigma\Delta$ modulators on an field-programmable gate array results in a significant acceleration, reducing the simulation time by a factor of more than $\hbox{10}^{5}$ compared to a commonly used Simulink simulation. This allows simulating 10 000 of modulators per second, enabling the use of heuristic search algorithms for real-time design for CT $\Sigma\Delta$ modulators.

Integrated System-Level Electronic Design Automation (EDA) for Designing Plasmonic Nanocircuits

This paper proposes a system-level circuit simulation framework for nanoplasmonic devices, and presents an example of the simulation of a plasmonic nanocircuit. The electronic design automation environment provides an equivalent circuit model library for several plasmonic metal-insulator-metal-based devices. The accuracy of the equivalent models for the plasmonic nanocircuit library is verified by using full-wave simulations and analytical equations. These models are then used to design an ultracompact Mach-Zehnder plasmonic modulator. It is shown that the voltage required to achieve a π phase shift Vπ in the modulator can be predicted by the simulator with reasonable accuracy. The optimized design of the modulator is also presented that reduces the value of Vπ according to the required specification.

Wind turbine design through evolutionary algorithms based on surrogate CFD methods

An automatic design environment using evolutionary techniques has been developed for the design of Horizontal Axis Wind Turbine (HAWT) blades taking into account both the aerodynamics and the structural constraints of the blades. This design environment is based on a simple, fast, and robust aerodynamic simulator intended for the prediction of the performance of any turbine blade produced as an intermediate individual of the evolutionary search process. In order to reduce the computational costs, the results obtained by this simple simulator have been corrected through the application of Artificial Neural Network (ANN) based approximations. An additional stress analysis stage has been introduced in order to take into account the structural resistance of the blades as a constraint throughout the optimization process. Results of the simulations obtained using this technique, of the application of the automatic design procedure and of the performance of the wind turbines thus produced are presented. In a first test case the rotor designed through the proposed method is compared to the one obtained analytically for a given air speed. This comparison to an analytical optimum provides a good index in order to evaluate the performance of the method. In a second case the rotor is optimized for a typical wind speed distribution, which is a more realistic scenario where the cost performance of the resulting turbines needs to be evaluated.

Nullor Equivalents of Active Devices for Symbolic Circuit Analysis

The new pathological elements, the voltage mirror (VM) and current mirror (CM), have shown advantages in analog behavioral modeling and circuit synthesis. Recently, the floating mirror elements have been used to derive pathological sections to ideally represent various popular analog signal processing properties that involve differential or multiple single-ended signals. In order to take advantage of the symbolic nodal analysis (NA) of nullor-mirror networks, we present the nullor equivalents of a differential voltage cell, a differential voltage conveying cell, and a current replication cell in this paper. The proposed nullor equivalents can be used to represent many popular active devices in performing symbolic NA. Two representative filter circuits containing differential characteristics of active devices are given to verify the feasibility. We expect them to be used within an analog design automation environment to enhance circuit analysis and modeling.

Novel 3D modeling methods for virtual fabrication and EDA compatible design of MEMS via parametric libraries

This paper provides a brief summary of the state-of-the-art of MEMS-specific modeling techniques and describes the validation of new models for a parametric component library. Two recently developed 3D modeling tools are described in more detail. The first one captures a methodology for designing MEMS devices and simulating them together with integrated electronics within a standard electronic design automation (EDA) environment. The MEMS designer can construct the MEMS model directly in a 3D view. The resulting 3D model differs from a typical feature-based 3D CAD modeling tool in that there is an underlying behavioral model and parametric layout associated with each MEMS component. The model of the complete MEMS device that is shared with the standard EDA environment can be fully parameterized with respect to manufacturing- and design-dependent variables. Another recent innovation is a process modeling tool that allows accurate and highly realistic visualization of the step-by-step creation of 3D micro-fabricated devices. The novelty of the tool lies in its use of voxels (3D pixels) rather than conventional 3D CAD techniques to represent the 3D geometry. Case studies for experimental devices are presented showing how the examination of these virtual prototypes can reveal design errors before mask tape out, support process development before actual fabrication and also enable failure analysis after manufacturing.

Towards modeling and integrated design automation of supercomputing clusters (MIDAS)

The choice of supercomputers, by the user community, should not merely be based on the benchmarks. With the advent of supercomputers delivering petaops performance, computationally intensive applications such as brain modeling and energy requirement prediction have become predominant. Conventional benchmarks do not reflect the functional characteristics of these applications. Thus, the gap between the performance projected and the actual performance delivered when the application is ported onto the cluster is wide. The primary cause for this disparity in performance is due to the user community’s lack of knowledge about the system and improper design choices. With the supercomputer market being seller biased this problem is worsened. Design and development of very large systems like the clusters involve massive efforts and financial investment. Creating a design automation environment for the clusters is bound to bring down the man years and hence the production cost. Currently there are adhoc approaches which lack an integrated design space to cater to the wider needs of the user community. Thus, an integrated design framework that takes all the components of the supercomputing cluster and the relationship across the design spaces is essential. In this paper we propose a novel methodology called the Modeling and Integrated Design Automation of Supercomputing Cluster (MIDAS). MIDAS is the birth of a new design philosophy which requires lot of research and tuning, providing scope for evolution and optimization.

Computer aided analysis and design of power transformers

In this paper, an integrated, three-dimensional, finite element package for the analysis and design of power transformers is developed, requiring no prior user experience in numerical methods and magnetic field simulation. The package consists of an automated pre-processor, magnetostatic solver and post-processor. High accuracy, low computational cost, minimization of user interaction and functional interface are the main advantages of the software, rendering it a powerful computational tool for characteristics prediction of single and dual voltage transformers, suitable for an automated design environment. For the development of the package, a particular scalar potential formulation was adopted. This method, in conjunction with the detailed representation of the real transformer geometry enables the achievement of high accuracy with the use of meshes of low density. The computational efficiency is also enhanced by the use of Morse technique for the storage of finite element matrices and Preconditioned Conjugate Gradient method for the solution of the finite element equations. The software has been incorporated in the design process of a transformer manufacturing industry for the evaluation of the leakage field and short-circuit impedance. The comparison of its results with measured values indicates the improvement of accuracy in comparison to the existing methodology, resulting in reduction of the design margin. Moreover, its employment has contributed to the decrease of the transformer industrial cycle and production cost.

Automated design environment for serial industrial manipulators

PurposeResulting from the need for fast and insightful modeling combined with the drawbacks of available modeling environments, provides details of work developed on an automated modelling environment.Design/methodology/approachAn automated modeling environment for serial manipulators has been implemented in Matlab/Simulink.FindingsThe manipulator configuration is defined by using a graphical user interface and the corresponding mathematical model is automatically generated. The model is exported to Matlab for analysis and control design, as well as to Simulink for simulation and verification purposes. Friction and stiction phenomena are included in the model. The simulation results can be visualized in standard plots and scopes as well as through virtual reality animations.Practical implicationsThe modeling environment has been used in the design of a control system for a seven‐degree‐of‐freedom manipulator in a tunnel‐boring machine.Originality/valueInformation on the implementation of an automated modelling environment to facilitate the simultaneous design of the configuration and the corresponding control system of serial manipulators

An Efficient 2-D DCT/IDCT Core Design Using Cyclic Convolution and Adder-Based Realization

This paper proposes an efficient two-dimensional (2-D) discrete cosine and inverse discrete cosine transform (DCT/IDCT) core design. Adopting the row-column decomposition technique for computing 2-D DCT/IDCT, we formulate the one-dimensional (1-D) DCT/IDCT into cyclic convolution by properly arranging the input sequence, optimize the multiplications based on the concept of common subexpression sharing, and carry out the multiplications through carry-save adders (CSAs). Using cyclic convolution is helpful in exploiting the word-level data sharing in computing different DCT/IDCT outputs. Adopting the common subexpression sharing is beneficial to the bit-level data sharing in computing the outputs. As compared with some existing approaches of realizing DCT/IDCT, the proposed approach can save on average 20%/spl sim/33% in the delay-area product (gate-count * time-unit) based on a 0.35-/spl mu/m CMOS technology under the data word-lengths ranging from 16/spl sim/24 b. Besides, we have also proposed an IP generator for designing the 2-D DCT/IDCT based on the proposed approach. It provides a design-automation environment with parameter configurations in designing a 2-D DCT/IDCT core that is suitable for most image and video compression applications.

An expert design environment for electrical devices and its engineering assistant

The authors present their conceptual design of an automated design environment for electric motors, its tools, and their implementation. From suitable specifications and requirements, the challenging automation of the initial stage of engineering design involves the use of heuristic and experiential knowledge of experts. This is followed by mathematical optimization of the initial design. The authors focus here on their knowledge-based engineering assistant that employs codified rules of the National Electrical Manufacturers' Association.

Design automation methodology and rf/analog modeling for rf CMOS and SiGe BiCMOS technologies

The rapidly expanding telecommunications market has led to a need for advanced rf integrated circuits. Complex rf- and mixed-signal system-on-chip designs require accurate prediction early in the design schedule, and time-to-market pressures dictate that design iterations be kept to a minimum. Signal integrity is seen as a key issue in typical applications, requiring very accurate interconnect transmission-line modeling and RLC extraction of parasitic effects. To enable this, IBM has in place a mature project infrastructure consisting of predictive device models, complete rf characterization, statistical and scalable compact models that are hardware-verified, and a robust design automation environment. Finally, the unit and integration testing of all of these components is performed thoroughly. This paper describes each of these aspects and provides an overview of associated development work.

Dynamic stiffness evaluation for reconfigurable machine tools including weakly non-linear joint characteristics

A systematic procedure is proposed to evaluate the dynamic characteristics of design alternatives for a reconfigurable machine tool (RMT). The procedure is intended to be used in an automated design environment where various design alternatives are generated by kinematic synthesis based on a given task and specification. The evaluation procedure makes use of a substructuring method called non-linear receptance coupling. The coupling method includes the effects of weakly non-linear compliant joints through the use of describing functions for the non-linearities involved. Experimental data obtained from a prototype RMT are used to show the validity of the coupling method. To demonstrate the utility of the proposed evaluation procedure design alternatives are generated based on a lumped parameter model of the RMT and examined with respect to the proposed criteria. It is shown that joint non-linearities may affect dynamic stiffness considerably. It is also shown that the suggested criteria can distinguish various design alternatives with respect to their expected dynamic behaviour.

A formal approach to context scheduling for multicontext reconfigurable architectures

In this paper, we analyze the main issues in context scheduling for multicontext reconfigurable architectures from a formal point of view. We first provide an intuitive approach. which is later supported by a detailed analysis of the mathematical relations that express the reconfiguration process. This enables us to deduce a methodology for the minimization of context loading overhead, which considers the tradeoff between achievable system performance and algorithm efficiency. In this respect, the optimality necessary conditions are established in order to contrive an optimal search. However, as this approach is very time consuming we propose some heuristic techniques that reduce the algorithm complexity and accomplish very good results in relatively short execution time. This work has been developed as a part of an automated design environment for reconfigurable systems. A set of experiments has been developed so as to validate the theoretical results.

From AHPL to VHDL: a course in hardware description languages

As the size and complexity of digital systems increase, more CAD tools are introduced in the hardware design process; a recent addition to this process is the use of hardware description languages (HDLs). Historically, HDL-based design courses have been taught mostly at the graduate level. Undergraduate courses have mainly emphasized the principles of digital systems design, at both the logic and architectural levels. The laboratory component of these courses often introduces the students to graphical design capture tools and their associated simulators. However, within the past few years industry has been moving away from graphical design captures and is more openly adopting HDL-based design methodologies. Based on these industry shifts, one can easily conclude that HDLs are becoming an integral part of the design automation environments; this in turn requires the updating of the curricula, either by incorporating new courses or by updating existing ones. Specifically, courses that introduce undergraduates to HDLs in general and a standard language such as VHDL or Verilog are becoming essential in preparing future engineers. This paper discusses an HDL-based design course offered at Northern Arizona University (NAU). The course is used as a vehicle to introduce NAU students to the underlying concepts behind modeling, simulating, and verifying-digital systems design using hardware description languages.

The REAR Framework for Emulation and Analysis of Embedded Hard Real-Time Systems

The aim of rapid prototyping real-time applications is to substantially reduce development times by confirming the functional and temporal requirements of the application at a very early stage of development with the help of an executable prototype. Hence, the real-time rapid prototyping system presented in this paper integrates two complementary tasks: On one hand it provides an automated design environment for a rapid and facile generation of a working prototype. On the other hand, the design process is extended with real-time requirement specification and analysis in order to prove that the embedded system will meet all timing requirements, and to verify that the timing requirements have been modeled correctly. The REAR framework uses annotated SDL for the system specification, from which both, the compilable source codes and the real-time analysis model are generated. After instrumentation for timing measurements, the C and VHDL source code is compiled and synthesized, linked with communication libraries and executed on the configurable, heterogeneous multiprocessor target system. Several case studies demonstrate the feasibility of this approach.

VHDL Modeling of Optoelectronic Interconnect Networks

High performance computer and communication systems of today demands improvements in communication delay and connectivity. Optoelectronic interconnect is well recognized as a technology to provide the necessary improvement. However the complexity of optoelectronic systems is motivating a need for CAD tools which can simulate electronic and optoelectronic device and circuit behaviors simultaneously and at multiple levels of abstraction. This paper describes VHDL modeling of optical signals and integrated optical waveguides which enables seamless integration of mixed electronic/optoelectronic simulations in an established electronic design automation environment.