PRECISE Photonic Hybrid Electromagnetic Solver

Sense and sensibility: of synthetic biology and the redesign of bioreporter circuits.

As a result of increasing design size and complexity, the multiple clock domain design style has become a new trend in the industry. Several techniques to test circuits with multiple clocks are known; however, they often result in increased test time and tester memory for large and complex circuits. This paper presents a strategy to reduce the test pattern count during ATPG by forcing a safe capture behavior when multiple clocks are applied during capture. The usage of multiple clocks allows additional observability, which can significantly reduce the pattern count for circuits with many clocks. Experimental results indicate that proposed strategy results in larger and moreover, more consistent reduction in test sizes.

The problem of scale has left the Evolvable Hardware (EHW) community wondering about the viability of this approach as an alternative design methodology for large and practical circuits. Despite the move from conventional direct mapped techniques to developmental approaches, so far only small circuits have been evolved. This paper shows that, by partitioning a digital circuit and making use of a developmental approach, namely the Developmental Cartesian Genetic Programming (DCGP) technique, it is possible to evolve large circuits. The advantages of this approach with respect to evolution time, area overhead and fault tolerance are highlighted for different adder and multiplier circuits and the ISCAS?89-benchmark circuit rd84. This concept can be easily extended to any combinational circuit, thus proving that this is a viable solution towards evolving large and complex circuits.

A micromechanics based analytical model under combined loading for unidirectional composites has been developed. The peak compressive load predicted from the combined loading analytical model is compared with the experimental results of carbon epoxy pultruded rod having a volume fraction 60%. The specimens were subjected to torsional load under rotational control and longitudinal compressive load using displacement control. The model captures the compressive strength of the composite subjected to remotely applied shear stress. It is observed that the peak compressive strength of the composite decreases linearly with an increase in shear stress. The analytical modeling results are in good agreement with the experiment data. The analytical model and the experimental results are used to find the effect of shear stress on longitudinal compressive loading. The peak compressive strength caused in the presence of applied shear stress and compressive load and the effect of shear on the compressive strength are predicted using a 2D analytical model in this study. The model results are confirmed using experimental data from combined loading.

For single-step reactions there is a unique relation between reaction rate and reactedness for a given combustible mixture at a specified pressure and initial temperature. This paper examines whether the relation is still unique when chain reactions are present, by considering three types of flame—spontaneous ignition, laminar-flame propagation, and the homogeneous steady-flow reaction zone—with a chain-reaction scheme proposed by Adams & Stocks for the decomposition of hydrazine. It is found that the relation is not unique but that similarities exist between the relation for laminar-flame propagation and the relation for the homogeneous reaction zone. Incidentally, a general method of calculating laminar-flame speeds with reaction schemes of arbitrary complexity is presented. When applied to the hydrazine decomposition flame the predictions of the theory are in fair agreement with experimental results. In particular, the variation of flame speed with temperature is correctly predicted. It is shown that the use of the Karman-Penner 'steady-state assumption' would lead to an overestimate of the flame speed. Consideration of the changes which would result if the chain reaction should branch shows that there would once again tend to be a unique reaction rate versus reactedness relation, and that the laminar-flame speed would be increased by a factor of about three for the hottest flame considered but by larger factors for cooler flames.

At SODA 2017 Lokshtanov et al. presented the first worst-case algorithms with exponential speedup over exhaustive search for solving polynomial equation systems of degree d in n variables over finite fields. These algorithms were based on the polynomial method in circuit complexity which is a technique for proving circuit lower bounds that has recently been applied in algorithm design. Subsequent works further improved the asymptotic complexity of polynomial method-based algorithms for solving equations over the field \(\mathbb {F}_2\). However, the asymptotic complexity formulas of these algorithms hide significant low-order terms, and hence they outperform exhaustive search only for very large values of n.In this paper, we devise a concretely efficient polynomial method-based algorithm for solving multivariate equation systems over \(\mathbb {F}_2\). We analyze our algorithm’s performance for solving random equation systems, and bound its complexity by about \(n^2 \cdot 2^{0.815n}\) bit operations for \(d = 2\) and \(n^2 \cdot 2^{\left( 1 - 1/2.7d\right) n}\) for any \(d \ge 2\).We apply our algorithm in cryptanalysis of recently proposed instances of the Picnic signature scheme (an alternate third-round candidate in NIST’s post-quantum standardization project) that are based on the security of the LowMC block cipher. Consequently, we show that 2 out of 3 new instances do not achieve their claimed security level. As a secondary application, we also improve the best-known preimage attacks on several round-reduced variants of the Keccak hash function.Our algorithm combines various techniques used in previous polynomial method-based algorithms with new optimizations, some of which exploit randomness assumptions about the system of equations. In its cryptanalytic application to Picnic, we demonstrate how to further optimize the algorithm for solving structured equation systems that are constructed from specific cryptosystems.

The present work is an attempt to better understand the flexural behavior of an instrumented reinforced concrete beam with the cyclic four-point load test. Here, an analytic model that computes the load-moment and load-deformation relationships by taking into account the nonlinearity of section caused by stiffness reduction due to tensile cracking and the validity of moment of inertia is developed. Validity of this model is verified by the excellent agreement between the analytic modeling results and the theoretical solution. The experimental results are compared with the modeling result for assessing applicability of the optic fiber sensor in the beam specimen. After that, a curved beam member representing a smart tunnel lining segment (STLS) is loaded using the same manner. The comparison on flexural behavior shows that the proposed analytic model can provide the best prediction.

Evolutionary algorithms (EAs) are population-based search algorithms that have been successfully applied to solve hard optimization problems in many application domains. Since the early 1990's researchers have begun to apply evolutionary algorithms to synthesize electronic circuits. Nowadays it is evident that the evolutionary design approach can automatically create efficient electronic circuits in many domains. In this tutorial, fundamental concepts of evolutionary design of digital circuits are presented. In particular, the tutorial deals with Cartesian Genetic Programming (CGP) — a method of genetic programming that in many cases outperforms conventional synthesis tools in terms of achievable circuit size reduction. Innovative designs will be presented in domains of small combinational circuits (where the goal is to minimize the number of gates), middle-size circuits (such as image filters intended for FPGAs where the goal is to obtain the quality of filtering of conventional methods for a significantly lower cost on a chip) and large circuits (such as benchmark circuits for comparison of testability analysis methods), covering thus circuit complexity from a few gates to millions of gates. For example, one of evolved image filters is now protected by utility model in the Czech Republic (patent pending). Evolved circuits will be compared with the best-known conventional designs. We will also show how to deal with the so-called scalability problems of evolutionary design which have been identified as the most important problems from the point of view of practical applications. In summary, tutorial participants will become familiar with the state of the art methods in the area of digital circuit evolution. They will learn how to apply CGP, construct the fitness function and run experiments.

In this paper, a new simple analytical model for perforation process of composite sandwich panels subjected to high-velocity impact of flat-ended projectile is presented. The panels consist of foam core sandwiched between two composite skins. In the analytical model, global deformation, plug shearing or localized tensile fracture, delamination of front and back-up composite skins, and the absorbed energy during the perforation of the sandwich panel are calculated considering the local indentation and also the energy balancing equation is employed to determine the ballistic limit and residual velocity of projectile. The results of current new model are compared with the experimental results available in the open literature and the finite element simulation results obtained by the LS-Dyna code. A good agreement is observed between the analytical and numerical model results and the experimental results.

With the arrival of nanometer technologies wire delays are no longer negligible with respect to gate delays, and timing-closure becomes a major challenge to system-on-chip designers. Latency-insensitive design (LID) has been proposed as a "correct-by-construction" design methodology to cope with this problem. In this paper we present the design and implementation of a new class of interface circuits to support LID that offers substantial performance improvements with limited area overhead with respect to previous designs proposed in the literature. This claim is supported by the experimental results that we obtained completing semi-custom implementations of the three designs with a 90 nm industrial standard-cell library. We also report on the formal verification of our design: using the NuSMV model checker we verified that the RTL synthesizable implementations of our LID interface circuits (relay stations and shells) are correct refinements of the corresponding abstract specifications according to the theory of LID.

This paper will present theory, analysis and experimental work on new and novel SAW noise-like-reflector (NLR) structures for use in SAW coded reflectors. The NLR structures produce a very wideband, noise like reflectivity. This reflectivity is very different than that produced from typical single frequency CDMA coded reflectors or orthogonal frequency coded (OFC) reflectors. CDMA and OFC structures are designed based on a standard communication approach where the time information is divided into chips. These chips then provide both the processing gain and also limit the sidelobe level of the auto-correlated reflected pulse. The processing gain is defined by the number of chips and operation bandwidth, and the correlation peak-to-sidelobe ratio is increased by increasing the chip count. The NLR structure has no chips; it is designed using a random sequence of varying width and pitch electrodes. The very wideband nature of the NLR yields very different auto- and cross-correlation properties, compared to CDMA and OFC approaches. Work presented will discuss basic theory that was used to predict the performance of the NLR structures and devices. A simple analytic mathematical model was used as a first order approach, which allows both insight and synthesis. The unit cell for each reflector is determined and an ideal time and frequency response is predicted. A random code generator is used to pick the phase and unit cell design. The composite reflector bank is synthesized and the overall performance evaluated. This model provides both the reflector characteristics as well as the auto-correlation properties. Next, a coupling of modes (COM) model was developed to simulate the complex structure, and predict the overall frequency dependent reflectance or transmittance of the structure. Two types of structures: random and random with pulse position modulation (PPM) were examined. The PPM provides another level of possible coding to the NLR. The analytic model and COM model results are compared and show remarkably good correlation, which confirms that the analytic model provides a good synthesis tool. Both models confirmed the performance and expected advantages of NLR structures. Experimental SAW NLR devices were built at approximately 250 MHz on YZ LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . Several different device designs were fabricated and the measured reflector and correlator results agreed well with both the analytic and COM models. The paper will present the design and layout principles, the basic theory, and several designed NLR structures. It will be shown that this new NLR structure will provide unique methods for device coding, as well as other applications.

Horseshoes in a class of simple circuits

We present a simplified 2-D analytical subdomain model to predict the open-circuit magnetic field of a tubular linear permanent magnet oscillation generator (T-LPMOG) to account for its primary and secondary end effects. At present, the magnetic field calculations of the T-LPMOG are typically analyzed in cylindrical coordinates, and the end effect is neglected accordingly to apply the periodic boundary. In this paper, a simplified 2-D analytical subdomain model in polar coordinates is proposed to consider the end effect. First, a coordinate transformation method is adopted to establish the 2-D subdomain analytical model, the cylindrical coordinates are converted into polar coordinates, and the T-LPMOG is analyzed under this new coordinate system. Next, the subdomain method is used to analyze the analytical model by solving Laplace’s equation and the Poisson equation. Based on the simplified analytical model, the flux density and back-electromotive force are obtained. The analytical results are verified using the finite element analysis (FEA) method, and the computational times compared with the FEA method are provided. Finally, a T-LPMOG prototype is manufactured and tested, and the results show that the proposed analytical model can be useful in the initial design and optimization of the T-LPMOG.

Coupling constant of microcavity waveguides based on coupled mode theory

Purpose Characterisation and use of dielectric materials with high permittivity are one of the most developed areas of research in microwave circuit simulation. This is mainly because of their various applications in VHF/UHF and microwave frequencies (correlators, instrumentation systems, …). The primary virtue of high-dielectric substrates for microwave circuits is the reduced size. Since the high dielectric microstrip line also exhibit low loss and useful impedance range, this class of circuits will undoubtedly find wide applications in microwave integrated circuitry. Design/methodology/approach Owing to the complexity of the electromagnetic problem, numerical methods become an indispensable tool for analysis and modeling of electromagnetic structures. They are the basis to set-up computer-aided design (CAD) packages. These models must be accurate, reliable, easily extracted and need limited computational requirements. Since there was a demand for a model able to describe these parameters accurately, an extension of the spectral domain approach (SDA) is proposed for microstrip lines with high permittivity. The analysis is based on the solution of a system of algebraic equations, which are derived from Galerkin's technique in the spectral domain. Findings Analytical expressions are deduced by curve-fitting techniques. These expressions can be easily implemented in a CAD simulation tool to design wireless communication components. In this paper, we have developed accurate and suitable general expressions for characteristic parameters for a wide range of εr between 1 and 500. The computed results were compared to those available in the literature when possible. In order to validate our models for high values of dielectric constant (128 &amp;lt; εr&amp;lt;500), neural models were generated for the characteristic impedance and effective permittivity. A very good agreement is demonstrated. Originality/value The originality of this paper consists on the development of design formulas to characterise the microstrip lines with high dielectric constant substrate. Closed form equations are almost non-existent in the technical literature since the available design formulas have been developed only for dielectric media value εr not exceed 128.