Search

Recently, Yu et al. presented an algorithm for a canonic DBC of a positive integer n by solving certain subproblems recursively and it requires O ( ( log n ) 2 log log n ) bit operations and O ( ( log n ) 2 ) bits of memory. This is currently the most efficient recoding type algorithm for canonic DBCs when balanced computing power and memory are available. In this paper, we present a memory efficient algorithm to compute a nearly DBC from the idea of Yu et al. We present a simple overview of Yu et al.’s algorithm focusing on canonic DBC and refine Yu et al.’s proof for range of the leading term of canonic DBCs. By using the refined range, we suggest how to improve the efficiency of Yu et al.’s algorithm computationally and present an algorithm for nearly canonic DBC with memory requirement O ( log n ) . We also present experimental comparison on the Hamming weights of Yu et al.’s algorithm, tree based algorithm, the classic greedy DBC algorithm, and our memory efficient algorithm.

Scalar multiplications are considered an essential aspect of implementations of isogeny-based cryptography. The efficiency of scalar multiplication depends on the equation of the underlying elliptic curves and the addition chain employed. Bos and Friedberger recently stated that, for larger scalar multiplication, addition-subtraction chains will become more useful for twisted Edwards curves because of the differential restriction on Montgomery curves in the setting of isogeny-based cryptosystem. Motivated by these comments, we attempt to increase the efficiency of scalar multiplication in twisted Edwards curves in terms of the memory of algorithms. In this paper, we present a double-base addition-subtraction chain algorithm with memory efficiency for scalar multiplication. The memory usage of this part is O log n 2 / log log n , which is better than the result of the tree-based approach, which is O log n 2 .

The security of most lattice based cryptography relies on the hardness of computing a shortest nonzero vector of lattices. We say that a lattice basis is SV-reduced if it contains a shortest nonzero vector of the lattice. In this paper, we prove that, π ∕ 6 orthogonality between the shortest vector of the basis and the vector space spanned by other vectors of the basis is enough to be SV-reduced under the assumption that a plausible condition C n holds. By using the π ∕ 6 orthogonality under C 2 , we prove a new complexity bound log 3 ∥ x ∥ 2 3 det L + 1 for Gauss–Lagrange algorithm which clarifies why the currently known complexity is so far fall short to expose the efficiency of the algorithm we experience in practice. Our experiments suggest that our complexity bound of Gauss–Lagrange algorithm is somewhat close to actual efficiency of the algorithm. We also show that LLL( δ ) algorithm outputs a S V -reduced basis if δ ≥ 1 ∕ 3 for two dimensional lattice. We present an efficient three dimensional SV-reduction algorithm by using the condition C 3 and π ∕ 6 orthogonality and how to generalize the algorithm for higher dimension.

We study the dynamical systems consisting of the set of 5-adic integers Z 5 and polynomial maps from Z 5 into itself. A polynomial map decomposes the set Z 5 into minimal components, which is usual...

The concept of a coupling factor was introduced in International Electrotechnical Commission (IEC) 62311 and 62233 to provide a product safety assessment that considers the localized exposure when an electromagnetic field (EMF) source is close to the human body. To calculate the coupling factors between the human body and EMF source, a numerical calculation should be carried out to calculate the internal quantities of the human body models. However, at frequencies below 10 MHz, the computed current density or internal electric field has computational artifacts from segmentation or discretization errors. Specifically, coupling factors are calculated based on the maximum values, which may include computational artifacts due to abnormal peaks. In this study, we propose an improved calculation method to remove computational artifacts by applying the 99.99th percentile in calculating the coupling factors without underestimation. The performance of the proposed method is verified through a comparison based on various human body models with wireless power transfer (WPT) systems and compliance with the reference levels and basic restrictions. The results indicate that the proposed method can provide uniform coupling factors by reducing the computational errors by up to 65.3% compared to a conventional method.

In recent years, the interest of the electromagnetic pulse (EMP) threat is increasing with the rapid development of the electronics industry. Especially, the power cable is one of the targets that can be exposed to EMP and affect to the appliance. However, the EMP-coupling method is previously insufficient and is partially analyzed between EMP sources and cable. Because the simulation method such as the finite-difference time-domain (FDTD) and an experiment often take a very long time to present the EMP-cable coupling. Therefore, in this paper, we propose the EMP-estimation coupling method to analyze from the overall perspective based on the hybrid electromagnetic (EM) numerical method. In addition, the protection guideline for the appliance is evaluated as the cable length is changed.

For each Sophie Germain prime $g \geq 5,$ we construct an absolutely simple polarized abelian variety of dimension $g$ over a finite field, whose automorphism group is a cyclic group of order $4g+2$. We also provide a description on the asymptotic behavior of prime numbers that are related to our construction., 13 pages. arXiv admin note: substantial text overlap with arXiv:2002.05535, arXiv:1901.04470, arXiv:1809.06251

It is necessary to reduce the crosstalk noise in high-speed signaling channels. In the channel routing area, the tabbed routing pattern is used to mitigate far-end crosstalk (FEXT), and the electrical length is controlled with a time domain reflectometer (TDR) and time domain transmission (TDT). However, unlike traditional channels having uniform width and space, the width and space of tabbed routing changes by segment, and the capacitance and inductance values of tabbed routing also change. In this paper, we propose a tabbed routing equivalent circuit modeling method using the segmentation approach. The proposed model was verified using 3D EM simulation and measurement results in the frequency domain. Based on the calculated inductance and capacitance parameters, we analyzed the insertion loss, FEXT, and self-impedance in the frequency domain, and TDT and FEXT in the time domain, by comparing the values of these metrics with and without tabbed routing. Using the proposed tabbed routing model, we analyzed tabbed routing with variations of design parameters based on self- and mutual-capacitance and inductance.

Recently, semiconductor devices are becoming more diverse and scaled down for various applications such as electronic devices, communication systems and automotive components. Such applications can utilize sputtered shielding structures to solve electromagnetic interference (EMI) issues. To reduce the EMI issues, copper and nickel are commonly used as sputtered shielding materials. To analyze the shielding effectiveness, we applied the Schelkunoff's theory. For the verification of the Schelkunoff's theory, we simulated and measured the shielding effectiveness of copper and nickel at the frequency range between 100 kHz and 10 MHz using two identical coils.

3D XPoint memory is one of the new memory using phase change memory (PCM) and ovonic threshold switch (OTS) with 20 nm 3-dimensional cross array structure. This memory is non-volatile and has better performance in terms of memory process speed than NAND flash memory and memory density than DRAM. The space between interconnections are close so, the voltage coupling affects to the adjacent interconnections during read operation. In this paper, we analyzed the 3D XPoint memory with memory size variation during read operation considering signal integrity (SI). For the analysis, we assumed the overall structure of the 3D XPoint memory and modeled the memory cell that consist of PCM and OTS as behavior model and the interconnections as RC model with 3D electromagnetic (EM) simulator. We fully simulated the 3D XPoint memory including memory behavior model, RC model of interconnections and peripheral circuits such as the addressor and current sense amplifier. With variation of the memory size during read operation, there are SI issues such as voltage coupling and drop trends through the interconnections.

Recently, high density integrated circuits are packaged in the electronic devices such as smartphones and smartwatches. Power amplifier modules integrated in such devices interact with other circuits due to its inductive components, and may cause the electromagnetic interference issues. To reduce the electromagnetic issues, sputtering technology can be used. In this paper, we present the shielding effectiveness measurement results of sputtered shielding materials in the low-frequency range from 30 kHz to 20 MHz using a vector network analyzer. Sputtered shielding materials are copper, nickel, titanium and stainless steel. By comparing the insertion loss, the shielding effectiveness is analyzed. The effect of the sputtered materials' thickness is also analyzed. Among the four materials, sputtered copper has the highest shielding effectiveness.

In this paper, we propose low electromagnetic interference (EMI) high-k tightly-coupled resonant magnetic field (TCR-HMF) charger. The high coupling coefficient, k, between Tx and Rx coils is essential for increasing power transfer efficiency (PTE) and reducing size of proposed TCR-HMF charger. As the k increase, the mutual inductance also increases. Moreover, the larger mutual inductance results in frequency splitting phenomena. Because the current harmonics are determined by the ratio of the magnitude of the input impedance at the resonant frequency to the magnitude in its harmonic frequencies, the current harmonics are increased by the frequency splitting phenomena. In this paper, a reduction method of the harmonic currents in TCR-HMF charger with impedance design method is proposed. The circuit simulation results show that the harmonic currents flowing through Tx and Rx coils can significantly be reduced by applying the proposed method. The circuit simulation results of TCR-HMF charger show that proposed method can reduces THD of Tx current and Rx current by 14.55 % and 57.13 %, respectively.