Admissible Parameter Sets and Complexity Estimation of Crossbred Algorithm

The Crossbred algorithm is one of the algorithms for solving a system of polynomial equations, proposed by Joux and Vitse in 2017. It has been implemented in Fukuoka MQ challenge, which is related to the security of multivariate crytography, and holds several records. A framework for estimating the complexity has already been provided by Chen et al. in 2017. However, it is generally unknown which parameters are actually available. This paper investigates how to select available parameters for the Crossbred algorithm. As a result, we provide formulae that give an available parameter set and estimate the complexity of the Crossbred algorithm

ZZ-Interaction-Free Single-Qubit-Gate Optimization in Superconducting Qubits

Overcoming the issue of qubit-frequency fluctuations is essential to realize stable and practical quantum computing with solid-state qubits. Static ZZ interaction, which causes a frequency shift of a qubit depending on the state of neighboring qubits, is one of the major obstacles to integrating fixed-frequency transmon qubits. Here we propose and experimentally demonstrate ZZ-interaction-free single-qubit-gate operations on a superconducting transmon qubit by utilizing a semi-analytically optimized pulse based on a perturbative analysis. The gate is designed to be robust against slow qubit-frequency fluctuations. The robustness of the optimized gate spans a few MHz, which is sufficient for suppressing the adverse effects of the ZZ interaction. Our result paves the way for an efficient approach to overcoming the issue of ZZ interaction without any additional hardware overhead.Comment: 6 pages, 2 figures plus Supplementary Information (4 pages, 2 figures

Analysis on the MinRank Attack using Kipnis-Shamir Method Against Rainbow

Minrank problem is investigated as a problem related to a rank attack in multivariate cryptography and decoding of a rank code in coding theory. Recently, the Kipnis-Shamir method for solving this problem has been made significant progress due to Verbel et al. As this method reduces the problem to the MQ problem that asks for a solution of a system of quadratic equations, its complexity depends on the solving degree of a quadratic system deduced from the method. A theoretical value introduced by Verbel et al. approximates the minimal solving degree of the quadratic systems in the method although their value is defined under a certain limit for a considering system. A quadratic system outside their limitation often has the larger solving degree, but its solving complexity is not necessary larger since it has a smaller number of variables and equations. Thus, in order to discuss the best complexity of the Kipnis-Shamir method, we need a theoretical value approximating the solving degree of each deduced quadratic system. A quadratic system deduced from the Kipnis-Shamir method has a multi-degree always, and its solving complexity is influenced by this property. In this paper, we introduce a theoretical value defined by such a multi-degree and show it approximates the solving degree of each quadratic system. Thus we are able to compare the systems in the method and to discuss the best complexity. As its application, in the Minrank problem from the rank attack using the Kipnis-Shamir method against Rainbow, we show a case that a quadratic system outside Verbel et al.\u27s limitation is the best. Consequently, by using our estimation, the complexities of the attack against Rainbow parameter sets Ia, IIIc and Vc are improved as $2^{160.6}, 2^{327.9}$ and $2^{437.0}$, respectively

X-ray Irradiation Induced Discharge of Spherical Void in Epoxy Resin

It is crucial for proper insulation design of cast resin transformer to consider voids and delamination which might exist in cast molding process and/or under long-term operation because of several surface boundaries between resin and conductor. Should such defects in the insulation system exist, it would lead to reduction of the life of the apparatus. In this report, we investigate the relation between the void size and apparent charge of partial discharge (PD) occurring in a model simulating the insulation system of cast resin transformer. It is also important to determine necessary PD detection sensitivity of PD test in a factory as well as in a field. In addition, we investigate X-ray irradiation induced discharge of spherical void in epoxy resin. Physical consideration of the effect of X-ray irradiation on void discharges in epoxy resin was also made. Time lag of void discharges in epoxy resin was also made with attenuation of X-ray irradiation dose considered.2011 Electrical Insulation Conference (EIC), 5-8 June 2011, Annapolis, M

Security Analysis on an El-Gamal-like Multivariate Encryption Scheme Based on Isomorphism of Polynomials

Isomorphism of polynomials with two secrets (IP2S) problem was proposed by Patarin et al. at Eurocrypt 1996 and the problem is to find two secret linear maps filling in the gap between two polynomial maps over a finite field. At PQC 2020, Santoso proposed a problem originated from IP2S, which is called block isomorphism of polynomials with circulant matrices (BIPC) problem. The BIPC problem is obtained by linearizing IP2S and restricting secret linear maps to linear maps represented by circulant matrices. Using the commutativity of products of circulant matrices, Santoso also proposed an El-Gamal-like encryption scheme based on the BIPC problem. In this paper, we give a new security analysis on the El-Gamal-like encryption scheme. In particular, we introduce a new attack (called linear stack attack) which finds an equivalent key of the El-Gamal-like encryption scheme by using the linearity of the BIPC problem. We see that the attack is a polynomial-time algorithm and can break some 128-bit proposed parameters of the El-Gamal-like encryption scheme within 10 hours on a standard PC

Transcriptional Rewiring of the Sex Determining dmrt1 Gene Duplicate by Transposable Elements

Control and coordination of eukaryotic gene expression rely on transcriptional and posttranscriptional regulatory networks. Evolutionary innovations and adaptations often require rapid changes of such networks. It has long been hypothesized that transposable elements (TE) might contribute to the rewiring of regulatory interactions. More recently it emerged that TEs might bring in ready-to-use transcription factor binding sites to create alterations to the promoters by which they were captured. A process where the gene regulatory architecture is of remarkable plasticity is sex determination. While the more downstream components of the sex determination cascades are evolutionary conserved, the master regulators can switch between groups of organisms even on the interspecies level or between populations. In the medaka fish (Oryzias latipes) a duplicated copy of dmrt1, designated dmrt1bY or DMY, on the Y chromosome was shown to be the master regulator of male development, similar to Sry in mammals. We found that the dmrt1bY gene has acquired a new feedback downregulation of its expression. Additionally, the autosomal dmrt1a gene is also able to regulate transcription of its duplicated paralog by binding to a unique target Dmrt1 site nested within the dmrt1bY proximal promoter region. We could trace back this novel regulatory element to a highly conserved sequence within a new type of TE that inserted into the upstream region of dmrt1bY shortly after the duplication event. Our data provide functional evidence for a role of TEs in transcriptional network rewiring for sub- and/or neo-functionalization of duplicated genes. In the particular case of dmrt1bY, this contributed to create new hierarchies of sex-determining genes

Silicate Microfiber Scaffolds Support the Formation and Expansion of the Cortical Neuronal Layer of Cerebral Organoids With a Sheet-Like Configuration

Terada Eisaku, Bamba Yohei, Takagaki Masatoshi, et al. Silicate Microfiber Scaffolds Support the Formation and Expansion of the Cortical Neuronal Layer of Cerebral Organoids With a Sheet-Like Configuration. Stem Cells Translational Medicine 9, 519 (2023); https://doi.org/10.1093/stcltm/szad066.Cerebral organoids (COs) are derived from human-induced pluripotent stem cells in vitro and mimic the features of the human fetal brain. The development of COs is largely dependent on “self-organization” mechanisms, in which differentiating cells committed to cortical cells autonomously organize into the cerebral cortex-like tissue. However, extrinsic manipulation of their morphology, including size and thickness, remains challenging. In this study, we discovered that silicate microfiber scaffolds could support the formation of cortical neuronal layers and successfully generated cortical neuronal layers, which are 9 times thicker than conventional COs, in 70 days. These cortical neurons in the silicate microfiber layer were differentiated in a fetal brain-like lamination pattern. While these cellular characteristics such as cortical neurons and neural stem/progenitor cells were like those of conventional COs, the cortical neuronal layers were greatly thickened in sheet-like configuration. Moreover, the cortical neurons in the scaffolds showed spontaneous electrical activity. We concluded that silicate microfiber scaffolds support the formation of the cortical neuronal layers of COs without disturbing self-organization-driven corticogenesis. The extrinsic manipulation of the formation of the cortical neuronal layers of COs may be useful for the research of developmental mechanisms or pathogenesis of the human cerebral cortex, particularly for the development of regenerative therapy and bioengineering