Comparing Large-unit and Bitwise Linear Approximations of SNOW 2.0 and SNOW 3G and Related Attacks

In this paper, we study and compare the byte-wise and bitwise linear approximations of SNOW 2.0 and SNOW 3G, and present a fast correlation attack on SNOW 3G by using our newly found bitwise linear approximations. On one side, we reconsider the relation between the large-unit linear approximation and the smallerunit/ bitwise ones derived from the large-unit one, showing that approximations on large-unit alphabets have advantages over all the smaller-unit/bitwise ones in linear attacks. But then on the other side, by comparing the byte-wise and bitwise linear approximations of SNOW 2.0 and SNOW 3G respectively, we have found many concrete examples of 8-bit linear approximations whose certain 1-dimensional/bitwise linear approximations have almost the same SEI (Squared Euclidean Imbalance) as that of the original 8-bit ones. That is, each of these byte-wise linear approximations is dominated by a single bitwise approximation, and thus the whole SEI is not essentially larger than the SEI of the dominating single bitwise approximation. Since correlation attacks can be more efficiently implemented using bitwise approximations rather than large-unit approximations, improvements over the large-unit linear approximation attacks are possible for SNOW 2.0 and SNOW 3G. For SNOW 3G, we make a careful search of the bitwise masks for the linear approximations of the FSM and obtain many mask tuples which yield high correlations. By using these bitwise linear approximations, we mount a fast correlation attack to recover the initial state of the LFSR with the time/memory/data/pre-computation complexities all upper bounded by 2174.16, improving slightly the previous best one which used an 8-bit (vectorized) linear approximation in a correlation attack with all the complexities upper bounded by 2176.56. Though not a significant improvement, our research results illustrate that we have an opportunity to achieve improvement over the large-unit attacks by using bitwise linear approximations in a linear approximation attack, and provide a newinsight on the relation between large-unit and bitwise linear approximations.

Heterometallic Al6Zn12 nano-plate with π-conjugated ligand: synthesis and nonlinear absorption properties

Present herein is the synthesis, structure, and optical properties of aluminum(III)-zinc(II) heterometallic compound AlOC-57. This compound possesses a large unit cell (approximately sixteen thousand atoms) and three-shell nano-plate structure. The...

Genetic Effects of Soluble Starch Synthase IV-2 and It with ADPglucose Pyrophorylase Large Unit and Pullulanase on Rice Qualities

Background: Rice amylose content and amylopectin structure corporately determine rice eating and cooking qualities (ECQs). Soluble starch synthase ( SS ) IV-2 is a member of the soluble starch synthesis gene family but with unknown effects on ECQs. Results: In this study, three populations derived from a cross of two parents who possess the same major genes of starch bio-synthesis were employed to investigate the influence of SSIV-2 and its combined effects with ADPglucose pyrophorylase large unit ( AGPlar ) and Pullulanase ( PUL ) on ECQs. The results illustrated that the polymorphism of SSIV-2 alleles significantly affected gel consistency (GC), gelatinization temperature (GT), percent of retrogradation (PR) and three crucial rapid viscosity analysis (RVA) profile parameters: peak viscosity (PKV), breakdown viscosity (BDV) and setback viscosity (SBV). And SSIV-2 allele derived from CG173R had better quality traits with lower GT, SBV and PR. Moreover, its interaction with AGPlar was responsible for the variations of GC, apparent amylose content (AAC), GT, PR and all RVA parameters except for pasting temperature (PaT) and peak time (PeT), in terms of GC, PKV and CSV, AGPlar derived from CG173R had an epistatic effect on SSIV-2 ; additionally, interaction of SSIV-2 and PUL mainly affected GC, AAC, PKV, CPV, CSV and SBV. I-C and C-1 (I, allele of AGPlar from Guangzhan 63S; C, allele of SSIV-2 from CG173R; 1, allele of PUL from Guangzhan 63S) combinations had better ECQs. Conclusions: SSIV-2 alleles significantly affect rice quality, especially the parameters relevant to gelatinized and thermal characteristics of starch (GC, PR, GT, PKV, BDV and SBV) under the same major genes ( Waxy and SSII-3 ) background. It indicates that SSIV-2 functions elongation of starch chain. These findings suggest that the effects of SSIV-2 and its interaction with AGPlar and PUL are vital for rice quality breeding with the same major genes.

Identification method of dynamic characteristics coefficients of tilting pad bearing in critical speed range of large unit

For tilting pad bearing of large unit, it is not easy to identify stiffness and damping coefficients in full-size unit test. Because of many limiting factors in large unit test, the stiffness and damping test methods are not fully applicable to large units, which can be easily implemented in laboratory. The nonexcitation methods are proposed in this paper to identify the stiffness and damping coefficients of tilting pad bearing in the critical speed range of large unit, including direct method and iterative method. Firstly, the rotor speed and vibration during the whole period are obtained. The vibration data of the first-order critical speed range in the startup stage are selected, and the stiffness and damping coefficients of tilting pad bearing are identified through the two methods. The results show that the stiffness and damping coefficients identified through the direct method are generally less than the theoretical values. The identification error of stiffness coefficient is within ±9%, and the identification accuracy of stiffness coefficient is significantly higher than that of damping coefficient. The damping coefficient identified by the iterative method agrees well with the theoretical value, and the identification error is about −3%. In conclusion, the stiffness and damping coefficients of tilting pad bearing in the range of first-order critical speed can be obtained by combining the two identification methods. These identification results are relatively reliable and can basically meet the analysis requirements of important vibration problems of bearing-rotor system.

Genetic Effects of Soluble Starch Synthase IV -2 and It with ADPglucose Pyrophorylase Large Unit and Pullulanase on Rice Qualities

BackgroundRice amylose content and amylopectin structure corporately determine rice eating and cooking qualities (ECQs). Soluble starch synthase IV-2 (SSIV-2) is a member of the soluble starch synthesis gene family but with unknown effects on ECQs.Results In this study, three populations derived from a cross of two parents who possess the same major genes of starch bio-synthesis were employed to investigate the influence of SSIV-2 and its combined effects with ADPglucose pyrophorylase large unit (AGPlar) and Pullulanase (PUL) on ECQs. The results illustrated that the polymorphism of SSIV-2 alleles significantly affected gel consistency (GC), gelatinization temperature (GT), percent of retrogradation (R) and three crucial RVA profile parameters: peak viscosity (PKV), breakdown viscosity (BDV) and setback viscosity (SBV). And SSIV-2 allele derived from CG173R had better quality traits with lower GT, SBV and R. Moreover, its interaction with AGPlar was responsible for the variations of GC, apparent amylose content (AAC), GT, R and all RVA parameters except for pasting temperature (PaT) and peak time (PeT), in terms of GC, PKV and CSV, AGPlar derived from CG173R had an epistasis effect on SSIV-2; additionally, interaction of SSIV-2 and PUL mainly affected GC, AAC, PKV, CPV, CSV and SBV. I-C and C-1 (I, allele of AGPlar from Guangzhan 63S; C, allele of SSIV-2 from CG173R; 1, allele of PUL from Guangzhan 63S) combinations had better ECQs. The findings suggest that genetic effects of SSIV-2 and its interaction with AGPlar and PUL are vital for rice quality under the same major genes (Wx and SSII-3) background. ConclusionsSS IV-2 significantly affect GC, R, GT, PKV, BDV and SBV of rice starch. The I-C and C-1 have better ECQs. These findings suggest that the effects of SS IV-2 and its interaction with AGPlar and PUL are vital for rice quality breeding.