Bipartite modular multiplication with twice the bit-length of multipliers

This paper presents a new technique to compute 2ℓ-bit bipartite multiplications with ℓ-bit bipartite multiplication units. Low-end devices such as smartcards are usually equipped with crypto-coprocessors for accelerating the heavy computation of modular multiplications; however, security standards such as NIST and EMV have declared extending the bit length of RSA cryptosystem to resist mathematical attacks, making the multiplier quickly outdated. Therefore, the double-size techniques have been studied this decade to extend the life expectancy of such multipliers. This paper proposes new double-size techniques based on the multipliers implementing either classical or Montgomery modular multiplications, or even both simultaneously (bipartite modular multiplication), in which case one can potentially compute modular multiplications twice faster. Furthermore, in order to get a more realistic estimation than the other works, this paper considers not only the cost of the multiplication, but also the cost of the other arithmetic instructions. In our estimation, the proposal provides comparable results for classical multiplier and Montgomery multiplier, and is the only available method for the bipartite multiplier. A preliminary version of this paper was presented at the 12th Australasian Conference on Information Security and Privacy, ACISP’07.     

A study of a simulated moving bed adsorber based on the axial dispersion model

On the basis of the axial dispersion model, the concentration profiles for a simulated moving bed adsorber were theoretically predicted. Experimentally, an apparatus consisting of four sections was employed. Glucose and sorbitol were separated from the liquid dissolved with these components both co-currently and counter-currently. The experimental results seemed to support the predicted curves.     

Ethylene/(meth)acrylic acid ionomers plasticized and reinforced by metal soaps

Metal soaps, also known as fatty acid salts, resemble oligomers of ethylene/methacrylic or ethylene/acrylic acid (E/(M)AA) ionomers, in that they contain carboxylic salt headgroups and long methylene sequences in their hydrocarbon tails. Such soaps might thus be expected to form miscible blends with E/(M)AA ionomers under suitable conditions, providing a separate route to increasing an ionomer's ion content and modifying its physical properties. We show here that the structure and property modifications induced by blending metal soaps into E/(M)AA ionomers are complex, and depend on both the neutralizing cation and on whether the hydrocarbon tails are crystallizable. In the melt at sufficiently high temperatures, all blends show a coassembled structure, where the salt groups of the soap coaggregate with the salt groups on the ionomer; despite the high ion content of these blends, they retain the melt processability characteristic of neat E/(M)AA ionomers of much lower ion content. Non-crystallizable magnesium oleate and magnesium erucate act as permanent plasticizers, lowering the matrix glass transition temperature. Magnesium stearate, whose alkyl tails easily form a rotator phase, can slowly ‘cocrystallize’ with ethylene sequences in the ionomers, leading to high moduli; however, primary crystallization is suppressed in these blends. Finally, while sodium stearate is miscible with the ionomers at elevated temperatures, it phase-separates on cooling, prior to crystallization of the ionomer; such blends are essentially composites of pure stearate and ionomer phases, with their associated individual properties, rather than possessing new structures or properties resulting from coassembly.     

Development of a PFM code for evaluating reliability of pressure components subject to transient loading

In order to improve the PFM methodology and to evaluate the reliability and integrity of an aged RPV, the PFM code PASCAL is being developed. This code evaluates the conditional probability of crack initiation and fracture of pressure components subject to a transient loading based on Monte Carlo simulation. In addition to the common functions established in existing codes, the code has some original functions and features in the elasto-plastic fracture criterion based R6 method, the simulation models for the semi-elliptical crack extension and the effect of thermal annealing, improvement in Monte Carlo simulation and so on. This paper describes the main features of the code, the results of verification analysis and case studies on influence parameters by using above functions. The verification analysis and case studies are carried based on NRC/EPRI PTS benchmark problem. The basic performance of the code was verified by comparing the results with those by existing codes. From the result of case studies, the effectiveness and performance of main functions are examined and the influence of some parameters, such as fracture criterion, WPS, semi-elliptical crack extension models, existence of overlay clad, initial aspect ratio on the failure probability are also discussed.     

Effects of the depth of NO and N2O productions in soil on their emission rates to the atmosphere: analysis by a simulation model

Many factors are concerned in the changing forms of nitrogen compounds in soil, so it is not easy to make precise models to simulate the concentration profiles of soil nitric oxide (NO) and nitrous oxide (N₂O) and their emission rates under various soil conditions. We prepared a simple mathematical simulation model based on soil concentration profiles of NO and N₂O. The profiles were measured at lysimeters filled with Andosol soil and fertilized with ammonium sulfate at rate of 200 kgNha^-1, incorporating to plow layer (Hirose & Tsuruta, 1996). In this model, diffusion of gases in soil followed Fick's law and the diffusion coefficient was adopted from Sallam et al. (1984). The gas production rate was set up at constant value in the site of gas production, and the gaseous consumption followed Michaelis-Menten kinetics. By changing only the depth of NO and N₂O production in soil in this model, we obtained the following results.(1) When the depth of gas production was set at near the soil surface (NO: 0–10 cm, N₂O: 0-8 cm), the emission rates of both gases corresponded with the results of the lysimeter-measurement.(2) When the depth of gas production was shifted down 10 cm deeper (NO: 10–20 cm, N₂O: 10-18 cm), the gas emission rate of NO decreased to 1.3% of (1), while that of N₂O was almost the same as (1).(3) In the case that the total intensity of produced gases was not changed from (1) or (2), but that the extent of gas productions expanded 3 times wider (NO: 0–30 cm, N₂O: 0–24 cm) than (1) or (2), the emission rates of NO and N₂O became 26% and 95% of (1), respectively.The above results suggest the possibility of mitigating NO emission by setting the site of gaseous production in deeper soil, e.g. by means of deep application of fertilizer.     

Effect on Wettability of FEP Teflon Surface Morphology

Wettability of FEP Teflon® (a perfluorinated ethylene-propylene copolymer) is vastly improved by heterogeneous nucleation and crystallization in contact with gold, a high surface free energy substrate. The critical surface tension of wetting (γ_e) increases from 18.8 dynes/cm to 40.4 dynes/cm. We compute that this rise in γ_e results from a 20 percent increase in the surface density of gold-nucleated FEP Teflon®. The increase in critical surface tension from 18.8 dynes/cm to 20.6 dynes/cm, for as received FEP Teflon which had been crosslinked by helium in a glow discharge (CASING technique), suggests an increase of the surface density with crosslinking. The critical surface tension of the gold-nucleated FEP Teflon® is sharply decreased from 40.4 dynes/cm to 22.0 dynes/cm by short exposure to the CASING treatment in helium. The results of ATR infrared spectroscopy show that in the surface region of the polymer there are no chemical changes such as the presence of unsaturated groups or the introduction of polar groups by oxidation. We conclude from this study that wettability of the polymer surface is affected by the surface morphology.     

A simple determination method of the absolute adsorbed amount for high pressure gas adsorption

A new determination method of the absolute adsorbed amount is proposed. The present method, which is called the buoyancy-mediated (BM) method, is simpler than the adsorbed volume mapping (AVM) method [Chem. Phys. Lett., 321 (2000) 342]. If there are data of the experimental surface excess mass up to the high pressure region, the BM method coincides with the AVM method. In the case of methane adsorption on pitch-based activated carbon fiber (ACF: P-5), the obtained volume of the adsorbed layer is from 0.84 to 20 ml/g. The isosteric heat of adsorption from the absolute adsorption isotherms is in the range of 19 to 25 kJ/mol, which almost coincides with the value calculated from grand canonical Monte-Carlo simulation.     

Development of neural networks integrated circuit driving electrostatic motors for microrobot

Artificial Life and Robotics - The authors are studying an insect-type microrobot using Micro-Electro-Mechanical Systems (MEMS) technology. The microrobot actuates by electrostatic motors that use...