A comparison of Carlet's second-order nonlinearity bounds

Carlet provides two bounds on the second-order nonlinearity of Boolean functions. We construct a family of Boolean functions where the first bound (the presumed weaker bound) is tight and the second bound is strictly worse than the first bound. We show that the difference between the two bounds can be made arbitrarily large.     

Efficient Telomerization of Butadiene with Starch in Water: The Role of the Surfactant

The synthesis of hydrophobic starch was performed via palladium-catalyzed telomerization of butadiene with native starch. This reaction is efficiently performed in water in the presence of neutral or cationic surfactant with high HLB. After optimization of the reaction conditions, TOF up to 446 was achieved.     

Improving the Lower Bound on the Higher Order Nonlinearity of Boolean Functions With Prescribed Algebraic Immunity

The recent algebraic attacks have received a lot of attention in cryptographic literature. The algebraic immunity of a Boolean function quantifies its resistance to the standard algebraic attacks of the pseudorandom generators using it as a nonlinear filtering or combining function. Very few results have been found concerning its relation with the other cryptographic parameters or with the rth-order nonlinearity. As recalled by Carlet at CRYPTO'06, many papers have illustrated the importance of the r th-order nonlinearity profile (which includes the first-order nonlinearity). The role of this parameter relatively to the currently known attacks has been also shown for block ciphers. Recently, two lower bounds involving the algebraic immunity on the rth-order nonlinearity have been shown by Carlet . None of them improves upon the other one in all situations. In this paper, we prove a new lower bound on the rth-order nonlinearity profile of Boolean functions, given their algebraic immunity, that improves significantly upon one of these lower bounds for all orders and upon the other one for low orders.     

Interleaver design for serial concatenated convolutional codes

In this paper, we present an interleaver design method for SCCC. Our design criterion is to minimize the message-round probability in the SCCC graph which is specially well suited for SCCC. The message-round probability characterizes the message flow in the SCCC graph. By minimizing it, we can get a large interleaving gain. The simulation results confirm our approach.     

Interleaver design for turbo codes from convergence analysis

In this letter, we present an analysis tool for the convergence of a turbo decoder using the min-sum algorithm. First of all, we classify cycles on a turbo code factor graph. We define and develop a quantity which characterizes the trellis convergence and a probability of a message round on a cycle. Our analysis is then applied to an interleaver design for a turbo decoder using the min-sum algorithm. Since the probability of a message round is closely related to the convergence property, the constructed interleaver optimizes the convergence property. The performance is compared with several referential interleavers.     

Improving the Upper Bounds on the Covering Radii of Binary Reed–Muller Codes

By deriving bounds on character sums of Boolean functions and by using the characterizations, due to Kasami , of those elements of the Reed-Muller codes whose Hamming weights are smaller than twice and a half the minimum distance, we derive an improved upper bound on the covering radius of the Reed-Muller code of order 2, and we deduce improved upper bounds on the covering radii of the Reed-Muller codes of higher orders     

Preliminary reliability assessment and failure physical analysis on AlGaN/GaN HEMTs COTS

GaN based FETs have demonstrated high microwave performance since several years, and exhibit attractive potential for microwave power source in electronic warfare and military radar application, and also for civilian telecommunication applications like wireless basestations, Wi-Max, Wi-Fi as well. Up to now, the main challenge remaining for this technology is the proof of good reliability. The Information Warfare Technology Center (CELAR) launched a GaN COTS assessment campaign in order to achieve a state of the art on this topic. In this paper, we presented and discussed the first results of a life test evaluation on HFET GaN/AlGaN structure on silicon substrate and the first results of investigations by physical analysis on a failed device. These preliminary reliability investigations show all the importance of reliability tests conditions applied in order to compare reliability results and also, the benefits of a screening to obtain representative technology quality of the batch of sample before stress. Our investigations on failure analysis by STEM around the gate area of a failed device show defects which could be responsible of a degradation of the Schottky gate.