In this paper, we consider an implicit block backward differentiation formula (BBDF) for solving Volterra Integro-Differential Equations (VIDEs). The approach given in this paper leads to numerical methods for solving VIDEs which avoid the need for special starting procedures. Convergence order and linear stability properties of the methods are analyzed. Also, methods with extensive stability r...

This paper deals with the security of iterated hash functions against generic attacks, such as, e.g., Joux’ multicollision attacks from Crypto 04 [6]. The core idea is to increase the size of the internal state of an n-bit hash function to w > n bit. Variations of this core idea allow the use of a compression function with n output bits, even if the compression function itself is based on a blo...

In this paper, a class of Generalized Quasi-Orthogonal Space-Time Block Code is proposed to achieve full-rate transmission with low-complexity maximum likelihood decoding. Full transmit-diversity is achieved through rhe constellation rotation technique. Code construction criteria for this class of code are listed. Average lideterminant criterion is proposed for optimizing the degree of constell...

We document the performance of space–time block codes [13], [14], which provide a new paradigm for transmission over Rayleigh fading channels using multiple transmit antennas. Data is encoded using a space–time block code, and the encoded data is split into n streams which are simultaneously transmitted using n transmit antennas. The received signal at each receive antenna is a linear superposi...

This letter introduces two fast maximum-likelihood (ML) detection methods for 4*4 quasi-orthogonal space-time block code (QOSTBC). The first algorithm with a relatively simple design exploits structure of quadrature amplitude modulation (QAM) constellations to achieve its goal and the second algorithm, though somewhat more complex, can be applied to any arbitrary constellation. Both decoders ut...

In multiple antenna transmission the multiplexing gain strictly depends on transmit and receive antenna allocation, transmit antenna synchronization and the process used to eliminate the inter channel interference (ICI). Spatial modulation (SM) is a low-complexity scheme for multiple antenna system. The work and research on Spatial Modulation shows that SM is useful to achieve the multi block-c...

This paper proposes a full-rate, full-diversity spacetime block code (STBC) with low maximum likelihood (ML) decoding complexity and high coding gain for the 4 transmit antenna, 2 receive antenna (4×2) multiple-input multiple-output (MIMO) system that employs 4/16-QAM. For such a system, the best code known is the DjABBA code and recently, Biglieri, Hong and Viterbo have proposed another STBC (...

This paper reports on an experimental application of formal specification to inform analysis of compiled code. The analyses with which we are concerned attempt to recover abstraction and order from the potentially chaotic world of machine code. To illustrate the kind of abstractions of interest, we give a formal model of a simple microprocessor. This is based on a traditional state-based Z spec...

The maximum-likelihood decoding problem is known to be NP-hard for general linear and Reed-Solomon codes [1, 4]. In this paper, we introduce the notion of A-covered codes, that is, codes that can be decoded through a polynomial time algorithm A whose decoding bound is beyond the covering radius. For these codes, we show that the maximum-likelihood decoding problem is reachable in polynomial tim...